Abstract P009: Plasma concentrations of multiple oxysterols and risk of colorectal adenomas

Oxysterols are metabolites of cholesterol and intermediates in pathways for primary bile acid synthesis that regulate homeostasis of cholesterol, fatty acids, and glucose by interacting with widely expressed nuclear receptors. These metabolites are generated throughout the body, either enzymatically or from oxidative stress, and are detectable in peripheral circulation at concentrations much lower than total cholesterol. We previously reported that circulating 27-hydroxycholesterol (27-OHC), the most abundant oxysterol in circulation and an endogenous selective estrogen receptor modulator, may be a risk factor for colorectal adenomas. Here, we report on four other circulating oxysterols: 25-hydroxycholesterol (25-OHC), 24(S)-hydroxycholesterol (24(S)-OHC), 7ɑ-hydroxycholesterol (7ɑ-OHC), and 4β-hydroxycholesterol (4β-OHC). We used high-sensitivity liquid chromatography-mass spectrometry to measure oxysterol concentrations in fasting plasma collected at baseline from 1,440 participants of the Vitamin D/Calcium Polyp Prevention Study, a completed randomized clinical trial that enrolled men and women recently diagnosed with colorectal adenomas with follow-up timed to colonoscopic surveillance intervals. Advanced adenomas were defined as tubulovillous or villous lesions, ≥1 cm in diameter, with high-grade dysplasia, or invasive adenocarcinoma. Risk ratios (RR) with 95% confidence intervals (CI) of new colorectal adenomas occurring during follow-up were estimated using repeated-measures log-linear regression for log-transformed circulating oxysterols. Primary analyses adjusted for multiple potential confounding factors and the five circulating oxysterols simultaneously, including 27-OHC. One geometric standard deviation (SD) higher circulating 7ɑ-OHC at the time of initial adenoma diagnosis was associated with 9% and 20% higher subsequent risk of any adenomas and advanced adenomas, respectively (RR of any adenomas per SD circulating 7ɑ-OHC, 1.09; 95% CI, 1.03-1.15 and RR of advanced adenomas, 1.20; 95% CI, 1.04-1.39). The positive association with adenoma risk that we previously reported for circulating 27-OHC persisted controlling for the other oxysterols including 7ɑ-OHC (RR of any adenomas per SD circulating 27-OHC 1.07; 95% CI, 0.99-1.15 and RR of advanced adenomas, 1.23; 95% CI, 1.03-1.48). No statistically significant associations were observed for circulating 25-OHC, 24(S)-OHC, and 4β-OHC. We conclude that circulating 7ɑ-OHC and 27-OHC may be independently associated with colorectal adenoma risk. Given these two oxysterols are the initial products of the classic (neutral) and alternative (acidic) pathways for primary bile acid synthesis, respectively, our findings provide additional evidence in support of a role for bile acids in the development of colorectal neoplasia. Novel colorectal cancer prevention strategies may target oxysterol formation.

Citation Format: Michael N. Passarelli, Bonne M. Thompson, Jeffrey G. McDonald, Thomas J. Palys, Judy R. Rees, Elizabeth L. Barry, John A. Baron. Plasma concentrations of multiple oxysterols and risk of colorectal adenomas. [abstract]. In: Proceedings of the AACR Special Conference: Precision Prevention, Early Detection, and Interception of Cancer; 2022 Nov 17-19; Austin, TX. Philadelphia (PA): AACR; Can Prev Res 2023;16(1 Suppl): Abstract nr P009.

Abstract P038: Transcriptome-wide association study identifies novel genes associated with bladder cancer risk

Background: Genome-wide association studies (GWAS) have identified several common germline variants associated with bladder cancer risk. However, the genetic architecture of bladder cancer risk is still largely unknown. Therefore, we conducted a transcriptome-wide association study (TWAS) to identify gene expression patterns associated with bladder cancer risk. Methods: Individual-level genotype data from bladder cancer cases and controls was accessed from dbGaP (phs000346.v2.p2). We included 3,630 muscle invasive and non-muscle invasive bladder cancer cases and 3,356 controls from the Spanish Bladder Cancer Study (1,145 cases and 1,083 controls) and the New England Bladder Cancer Study (Maine and Vermont, 2,485 cases and 2,273 controls) with imputed genotype data for 22 million single-nucleotide polymorphisms (SNPs). We used PrediXcan to predict gene expression in whole blood using reference data from the Depression Genes and Networks (DGN). Covariate-adjusted logistic regression was used to estimate the associations between gene expression and bladder cancer risk. Results were validated using data from 280 non-muscle invasive bladder cancer cases and 353 controls of the New Hampshire Bladder Cancer Study. Results: We identified five genes associated with bladder cancer risk, including a previously reported locus (1p13.3: GSTM1) and four other loci (4p16.3: FAM53A, 7q22.3: RP11-325F22.2, 8p23.1: RP11-297N6.4, 11q24.1: JHY). Among them, higher predicted expression of GSTM1 in whole blood was associated with lower risk of bladder cancer (Discovery dataset OR = 0.78, 95% CI = 0.67, 0.92; Validation dataset OR = 0.58, 95% CI = 0.34, 0.98). Higher predicted expression of FAM53A (Discovery OR = 1.34, 95% CI = 1.08, 1.68; Validation OR = 3.79, 95% CI = 1.76, 8.29), RP11-325F22.2 (Discovery OR = 1.34, 95% CI = 1.09, 1.65; Validation OR = 2.11, 95% CI = 1.05, 4.30), RP11-297N6.4 (Discovery OR = 1.78, 95% CI = 1.22, 2.60; Validation OR = 6.32, 95% CI = 1.74, 23.34) and JHY (Discovery OR = 1.94, 95% CI = 1.30, 2.91; Validation OR = 6.78, 95% CI = 1.85, 25.76) in whole blood was associated with higher risk of bladder cancer. Conclusion: Our TWAS identified five genes associated with bladder cancer risk: GSTM1, a previously reported locus associated with bladder cancer risk, is related to metabolic detoxification. Four novel loci were identified: FAM53A (related to neural tube development and was previously reported to be related to breast cancer progression), JHY (related to axoneme structure), RP11-325F22.2 (lincRNA), and RP11-297N6.4 (lncRNA). These loci require further validation and may help to reveal the underlying mechanism of the relationship between gene expression and bladder cancer risk.

Citation Format: Siting Li, Jiang Gui, Margaret R. Karagas, Michael N. Passarelli. Transcriptome-wide association study identifies novel genes associated with bladder cancer risk. [abstract]. In: Proceedings of the AACR Special Conference: Precision Prevention, Early Detection, and Interception of Cancer; 2022 Nov 17-19; Austin, TX. Philadelphia (PA): AACR; Can Prev Res 2023;16(1 Suppl): Abstract nr P038.

Adaptive-mixture-categorization (AMC)-based g-computation and its application to trace element mixtures and bladder cancer risk

Several new statistical methods have been developed to identify the overall impact of an exposure mixture on health outcomes. Weighted quantile sum (WQS) regression assigns the joint mixture effect weights to indicate the overall association of multiple exposures, and quantile-based g-computation is a generalized version of WQS without the restriction of directional homogeneity. This paper proposes an adaptive-mixture-categorization (AMC)-based g-computation approach that combines g-computation with an optimal exposure categorization search using the F statistic. AMC-based g-computation reduces variance within each category and retains the variance between categories to build more powerful predictors. In a simulation study, the performance of association analysis was improved using categorizing by AMC compared with quantiles. We applied this method to assess the association between a mixture of 12 trace element concentrations measured from toenails and the risk of non-muscle invasive bladder cancer. Our findings suggested that medium-level (116.7-145.5 μg/g) vs. low-level (39.5-116.2 μg/g) of toenail zinc had a statistically significant positive association with bladder cancer risk.

Plasma Metabolomics Analysis of Aspirin Treatment and Risk of Colorectal Adenomas

Despite substantial observational and experimental evidence that aspirin use can provide protection against the development of colorectal neoplasia, our understanding of the molecular mechanisms involved is inadequate and limits our ability to use this drug effectively and safely for chemoprevention. We employed an untargeted plasma metabolomics approach using liquid chromatography with high-resolution mass spectroscopy to explore novel metabolites that may contribute to the chemopreventive effects of aspirin. Associations between levels of metabolic features in plasma and aspirin treatment were investigated among 523 participants in a randomized placebo-controlled clinical trial of two doses of aspirin (81 or 325 mg/day) and were linked to risk of colorectal adenoma occurrence over 3 years of follow-up. Metabolic pathways that were altered with aspirin treatment included linoleate and glycerophospholipid metabolism for the 81-mg dose and carnitine shuttle for both doses. Metabolites whose levels increased with 81 mg/day aspirin treatment and were also associated with decreased risk of adenomas during follow-up included certain forms of lysophosphatidylcholine and lysophosphatidylethanolamine as well as trihydroxyoctadecenoic acid, which is a derivative of linoleic acid and is upstream of cyclooxygenase inhibition by aspirin in the linoleate and arachidonic acid metabolism pathways. In conclusion, our findings regarding lysophospholipids and metabolites in the linoleate metabolism pathway may provide novel insights into the chemopreventive effects of aspirin in the colorectum, although they should be considered hypothesis-generating at this time.

PREVENTION RELEVANCE

This research used metabolomics, an innovative discovery-based approach, to identify molecular changes in human blood that may help to explain how aspirin use reduces the risk of colorectal neoplasia in some individuals. Ultimately, this work could have important implications for optimizing aspirin use in the prevention of colorectal cancer.

Diet quality, common genetic polymorphisms, and bladder cancer risk in a New England population-based study

PURPOSE

We examined the interaction between common genetic bladder cancer variants, diet quality, and bladder cancer risk in a population-based case-control study conducted in New England.

METHODS

At the time of enrollment, 806 bladder cancer cases and 974 controls provided a DNA sample and completed a diet history questionnaire. Diet quality was assessed using the 2010 Alternate Healthy Eating Index (AHEI-2010) score. Single nucleotide polymorphisms (SNPs) reported in genome-wide association studies to be associated with bladder cancer risk were combined into a polygenic risk score and also examined individually for interaction with the AHEI-2010. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were calculated using logistic regression.

RESULTS

A 1-standard deviation increase in polygenic risk score was associated with higher bladder cancer risk (OR, 1.34; 95% CI 1.21-1.49). Adherence to the AHEI-2010 was not associated with bladder cancer risk (OR, 0.99; 95% CI 0.98-1.00) and the polygenic risk score did not appear to modify the association between the AHEI-2010 and bladder cancer risk. In single-SNP analyses, rs8102137 (bladder cancer risk allele, C) modified the association between the AHEI-2010 total score and bladder cancer risk, with the strongest evidence for the AHEI-2010 long chain fat guideline (OR for TT, 0.92; 95% CI 0.87-0.98; OR for CT, 1.02; 95% CI 0.96-1.08; OR for CC, 1.03; 95% CI 0.93-1.14; p for interaction, 0.02).

CONCLUSIONS

In conclusion, rs8102137 near the cyclin E1 gene ( CCNE1 ) may be involved in gene-diet interactions for bladder cancer risk.

Association of demographic and health characteristics with circulating oxysterol concentrations

BACKGOUND

Circulating oxysterols, cholesterol metabolites with important signaling functions, are increasingly being recognized as candidate biomarkers for several diseases, but associations with demographic and health characteristics remain poorly described.

OBJECTIVE

This study aims to characterize associations of major circulating oxysterols with sex, age, race/ethnicity, body mass index (BMI), lifestyle factors, and use of common medications.

METHODS

We measured plasma concentrations of 27-hydroxycholesterol (27-OHC), 25-hydroxycholesterol (25-OHC), 24(S)-hydroxycholesterol (24(S)-OHC), 7ɑ-hydroxycholesterol (7ɑ-OHC), and 4β-hydroxycholesterol (4β-OHC) from 1,440 participants of a completed clinical trial for the chemoprevention of colorectal adenomas. Adjusted percent difference in means were calculated using linear regression.

RESULTS

Women had 18% (95% CI, 14%, 22%) lower 27-OHC and 21% (15%, 27%) higher 4β-OHC than men. Blacks had 15% (7%, 23%) higher 4β-OHC than Non-Hispanic Whites, and Asian or Pacific Islanders had 19% (2%, 35%) higher 7ɑ-OHC than Non-Hispanic Whites. Individuals of BMI ≥35 kg/m2 had 33% (25%, 41%) lower 4β-OHC than those <25 kg/m2. Current smokers had 15% (5%, 24%) higher 7ɑ-OHC than never smokers, and daily alcohol drinkers had 17% (10%, 24%) higher 7ɑ-OHC than never drinkers. Statin use was associated with lower concentrations of all 5 oxysterols. Differences in mean <15% were found for characteristics such as age, total dietary energy intake, physical activity, diabetes, and anti-inflammatory drug use.

CONCLUSION

Circulating oxysterols are uniquely associated with multiple demographic and health characteristics.

Diet Quality and Survival in a Population-Based Bladder Cancer Study

Nutrition may impact bladder cancer survival. We examined the association between diet quality and overall and bladder cancer-specific survival. Bladder cancer cases from a population-based study reported pre-diagnosis diet. Diet quality was assessed using the 2010 Alternate Healthy Eating Index (AHEI-2010). Vital status was ascertained from the National Death Index. Adjusted hazard ratios (HR) and 95% confidence intervals (CI) were estimated using proportional hazards and competing risks regression models. Overall AHEI-2010 adherence was not associated with overall or bladder cancer-specific survival among non-muscle invasive bladder cancer (NMIBC) cases (HR, 1.00; 95% CI, 0.98-1.01; HR, 1.00; 95% CI, 0.97-1.02) or muscle invasive bladder cancer (MIBC) cases (HR, 0.99; 95% CI, 0.96-1.03; HR, 1.01, 95% CI 0.97-1.06). AHEI-2010 sugar-sweetened beverages adherence was associated with poorer overall survival (HR, 1.04; 95% CI, 1.01-1.08) and AHEI-2010 sodium adherence was associated with better overall and bladder cancer-specific survival after NMIBC diagnosis (HR, 0.92, 95% CI, 0.85-1.00; HR, 0.82; 95% CI, 0.68-0.98). AHEI-2010 fruit adherence was associated with poorer overall and bladder cancer-specific survival after MIBC diagnosis (HR, 1.17; 95% CI, 1.02-1.33; HR, 1.26; 95% CI, 1.03-1.55). Consumption of sugar-sweetened beverages, sodium, and fruit, not overall AHEI-2010 adherence, may be associated with bladder cancer survival.

Proliferation, apoptosis and their regulatory protein expression in colorectal adenomas and serrated lesions

BACKGROUND

Adenomas and serrated lesions represent heterogeneous sets of early precursors in the colorectum with varying malignant potential. They are often distinguished by their histopathologic differences, but little is known about potential differences in regulation of epithelial proliferation and apoptosis.

METHODS

We conducted a protein expression analysis using tissue microarrays of 625 colorectal adenomas and 142 serrated lesions to determine potential differences in regulation of epithelial proliferation and apoptosis. We quantitated proliferation with Ki-67; apoptosis with activated caspase-3 (CASP3); up- and down-regulators of proliferation with cyclin D1, p16INK2, and p21Cip1; and apoptosis regulators with BAX, BCL2, and survivin. Linear mixed effects models and circos diagrams were used to determine relationships among expression and lesion characteristics.

RESULTS

Adenomas had a significantly higher CASP-3 labeling index (LI) than serrated lesions, resulting in a lower net growth ratio (Ki-67 LI/activated CASP-3 LI, p-value<0.0001). Cyclin D1 LI, p16 LI and p21 LI were lower in adenomas compared to serrated lesions, while expression of both BCL2 and BAX were higher (p <0.001). Among adenomas, cyclin D1 LI and p16 LI levels increased with greater villous component, and the highest BAX expression was detected in adenomas larger than 2 cm (both p<0.0001). Right-sided adenomas had higher CASP3 LI than left colorectal adenomas (p = 0.008). Significant differences in cyclin D1 LI, p21 LI and survivin LI were also observed across histopathologic subtypes of serrated lesions.

CONCLUSIONS

Our findings demonstrate different patterns of regulatory protein expression in adenomas than serrated lesions, especially involving apoptosis. ClinicalTrials.gov Identifier: NCT00272324.

Circulating Sex Hormones and Risk of Colorectal Adenomas and Serrated Lesions in Men

BACKGROUND

Sex hormones have been implicated in the etiology of colorectal neoplasia in women for over 40 years, but there has been very little investigation of the role of these hormones in men.

METHODS

Using data from an adenoma chemoprevention trial, we conducted a secondary analysis to examine serum hormone levels [testosterone, androstenedione, DHEA sulfate (DHEAS), and sex hormone binding globulin (SHBG)] and risk of colorectal precursors in 925 men. Multivariable logistic regression models were fit to evaluate adjusted associations between hormone levels and risk of "low-risk" (single tubular adenoma < 1 cm) and "high-risk" lesions (advanced adenoma or sessile serrated adenoma or right-sided serrated polyp or >2 adenomas of any size).

RESULTS

Overall, levels of free testosterone, total testosterone, androstenedione, DHEAS, or SHBG were not associated with either "low-risk" or "high-risk" early precursor lesions in the colorectum.

CONCLUSIONS

These findings do not support the role of sex hormones in early colorectal neoplasia among men.

IMPACT

This large prospective study address a missing gap in knowledge by providing information on the role of sex hormones in colorectal neoplasia in males.

Oral Antibiotics and Risk of New Colorectal Adenomas During Surveillance Follow-up

BACKGROUND

Antibiotics may increase colorectal neoplasia risk by modifying the gut microbiome. It is unknown whether use is associated with the risk of new colorectal adenomas among individuals with prior adenomas.

METHODS

We performed a secondary analysis of four randomized clinical trials for the chemoprevention of colorectal adenomas. Participants self-reported all currently used prescription drugs shortly after an initial colorectal adenoma diagnosis and two or three times a year thereafter over 3 to 5 years of follow-up. We estimated adjusted risk ratios (RR) with 95% confidence intervals (CI) for incident adenomas, analyzing the four trials together.

RESULTS

Cumulatively, the four trials enrolled 5,174 participants (3,491 men and 1,683 women), of whom 4,769 (92%) completed ≥1 follow-up colonoscopy. A total of 763 (15%) participants reported using oral antibiotics on ≥2 occasions. Overall, 39% of those using oral antibiotics at least twice developed new colorectal adenomas compared with 40% of those with no use or a single report of use (RR, 0.99; 95% CI, 0.90-1.10). No statistically significant associations were found in study-specific analyses, and results were similar for high- and low-risk adenoma findings, antibiotic class, anatomic location of adenomas, and analyses excluding those with interim colorectal exams.

CONCLUSIONS

Oral antibiotic use during colonoscopic surveillance after an initial adenoma diagnosis was not associated with risk of these polyps.

IMPACT

Any changes to the gut microbiome as a consequence of oral antibiotic use during surveillance may not affect the development of metachronous colorectal adenomas.

Circulating 27-hydroxycholesterol and Risk of Colorectal Adenomas and Serrated Polyps

The oxysterol 27-hydroxycholesterol (27-OHC) is an endogenous selective estrogen receptor modulator implicated in breast cancer etiology. It is unknown whether circulating 27-OHC is associated with colorectal neoplasia risk. Circulating 27-OHC was measured using LC/MS in fasting plasma collected at baseline from participants of the Vitamin D/Calcium Polyp Prevention Study, a completed randomized clinical trial. Participants were between 45 and 75 years old, recently diagnosed with ≥1 colorectal adenoma, and followed for new colorectal polyps during colonoscopic surveillance. Adjusted risk ratios (RR) with 95% confidence intervals (CI) of new colorectal polyps were estimated for quartiles of circulating 27-OHC using log-linear regression for repeated outcomes. Polyp phenotypes included any adenomas, advanced adenomas, hyperplastic polyps, and sessile serrated adenomas/polyps. Circulating 27-OHC was measured at baseline for 1,246 participants. Compared with participants with circulating 27-OHC below the first quartile (<138 ng/mL), those with circulating 27-OHC at or above the fourth quartile (≥201 ng/mL) had 24% higher risk of adenomas (RR, 1.24; 95% CI, 1.05-1.47) and 89% higher risk of advanced adenomas (RR, 1.89; 95% CI, 1.17-3.06). Stronger associations were observed among participants with advanced adenomas at baseline. Circulating 27-OHC was not associated with risk of hyperplastic polyps (RR, 0.90; 95% CI, 0.66-1.22) or sessile serrated adenomas/polyps (RR, 1.02; 95% CI, 0.50-2.07). Circulating 27-OHC may be a risk factor for colorectal adenomas but not serrated polyps. PREVENTION RELEVANCE: This study found that plasma concentration of 27-hydroxycholesterol, a metabolite of cholesterol that regulates lipid metabolism and acts as a selective estrogen receptor modulator, is associated with the risk of developing precursor lesions for colorectal cancer.

Risk of keratinocyte carcinomas with vitamin D and calcium supplementation: a secondary analysis of a randomized clinical trial

BACKGROUND

It is unknown whether dietary supplementation with vitamin D or calcium prevents keratinocyte carcinomas, also known as nonmelanoma skin cancers.

OBJECTIVES

This study aimed to determine whether daily vitamin D or calcium supplementation alters the risk of basal cell carcinoma (BCC) or invasive cutaneous squamous cell carcinoma (SCC).

METHODS

The Vitamin D/Calcium Polyp Prevention Study is a completed multicenter, double-blind, placebo-controlled, partial 2 × 2 factorial, randomized clinical trial of vitamin D, calcium, or both for the prevention of colorectal adenomas. During 2004-2008, a total of 2259 men and women, 45-75 y of age, recently diagnosed with a colorectal adenoma, were randomly assigned to 1000 IU/d of vitamin D3 or placebo and 1200 mg/d of calcium carbonate or placebo for 3 or 5 y, and followed after treatment ended. Reports of incident BCC or SCC were confirmed from pathology records.

RESULTS

During a median follow-up of 8 y, 200 (9%) participants were diagnosed with BCC and 68 (3%) participants were diagnosed with SCC. BCC incidence was unrelated to treatment with vitamin D compared with no vitamin D (HR: 0.96; 95% CI: 0.73, 1.26), calcium compared with no calcium (HR: 1.01; 95% CI: 0.74, 1.39), and both agents compared with neither (HR: 0.99; 95% CI: 0.65, 1.51). SCC incidence was unrelated to treatment with vitamin D compared with no vitamin D (HR: 0.79; 95% CI: 0.49, 1.27), but there was suggestive evidence of beneficial treatment effects for calcium compared with no calcium (HR: 0.60; 95% CI: 0.36, 1.01) and both agents compared with neither (HR: 0.42; 95% CI: 0.19, 0.91).

CONCLUSIONS

Calcium alone or in combination with vitamin D may reduce the risk of SCC, but not BCC. This trial was registered at clinicaltrials.gov as NCT00153816.

Abstract 1143: Circulating 27-hydroxycholesterol and risk of metachronous colorectal adenomas

Purpose: Oxysterols are cholesterol metabolites thought to play a role in basic carcinogenic mechanisms. One of the most abundant oxysterols in circulation is 27-hydroxycholesterol (27HC), which has been shown to be an endogenous selective estrogen receptor modulator and implicated in breast cancer etiology. 27HC is a ligand for liver X receptors expressed in the liver, gut, adipose tissue, and macrophages. In the colorectum, expression of these receptors suppresses cellular proliferation. It is unknown whether circulating 27HC is associated with the risk of developing colorectal neoplasia.

Methods: Circulating 27HC was measured in plasma collected at baseline from participants of the Vitamin D/Calcium Polyp Prevention Study, a completed placebo-controlled randomized clinical trial of daily supplementation with vitamin D, calcium, or both for the prevention of colorectal adenomas. Participants were 2,259 men and women, 45-75 years old, diagnosed with ≥1 colorectal adenoma within 120 days prior to enrollment. Each was followed for new colorectal adenomas during a 3- or 5-year colonoscopy surveillance interval. 27HC concentrations were quantified using high-performance liquid chromatography/mass spectrometry for those who reported fasting ≥8 hours at the time of blood draw. Premenopausal women and postmenopausal women currently using hormone therapy were excluded from analyses. Risk ratios (RR) and 95% confidence intervals (CI) were estimated from log-linear regression models with adjustment for sex, age, race/ethnicity, body mass index, smoking status, family history of colorectal cancer, aspirin use, nonsteroidal anti-inflammatory drug use, and former use of postmenopausal hormone therapy. High-risk colorectal adenoma findings were defined as ≥1 advanced adenoma (≥1 cm in diameter, with 25% villous components, high-grade dysplasia, or adenocarcinoma) or ≥3 synchronous adenomas of any type. Secondary analyses considered results stratified by sex and anatomic location of lesions (proximal colon vs. distal colon/rectum).

Results: In total, 27HC was measured for 1,246 participants (894 men and 352 women). Circulating 27HC was higher among men (mean, 181 ng/mL; standard deviation, SD, 49 ng/mL) than among postmenopausal women (mean, 154 ng/mL; SD, 46 ng/mL). During follow-up, 596 (46%) participants were diagnosed with ≥1 new colorectal adenoma. Circulating 27HC was associated with 9% higher risk of any colorectal adenoma per SD increase (RR, 1.09; 95% CI, 1.02-1.15; P=0.008) and 19% higher risk of high-risk colorectal adenoma findings per SD increase (RR, 1.19; 95% CI, 1.07-1.33; P=0.002). Sex-stratified results were of similar magnitude, and there were no meaningful differences according to anatomic location of adenomas.

Conclusions: Circulating 27HC concentration may be a novel risk factor for metachronous colorectal adenomas.

Citation Format: Michael N. Passarelli, Bonne M. Thompson, Jeffrey G. McDonald, Thomas J. Palys, Judy R. Rees, Elizabeth L. Barry, John A. Baron. Circulating 27-hydroxycholesterol and risk of metachronous colorectal adenomas [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1143.

Abstract B15: Bladder cancer susceptibility polymorphisms and mortality from non-muscle and muscle-invasive bladder cancer

Introduction: Genome-wide association studies (GWAS) have identified several common germline single-nucleotide polymorphisms (SNPs) associated with increased risk of bladder cancer. Little is known about whether these variants are also associated with overall and bladder cancer-specific mortality. We examined the association between 13 GWAS-identified bladder cancer risk SNPs and overall and bladder cancer-specific survival in 316 bladder cancer cases recruited as part of a population-based case-control study.

Methods: Residents of New Hampshire with primary bladder cancer diagnosed between 2002-2004 were identified from the New Hampshire State Cancer Registry. Medical history and lifestyle factors were collected via in-person interviews at time of enrollment. DNA was isolated from peripheral blood or buccal specimens and genotyping was performed using the Illumina Human610-Quad BeadChip. Date and cause of death were ascertained from the National Death Index with follow-up through December 31, 2013. Non-muscle invasive bladder cancer (NMIBC) and muscle-invasive bladder cancer (MIBC) were examined separately. We used Cox proportional hazards models to estimate adjusted hazard ratios (HR) and 95% confidence intervals (CI) for overall and bladder cancer-specific survival, assuming a log-additive genetic model. HR estimates for MIBC individuals were adjusted for age at diagnosis, sex, smoking status, American Joint Committee on Cancer stage, initial treatment (including extent of resection, cystectomy, and use of chemotherapy or radiation), and three principal components for genetic ancestry. HR estimates for NMIBC were additionally adjusted for 2004 World Health Organization/International Society of Urologic Pathologists classification. An alpha of 0.05 was used to determine statistical significance.

Results: Among 43 participants with MIBC, 30 deaths occurred over a median follow-up of 6.4 years, including 19 from bladder cancer. Among 273 participants with NMIBC, 94 deaths occurred over a median follow-up of 10.3 years, including 23 from bladder cancer. The risk allele [A] of enhancer-associated intergenic SNP rs710521 near TP63 was associated with poorer overall survival after MIBC diagnosis (HR=3.21, 95% CI=1.26-8.16). The risk allele [C] of synonymous SNP rs10936599 of MYNN/TERC was associated with better overall survival after NMIBC diagnosis (HR=0.66, 95% CI=0.46-0.94). No associations with bladder cancer-specific survival were identified.

Conclusions: Common bladder cancer susceptibility variants rs710521 and rs10936599 may be associated with overall survival after diagnosis of MIBC and NMIBC, respectively.

Citation Format: Reno C. Leeming, Michael S. Zens, John D. Seigne, Brock C. Christensen, Diane Gilbert-Diamond, Margaret R. Karagas, Michael N. Passarelli. Bladder cancer susceptibility polymorphisms and mortality from non-muscle and muscle-invasive bladder cancer [abstract]. In: Proceedings of the AACR Special Conference on Bladder Cancer: Transforming the Field; 2019 May 18-21; Denver, CO. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(15_Suppl):Abstract nr B15.

Metabolomics Analysis of Aspirin's Effects in Human Colon Tissue and Associations with Adenoma Risk

Although substantial evidence supports aspirin's efficacy in colorectal cancer chemoprevention, key molecular mechanisms are uncertain. An untargeted metabolomics approach with high-resolution mass spectrometry was used to elucidate metabolic effects of aspirin treatment in human colon tissue. We measured 10,269 metabolic features in normal mucosal biopsies collected at colonoscopy after approximately 3 years of randomized treatment with placebo, 81 or 325 mg/day aspirin from 325 participants in the Aspirin/Folate Polyp Prevention Study. Linear regression was used to identify aspirin-associated metabolic features and network analysis was used to identify pathways and predict metabolite identities. Poisson regression was used to examine metabolic features associations with colorectal adenoma risk. We detected 471 aspirin-associated metabolic features. Aside from the carnitine shuttle, aspirin-associated metabolic pathways were largely distinct for 81 mg aspirin (e.g., pyrimidine metabolism) and 325 mg (e.g., arachidonic acid metabolism). Among aspirin-associated metabolic features, we discovered three that were associated with adenoma risk and could contribute to the chemopreventive effect of aspirin treatment, and which have also previously been associated with colorectal cancer: creatinine, glycerol 3-phosphate, and linoleate. The last two of these are in the glycerophospholipid metabolism pathway, which was associated with 81 mg aspirin treatment and provides precursors for the synthesis of eicosanoids from arachidonic acid upstream of cyclooxygenase inhibition by aspirin. Conversely, carnitine shuttle metabolites were increased with aspirin treatment and associated with increased adenoma risk. Thus, our untargeted metabolomics approach has identified novel metabolites and pathways that may underlie the effects of aspirin during early colorectal carcinogenesis.

Folic acid supplementation and risk of colorectal neoplasia during long-term follow-up of a randomized clinical trial

BACKGROUND

The Aspirin/Folate Polyp Prevention Study previously found folic acid increased risk of advanced and multiple colorectal adenomas during a surveillance colonoscopy interval starting about 3 y after randomization.

OBJECTIVE

We conducted secondary analyses to evaluate folic acid effects with additional follow-up after treatment was stopped.

METHODS

In total, 1021 participants recently diagnosed with colorectal adenomas were randomly assigned to 1 mg/d of folic acid (n = 516) or placebo (n = 505), with or without aspirin, beginning 6 July 1994. The original 3-y treatment period was extended into a subsequent colonoscopy interval, but eventually stopped prematurely on 1 October 2004. With additional post-treatment follow-up, a total of 663 participants who extended treatment completed a second colonoscopic surveillance interval after the initial 3-y follow-up. In addition, 490 participants provided information regarding a subsequent surveillance colonoscopy occurring before completion of follow-up on 31 May 2012, including 325 who had agreed to extended treatment. Study endpoints included conventional adenomas, sessile serrated adenomas/polyps (SSA/Ps), or colorectal cancer, and RRs with 95% CIs were adjusted for baseline characteristics associated with availability of follow-up.

RESULTS

Among those who extended treatment, any colorectal neoplasia was found in 118 (36%) participants assigned to placebo and 146 (43%) assigned to folic acid during the second surveillance interval (RR: 1.21; 95% CI: 0.99, 1.47; P = 0.06). Increased risk of SSA/P with extended folic acid supplementation was statistically significant during the second surveillance interval (RR: 1.94; 95% CI: 1.02, 3.68; P = 0.04). There was no evidence of post-treatment effects for any colorectal neoplasia (RR: 1.01; 95% CI: 0.80, 1.28; P = 0.94), and the post-treatment effect for SSA/P was no longer statistically significant (RR: 1.38; 95% CI: 0.59, 3.19; P = 0.46).

CONCLUSIONS

Delayed treatment effects were not observed, but folic acid may increase SSA/P risk. This trial was registered at clinicaltrials.gov as NCT00272324.

Body Composition and Aspirin Dose for Colorectal Adenoma Prevention in a Randomized Clinical Trial

BACKGROUND

Visceral adiposity is a risk factor for colorectal adenomas, and aspirin is an established chemopreventive agent. Evidence from clinical trials suggests the effectiveness of aspirin at preventing cardiovascular disease and cancer may require higher doses for higher body weight.

METHODS

Body mass index, body surface area, fat-free mass, and fat mass were calculated from baseline height and weight in 1,121 participants of the Aspirin/Folate Polyp Prevention Study, a double-blind, placebo-controlled, 3 × 2 factorial randomized clinical trial of low-dose (81 mg/day) or high-dose (325 mg/day) aspirin and/or 1 mg/day folic acid to prevent metachronous colorectal adenomas. Participants were treated during a surveillance colonoscopy interval of approximately 3 years. Risk ratios (RR) with 95% confidence intervals (CI) for any colorectal neoplasia and high-risk adenoma (HRA, advanced or ≥3 adenomas) were estimated from log-linear regression.

RESULTS

We did not find evidence to suggest aspirin dose-response differed by body composition measurements, including weight alone. Among those weighing ≥ 80 kg, treatment effects for low-dose aspirin (RR for colorectal neoplasia, 0.75; 95% CI, 0.60-0.94; RR for HRA, 0.52; 95% CI, 0.31-0.86) and high-dose aspirin (RR for colorectal neoplasia, 0.88; 95% CI, 0.72-1.08; RR for HRA, 0.68; 95% CI, 0.43-1.09) were not meaningfully different than for those weighing 70-79 kg or <70 kg.

CONCLUSIONS

Measurements of body composition calculated from height and weight did not modify aspirin treatment effects for colorectal adenoma prevention.

IMPACT

Aspirin dosing strategies accounting for body weight suggested in previous trials of colorectal cancer may not apply to adenomas.

No Evidence for Posttreatment Effects of Vitamin D and Calcium Supplementation on Risk of Colorectal Adenomas in a Randomized Trial

Vitamin D and calcium supplementation are postulated to have chemopreventive effects against colorectal neoplasia, yet in our previously reported randomized trial, there was no overall efficacy of calcium and/or vitamin D₃ against colorectal adenoma recurrence. It is possible vitamin D₃ and calcium chemopreventive effects are not detectable until beyond the 3- to 5-year follow-up captured in that trial. Accordingly, we explored possible vitamin D and calcium effects on posttreatment (observational) adenoma occurrence. In this secondary analysis of the observational follow-up phase of the Vitamin D/Calcium Polyp Prevention Study, participants who completed the treatment phase were invited to be followed for one additional surveillance colonoscopy cycle. We evaluated adenoma occurrence risk at surveillance colonoscopy, with a mean of 55 ± 15 months after treatment follow-up, according to randomized treatment with vitamin D versus no vitamin D, calcium versus no calcium, and calcium plus vitamin D versus calcium alone. Secondary outcomes included advanced and multiple adenomas. Among the 1,121 participants with observational follow-up, the relative risk (95% confidence interval, CI) of any adenoma was 1.04 (0.93-1.17) for vitamin D versus no vitamin D; 0.95 (0.84-1.08) for calcium versus no calcium; 1.07 (0.91-1.25) for calcium plus vitamin D versus calcium; and 0.96 (0.81-1.15) for calcium plus vitamin D versus neither. Risks of advanced or multiple adenomas also did not differ by treatment. Our results do not support an association between supplemental calcium and/or vitamin D₃ for 3 to 5 years and risk of recurrent colorectal adenoma at an average of 4.6 years after treatment.

Risk of basal cell carcinoma in a randomized clinical trial of aspirin and folic acid for the prevention of colorectal adenomas

BACKGROUND

Aspirin may reduce the risk of several types of cancer.

OBJECTIVES

To evaluate if folic acid is associated with risk of basal cell carcinoma (BCC).

METHODS

BCC incidence was evaluated in a randomized, double-blind, placebo-controlled clinical trial of aspirin (81 mg daily or 325 mg daily for ~3 years) and/or folic acid (1 mg daily for ~6 years) for the prevention of colorectal adenomas among 1121 participants with a previous adenoma. BCC was confirmed by blinded review of pathology reports.

RESULTS

One hundred and four of 958 non-Hispanic white participants were diagnosed with BCC over a median follow-up of 13·5 years. Cumulative incidence of BCC was 12% [95% confidence interval (CI) 7-17] for placebo, 16% (95% CI 11-21) for 81 mg aspirin daily and 15% (95% CI 10-20) for 325 mg aspirin daily [hazard ratio (HR) for any aspirin 1·45 (95% CI 0·93-2·26); HR for 81 mg daily 1·57 (95% CI 0·96-2·56); HR for 325 mg daily 1·33 (95% CI 0·80-2·20)]. BCC risk was higher with aspirin use in those without previous skin cancer but lower with aspirin use in those with previous skin cancer (P_interaction = 0·02 for 81 mg aspirin daily; P_interaction = 0·03 for 325 mg aspirin daily). Folic acid supplementation was unrelated to BCC incidence (HR 0·85; 95% CI 0·57-1·27).

CONCLUSIONS

Neither aspirin nor folic acid treatment had a statistically significant effect on risk of BCC. Subgroup analysis suggested that chemopreventive effects of nonsteroidal anti-inflammatory drugs may be specific to those at high risk for BCC.

Postmenopausal Fracture History and Survival After Reproductive Cancer Diagnosis

Background

Postmenopausal bone fracture's have been proposed as a marker of lifetime estrogen exposure and have been associated with decreased risk of breast and endometrial cancer. It is plausible that prediagnostic fractures may be related to survival of estrogen-sensitive cancers.

Methods

We evaluated a cohort of breast (n = 6411), endometrial (n = 1127), and ovarian (n = 658) cancer cases diagnosed between 1992 and 2010 while participating in the Women’s Health Initiative. Postmenopausal fracture history was assessed from baseline reports of fractures after age 55 years and incident fractures that occurred at least one year prior to cancer diagnosis during study follow-up. Using Cox regression, we compared women with and without a history of fractures with respect to overall and cancer-specific survival. Estimates were adjusted for participant factors, including hormone therapy use; hormone receptor status was not included in our analysis.

Results

Among women with breast cancer, a history of prediagnostic fractures at any site was associated with poorer overall survival (hazard ratio [HR] = 1.22, 95% confidence interval [CI] = 1.05 to 1.43). A history of hip, forearm, or spine fractures, or hip fracture alone, was associated with increased risk of mortality (HR = 1.26, 95% CI = 1.01 to 1.58, and HR = 2.05, 95% CI = 1.27 to 3.32, respectively). Fracture history was associated neither with cancer-specific survival among breast cancer survivors, nor with overall or disease-specific mortality among endometrial and ovarian cancer survivors.

Conclusions

Postmenopausal breast cancer patients with a history of fractures, especially of the hip, are more likely to die of any cause than breast cancer survivors without a fracture history. Identifying and intervening in fracture risk factors should be standard of care for all women diagnosed with breast cancer.

Identification of Pleiotropic Cancer Susceptibility Variants from Genome-Wide Association Studies Reveals Functional Characteristics

Background: There exists compelling evidence that some genetic variants are associated with the risk of multiple cancer sites (i.e., pleiotropy). However, the biological mechanisms through which the pleiotropic variants operate are unclear.Methods: We obtained all cancer risk associations from the National Human Genome Research Institute-European Bioinformatics Institute GWAS Catalog, and correlated cancer risk variants were clustered into groups. Pleiotropic variant groups and genes were functionally annotated. Associations of pleiotropic cancer risk variants with noncancer traits were also obtained.Results: We identified 1,431 associations between variants and cancer risk, comprised of 989 unique variants associated with 27 unique cancer sites. We found 20 pleiotropic variant groups (2.1%) composed of 33 variants (3.3%), including novel pleiotropic variants rs3777204 and rs56219066 located in the ELL2 gene. Relative to single-cancer risk variants, pleiotropic variants were more likely to be in genes (89.0% vs. 65.3%, P = 2.2 × 10-16), and to have somewhat larger risk allele frequencies (median RAF = 0.49 versus 0.39, P = 0.046). The 27 genes to which the pleiotropic variants mapped were suggestive for enrichment in response to radiation and hypoxia, alpha-linolenic acid metabolism, cell cycle, and extension of telomeres. In addition, we observed that 8 of 33 pleiotropic cancer risk variants were associated with 16 traits other than cancer.Conclusions: This study identified and functionally characterized genetic variants showing pleiotropy for cancer risk.Impact: Our findings suggest biological pathways common to different cancers and other diseases, and provide a basis for the study of genetic testing for multiple cancers and repurposing cancer treatments. Cancer Epidemiol Biomarkers Prev; 27(1); 75-85. ©2017 AACR.

Pro-inflammatory fatty acid profile and colorectal cancer risk: A Mendelian randomisation analysis

BACKGROUND

While dietary fat has been established as a risk factor for colorectal cancer (CRC), associations between fatty acids (FAs) and CRC have been inconsistent. Using Mendelian randomisation (MR), we sought to evaluate associations between polyunsaturated (PUFA), monounsaturated (MUFA) and saturated FAs (SFAs) and CRC risk.

METHODS

We analysed genotype data on 9254 CRC cases and 18,386 controls of European ancestry. Externally weighted polygenic risk scores were generated and used to evaluate associations with CRC per one standard deviation increase in genetically defined plasma FA levels.

RESULTS

Risk reduction was observed for oleic and palmitoleic MUFAs (OROA = 0.77, 95% CI: 0.65-0.92, P = 3.9 × 10-3; ORPOA = 0.36, 95% CI: 0.15-0.84, P = 0.018). PUFAs linoleic and arachidonic acid had negative and positive associations with CRC respectively (ORLA = 0.95, 95% CI: 0.93-0.98, P = 3.7 × 10-4; ORAA = 1.05, 95% CI: 1.02-1.07, P = 1.7 × 10-4). The SFA stearic acid was associated with increased CRC risk (ORSA = 1.17, 95% CI: 1.01-1.35, P = 0.041).

CONCLUSION

Results from our analysis are broadly consistent with a pro-inflammatory FA profile having a detrimental effect in terms of CRC risk.

Familial Risk and Heritability of Colorectal Cancer in the Nordic Twin Study of Cancer

BACKGROUND & AIMS

We analyzed data from twins to determine how much the familial risk of colorectal cancer can be attributed to genetic factors vs environment. We also examined whether heritability is distinct for colon vs rectal cancer, given evidence of distinct etiologies.

METHODS

Our data set included 39,990 monozygotic and 61,443 same-sex dizygotic twins from the Nordic Twin Study of Cancer. We compared each cancer's risk in twins of affected co-twins relative to the cohort risk (familial risk ratio [FRR]). We then estimated the proportion of variation in risk that could be attributed to genetic factors (heritability).

RESULTS

From earliest registration in 1943 through 2010, there were 1861 individuals diagnosed with colon cancer and 1268 diagnosed with rectal cancer. Monozygotic twins of affected co-twins had an FRR for colorectal cancer of 3.1 (95% confidence interval [CI], 2.4-3.8) relative to the cohort risk. Dizygotic twins of affected co-twins had an FRR for colorectal cancer of 2.2 (95% CI, 1.7-2.7). We estimated that 40% (95% CI, 33%-48%) of the variation in colorectal cancer risk could be attributed to genetic factors; unique environment only accounted for the remaining liability. For colon cancer, the FRR was 3.3 (95% CI, 2.1-4.5) for monozygotic twins and 2.6 (95% CI, 1.7-3.5) for dizygotic twins. For rectal cancer, comparable estimates were 3.3 (95% CI, 1.5-5.1) for monozygotic twins and 2.6 (95% CI, 1.2-4.0) for dizygotic twins. Heritability estimates for colon and rectal cancer were 16% (95% CI, 0-46%) and 15% (95% CI, 0-50%), common environment estimates were 15% (95% CI, 0-38%) and 11% (95% CI, 0-38%), and unique environment estimates were 68% (95% CI, 57%-79%) and 75% (95% CI, 61%-88%), respectively.

CONCLUSIONS

Interindividual genetic differences could account for 40% of the variation in susceptibility to colorectal cancer; risk for colon and rectal cancers might have less of a genetic component than risk for colorectal cancer. Siblings, and particularly monozygotic co-twins, of individuals with colon or rectal cancer should consider personalized screening.

Abstract 1310: Identification of pleiotropic cancer susceptibility variants from genome-wide association studies reveals functional characteristics

Background: There exists compelling evidence that some genetic variants are associated with the risk of multiple cancers (i.e., pleiotropy). However, the biological mechanisms of the pleiotropic effects are unclear. Thus, we investigated the functional effects for genetic variants associated with the risk of multiple cancers.

Methods: The National Human Genome Research Institute-European Bioinformatics Institute (NHGRI-EBI) GWAS Catalog contains 28,643 variant-trait associations with p &lt; 10-5. We utilized the Experimental Factor Ontology (EFO) to classify cancer traits and obtained all associations between variants and cancer risk. Based on pairwise linkage disequilibrium (LD) determined from the European (EUR) population of Phase 3 of the 1000 Genomes Project in LDlink, correlated variants (R-squared ≥ 0.8) were clustered into groups. Variant groups associated with the risk of multiple cancers were annotated using the Ensembl Variant Effect Predictor (VEP), and tested for functional enrichment using the DAVID Functional Annotation Tool.

Results: We identified 1,456 variant-cancer risk associations. The majority (57.1%) of the associations were discovered in European ancestry populations, 19.0% in East Asians, 7.9% in an African Americans or Afro-Caribbeans, and 7.1% in Hispanics or Latin Americans. Removing duplicates, we found 1,034 unique variant-cancer risk associations for 1,005 unique variants and 27 unique cancer sites. After clustering correlated variants, we identified 29 pleiotropic variant groups, of which 2 were associated with risk of five different cancer sites. Variant group rs10936599 and rs12696304 within the MYNN gene (7.8 kb from the TERC gene) was associated with leukemia, multiple myeloma, and colorectal, skin, and bladder cancer. Variant group rs31489, rs31490, rs401681, and rs4975616 within the CLPTM1L gene (22.8 kb from the TERT gene) was associated with leukemia, and lung, pancreatic, skin, and bladder cancer. Among the 42 unique variants that composed the 29 pleiotropic variant groups, 41 variants were within a known gene, and only 1 variant was in an intergenic region. The 41 variants mapped to 26 genes, which were enriched in cellular response to hypoxia (p= 0.0071), establishment of protein localization to telomere (p= 0.0071), and ubl conjugation (p= 0.0072).

Conclusion: This study identified and functionally characterized genetic variants showing pleiotropic effects on cancer risk. Our findings improve the understanding of shared biological mechanisms common to different cancers. Clinical implications could include the classification of cancers based on etiology, genetic testing for multiple cancers, and repurposing cancer treatments.

Citation Format: Yi-Hsuan Wu, Rebecca E. Graff, Michael N. Passarelli, Thomas J. Hoffmann, Elad Ziv, John S. Witte. Identification of pleiotropic cancer susceptibility variants from genome-wide association studies reveals functional characteristics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1310. doi:10.1158/1538-7445.AM2017-1310

Abstract 1297: Genetic reclassification of prostate-specific antigen levels for personalized prostate cancer screening

Background: Prostate-specific antigen (PSA) screening for prostate cancer results missed diagnoses as well as many unnecessary biopsies and their associated morbidities. Because PSA levels are heritable, traditional PSA screening may be improved by adjustment for constitutive germline genetics that influence PSA independently of prostate cancer.

Methods: In a previous genome-wide association study in non-Hispanic white men without prostate cancer in the Kaiser Permanente Research Program on Genes, Environment and Health cohort, we identified 40 single nucleotide polymorphisms (SNP) independently and significantly associated with PSA levels. Among them, 24 were not associated with prostate cancer risk. To calculate genetically normalized PSA (i.e., PSA’), we multiplied each man’s most recent PSA measurement by a factor that adjusted for the amount by which his 24 PSA-specific SNPs may have increased his PSA level. We then compared how men without prostate cancer were classified based on their PSA and PSA’ levels with regard to decisions for diagnostic testing.

Results: PSA and PSA’ were highly correlated among non-Hispanic white men without prostate cancer (r2: 0.959; 95% CI: 0.958-0.960). Still, 4.6% were reclassified from above to below a cutpoint of 2.5 ng/ml when using the PSA’ measure, and 2.7% were reclassified from below to above this cutpoint (4.6% - 2.7% = 1.9% net reclassified to below the cutoff). The reclassification was even more pronounced when restricting to controls with a negative prostate biopsy: 5.0% downward and 1.5% upward (3.5% net reclassified to below the cutoff).

Conclusions: Normalizing PSA levels using germline PSA variants may reduce the number of subjects without prostate cancer receiving unnecessary biopsies.

Citation Format: Rebecca E. Graff, Thomas J. Hoffmann, Michael N. Passarelli, Nima C. Emami, Lori C. Sakoda, Eric Jorgenson, Laurel A. Habel, Jun Shan, Dilrini K. Ranatunga, Charles P. Quesenberry, Chun R. Chao, Nirupa R. Ghai, David Aaronson, Joseph Presti, Tobias Nordström, Zhaoming Wang, Sonja I. Berndt, Stephen J. Chanock, Jonathan D. Mosley, Robert J. Klein, Mridu Middha, Hans Lilja, Olle Melander, Mark N. Kvale, Pui-Yan Kwok, Catherine Schaefer, Neil Risch, Neil Risch, Stephen K. Van Den Eeden, John S. Witte. Genetic reclassification of prostate-specific antigen levels for personalized prostate cancer screening [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1297. doi:10.1158/1538-7445.AM2017-1297

Mendelian randomisation implicates hyperlipidaemia as a risk factor for colorectal cancer

While elevated blood cholesterol has been associated with an increased risk of colorectal cancer (CRC) in observational studies, causality is uncertain. Here we apply a Mendelian randomisation (MR) analysis to examine the potential causal relationship between lipid traits and CRC risk. We used single nucleotide polymorphisms (SNPs) associated with blood levels of total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) as instrumental variables (IV). We calculated MR estimates for each risk factor with CRC using SNP-CRC associations from 9,254 cases and 18,386 controls. Genetically predicted higher TC was associated with an elevated risk of CRC (odds ratios (OR) per unit SD increase = 1.46, 95% confidence interval [CI]: 1.20-1.79, p = 1.68 × 10-4 ). The pooled ORs for LDL, HDL, and TG were 1.05 (95% CI: 0.92-1.18, p = 0.49), 0.94 (95% CI: 0.84-1.05, p = 0.27), and 0.98 (95% CI: 0.85-1.12, p = 0.75) respectively. A genetic risk score for 3-hydoxy-3-methylglutaryl-coenzyme A reductase (HMGCR) to mimic the effects of statin therapy was associated with a reduced CRC risk (OR = 0.69, 95% CI: 0.49-0.99, p = 0.046). This study supports a causal relationship between higher levels of TC with CRC risk, and a further rationale for implementing public health strategies to reduce the prevalence of hyperlipidaemia.

Cis-eQTL-based trans-ethnic meta-analysis reveals novel genes associated with breast cancer risk

Breast cancer is the most common solid organ malignancy and the most frequent cause of cancer death among women worldwide. Previous research has yielded insights into its genetic etiology, but there remains a gap in the understanding of genetic factors that contribute to risk, and particularly in the biological mechanisms by which genetic variation modulates risk. The National Cancer Institute's "Up for a Challenge" (U4C) competition provided an opportunity to further elucidate the genetic basis of the disease. Our group leveraged the seven datasets made available by the U4C organizers and data from the publicly available UK Biobank cohort to examine associations between imputed gene expression and breast cancer risk. In particular, we used reference datasets describing the breast tissue and whole blood transcriptomes to impute expression levels in breast cancer cases and controls. In trans-ethnic meta-analyses of U4C and UK Biobank data, we found significant associations between breast cancer risk and the expression of RCCD1 (joint p-value: 3.6x10-06) and DHODH (p-value: 7.1x10-06) in breast tissue, as well as a suggestive association for ANKLE1 (p-value: 9.3x10-05). Expression of RCCD1 in whole blood was also suggestively associated with disease risk (p-value: 1.2x10-05), as were expression of ACAP1 (p-value: 1.9x10-05) and LRRC25 (p-value: 5.2x10-05). While genome-wide association studies (GWAS) have implicated RCCD1 and ANKLE1 in breast cancer risk, they have not identified the remaining three genes. Among the genetic variants that contributed to the predicted expression of the five genes, we found 23 nominally (p-value < 0.05) associated with breast cancer risk, among which 15 are not in high linkage disequilibrium with risk variants previously identified by GWAS. In summary, we used a transcriptome-based approach to investigate the genetic underpinnings of breast carcinogenesis. This approach provided an avenue for deciphering the functional relevance of genes and genetic variants involved in breast cancer.

Blood Lipid Concentrations and Colorectal Adenomas: A Systematic Review and Meta-Analysis of Colonoscopy Studies in Asia, 2000-2014

It is unclear whether dyslipidemia is associated with risk of colorectal neoplasia. The incidence of both conditions is increasing in Asia, motivating a number of new studies from this region. We performed a systematic literature search of Asian colonoscopy-based studies that collected blood lipid concentrations at the time of endoscopy. Persons found to have colorectal adenoma were considered cases, and those found to be adenoma-free were considered controls. Seventeen studies published between 2000 and 2014 met inclusion criteria, collectively enrolling 17,387 cases and 30,427 controls. Mean differences and adjusted odds ratios were summarized with random-effects meta-analyses. Compared with controls, cases had higher total cholesterol (mean difference (MD) = 2.4 mg/dL, 95% confidence interval (CI): 0.2, 4.6), higher low-density lipoprotein cholesterol (MD = 1.3 mg/dL, 95% CI: 0.1, 2.6), higher triglyceride (MD = 16.4 mg/dL, 95% CI: 11.2, 21.5), and lower high-density lipoprotein (HDL) cholesterol (MD = -2.1 mg/dL, 95% CI: -2.7, -1.6) concentrations. Based on adjusted odds ratios, associations for 40-mg/dL-higher triglyceride levels (odds ratio = 1.13, 95% CI: 1.05, 1.21) and 10-mg/dL-higher HDL cholesterol levels (odds ratio = 0.96, 95% CI: 0.92, 1.00) achieved statistical significance. Persons with adenoma were more likely to have unfavorable cholesterol profiles at the time of colonoscopy than those without adenoma. The most convincing evidence for an association between dyslipidemia and colorectal neoplasia was observed for hypertriglyceridemia.

Cigarette Smoking Before and After Breast Cancer Diagnosis: Mortality From Breast Cancer and Smoking-Related Diseases

PURPOSE

Cigarette smoking increases overall mortality, but it is not established whether smoking is associated with breast cancer prognosis.

METHODS

We evaluated the association between smoking status before and after breast cancer diagnosis and mortality in the Collaborative Breast Cancer and Women's Longevity Study, a population-based prospective observational study conducted in Wisconsin, New Hampshire, and Massachusetts. Participants included 20,691 women, ages 20 to 79 years, diagnosed with incident localized or regional invasive breast cancer between 1988 and 2008; a subset of 4,562 of these women were recontacted a median of 6 years after diagnosis. Hazard ratios (HRs) with 95% CIs were calculated according to smoking status for death as a result of breast cancer; cancers of the lung, pharynx, or intrathoracic organs; other cancer; respiratory disease; and cardiovascular disease.

RESULTS

During a median of 12 years, 6,778 women died, including 2,894 who died as a result of breast cancer. Active smokers 1 year before breast cancer diagnosis were more likely than never smokers to die of breast cancer (HR, 1.25; 95% CI, 1.13 to 1.37), respiratory cancer (HR, 14.48; 95% CI, 9.89 to 21.21), other respiratory disease (HR, 6.02; 95% CI, 4.55 to 7.97), and cardiovascular disease (HR, 2.08; 95% CI, 1.80 to 2.41). The 10% of women who continued to smoke after diagnosis were more likely than never smokers to die of breast cancer (HR, 1.72; 95% CI, 1.13 to 2.60). When compared with women who continued to smoke after diagnosis, those who quit smoking after diagnosis had lower mortality from breast cancer (HR, 0.67; 95% CI, 0.38 to 1.19) and respiratory cancer (HR, 0.39; 95% CI, 0.16 to 0.95).

CONCLUSION

Smoking before or after diagnosis was associated with a higher mortality from breast cancer and several other causes.

Fractures in association with breast and endometrial cancer survival in the Women’s Health Initiative

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Background: Postmenopausal fracture rates appear to be an integrated marker of usual estrogen levels and have been associated with decreased risk of breast and endometrial cancer. The association between fractures and cancer mortality has been difficult to assess, as fractures are a consequence of both the pathological process and the treatment of cancer. Due to the reduced proliferative effects of the hormonal milieu, pre-diagnosis fractures may be a hallmark of decreased cancer mortality. Methods: We evaluated a cohort of breast (N = 6,458) and endometrial (N = 1,138) cancer cases who were diagnosed with cancer during the Women’s Health Initiative (WHI; 1992-2010). Fracture history was assessed by combining baseline reports of fractures prior to WHI and after age 50; with fractures ascertained during WHI follow-up, but prior to cancer diagnosis. We used Cox proportional hazards models based on time since cancer diagnosis to estimate hazard ratios (HR) with 95% confidence intervals for overall and cancer-specific mortality, comparing women with prior fractures to those without fractures. Clinical factors, including bisphosphonate and hormone use, were in the model. Results: Among breast cancer cases, during the average 6.2 years of follow-up, 1,464 had a prior fracture and 905 deaths occurred (415 due to breast cancer). Among endometrial cancer cases, during follow-up, 267 had a prior fracture and 192 deaths occurred (83 due to endometrial cancer). Any pre-diagnosis fracture was associated with increased all-cause mortality (breast HR: 1.39 (1.20, 1.62); endometrial HR: 1.41 (1.02, 1.95)). Among breast cancer cases, the strongest association was with hip fracture (HR: 2.76 (1.80, 4.25)). Associations with cancer-specific mortality were similar in direction and magnitude, but did not reach statistical significance. Conclusions: A history of pre-diagnostic fractures was associated with increased overall but not cancer-specific mortality. Fracture history may be indicative of frailty or other co-morbidities. Breast and endometrial cancer cases with a fracture history may benefit from concurrent supportive care to mediate risk of death due to co-morbid health conditions.

Common genetic variation and survival after colorectal cancer diagnosis: a genome-wide analysis

Genome-wide association studies have identified several germline single nucleotide polymorphisms (SNPs) significantly associated with colorectal cancer (CRC) incidence. Common germline genetic variation may also be related to CRC survival. We used a discovery-based approach to identify SNPs related to survival outcomes after CRC diagnosis. Genome-wide genotyping arrays were conducted for 3494 individuals with invasive CRC enrolled in six prospective cohort studies (median study-specific follow-up = 4.2-8.1 years). In pooled analyses, we used Cox regression to assess SNP-specific associations with CRC-specific and overall survival, with additional analyses stratified by stage at diagnosis. Top findings were followed-up in independent studies. A P value threshold of P < 5×10(-8) in analyses combining discovery and follow-up studies was required for genome-wide significance. Among individuals with distant-metastatic CRC, several SNPs at 6p12.1, nearest the ELOVL5 gene, were statistically significantly associated with poorer survival, with the strongest associations noted for rs209489 [hazard ratio (HR) = 1.8, P = 7.6×10(-10) and HR = 1.8, P = 3.7×10(-9) for CRC-specific and overall survival, respectively). No SNPs were statistically significantly associated with survival among all cases combined or in cases without distant-metastases. SNPs in 6p12.1/ELOVL5 were associated with survival outcomes in individuals with distant-metastatic CRC, and merit further follow-up for functional significance. Findings from this genome-wide association study highlight the potential importance of genetic variation in CRC prognosis and provide clues to genomic regions of potential interest.

A large multiethnic genome-wide association study of prostate cancer identifies novel risk variants and substantial ethnic differences

A genome-wide association study (GWAS) of prostate cancer in Kaiser Permanente health plan members (7,783 cases, 38,595 controls; 80.3% non-Hispanic white, 4.9% African-American, 7.0% East Asian, and 7.8% Latino) revealed a new independent risk indel rs4646284 at the previously identified locus 6q25.3 that replicated in PEGASUS (N = 7,539) and the Multiethnic Cohort (N = 4,679) with an overall P = 1.0 × 10(-19) (OR, 1.18). Across the 6q25.3 locus, rs4646284 exhibited the strongest association with expression of SLC22A1 (P = 1.3 × 10(-23)) and SLC22A3 (P = 3.2 × 10(-52)). At the known 19q13.33 locus, rs2659124 (P = 1.3 × 10(-13); OR, 1.18) nominally replicated in PEGASUS. A risk score of 105 known risk SNPs was strongly associated with prostate cancer (P < 1.0 × 10(-8)). Comparing the highest to lowest risk score deciles, the OR was 6.22 for non-Hispanic whites, 5.82 for Latinos, 3.77 for African-Americans, and 3.38 for East Asians. In non-Hispanic whites, the 105 risk SNPs explained approximately 7.6% of disease heritability. The entire GWAS array explained approximately 33.4% of heritability, with a 4.3-fold enrichment within DNaseI hypersensitivity sites (P = 0.004).

SIGNIFICANCE

Taken together, our findings of independent risk variants, ethnic variation in existing SNP replication, and remaining unexplained heritability have important implications for further clarifying the genetic risk of prostate cancer. Our findings also suggest that there may be much promise in evaluating understudied variation, such as indels and ethnically diverse populations.

Detecting gene-environment interactions in human birth defects: Study designs and statistical methods

BACKGROUND

The National Birth Defects Prevention Study (NBDPS) contains a wealth of information on affected and unaffected family triads, and thus provides numerous opportunities to study gene-environment interactions (G×E) in the etiology of birth defect outcomes. Depending on the research objective, several analytic options exist to estimate G×E effects that use varying combinations of individuals drawn from available triads.

METHODS

In this study, we discuss important considerations in the collection of genetic data and environmental exposures.

RESULTS

We will also present several population- and family-based approaches that can be applied to data from the NBDPS including case-control, case-only, family-based trio, and maternal versus fetal effects. For each, we describe the data requirements, applicable statistical methods, advantages, and disadvantages.

CONCLUSION

A range of approaches can be used to evaluate potentially important G×E effects in the NBDPS. Investigators should be aware of the limitations inherent to each approach when choosing a study design and interpreting results.

Oral bisphosphonate use and risk of postmenopausal endometrial cancer

PURPOSE

Bisphosphonates are common medications used for the treatment of osteoporosis and are also used to reduce metastases to bone in patients with cancer. Several studies, including the Women's Health Initiative (WHI), have found that use of bisphosphonates is associated with reduced risk of developing breast cancer, but less is known about associations with other common malignancies. This study was aimed at examining the effects of bisphosphonates on the risk of endometrial cancer.

METHODS

We evaluated the relationship between use of oral bisphosphonates and endometrial cancer risk in a cohort of 89,918 postmenopausal women participating in the WHI. A detailed health interview was conducted at baseline, and bisphosphonate use was ascertained from an inventory of regularly used medications at baseline and over follow-up. All women had an intact uterus at the time of study entry.

RESULTS

During a median follow-up of 12.5 years, 1,123 women were diagnosed with incident invasive endometrial cancer. Ever use of bisphosphonates was associated with reduced endometrial cancer risk (adjusted hazard ratio, 0.80; 95% CI, 0.64 to 1.00; P = .05), with no interactions observed with age, body mass index, or indication for use.

CONCLUSION

In this large prospective cohort of postmenopausal women, bisphosphonate use was associated with a statistically significant reduction in endometrial cancer risk.

Abstract 2187: Colorectal cancer survival is not associated with genetic variants related to risk of other cancers: The GECCO study

Background:

Colorectal cancer (CRC) is a major cause of morbidity and mortality. Previous genome-wide association studies (GWAS) have identified a large number of single nucleotide polymorphisms (SNPs) associated with CRC, at least one of which has also been found to be associated with CRC survival. Furthermore, some SNPs have demonstrated risk associations with multiple cancers (i.e. pleiotropy), including CRC. Together, this raises the possibility that SNPs associated with risk of other cancers may also be associated with survival after a diagnosis of CRC. To investigate this question, we evaluated 526 SNPs reported as strongly associated with risk of any type of cancer in the National Human Genome Research Institute GWAS catalog (as of 11/13/2013) for an association with CRC-specific and overall survival. This study utilized data available from multiple studies in the Genetic Epidemiology of Colorectal Cancer Consortium (GECCO).

Methods:

We evaluated 526 SNPs associated with risk of cancers other than CRC in six studies participating in GECCO: the Health Professionals Follow-up Study; the Nurses' Health Study; the Physicians' Health Study; the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial; the VITamins And Lifestyle Study; and the Women's Health Initiative. A total of 3,494 colorectal cancer cases were evaluated, of whom 1,223 (35%) died (830 from CRC, 24%) during follow-up (average median follow-up time of 6.8 years). Cox proportional hazards regression was used to calculate the per-allele hazard ratio (HR) and 95% confidence interval (95% CI) for the association between each SNP and CRC-specific or overall survival, adjusting for age at diagnosis, sex, study sample, and the first three principal components of genetic ancestry.

Results:

After Bonferroni correction for multiple comparisons (P = 0.05/526 = 9.51e-5), no SNPs were statistically significantly associated with either CRC-specific or overall survival. For CRC-specific survival, 35 SNPs showed a nominal association (p&lt;0.05), the strongest being breast cancer SNP rs6504950 in STXBP4 (HR = 1.19, 95% CI = 1.06-1.31, p = 0.0018). For overall survival, 38 SNPs showed a nominal association, the strongest being melanoma SNP rs1393350 in TYR (HR = 1.15, 95% CI = 1.06-1.26, p = 0.0012). More SNPs showed a nominal association with survival than expected by chance (0.05*526 = 26 SNPs).

Conclusion:

These preliminary results broadly suggest that CRC-specific and overall survival do not appear to be strongly associated with genetic variants related to incidence for other cancers. However, some suggestive evidence of nominal associations with survival supports further investigation. Planned future steps include the incorporation of two additional studies (Cancer Prevention Study II; Diet, Activity, and Lifestyle Study), as well as analyses stratified by factors such as cancer site, stage at diagnosis, and sex.

Citation Format: Jonathan M. Kocarnik, Michael N. Passarelli, Amanda I. Phipps, Andrew T. Chan, Manish Gala, Amit Joshi, Peter T. Campbell, Martha L. Slattery, John Potter, Emily White, Sonja Berndt, Ulrike Peters, Polly A. Newcomb. Colorectal cancer survival is not associated with genetic variants related to risk of other cancers: The GECCO study. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2187. doi:10.1158/1538-7445.AM2014-2187

Abstract 294: Blood lipids, colorectal adenomas, and non-adenomatous polyps: A comparison of associations from clinical measurements and Mendelian randomization

Background: Numerous studies have assessed associations between lipid levels and risk of colorectal neoplasia, but findings have been inconsistent. Recent genetic studies have identified &gt;100 loci associated with lipid levels. Knowledge of the magnitude and direction of genetic effects permits evaluation of allele scores that can serve as proxies for phenotypes.

Methods: We collected information on blood lipids as part of a colonoscopy study among enrollees, ages 25-79, of Group Health, a large healthcare system in Washington State. Low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglycerides (TG), and total cholesterol (TC) measurements were extracted from electronic medical records for 98% of participants. For each participant, we identified the highest LDL, TG, and TC measurement (zenith) and lowest HDL measurement (nadir) prior to colonoscopy. All participants were genotyped for 96 single-nucleotide polymorphisms (SNPs) identified by the Global Lipids Genetics Consortium. For each lipid trait, we estimated 3 associations: 1) phenotype-polyp odds ratios (OR) with 95% confidence intervals (CI) comparing non-advanced adenoma cases to controls, advanced adenoma cases (≥10 mm in diameter, with villous components, or high-grade dysplasia) to controls, and non-adenomatous polyp cases to controls from polytomous logistic regression; 2) genotype-phenotype associations from linear regression; and 3) genotype-polyp ORs from two-stage linear-logistic regression.

Results: In total, 1,791 participants had information on phenotype and genotype (518 non-advanced adenoma cases, 139 advanced adenoma cases, 380 non-adenomatous polyp cases, and 754 polyp-free controls). Individuals with advanced adenomas were more likely than controls to have higher LDL and TG (adjusted OR per 20 mg/dL increase in zenith LDL: 1.16, CI 1.03-1.30 and OR per 40 mg/dL increase in zenith TG: 1.09, 1.03-1.16). Associations from allele scores were in the same direction (OR per increase in allele score scaled to be comparable to a 20 mg/dL LDL increase: 1.17, CI 0.78-1.75, and OR per increase in allele score scaled to be comparable to a 40 mg/dL TG increase: 1.12, 0.91-1.38). SNPs most strongly related to phenotype, however, were not associated with polyps, and SNPs that were, including variants of NAT2, MC4R, and APOE, may function through alternative pathways. Analyses among statin-naïve participants were not meaningfully different.

Conclusions: Mendelian randomization estimates did not achieve statistical significance, but the direction of associations suggests that polyps are more prevalent among those with inherited susceptibility to increased LDL and TG. Results also highlight difficulties interpreting results from Mendelian randomization analyses of traits with complex biology, given that variants may be pleiotropic and not suitable for use as instrumental variables.

Citation Format: Michael N. Passarelli, Polly A. Newcomb, Karen W. Makar, Andrea N. Burnett-Hartman, John D. Potter, Melissa P. Upton, Lee-Ching Zhu, Michael E. Rosenfeld, Stephen M. Schwartz, Carolyn M. Rutter. Blood lipids, colorectal adenomas, and non-adenomatous polyps: A comparison of associations from clinical measurements and Mendelian randomization. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 294. doi:10.1158/1538-7445.AM2014-294

Abstract 2172: Physical activity in relation to overall and colorectal cancer specific survival in the Seattle Colon Cancer Family Registry

Background

Previous studies have suggested that physical activity is associated with a reduced risk of colon cancer. The association of physical activity with colorectal cancer (CRC) survival, however, is less clear. Studies evaluating the association between post-diagnostic physical activity and CRC survival suggest a favorable survival among those who engage in regular physical activity after diagnosis. However, such studies are limited by the possibility of reverse causality since individuals engaging in regular physical activity after diagnosis may have had a better prognosis to begin with.

Methods

We evaluated the association between pre-diagnostic physical activity and survival, both overall and CRC-specific, within the Seattle Colon Cancer Family Registry (SCCFR), a prospective cohort of persons diagnosed with CRC between 1997 and 2002. All cases completed a risk-factor questionnaire including information on medical history, demographic and lifestyle factors, such as obesity and decade-specific recreational physical activity. Vital status and cause of death was determined through linkage to a regional cancer registry and National Death Index. Tumor markers (BRAF and KRAS mutation status) were evaluated for a subset of cases. Physical activity was summarized as average weekly metabolic equivalent-task hours (MET-h/week). Adjusted hazard ratios (HR) and 95% confidence limits (95%CI) were estimated using Cox regression.

Results

Primary analyses included 1171 persons who self-reported their physical activity status, of whom 471 died (292 deaths attributable to CRC; median follow-up 6.3 years). After adjusting for age at diagnosis, sex, body mass index and smoking status, those who engaged in physical activity had a significantly lower risk of dying from any cause compared to those who did not engage in any physical activity (HR 0.72, 95%CI 0.51-0.99; HR 0.62, 95%CI 0.44-0.87; and HR 0.60, 95%CI 0.43-0.85 for &gt;0-6.4, 6.4-19.2, and &gt;19.2 MET-h/wk, respectively; P for trend=0.035). Results for CRC-specific survival were similar and suggested improved survival among physically active individuals compared to those that were inactive, although no trend was evident (HR 0.81, 95%CI 0.51-1.28; HR 0.72, 95%CI 0.45-1.15; and HR 0.72, 95% CI 0.44-1.14 for &gt;0-6.4, 6.4-19.2, &gt;19.2 MET-h/wk respectively; P for trend= 0.52). Further adjustment for stage at diagnosis or BRAF and KRAS mutation status did not alter the results.

Conclusion

Our results suggest that individuals who are physically active prior to CRC diagnosis experience more favorable survival than those who are inactive. Increased physical activity was also associated with better CRC-specific survival, but this trend was not statistically significant. Continued follow-up of this and other larger cohorts is needed to further clarify the role of physical activity in CRC prognosis.

Citation Format: Sheetal S. Hardikar, Polly A. Newcomb, Michael N. Passarelli, Peter T. Campbell, Amanda I. Phipps. Physical activity in relation to overall and colorectal cancer specific survival in the Seattle Colon Cancer Family Registry. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2172. doi:10.1158/1538-7445.AM2014-2172

Variation in the association between colorectal cancer susceptibility loci and colorectal polyps by polyp type

We conducted a case-control study of the association between subsets of colorectal polyps, including adenomas and serrated polyps, and single-nucleotide polymorphisms (SNPs) related to colorectal cancer through prior genome-wide association studies (GWAS). Participants were enrollees in the Group Health Cooperative (Seattle, Washington) aged 24-79 years who received a colonoscopy from 1998 to 2007, donated a buccal or blood sample, and completed a structured questionnaire. We performed genotyping of 13 colorectal cancer susceptibility SNPs. Polytomous logistic regression models were used to estimate odds ratios and 95% confidence intervals for associations between polyps and the colorectal cancer risk allele for each SNP under a log-additive model. Analyses included 781 controls, 489 cases with adenoma, 401 cases with serrated polyps, and 188 cases with both polyp types. The following SNPs were associated with advanced adenomas: rs10936599, rs10795668, rs16892766, and rs9929218 (P < 0.05). For nonadvanced adenomas and for serrated polyps overall, only rs961253 was statistically significant (P < 0.05). These associations were in the same directions as those in prior colorectal cancer GWAS. No SNP was significantly associated with hyperplastic polyps, and only rs6983267 was significantly associated with sessile serrated polyps, but this association was opposite of that found in colorectal cancer GWAS. Our results suggest that the association between colorectal cancer susceptibility SNPs and colorectal polyps varies by polyp type.

Characterisation of familial colorectal cancer Type X, Lynch syndrome, and non-familial colorectal cancer

BACKGROUND

Familial Colorectal Cancer Type X (FCCTX) is defined as individuals with colorectal cancer (CRC) who families meet Amsterdam Criteria-1 (AC1), but whose tumours are DNA-mismatch-repair-proficient, unlike Lynch syndrome (LS). FCCTX does not have an increased risk of extra-colonic cancers. This analysis compares epidemiologic and clinicopathologic features among FCCTX, LS, and 'non-familial' (non-AC1) CRC cases.

METHODS

From the Colon Cancer Family Registry, FCCTX (n=173), LS (n=303), and non-AC1 (n=9603) CRC cases were identified. Questionnaire-based epidemiologic information and CRC pathologic features were compared across case groups using polytomous logistic regression.

RESULTS

Compared with LS, FCCTX cases were less likely to be current (vs never) smokers; have a proximal subsite (vs rectal) tumour; or have mucinous histology, poor differentiation, or tumour-infiltrating lymphocytes. There were no observed differences in co-morbidities or medication usage.

CONCLUSIONS

FCCTX were less likely to be current tobacco users; other exposures were similar between these groups. Histopathologic differences highly suggestive of LS CRCs do not appear to be shared by FCCTX.

Genetic variation in prostaglandin synthesis and related pathways, NSAID use and colorectal cancer risk in the Colon Cancer Family Registry

Although use of non-steroidal anti-inflammatory drugs (NSAIDs) generally decreases colorectal cancer (CRC) risk, inherited genetic variation in inflammatory pathways may alter their potential as preventive agents. We investigated whether variation in prostaglandin synthesis and related pathways influences CRC risk in the Colon Cancer Family Registry by examining associations between 192 single nucleotide polymorphisms (SNPs) and two variable nucleotide tandem repeats (VNTRs) within 17 candidate genes and CRC risk. We further assessed interactions between these polymorphisms and NSAID use on CRC risk. Using a case-unaffected-sibling-control design, this study included 1621 primary invasive CRC cases and 2592 sibling controls among Caucasian men and women aged 18-90. After adjustment for multiple comparisons, two intronic SNPs were associated with rectal cancer risk: rs11571364 in ALOX12 [OR(het/hzv) = 1.87, 95% confidence interval (CI) = 1.19-2.95, P = 0.03] and rs45525634 in PTGER2 (OR(het/hzv) = 0.49, 95% CI = 0.29-0.82, P = 0.03). Additionally, there was an interaction between NSAID use and the intronic SNP rs2920421 in ALOX12 on risk of CRC (P = 0.03); among those with heterozygous genotypes, risk was reduced for current NSAID users compared with never or former users (OR(het) = 0.60, 95% CI = 0.45-0.80), though not among those with homozygous wild-type or variant genotypes. The results of this study suggest that genetic variation in ALOX12 and PTGER2 may affect the risk of rectal cancer. In addition, this study suggests plausible interactions between NSAID use and variants in ALOX12 on CRC risk. These results may aid in the development of genetically targeted cancer prevention strategies with NSAIDs.

Dietary cadmium exposure and risk of breast, endometrial, and ovarian cancer in the Women's Health Initiative

BACKGROUND

In vitro and animal data suggest that cadmium, a heavy metal that contaminates some foods and tobacco plants, is an estrogenic endocrine disruptor. Elevated estrogen exposure is associated with breast, endometrial, and ovarian cancer risk.

OBJECTIVES

We examined the association between dietary cadmium intake and risk of these cancers in the large, well-characterized Women's Health Initiative (WHI).

METHODS

A total of 155,069 postmenopausal women, 50-79 years of age, who were enrolled in the WHI clinical trials or observational study, participated in this study. We estimated dietary cadmium consumption by combining baseline food frequency questionnaire responses with U.S. Food and Drug Administration data on food cadmium content. Participants reported incident invasive breast, endometrial, or ovarian cancer, and WHI centrally adjudicated all cases through August 2009. We applied Cox regression to estimate adjusted hazard ratios (HRs) and 95% CIs for each cancer, comparing quintiles of energy-adjusted dietary cadmium intake.

RESULTS

Over an average of 10.5 years, 6,658 invasive breast cancers, 1,198 endometrial cancers, and 735 ovarian cancers were reported. We observed no statistically significant associations between dietary cadmium and risk of any of these cancers after adjustment for potential confounders including total dietary energy intake. Results did not differ in any subgroup of women examined.

CONCLUSIONS

We found little evidence that dietary cadmium is a risk factor for breast, endometrial, or ovarian cancers in postmenopausal women. Misclassification in dietary cadmium assessment may have attenuated observed associations.

Smoking History in Relation to Survival after a Breast Cancer Diagnosis

Smoking history is associated with increased risk of most cancers, including breast cancer. Given the persistent effects of tobacco carcinogens, smoking history may also influence breast cancer survival. The few previous studies assessing this association were hindered by limited numbers of outcomes. METHODS: We assessed pre-diagnosis tobacco smoking in relation to survival in 22,870 female residents of Wisconsin, Massachusetts, or New Hampshire who were diagnosed with incident, invasive breast cancer between 1988–2008 at ages 20–79. All women reported pre-diagnosis tobacco use, as well as other known and suspected breast cancer risk factors. Information on breast cancer staging was obtained from state cancer registries. Proportional hazards regression with baseline hazard stratified on state of residence and study phase was used to estimate adjusted hazard ratios (HR) and 95% confidence intervals (CI) for cause-specific death according to current smoking (at the time of the breast cancer diagnosis) and long-term (&gt;30 years) smoking (prior to the diagnosis) adjusting for age at diagnosis, stage of disease at diagnosis, family history of breast cancer, age at first birth, menopausal status, hormone therapy use, body mass index, alcohol consumption, education, and mammography. RESULTS: During a median follow-up of 11.3 years from diagnosis, 7,807 deaths occurred, including 3,483 attributed to breast cancer, 328 to lung cancer, 415 to respiratory disease, and 1,553 to cardiovascular disease. Compared to nonsmokers, the HR were 1.2 (1.1–1.3. P = trend = 0.0003) for current smokers and 1.2 (1.1–1.3, P trend = 0.01) for &gt;30 years of smoking. Current smoking was also associated with increased mortality from lung cancer, HR = 14.5 (10.1–20.8), cardiovascular disease, HR = 2.2 (1.9–2.5), and respiratory disease HR = 6.3 (4.8–8.2). CONCLUSIONS: In this large population-based sample of breast cancer cases, current and long-term smokers at the time of diagnosis were 20% more likely to die from breast cancer than never smokers adjusting for breast cancer stage. The elevated mortality risk observed here for known smoking-related diseases adds confidence to the breast cancer findings.Smoking history is associated with increased risk of most cancers, including breast cancer. Given the persistent effects of tobacco carcinogens, smoking history may also influence breast cancer survival. The few previous studies assessing this association were hindered by limited numbers of outcomes. METHODS: We assessed pre-diagnosis tobacco smoking in relation to survival in 22,870 female residents of Wisconsin, Massachusetts, or New Hampshire who were diagnosed with incident, invasive breast cancer between 1988–2008 at ages 20–79. All women reported pre-diagnosis tobacco use, as well as other known and suspected breast cancer risk factors. Information on breast cancer staging was obtained from state cancer registries. Proportional hazards regression with baseline hazard stratified on state of residence and study phase was used to estimate adjusted hazard ratios (HR) and 95% confidence intervals (CI) for cause-specific death according to current smoking (at the time of the breast cancer diagnosis) and long-term (&gt;30 years) smoking (prior to the diagnosis) adjusting for age at diagnosis, stage of disease at diagnosis, family history of breast cancer, age at first birth, menopausal status, hormone therapy use, body mass index, alcohol consumption, education, and mammography. RESULTS: During a median follow-up of 11.3 years from diagnosis, 7,807 deaths occurred, including 3,483 attributed to breast cancer, 328 to lung cancer, 415 to respiratory disease, and 1,553 to cardiovascular disease. Compared to nonsmokers, the HR were 1.2 (1.1–1.3. P = trend = 0.0003) for current smokers and 1.2 (1.1–1.3, P trend = 0.01) for &gt;30 years of smoking. Current smoking was also associated with increased mortality from lung cancer, HR = 14.5 (10.1–20.8), cardiovascular disease, HR = 2.2 (1.9–2.5), and respiratory disease HR = 6.3 (4.8–8.2). CONCLUSIONS: In this large population-based sample of breast cancer cases, current and long-term smokers at the time of diagnosis were 20% more likely to die from breast cancer than never smokers adjusting for breast cancer stage. The elevated mortality risk observed here for known smoking-related diseases adds confidence to the breast cancer findings.Smoking history is associated with increased risk of most cancers, including breast cancer. Given the persistent effects of tobacco carcinogens, smoking history may also influence breast cancer survival. The few previous studies assessing this association were hindered by limited numbers of outcomes. METHODS: We assessed pre-diagnosis tobacco smoking in relation to survival in 22,870 female residents of Wisconsin, Massachusetts, or New Hampshire who were diagnosed with incident, invasive breast cancer between 1988–2008 at ages 20–79. All women reported pre-diagnosis tobacco use, as well as other known and suspected breast cancer risk factors. Information on breast cancer staging was obtained from state cancer registries. Proportional hazards regression with baseline hazard stratified on state of residence and study phase was used to estimate adjusted hazard ratios (HR) and 95% confidence intervals (CI) for cause-specific death according to current smoking (at the time of the breast cancer diagnosis) and long-term (&gt;30 years) smoking (prior to the diagnosis) adjusting for age at diagnosis, stage of disease at diagnosis, family history of breast cancer, age at first birth, menopausal status, hormone therapy use, body mass index, alcohol consumption, education, and mammography. RESULTS: During a median follow-up of 11.3 years from diagnosis, 7,807 deaths occurred, including 3,483 attributed to breast cancer, 328 to lung cancer, 415 to respiratory disease, and 1,553 to cardiovascular disease. Compared to nonsmokers, the HR were 1.2 (1.1–1.3. P = trend = 0.0003) for current smokers and 1.2 (1.1–1.3, P trend = 0.01) for &gt;30 years of smoking. Current smoking was also associated with increased mortality from lung cancer, HR = 14.5 (10.1–20.8), cardiovascular disease, HR = 2.2 (1.9–2.5), and respiratory disease HR = 6.3 (4.8–8.2). CONCLUSIONS: In this large population-based sample of breast cancer cases, current and long-term smokers at the time of diagnosis were 20% more likely to die from breast cancer than never smokers adjusting for breast cancer stage. The elevated mortality risk observed here for known smoking-related diseases adds confidence to the breast cancer findings.Smoking history is associated with increased risk of most cancers, including breast cancer. Given the persistent effects of tobacco carcinogens, smoking history may also influence breast cancer survival. The few previous studies assessing this association were hindered by limited numbers of outcomes. METHODS: We assessed pre-diagnosis tobacco smoking in relation to survival in 22,870 female residents of Wisconsin, Massachusetts, or New Hampshire who were diagnosed with incident, invasive breast cancer between 1988–2008 at ages 20–79. All women reported pre-diagnosis tobacco use, as well as other known and suspected breast cancer risk factors. Information on breast cancer staging was obtained from state cancer registries. Proportional hazards regression with baseline hazard stratified on state of residence and study phase was used to estimate adjusted hazard ratios (HR) and 95% confidence intervals (CI) for cause-specific death according to current smoking (at the time of the breast cancer diagnosis) and long-term (&gt;30 years) smoking (prior to the diagnosis) adjusting for age at diagnosis, stage of disease at diagnosis, family history of breast cancer, age at first birth, menopausal status, hormone therapy use, body mass index, alcohol consumption, education, and mammography. RESULTS: During a median follow-up of 11.3 years from diagnosis, 7,807 deaths occurred, including 3,483 attributed to breast cancer, 328 to lung cancer, 415 to respiratory disease, and 1,553 to cardiovascular disease. Compared to nonsmokers, the HR were 1.2 (1.1–1.3. P = trend = 0.0003) for current smokers and 1.2 (1.1–1.3, P trend = 0.01) for &gt;30 years of smoking. Current smoking was also associated with increased mortality from lung cancer, HR = 14.5 (10.1–20.8), cardiovascular disease, HR = 2.2 (1.9–2.5), and respiratory disease HR = 6.3 (4.8–8.2). CONCLUSIONS: In this large population-based sample of breast cancer cases, current and long-term smokers at the time of diagnosis were 20% more likely to die from breast cancer than never smokers adjusting for breast cancer stage. The elevated mortality risk observed here for known smoking-related diseases adds confidence to the breast cancer findings.

Oral bisphosphonate use and colorectal cancer incidence in the Women's Health Initiative

Bisphosphonates are widely prescribed to increase bone density in postmenopausal women with osteopenia or osteoporosis. Aminobisphosphonates have numerous anticancer properties and reduce bone metastases in cancer patients. Several studies, including the Women's Health Initiative (WHI), have found that use of oral bisphosphonates is associated with reduced risk of developing breast cancer, but less is known about associations with other common malignancies in women such as colorectal cancer (CRC). A few case-control and retrospective cohort studies have reported decreased risk of CRC among bisphosphonate users. In contrast, a prospective cohort study found no association. We evaluated the association between oral bisphosphonate use and CRC incidence in 156,826 postmenopausal women, ages 50 to 79 years, who participated in WHI clinical trials and observational study. A detailed health interview was conducted at baseline, and bisphosphonate use was ascertained from an inventory of regularly used medications at baseline and over follow-up. A total of 1931 women were diagnosed with incident invasive CRC during a median follow-up of 12 years. Alendronate was the most commonly used bisphosphonate, accounting for >90% of the total person-years of use. The association between oral bisphosphonate use and CRC risk did not reach statistical significance (hazard ratio [HR] from multivariable-adjusted models = 0.88; 95% confidence interval [CI] 0.72-1.07; p = 0.19). Furthermore, we did not observe greater risk reductions for women with longer duration of use. Uncontrolled confounding may explain why previous studies have observed an association.

Alcohol consumption before and after breast cancer diagnosis: associations with survival from breast cancer, cardiovascular disease, and other causes

PURPOSE

Alcohol intake is associated with increased risk of breast cancer. In contrast, the relation between alcohol consumption and breast cancer survival is less clear.

PATIENTS AND METHODS

We assessed pre- and postdiagnostic alcohol intake in a cohort of 22,890 women with incident invasive breast cancer who were residents of Wisconsin, Massachusetts, or New Hampshire and diagnosed from 198 to 200 at ages 20 to 79 years. All women reported on prediagnostic intake; a subsample of 4,881 reported on postdiagnostic intake.

RESULTS

During a median follow-up of 11.3 years from diagnosis, 7,780 deaths occurred, including 3,484 resulting from breast cancer. Hazard ratios (HR) and 95% CIs were estimated. Based on a quadratic analysis, moderate alcohol consumption before diagnosis was modestly associated with disease-specific survival (compared with nondrinkers, HR = 0.93 [95% CI, 0.85 to 1.02], 0.85 [95% CI, 0.75 to 0.95], 0.88 [95% CI, 0.75 to 1.02], and 0.89 [95% CI, 0.77 to 1.04] for two or more, three to six, seven to nine, and ≥ 10 drinks/wk, respectively). Alcohol consumption after diagnosis was not associated with disease-specific survival (compared with nondrinkers, HR = 0.88 [95% CI, 0.61 to 1.27], 0.80 [95% CI, 0.49 to 1.32], 1.01 [95% CI, 0.55 to 1.87], and 0.83 [95% CI, 0.45 to 1.54] for two or more, three to six, seven to nine, and ≥ 10 drinks/wk, respectively). Results did not vary by beverage type. Women consuming moderate levels of alcohol, either before or after diagnosis, experienced better cardiovascular and overall survival than nondrinkers.

CONCLUSION

Overall alcohol consumption before diagnosis was not associated with disease-specific survival, but we found a suggestion favoring moderate consumption. There was no evidence for an association with postdiagnosis alcohol intake and breast cancer survival. This study, however, does provide support for a benefit of limited alcohol intake for cardiovascular and overall survival in women with breast cancer.