Stool-Based Colorectal Cancer Screening Test Performance Characteristics in Those With and Without Hemorrhoids

Objective

To evaluate the effect of hemorrhoids on noninvasive stool test performance for colorectal cancer (CRC) screening.

Patients and Methods

We conducted a retrospective cohort study of test characteristics for the fecal immunochemical test (FIT) and the multitarget stool DNA (mt-sDNA) test, on the basis of hemorrhoid status, recorded at the time of colonoscopy, among patients enrolled in the pivotal prospective study for mt-sDNA that was conducted from June 2011, to May 2013. Test characteristics (sensitivity, specificity, positive, and negative predictive values) for FIT and mt-sDNA (performed < 90 days before colonoscopy) were stratified by the presence of hemorrhoids and compared.

Results

Hemorrhoids were found in 51.7% (5163 of 9989) of the study cohort. Across all test characteristics, there were no statistically significant differences for FIT or mt-sDNA when stratified by hemorrhoid status. Analysis revealed mt-sDNA sensitivity of 44% and 41% for advanced precancerous lesions in nonhemorrhoidal and hemorrhoid patients, respectively (P=.41). The FIT sensitivity among the same lesion category was 24.9% in patients without hemorrhoids and 22.8% in those with hemorrhoids (P=.48). The mt-sDNA specificity was 86.4% in patients without hemorrhoids vs 87.7% in those with hemorrhoids (P=.67), although FIT specificity was 95.0% among patients without hemorrhoids vs 94.7% in those with hemorrhoids (P=.44).

Conclusion

The presence of asymptomatic hemorrhoids did not adversely affect test performance in this large clinical study. These findings suggest that in the absence of overt gastrointestinal bleeding, FIT and mt-sDNA are options for CRC screening, irrespective of hemorrhoid status.

Trial Registration

clinicaltrials.gov Identifier: NCT01397747.

Patient and provider factors associated with colorectal cancer screening among average risk health plan enrollees in the US, 2015-2018

BACKGROUND

To assess patient and primary care provider (PCP) factors associated with adherence to American Cancer Society (ACS) and United States Preventive Services Task Force (USPSTF) guidelines for average risk colorectal cancer (CRC) screening.

METHODS

Retrospective case-control study of medical and pharmacy claims from the Optum Research Database from 01/01/2014 - 12/31/2018. Enrollee sample was adults aged 50 - 75 years with ≥ 24 months continuous health plan enrollment. Provider sample was PCPs listed on the claims of average-risk patients in the enrollee sample. Enrollee-level screening opportunities were based on their exposure to the healthcare system during the baseline year. Screening adherence, calculated at the PCP level, was the percent of average-risk patients up to date with screening recommendations each year. Logistic regression modelling was used to examine the association between receipt of screening and enrollee and PCP characteristics. An ordinary least squares model was used to determine the association between screening adherence among the PCP's panel of patients and patient characteristics.

RESULTS

Among patients with a PCP, adherence to ACS and USPSTF screening guidelines ranged from 69 to 80% depending on PCP specialty and type. The greatest enrollee-level predictors for CRC screening were having a primary/preventive care visit (OR = 4.47, p < 0.001) and a main PCP (OR = 2.69, p < 0.001).

CONCLUSIONS

Increased access to preventive/primary care visits could improve CRC screening rates; however, interventions not dependent on healthcare system contact, such as home-based screening, may circumvent the dependence on primary care visits to complete CRC screening.

Abstract 770: Provider communication contributes to colorectal cancer screening intention through improving screening outcome expectancies and perceived behavioral control

Background: Multiple guideline-recommended colorectal cancer (CRC) screening options have been shown to reduce CRC incidence and mortality among average-risk patients. Yet, CRC screening continues to be underutilized in the US. Provider recommendation has consistently shown to improve screening completion. Our study aimed to delineate the pathways through which provider communication influences CRC screening completion. We tested how provider communication about the "Why” and “How” of mt-sDNA screening contributes to mt-sDNA screening intention through influencing patients’ screening outcome expectancies and perceived behavioral control.

Methods: Data came from a behavioral theory-informed survey that we developed to identify psychosocial factors associated with mt-sDNA screening. The survey was administered between 3/22-6/22 by RTI International, with a sample of US adults ages 45-75 who received a valid order for mt-sDNA screening with a shipping date between 5/21-9/21. Participants completed an electronic or paper survey. We measured patients’ reports of providers’ “Why” communication with items on mt-sDNA screening performance, advantages/disadvantages, and cost. Providers’ “How” communication was measured with items on instructions and need for follow-up testing. We tested the proposed relationships using structural equation modeling and tested indirect effects using bootstrapping.

Results: A total of 2973 participants completed the survey (response rate: 21.7%). “Why” communication was positively associated with perceived effectiveness of mt-sDNA screening (b = 0.349, p &lt; .001) and negatively associated with CRC worry (b = -0.078, p = .002). “How” communication was positively associated with perceived ease of use (b = 0.392, p &lt; .001) and perceived comfort of mt-sDNA screening (b = 0.138, p &lt; .001). Perceived effectiveness and perceived ease of use were positively associated with intention to complete mt-sDNA screening (b = 0.404, p &lt; .001; b = 0.339, p &lt; .001). “Why” communication contributed to screening intention through influencing perceived effectiveness (b-indirect effect = 0.141, 95% CI: 0.115, 0.177). “How” communication contributed to screening intention through influencing perceived ease of use (b-indirect effect = 0.133, 95% CI: 0.104, 0.172).

Conclusions: Improving patients’ beliefs about the effectiveness and ease of use of screening may be one pathway through which provider communication contributes to CRC screening completion. Efforts are needed to develop and implement provider-patient communication strategies and toolkits that are efficacious at fostering patient understanding of the rationale for CRC screening and the effectiveness of available screening options as well as addressing barriers and enhancing patients’ self-efficacy in completing their preferred screening option.

Citation Format: Xuan Zhu, Paul Limburg, Linda Squiers, Leah Helmueller, Gabriel Madson, Brian Southwell, Carlye Gates, Shama Alam, Jennifer Laffin, Lila Finney Rutten. Provider communication contributes to colorectal cancer screening intention through improving screening outcome expectancies and perceived behavioral control [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 770.

Abstract 3031: Pilot study of EGFR inhibition with erlotinib in liver fibrosis for hepatocellular carcinoma prevention

BACKGROUND: Effective approaches for prevention of hepatocellular carcinoma (HCC) will have a significant impact on HCC-related mortality. Data from preclinical models strongly support epidermal growth factor receptor (EGFR) as a target for chemoprevention of HCC. Erlotinib is a small-molecular EGFR tyrosine kinase inhibitor that is FDA-approved for cancer treatment. The side effects of erlotinib observed in patients receiving the oncology dose (150 mg/day) render it unacceptable as a chemoprevention agent at this dose.

OBJECTIVE: The objective of this clinical trial was determination of a safe and minimum effective dose of erlortinib for which a ≥50% reduction phospho-EGFR immunohistochemical staining in the liver was observed.

RESULTS: 46 participants were pre-registered and 25 participants were registered in this multicenter trial. In a dose de-escalation trial design, cohorts of participants received a 7 day course of erlotinib 75 mg/day, 50 mg/day or 25 mg/day with liver tissue acquisition prior to and after erlotinib. A ≥50% reduction phospho-EGFR immunohistochemical staining in the liver was observed in a minimum of 40% of participants at each of the dose levels. Erlotinib was very well tolerated with few side effects observed, particularly at the dose of 25 mg/day. A favorable modulation of the Prognostic Liver Signature was observed in participants that received the higher erlotinib doses (50 and 75 mg/day).

CONCLUSION: These data support the selection a dose of 25 mg/day of erlotinib for a longer intervention to assess for evidence of efficacy as an HCC chemoprevention drug.

Citation Format: Kenneth K. Tanabe, David Zahrieh, Carrie A. Strand, Yujin Hoshida, Thomas J. Flotte, Gary Della’Zanna, Asad Umar, Paul Limburg. Pilot study of EGFR inhibition with erlotinib in liver fibrosis for hepatocellular carcinoma prevention [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3031.

Real-world upper endoscopy utilization patterns among patients with gastroesophageal reflux disease, Barrett esophagus, and Barrett esophagus-related esophageal neoplasia in the United States

This study fills a gap in literature by providing contemporary real-world evidence on the prevalence of patients with gastroesophageal reflux disease (GERD), Barrett esophagus (BE), and Barrett esophagus-related neoplasia (BERN) and their upper endoscopy utilization patterns in the United States. A retrospective cohort study design was used: adults with GERD, nondysplastic Barrett esophagus (NDBE), and BERN (indefinite for dysplasia [IND], low-grade dysplasia [LGD], high-grade dysplasia [HGD], or esophageal adenocarcinoma [EAC]) were identified from the MarketScan databases (January 01, 2015-December 31, 2019). For each disease stage, prevalence of adults in commercial claims by calendar year, annual number of upper endoscopies per patient and time between upper endoscopies were reported. In 2019, in commercial claims (N = 12,363,227), the annual prevalence rate of GERD was 13.7% and 0.70% for BE/BERN, among which, 87.1% had NDBE, 6.8% had IND, 2.3% had LGD, 1.0% had HGD, and 2.8% had EAC. From 2015-2019, the study included 3,310,385 patients with GERD, 172,481 with NDBE, 11,516 with IND, 4332 with LGD, 1549 with HGD, and 11,676 with EAC. Annual mean number of upper endoscopies was 0.20 per patient for GERD, 0.37 per patient for NDBE, 0.43 for IND, 0.58 for LGD, and 0.87 for HGD. Median time (months) to second upper endoscopy was 38.10 for NDBE, 36.63 for IND, 22.63 for LGD, and 11.90 for HGD. Upper endoscopy utilization increased from GERD to BE to BERN, and time between upper endoscopies decreased as the disease stage progressed from BE to BERN, with less frequent utilization in BERN than what would be expected from guideline recommendations for surveillance.

Healthcare Resource Utilization and Costs Among Patients With Gastroesophageal Reflux Disease, Barrett's Esophagus, and Barrett's Esophagus-Related Neoplasia in the United States

Background: Gastroesophageal reflux disease (GERD) is a risk factor for Barrett's esophagus (BE) and BE-related neoplasia (BERN). Objectives: This study aimed to evaluate healthcare resource utilization (HRU) and costs associated with GERD, BE, and BERN in the United States. Methods: Adult patients with GERD, nondysplastic BE (NDBE), and BERN (including indefinite for dysplasia [IND], low-grade dysplasia [LGD], high-grade dysplasia [HGD] or esophageal adenocarcinoma [EAC]), were identified from a large US administrative claims database, the IBM Truven Health MarketScan® databases (Q1/2015-Q4/2019). Patients were categorized into the corresponding mutually exclusive EAC-risk/diagnosis cohorts based on the most advanced stage from GERD to EAC using diagnosis codes in medical claims. Disease-related HRU and costs (2020 USD) were calculated for each cohort. Results: Patients were categorized into the following EAC-risk/diagnosis cohorts: 3 310 385 into GERD, 172 481 into NDBE, 11 516 into IND, 4332 into LGD, 1549 into HGD, and 11 676 into EAC. Disease-related annual mean number of inpatient admissions, office visits, and emergency department visits by cohort were 0.09, 1.45, and 0.19 for GERD; 0.08, 1.55, and 0.10 for NDBE; 0.10, 1.92, and 0.13 for IND; 0.09, 2.05, and 0.10 for LGD; 0.12, 2.16, and 0.14 for HGD; and 1.43, 6.27, and 0.87 for EAC. Disease-related annual mean total healthcare costs by cohort were $6955 for GERD, $8755 for NDBE, $9675 for IND, $12 241 for LGD, $24 239 for HGD, and $146 319 for EAC. Discussion: Patients with GERD, BE, and BERN had important HRU and costs, including inpatient admissions and office visits. As patients progressed to more advanced stages, there was substantially higher disease-related resource utilization, with associated costs being 16 times higher in patients with EAC than those with NDBE. Conclusions: Findings suggest the need for early identification of high-risk individuals prior to progression to EAC to potentially improve clinical and economic outcomes in this population.

Body mass index and molecular subtypes of colorectal cancer

BACKGROUND

Obesity is an established risk factor for colorectal cancer (CRC), but the evidence for the association is inconsistent across molecular subtypes of the disease.

METHODS

We pooled data on body mass index (BMI), tumor microsatellite instability status, CpG island methylator phenotype status, BRAF and KRAS mutations, and Jass classification types for 11 872 CRC cases and 11 013 controls from 11 observational studies. We used multinomial logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI) adjusted for covariables.

RESULTS

Higher BMI was associated with increased CRC risk (OR per 5 kg/m2 = 1.18, 95% CI = 1.15 to 1.22). The positive association was stronger for men than women but similar across tumor subtypes defined by individual molecular markers. In analyses by Jass type, higher BMI was associated with elevated CRC risk for types 1-4 cases but not for type 5 CRC cases (considered familial-like/Lynch syndrome microsatellite instability-H, CpG island methylator phenotype-low or negative, BRAF-wild type, KRAS-wild type, OR = 1.04, 95% CI = 0.90 to 1.20). This pattern of associations for BMI and Jass types was consistent by sex and design of contributing studies (cohort or case-control).

CONCLUSIONS

In contrast to previous reports with fewer study participants, we found limited evidence of heterogeneity for the association between BMI and CRC risk according to molecular subtype, suggesting that obesity influences nearly all major pathways involved in colorectal carcinogenesis. The null association observed for the Jass type 5 suggests that BMI is not a risk factor for the development of CRC for individuals with Lynch syndrome.

The cost-effectiveness of non-invasive stool-based colorectal cancer screening offerings from age 45 for a commercial and medicare population

AIM

The United States Preventive Services Taskforce (USPSTF) recently recommended lowering the age for average-risk colorectal cancer (CRC) screening from 50 to 45 years. While initiating screening at age 45 versus 50 provides a greater opportunity for CRC early detection and prevention, the full profile of benefits, risks, and cost-effectiveness of expanding the screen-eligible population requires further evaluation.

MATERIALS AND METHODS

The costs and clinical outcomes for screening at age 45 for triennial multi-target stool DNA [mt-sDNA], and other non-invasive stool-based modalities (annual fecal immunochemical test [FIT] and annual fecal-occult blood test [FOBT]), were estimated using the validated CRC-AIM microsimulation model over a lifetime horizon. Test sensitivity and specificity inputs were based on 2021 USPSTF modeling analyses; adherence rates were based on published real-world data and the costs of the screening test, follow-up colonoscopies, complications, and CRC care were included. Outcomes are reported from the perspective of a United States payer as clinical, life-years gained (LYG), and incremental cost-effectiveness ratio (ICER); stool-based and follow-up colonoscopy adherence ranges were explored in one-way, probabilistic and threshold analyses.

RESULTS

When compared to initiation of CRC screening at age 45 versus 50, all modalities reduced both the incidence of and mortality from CRC and increased LYG. Initiating CRC screening at age 45 was cost-effective with an ICER of $59,816 and $35,857 per quality-adjusted life year (QALY) for mt-sDNA versus FIT and FOBT, respectively. In the threshold analyses, at equivalent rates to stool-based screening, mt-sDNA was always cost-effective at a willingness-to-pay threshold of $100,000 per QALY versus FIT and FOBT.

CONCLUSIONS

Initiating average-risk CRC screening at age 45 instead of age 50 increases the estimated clinical benefit by reducing disease burden while remaining cost-effective. Among stool-based screening modalities, mt-sDNA provides the most clinical benefit in a Commercial and Medicare population.

Abstract PR002: A pilot study of a MUC1 vaccine in current and former smokers at high risk for lung cancer

Background: Smoking is the most common etiology for lung cancer and smoking cessation does not eliminate the risk. An emerging area of interest for risk reduction is immunoprevention. MUC1 glycoprotein is aberrantly expressed in adenocarcinomas, including lung cancer and their premalignant lesions. MUC1 vaccine in the premalignant or high-risk setting may be effective in halting neoplastic development and progression. Trial design: Through the NCI-funded Cancer Prevention Network (CPN), we conducted a two-center pilot trial to evaluate immunogenicity of the MUC1 vaccine (assessed at 12 weeks), and safety (assessed at up to 24 weeks) in current and former heavy smokers. 87 participants were screened in order to have at least 40 evaluable for baseline and 12-week immunogenicity assessments. Smoking history of ≥30 pack-years and either current (still smoking or quit &lt; 1 year prior to pre-registration) or former smoker (quit 1-15 years prior to pre-registration); ages 55-80 years; ECOG performance status ≤1; CT scan of the chest done ≤ 6 months prior to pre-registration showing either negative findings (no nodules) or solid or part-solid nodules &lt; 6 mm in size (consistent with &lt; 1% probability of malignancy, Lung-RADs Version 1.0). Exclusion criteria were standard for lung cancer screening. Methods: MUC1 peptide plus polyICLC adjuvant (Hiltonol) vaccine was given at week 0, 2 and 10. Blood was collected for safety tests and immune assays pre and 2 weeks post each vaccine, and at week 24. Anti-MUC1 IgG titer was evaluated by ELISA. Based on previous studies of this vaccine, 40 evaluable participants would provide 96% power to detect immune response rate of 15% versus 40%, using a 2-sided test of proportions with type I error rate of 0.05. PBMC were assayed for the presence of regulatory T cells (Treg) and myeloid derived suppressor cells (MDSC) (secondary endpoint). Circulating levels of inflammatory cytokines and hsCRP were evaluated using commercially available tests (exploratory endpoint). AEs and toxicities were monitored for up to 24 weeks from the first vaccine. Results: 87 individuals were screened and 50 registered. 45 completed the study, 26 current and 19 former smokers (time since last smoked: average 7.8 years; 11 months -13 years). The vaccine was well-tolerated with injection site reactions being the most common AE. Immune response to the vaccine was lower than expected, with 2 current and 2 former smokers developing anti-MUC1 IgG titers ≥2 fold higher at week 12 over baseline (10%). We found high circulating levels of MDSCs in PBMC of both current and former smokers and very low or no serum cytokines. Conclusions: A preventative vaccine trial was feasible in individuals at high risk for lung cancer. However, we discovered a high level of immune suppression, previously documented only in advanced lung cancer. Mitigating the development of lung cancer in heavy smokers through vaccine administration may be limited by related immunosuppression.

Citation Format: Olivera J. Finn, Julie Ward, Tami Krpata, Samantha Fatis, John McKolanis, Jia Xue, Pamela Beatty, Camille Jacqueline, Sharon Kaufman, Colleen Akerley, April Felt, Karrie Fursa, Anne Holland, Liz S. Ambulay, Nathan Foster, Ryan McMurray, Carrie Strand, Andres M. Salazar, Lisa Bengtson, Eva Szabo, Paul Limburg, Malgorzata Wojtowicz, David E. Midthun, Arjun Pennathur. A pilot study of a MUC1 vaccine in current and former smokers at high risk for lung cancer. [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 PR002.

Identifying colorectal cancer caused by biallelic MUTYH pathogenic variants using tumor mutational signatures

Carriers of germline biallelic pathogenic variants in the MUTYH gene have a high risk of colorectal cancer. We test 5649 colorectal cancers to evaluate the discriminatory potential of a tumor mutational signature specific to MUTYH for identifying biallelic carriers and classifying variants of uncertain clinical significance (VUS). Using a tumor and matched germline targeted multi-gene panel approach, our classifier identifies all biallelic MUTYH carriers and all known non-carriers in an independent test set of 3019 colorectal cancers (accuracy = 100% (95% confidence interval 99.87-100%)). All monoallelic MUTYH carriers are classified with the non-MUTYH carriers. The classifier provides evidence for a pathogenic classification for two VUS and a benign classification for five VUS. Somatic hotspot mutations KRAS p.G12C and PIK3CA p.Q546K are associated with colorectal cancers from biallelic MUTYH carriers compared with non-carriers (p = 2 × 10-23 and p = 6 × 10-11, respectively). Here, we demonstrate the potential application of mutational signatures to tumor sequencing workflows to improve the identification of biallelic MUTYH carriers.

Costs of colorectal cancer screening with colonoscopy, including post-endoscopy events, among adults with Medicaid insurance

OBJECTIVE

To examine the healthcare utilization and costs associated with colorectal cancer (CRC) screening by colonoscopy, including costs associated with post-endoscopy events, among average-risk adults covered by Medicaid insurance.

METHODS

This cohort study evaluated a population of adults (ages 50-75 years) with CRC screening between 1/1/2014 and 12/31/2018 (index = earliest test) from the IBM MarketScan Multi-State Medicaid database. Individuals at above-average risk for CRC or with prior CRC screening were excluded. CRC screening was reported by screening type: colonoscopy, fecal immunochemical test [FIT], fecal occult blood test [FOBT], multi-target stool DNA [mt-sDNA]. Frequency and costs of events potentially related to colonoscopy (defined as occurring within 30 days post-endoscopy) were reported overall, by event type, and by individual event.

RESULTS

We identified a total of 13,134 average-risk adults covered by Medicaid insurance who received screening by colonoscopy; 63.6% (8350) had Medicare dual-eligibility while 36.4% (4785) did not have Medicare dual-eligibility. The mean (SD) cost of a colonoscopy procedure was $684 ($907) and mean (SD) out-of-pocket costs were $6 ($132). Serious gastrointestinal (GI) events (perforation and bleeding) were observed in 4.6% of individuals with colonoscopy, 4.3% had other GI events, and 3.0% had an incident cardiovascular/cerebrovascular event. Mean (SD) event-related costs were $1233 ($5784) among individuals with a serious GI event, $747 ($1961) among individuals with other GI events, and $4398 ($19,369) among individuals with a cardiovascular/cerebrovascular event.

CONCLUSIONS

This large, claims-based cohort study reports average (SD) out-of-pocket costs for Medicaid beneficiaries at $6 ($132), which could be one factor contributing to the accessibility of CRC screening by colonoscopy. The incidence of events potentially associated with colonoscopy (i.e. within 30 days after the screening) was 3-4%, and the event-related costs were considerable.

Healthcare costs of colorectal cancer screening and events following colonoscopy among commercially insured average-risk adults in the United States

OBJECTIVE

To examine the healthcare costs associated with colorectal cancer (CRC) screening and the frequency and costs of events potentially related to colonoscopy among average-risk adults.

METHODS

In this cohort study, adults (ages 50-75 years) with CRC screening between 1/1/2014 and 6/30/2019 (index = earliest test) were selected from the IBM MarketScan Research databases. Individuals at above-average risk for CRC or with prior CRC screening were excluded. Frequency of utilization was reported by screening type: colonoscopy, fecal immunochemical test (FIT), fecal occult blood test (FOBT), multi-target stool DNA (mt-sDNA). For colonoscopy, frequency and costs of potential events were reported overall, by event type, and by an individual event in the 30 days after colonoscopy.

RESULTS

Among the 333,306 average-risk adults, colonoscopy was the most common CRC screening modality (70.6%), followed by FIT (17.7%), FOBT (8.1%), and mt-sDNA (3.2%). The mean cost of a colonoscopy procedure was $2,125 and the mean out-of-pocket costs were $79. Serious gastrointestinal (GI) events were observed in 1.3% of individuals with colonoscopy, 1.9% had other GI events, and 1.2% had an incident cardiovascular event. Mean event-related costs were $2,631 among individuals with a serious GI event, $1,774 among individuals with any other GI event, and $4,234 among individuals with a cardiovascular event.

CONCLUSIONS

This study provides updated and more detailed information regarding the costs of CRC screening and potential colonoscopy events based on a comprehensive review of a robust claims dataset.

Adherence to fecal immunochemical test screening among adults at average risk for colorectal cancer

PURPOSE

This study examined adherence to screening for fecal immunochemical test (FIT).

METHODS

Adults (≥ 50-75) with a FIT between 1/1/2014 and 6/30/2019 in MarketScan administrative claims were selected (index = earliest FIT). Patients were followed for 10 years pre- and 3 years post-index. Patients at increased risk for CRC or with prior screening were excluded. Year over year adherence was measured post-index.

RESULTS

Of 10,253 patients, the proportion adherent to repeat testing at year 2 was 23.4% and 10.6% at year 3. Of 76.6% not adherent in year 2, 5.4% were adherent in year 3.

CONCLUSION

Results suggest adherence to FIT tests is poor, minimizing potential benefits. Future studies are needed to consider alternative test options and whether more choice will improve long-term adherence.

Cost-Effectiveness of Outreach Strategies for Stool-Based Colorectal Cancer Screening in a Medicaid Population

Outreach, including patient navigation, has been shown to increase the uptake of colorectal cancer (CRC) screening in underserved populations. This analysis evaluates the cost-effectiveness of triennial multi-target stool DNA (mt-sDNA) versus outreach, with or without a mailed annual fecal immunochemical test (FIT), in a Medicaid population. A microsimulation model estimated the incremental cost-effectiveness ratio using quality-adjusted life years (QALY), direct costs, and clinical outcomes in a cohort of Medicaid beneficiaries aged 50–64 years, over a lifetime time horizon. The base case model explored scenarios of either 100% adherence or real-world reported adherence (51.3% for mt-sDNA, 21.1% for outreach with FIT and 12.3% for outreach without FIT) with or without real-world adherence for follow-up colonoscopy (66.7% for all). Costs and outcomes were discounted at 3.0%. At 100% adherence to both screening tests and follow-up colonoscopy, mt-sDNA costed more and was less effective compared with outreach with or without FIT. When real-world adherence rates were considered for screening strategies (with 100% adherence for follow-up colonoscopy), mt-sDNA resulted in the greatest reduction in incidence and mortality from CRC (41.5% and 45.8%, respectively) compared with outreach with or without FIT; mt-sDNA also was cost-effective versus outreach with and without FIT ($32,150/QALY and $22,707/QALY, respectively). mt-sDNA remained cost-effective versus FIT, with or without outreach, under real-world adherence rates for follow-up colonoscopy. Outreach or navigation interventions, with associated real-world adherence rates to screening tests, should be considered when evaluating the cost-effectiveness of CRC screening strategies in underserved populations.

Out-of-Pocket Costs for Colonoscopy After Noninvasive Colorectal Cancer Screening Among US Adults With Commercial and Medicare Insurance

This economic evaluation examines whether adult patients in the US who have commercial or Medicare insurance pay out-of-pocket costs associated with follow-up colonoscopy within 6 months of a noninvasive stool-based test.

Utilization of a Colorectal Cancer Screening Test Among Individuals With Average Risk

IMPORTANCE

Colorectal cancer (CRC) screening reduces CRC incidence and mortality. It is important to examine screening patterns over time, including after the introduction of new screening modalities.

OBJECTIVE

To compare use of CRC screening tests before and after the availability of the multitarget stool DNA (mt-sDNA) test, given that endorsed options have changed.

DESIGN, SETTING, AND PARTICIPANTS

This longitudinal cohort study used administrative claims data to examine CRC screening use in 2 discrete periods: before (August 1, 2011, to July 31, 2014) and after (August 1, 2016, to July 31, 2019) the mt-sDNA test became available. The MarketScan Commercial and Medicare Supplemental databases were queried for individuals aged 45 to 75 years between August 1, 2011, and July 31, 2019, with average risk of CRC and with continuous enrollment in the databases from August 1, 2001, to July 31, 2019.

MAIN OUTCOMES AND MEASURES

The proportion of individuals up to date or not due for CRC screening during each measurement year and the type of screening test used among individuals due for screening. Data were reported overall and among individuals aged 45 to 49 or 50 years and older on August 1, 2011.

RESULTS

A total of 97 776 individuals with average risk were identified. Individuals had a mean (SD) age of 50.8 (3.5) years, and 54 227 (55.5%) were women. The proportion of individuals with average risk aged 50 to 75 years with commercial or Medicare supplemental insurance who were up to date with CRC screening increased from 50.4% in 2011 (30 605 of 60 770) to 69.7% in 2019 (42 367 of 60 770). Among individuals due for screening and screened, the use of high-sensitivity fecal occult blood test (FOBT) decreased between 2011 (1088 of 6241 eligible individuals [17.7%]) and 2019 (195 of 2943 eligible individuals [6.6%]), and the use of mt-sDNA increased between 2016 (58 of 3014 eligible individuals [1.9%]) and 2019 (418 of 2943 eligible individuals [14.2%]). No consistent trends were observed with fecal immunochemical test (FIT) or screening colonoscopy. Computed tomography colonography, double-contrast barium enema, and flexible sigmoidoscopy were rarely performed.

CONCLUSIONS AND RELEVANCE

In this cohort study, the proportion of individuals with average risk who were up to date with CRC screening increased between 2011 and 2019 but remained suboptimal. There were no substantial changes in the use of the colonoscopy or FIT; however, there was an increase in the adoption of mt-sDNA and a decrease in the use of FOBT during the study period.

Diagnosis of digestive system tumours

The WHO Classification of Tumours provides the international standards for the classification and diagnosis of tumours. It enables direct comparisons to be made between different countries. In the new fifth edition, the series has gone digital with the launch of a website as well as a series of books, known widely as the WHO Blue Books. The first volume to be produced is on the classification of Digestive System tumours, replacing the successful 2010 version. It has been rewritten and updated accordingly. This article summarises the major diagnostic innovations that have occurred over the last decade and that have now been incorporated in the classification. As an example, it incorporates the recently proposed classification of neuroendocrine tumours, based on the recognition that neuroendocrine tumours and carcinomas differ substantially in the genetic abnormalities that drive their growth, findings relevant to treatment selection and outcome prediction. Several themes have emerged during the production process. One is the importance of the progression from hyperplasia to dysplasia to carcinoma in the evolution of the malignant process. Advances in imaging techniques and endoscopy have resulted in enhanced access to precancerous lesions in the gastrointestinal and biliary tract, necessitating both changes in classification schema and clinical practice. Diagnosis of tumours is no longer the sole purview of pathologists, and some patients now receive treatment before tissue is obtained, based on clinical, radiological and liquid biopsy results. This makes the classification relevant to many disciplines involved in the care of patients with tumours of the digestive system.

Real-world cost-effectiveness of stool-based colorectal cancer screening in a Medicare population

AIM

Multiple screening strategies are guideline-endorsed for average-risk colorectal cancer (CRC). The impact of real-world adherence rates on the cost-effectiveness of non-invasive stool-based CRC screening strategies remains undefined.

METHODS

This cost-effectiveness analysis from the perspective of Medicare as a primary payer used the Colorectal Cancer and Adenoma Incidence and Mortality Microsimulation Model (CRC-AIM) to estimate cost and clinical outcomes for triennial multi-target stool DNA (mt-sDNA), annual fecal immunochemical test (FIT) and annual fecal occult blood test (FOBT) screening strategies in a simulated cohort of US adults aged 65 years, who were assumed to either be previously unscreened or initiating screening upon entry to Medicare. Reported real-world adherence rates for initial stool-based screening and colonoscopy follow up (after a positive stool test result) were defined as 71.1% and 73.0% for mt-sDNA, 42.6% and 47.0% for FIT, and 33.4% and 47.0% for FOBT, respectively. The incremental cost-effectiveness ratio using quality-adjusted life years (QALY) was defined as the primary outcome of interest; other cost and clinical outcomes were also reported in secondary analyses. Multiple sensitivity and scenario analyses were conducted.

RESULTS

When reported real-world adherence rates were included only for initial stool-based screening, mt-sDNA was cost-effective versus FIT ($62,814/QALY) and FOBT ($39,171/QALY); mt-sDNA also yielded improved clinical outcomes. When reported real-world adherence rates were included for both initial stool-based screening and follow-up colonoscopy (when indicated), mt-sDNA was increasingly cost-effective compared to FIT and FOBT ($31,725/QALY and $28,465/QALY, respectively), with further improved clinical outcomes.

LIMITATIONS

Results are based on real-world cross-sectional adherence rates and may vary in the context of other types of settings. Only guideline-recommended stool-based strategies were considered in this analysis.

CONCLUSION

Comparisons of the effectiveness and benefits of specific CRC screening strategies should include both test-specific performance characteristics and real-world adherence to screening tests and, when indicated, follow-up colonoscopy.

Cross-sectional adherence with the multi-target stool DNA test for colorectal cancer screening: Real-world data from a large cohort of older adults

Objective

To determine cross-sectional adherence with the multi-target stool DNA test used for colorectal cancer screening in a large, fully insured Medicare population.

Methods

All patients aged 65–85 with a valid multi-target stool DNA test order from 1 September 2016 to 31 August 2017 identified from the Exact Sciences Laboratories (Madison, WI; sole-source national multi-target stool DNA test provider) database were evaluated for test adherence. Cross-sectional adherence, defined as multi-target stool DNA test completion within 365 days from order date, was analyzed overall and by time to adherence, as well as by available patient (age, sex, test order date, Medicare coverage type) and provider (specialty, year of first multi-target stool DNA test order, multi-target stool DNA test order frequency, and practice location) factors.

Results

Among 368,494 Medicare beneficiaries (64% female), overall cross-sectional adherence was 71%. Cumulative adherence rates increased more rapidly at 30 (44%) and 60 (65%) days, followed by more gradual increases at 90 (67%), 180 (70%), and 365 (71%) days. By provider specialty, primary care clinicians represented a higher percentage of multi-target stool DNA orders than gastroenterologists (88% vs. 6%), but had a lower associated patient adherence rate (71% vs. 78%).

Conclusions

In this large, national sample of Medicare insured older adults, nearly three-quarters of patients adhered with a multi-target stool DNA order for colorectal cancer screening. These real-world data should inform further clinical and population health applications, reimbursement model simulations, and guideline-endorsed colorectal cancer screening strategies adherence.

AACR White Paper: Shaping the Future of Cancer Prevention - A Roadmap for Advancing Science and Public Health

The recent pace, extent, and impact of paradigm-changing cancer prevention science has been remarkable. The American Association for Cancer Research (AACR) convened a 3-day summit, aligned with five research priorities: (i) Precancer Atlas (PCA). (ii) Cancer interception. (iii) Obesity-cancer linkage, a global epidemic of chronic low-grade inflammation. (iv) Implementation science. (v) Cancer disparities. Aligned with these priorities, AACR co-led the Lancet Commission to formally endorse and accelerate the NCI Cancer Moonshot program, facilitating new global collaborative efforts in cancer control. The expanding scope of creative impact is perhaps most startling-from NCI-funded built environments to AACR Team Science Awarded studies of Asian cancer genomes informing global primary prevention policies; cell-free epigenetic marks identifying incipient neoplastic site; practice-changing genomic subclasses in myeloproliferative neoplasia (including germline variant tightly linked to JAK2 V617F haplotype); universal germline genetic testing for pancreatic cancer; and repurposing drugs targeting immune- and stem-cell signals (e.g., IL-1β, PD-1, RANK-L) to cancer interception. Microbiota-driven IL-17 can induce stemness and transformation in pancreatic precursors (identifying another repurposing opportunity). Notable progress also includes hosting an obesity special conference (connecting epidemiologic and molecular perspectives to inform cancer research and prevention strategies), co-leading concerted national implementation efforts in HPV vaccination, and charting the future elimination of cancer disparities by integrating new science tools, discoveries and perspectives into community-engaged research, including targeted counter attacks on e-cigarette ad exploitation of children, Hispanics and Blacks. Following this summit, two unprecedented funding initiatives were catalyzed to drive cancer prevention research: the NCI Cancer Moonshot (e.g., PCA and disparities); and the AACR-Stand Up To Cancer bold "Cancer Interception" initiative.

Abstract CT222: A pilot study of a MUC1 vaccine in current and former smokers at high risk for lung cancer

Background: Smoking is the most common etiology for lung cancer. Smoking cessation, even when successful, does not eliminate risk of lung cancer. With inconsistent results of lung chemoprevention trials, an emerging area of interest is immunoprevention, in particular vaccines. MUC1 is a transmembrane glycoprotein aberrantly overexpressed in adenocarcinomas, including lung cancer. Abnormal MUC1 expression is also characteristic of premalignant lesions, including bronchial dysplasia and atypical adenomatous hyperplasia. This suggests that immunization with a MUC1 vaccine in the premalignant or high-risk setting, before the tumor and cytotoxic therapy could suppress the immune system, might be effective in inducing strong immunity and reducing cancer risk.

Trial design: Leveraging the infrastructure of the NCI-funded Cancer Prevention Network (CPN) consortium, we are conducting a two-center pilot trial to evaluate co-primary endpoints: immunogenicity of the MUC1 peptide plus polyICLC adjuvant vaccine (assessed at 12 weeks) and safety (assessed at up to 24 weeks) in current and former smokers who are at high risk for lung cancer. 50 participants will be screened in order to have 40 evaluable participants for baseline and 12-week immunogenicity assessments.

Eligibility: Smoking history of ≥30 pack-years and either current smoker (still smoking or quit &lt; 1 year prior to pre-registration) or former smoker (quit 1-15 years prior to pre-registration); ages 55-80 years; ECOG performance status ≤1; CT scan of the chest done ≤ 6 months prior to pre-registration showing either negative findings (no nodules) or solid or part-solid nodules &lt; 6 mm in size (consistent with &lt; 1% probability of malignancy, Lung-RADs Version 1.0). Exclusion criteria are standard.

Immunogenicity and safety: MUC1 peptide plus polyICLC adjuvant vaccine will be administered at week 0, 2 and 10. The primary endpoint is anti-MUC1 IgG titer that is ≥2 fold higher at week 12 compared to baseline. Based on previous studies of this vaccine, we expect that 40 evaluable participants will provide 96% power to detect immunogenicity response rate of 15% versus 40% using a 2-sided test of proportions with type I error rate of 0.05. AEs and toxicities will be monitored for up to 24 weeks from the first vaccine.

Secondary Objectives: We will explore differences, if any, in vaccine immunogenicity in current vs. former smokers. Smoking induces chronic inflammation (hallmark of cancer) associated with immunosuppression. We will evaluate pre-vaccination levels of circulating myeloid derived suppressor cells (MDSC) and correlate with the response to the vaccine. We will explore the impact, if any, of this vaccine on the markers of inflammation (hsCRP, IL-6) and the effect of baseline levels of these markers on the ability to successfully vaccinate. We will also assess the relationship between COPD status and immune response in current versus former smokers.

The trial is open to accrual.

Citation Format: Olivera J. Finn, Julie Ward, Tami Krpata, Lisa Bengtson, John McKolanis, Sharon Kaufman, Colleen Akerley, April Felt, Karrie Fursa, Anne Holland, Nathan Foster, Andres Salazar, Malgorzata Wojtowicz, Eva Szabo, Paul Limburg, David Midthun, Arjun Pennathur. A pilot study of a MUC1 vaccine in current and former smokers at high risk for lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT222.

Abstract 4662: Framework for clinical evaluation of chemopreventive agents: Defining criteria for future assessment

Background Although a number of cancer chemopreventive agents have now been evaluated in phase II and phase III clinical trials that assess their efficacy and tolerability in both high risk and general populations, few have shown clear efficacy and uptake of approved agents has been disappointingly low. Therefore, chemopreventive agents should undergo rigorous screening prior to clinical trial evaluation in order to improve the selection of suitable agents for testing in large, expensive multi-center phase III trials. The aim of this study is to develop a descriptive method for prioritizing candidate agents for further development.

Methods This framework was developed through a systematic literature review of Pubmed/Medline, Embase and The Cochrane Library. A semi-quantitative assessment focusing on efficacy and toxicity/tolerability was established based on expert input. Data from clinical trials, cancer epidemiological, observational and preclinical studies, including in vivo and in vitro basic research, was used to retrospectively evaluate the clinical application and effectiveness of cancer chemopreventive agents. Two chemopreventive agents with either a positive (aromatase inhibitors (AIs) for breast cancer) or negative (selenium for lung cancer) phase III clinical trial outcome were subsequently evaluated to determine the usefulness of the framework.

Results Chemopreventive agents must reduce or reverse the process of carcinogenesis in normal or pre-malignant tissue with minimal toxicity. Evaluation of efficacy included data from preclinical and animal models, epidemiological studies, and clinical trials (both early phase trials in the organ of interest as well as secondary endpoints from other relevant studies). Agent suitability evaluation included assessment of toxicities, tolerability, and agent specific attributes (PK/PD, bioavailability, dosing, etc.). Examination of selenium and AI historical data in these categories revealed strong concordance with phase III outcomes. The detailed descriptive evaluation of the agents will be presented.

Conclusion This framework provides a descriptive paradigm for cancer chemopreventive agent evaluation through systematic and rigorous interrogation. Thorough, standardized evaluation of all available preclinical, epidemiological, and clinical data should be strongly encouraged to better inform the investments required for clinical trials.

Citation Format: Naomi Walsh, David S. Alberts, Powel Brown, Paul Limburg, Mark Sherman, Eva Szabo. Framework for clinical evaluation of chemopreventive agents: Defining criteria for future assessment. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4662. doi:10.1158/1538-7445.AM2015-4662

Abstract LB-276: Prospective study of body mass index and adult weight change with colorectal cancer survival, overall and by tumor microsatellite instability status

Background: Tumor features such as stage, grade, and microsatellite instability (MSI) status have relevance for colorectal cancer survival whereas the prognostic role of body mass index (BMI) is unclear. We assessed the association of BMI and adult weight gain on colorectal cancer survival, overall and by strata of sex and MSI.

Methods: Participants were identified from a multi-center cohort that includes 6,763 colorectal cancer patients with invasive colorectal cancer who were enrolled into the Colon Cancer Family Registry from 1997 to 2008. Vital status was updated through direct contact with patients/next-of-kin and/or linkage with mortality records. BMI 2 years before diagnosis, BMI at age 20 years, and adult weight gain were derived from self-reports of height and weight (i.e., weight 2 years before diagnosis and weight at age 20 years). Tumor MSI status was available for 4,987 patients. Multivariable, two-sided hazard ratios (HR) and 95% confidence intervals (CIs) were estimated from delayed-entry Cox proportional hazards models, controlling for age at diagnosis, TNM summary stage (i.e., I, II, III, IV or missing), smoking (current, former, never), and study center.

Results: After a maximum of 13.7 years of follow-up from enrollment to end-of-study (median: 5.3 years), 2,335 patients had died. Higher BMI 2 years before cancer diagnosis (per 5-kg/m2) was associated with higher risk of all-cause mortality overall (HR, 1.10; 95% CI, 1.05 to 1.14), with similar associations when stratified by sex (men: HR, 1.07; 95% CI, 1.02 to 1.14; women: HR, 1.11: 95% CI, 1.05 to 1.17; p-interaction: 0.18) and MSI status (MS-stable/MSI-low: HR, 1.08; 95% CI, 1.03 to 1.14; MSI-high, HR: 1.19; 95% CI, 1.02 to 1.40; p-interaction: 0.88). In joint models, with MS-stable/MSI-low and normal BMI as the referent group, risk of death was lower for those with MSI-high and normal BMI (HR: 0.77; 95% CI: 0.59 to 1.00), higher for MS-stable/MSI-low and high (≥30) BMI (HR: 1.23; 95% CI: 1.07 to 1.42), and essentially the same for MSI-high and high BMI (HR: 0.97; 95% CI: 0.72 to 1.30). Similar patterns of association were observed for BMI at age 20 years and when the outcome was colorectal cancer-specific mortality, although not all associations remained statistically significant for some of the smaller sub-group analyses. After controlling for BMI at age 20 years, adult weight gain was only modestly associated with all-cause mortality (per 5 kg HR: 1.01; 95% CI: 1.00 to 1.02; p-trend: 0.07).

Conclusion: High pre-diagnosis BMI was associated with increased mortality after colorectal cancer diagnosis; this association was consistent for men and women and by tumor MSI status. These results also suggest that obesity attenuates the survival advantage observed with MSI-high tumors.

Citation Format: Peter T. Campbell, Christina Newton, Polly A. Newcomb, Dennis Ahnen, John Baron, Sean Cleary, Michelle Cotterchio, A. Brad Farris, Jane Figueiredo, Roger C. Green, Loic Le Marchand, John McLaughlin, Amanda Phipps, John D. Potter, Andrew Renehan, Aung Ko Win, Noralane Lindor, Paul Limburg. Prospective study of body mass index and adult weight change with colorectal cancer survival, overall and by tumor microsatellite instability status. [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 LB-276. doi:10.1158/1538-7445.AM2014-LB-276

Abstract 1151: cMYC amplification in colon cancer: A novel association with BRAF V600E and proficient DNA mismatch repair

Background: Colon cancer is categorized by the acquisition of a number of molecular alterations in both oncogenes and in tumor suppressor genes. Although cMYC alterations have been reported in colon cancer cell lines, little other information exists in primary colon tumors. We sought to determine the frequency of cMYC amplification in primary colon cancer and its relationship to other well defined colon tumor alterations. Methods: An initial set of 392 tumors were evaluated. All samples were tested for the BRAF V600E mutation and all were classified as proficient mismatch repair (pMMR) based on both IHC and microsatellite analysis of tumor tissue. A second set of 522 tumors was selected to replicate associations identified in the first set of samples. Similar to the initial cohort, both the BRAF V600E and the mismatch repair status of the tumors were assessed. The second cohort, however, included tumors that were both pMMR and dMMR. In both sets of samples, fluorescent in situ hybridization was used to evaluate cMYC gene amplification. Results: In cohort 1, cMYC amplification was observed in 15 of the 362 (4%) pMMR tumors successfully analyzed (Table 1). cMYC amplification was detected in 10 of 323 (3%) tumors with normal BRAF status vs. 5 of 39 (13%) tumors with altered BRAF status (p=0.015). In the second cohort, cMYC amplification was found in 20 of the 522 (4%) tumors. Only 1 of the 152 (&lt;1%) dMMR tumors had cMYC amplification vs. 19 of the 370 (5%) pMMR tumors (p=0.012). Of the pMMR tumors, cMYC amplification was detected in 13 of 333 (4%) tumors with normal BRAF status vs. 6 of 37 (16%) tumors with altered BRAF status (p=0.007), nearly identical to the first group. Conclusion: cMYC amplification in colon cancer is an infrequent event. However, when present, cMYC amplification occurs almost exclusively in tumors that are pMMR. Additionally, among pMMR tumors, cMYC amplification is associated with the presence of the BRAF V600E mutation.

Abstract 1677: Associations between cigarette smoking with incident colorectal cancer by p53 protein expression in a population-based cohort of older women

Background: Cigarette smoking (CS) is an established colorectal cancer (CRC) risk factor. The p53 protein, encoded by the TP53 tumor suppressor gene that is commonly mutated in CRC, is important in cell cycle arrest needed to repair DNA damage or induce apoptosis to prevent tumor propagation. In this prospective cohort study, we examined CS-associated CRC risks by p53 protein expression level in the population-based Iowa Women's Health Study (IWHS). Methods: The IWHS recruited 41,836 randomly selected Iowa women, ages 55-69 years, with a valid driver's license at study entry (1986). CS and other exposure variables were assessed at baseline, by self-report. Incident CRC cases were ascertained by annual linkage with the Iowa Cancer Registry. Archived, paraffin-embedded tissue specimens were collected from 732 CRC cases diagnosed through 12/31/2002. CS was categorized by smoking status (never, current, former), average number of cigarettes per day (1-19, 20-39, &gt; 40) and cumulative pack-years (1-19, 20-39, &gt; 40). P53 protein expression was determined by immunohistochemistry on tissue microarrays. Tumor cores were scored by combining both staining intensity and percent of cells stained to determine negative, low or high p53 protein expression levels. Multivariate Cox regression models were fit to estimate relative risks (RRs) and 95% confidence intervals (CIs). Results: Of the 732 available CRC cases, 486 (66%) had complete CS and p53 data. Associations between CS and CRC subtypes defined by p53 expression level are shown in the Table. Conclusions: These data demonstrate no clear heterogeneity of CS with CRC subtypes defined by p53 expression levels among older women.

Abstract 1891: Cigarette smoking and incident colorectal cancer by KRAS mutation status in a population-based cohort of older women

Background: Cigarette smoking (CS) is an established, although relatively modest, colorectal cancer (CRC) risk factor. Emerging data suggest that CS might affect distinct pathways of colorectal carcinogenesis. In this study, we examined CS-associated CRC risks by KRAS mutation status in the population-based Iowa Women's Health Study (IWHS).

Methods: The IIWHS recruited 41,836 randomly selected Iowa women, ages 55-69 years, with a valid driver's license at study entry (1986). CS and other exposure variables were assessed at baseline, by self-report. Incident CRC cases were ascertained by annual linkage with the Iowa Cancer Registry. Archived, paraffin-embedded tissue specimens were collected from 732 representative CRC cases diagnosed through 12/31/2002. CS was categorized by smoking status (current, former), average number of cigarettes per day (1-19, 20-39, &gt; 40) and pack-years (1-19, 20-39, &gt; 40); never smokers were defined as the reference group. KRAS mutation status (wildtype [wt] vs. mutated [mut]) was determined by direct sequence analysis of codons 12 and 13 (exon 2). Multivariate Cox regression models were fit to estimate relative risks (RRs) and 95% confidence intervals (CIs).

Results: Of the 732 available CRC cases, 507 (69%) had complete CS and KRAS data. Each of the CS-related variables was more strongly associated with KRAS-wt vs. KRAS-mut tumors (see Table). However, event rates were relatively small in some cells, and tests for heterogeneity between KRAS-defined subtypes were not statistically significant (p &gt; 0.05 for each comparison).

Conclusions: These findings suggest that CS may affect colorectal carcinogenesis through KRAS-independent pathways, but additional data are needed from larger, more diverse study populations.

Coffee phenolic phytochemicals suppress colon cancer metastasis by targeting MEK and TOPK

Epidemiological studies suggest that coffee consumption reduces the risk of cancers, including colon cancer, but the molecular mechanisms and target(s) underlying the chemopreventive effects of coffee and its active ingredient(s) remain unknown. Based on serving size or daily units, coffee contains larger amounts of phenolic phytochemicals than tea or red wine. Coffee or chlorogenic acid inhibited CT-26 colon cancer cell-induced lung metastasis by blocking phosphorylation of ERKs. Coffee or caffeic acid (CaA) strongly suppressed mitogen-activated MEK1 and TOPK activities and bound directly to either MEK1 or TOPK in an ATP-noncompetitive manner. Coffee or CaA, but not caffeine, inhibited ERKs phosphorylation, AP-1 and NF-κB transactivation and subsequently inhibited TPA-, EGF- and H-Ras-induced neoplastic transformation of JB6 P+ cells. Coffee consumption was also associated with a significant attenuation of ERKs phosphorylation in colon cancer patients. These results suggest that coffee and CaA target MEK1 and TOPK to suppress colon cancer metastasis and neoplastic cell transformation.

Is a solitary inguinal lymph node metastasis from adenocarcinoma of the rectum really a metastasis?

OBJECTIVE

Metastatic involvement of inguinal lymph nodes (ILN) from rectal adenocarcinoma is unusual, particularly without signs of distant spread to other organ sites. By current convention, ILN involvement, including solitary involvement, is classified as metastatic disease (M). However, anecdotal reports suggest that such patients are a distinct entity and should be managed differently. The aim of this study was to gain further insight regarding this seemingly distinct patient subset.

METHOD

This case series provides a descriptive report of patients with rectal adenocarcinoma and solitary inguinal lymph node metastasis (SILNM).

RESULTS

Upon retrospective review of medical records from 4480 patients with rectal adenocarcinoma seen at Mayo Clinic Rochester from 1995 to 2004, six patients (0.13%) with SILNM were identified. Three had metachronous and three had synchronous SILNM (four left sided, one right sided, and one bilateral). The mean age at SILNM diagnosis was 61.3 years, and three patients had originally stage II (and three had stage III disease). Five patients received concurrent chemo-radiation therapy and one declined treatment. Among those with metachronous SILNM, the mean survival after diagnosis of rectal cancer was 42 months. By comparison, all three patients with synchronous SILNM were still alive after a mean duration of 40 months of follow up.

CONCLUSION

Solitary involvement of ILNs might represent a distinct subset of patients with metastatic rectal adenocarcinoma who have a more favourable prognosis. If confirmed by larger studies, our data suggest that alternate management algorithms might be reasonable for such patients.

Alpha-1-antitrypsin deficiency and smoking as risk factors for mismatch repair deficient colorectal cancer: a study from the colon cancer family registry

In a previous study, alpha-1-antitrypsin (A1AT) deficiency alleles were found to be over represented among individuals with microsatellite unstable (MSI-high) colorectal cancers, and this was most significant in former or current smokers. We evaluated this association in a larger case-control study, stratified by microsatellite instability phenotypes. Concordant with prior observations, gender (female) and smoking history were positively associated with colorectal cancers having an MSI-high phenotype. No difference in frequency of A1AT deficiency alleles was found between cases and controls, irrespective of the MSI subtype.

Genetic variation in the vitamin D receptor (VDR) and the vitamin D-binding protein (GC) and risk for colorectal cancer: results from the Colon Cancer Family Registry

Epidemiologic evidence supports a role for vitamin D in colorectal cancer (CRC) risk. Variants in vitamin D-related genes might modify the association between vitamin D levels and CRC risk. In this analysis, we did a comprehensive evaluation of common variants in the vitamin D receptor (VDR) and the vitamin D-binding protein (GC; group-specific component) genes using a population-based case-unaffected sibling control design that included 1,750 sibships recruited into the Colon Cancer Family Registry. We also evaluated whether any associations differed by calcium supplement use, family history of CRC, or tumor characteristics. Heterogeneity by calcium and vitamin D intake was evaluated for a subset of 585 cases and 837 sibling controls who completed a detailed food frequency questionnaire. Age- and sex-adjusted associations were estimated using conditional logistic regression. Overall, we did not find evidence for an association between any single-nucleotide polymorphism (SNP) in VDR or GC and risk for CRC (range of unadjusted P values 0.01-0.98 for VDR and 0.07-0.95 for GC). None of these associations was significant after adjustment for multiple comparisons. We also found no evidence that calcium or vitamin D intake (food and supplement) from the food frequency questionnaire modified the association estimates between VDR and GC SNPs and CRC. We did observe associations between SNPs in GC and microsatellite unstable CRC, although these results should be confirmed in additional studies. Overall, our results do not provide evidence for a role of common genetic variants in VDR or GC in susceptibility to CRC.

Associations between smoking, alcohol consumption, and colorectal cancer, overall and by tumor microsatellite instability status

INTRODUCTION

Both smoking and alcohol consumption have been associated with modestly increased risks of colorectal cancer (CRC). Reports have suggested that these associations may differ by tumor molecular subtype, with stronger associations for microsatellite unstable (MSI-H) tumors.

METHODS

We used a population-based case-unaffected sibling design including 2,248 sibships (2,253 cases; 4,486 siblings) recruited to the Colon Cancer Family Registry to evaluate the association between smoking, alcohol consumption, and CRC. Associations were assessed using conditional logistic regression, treating sibship as the matching factor.

RESULTS

Although there were no statistically significant associations between any smoking variable and CRC overall, smoking did confer an increased risk of certain types of CRC. We observed an association between pack-years of smoking and rectal cancer [odds ratio (OR), 1.85; 95% confidence interval (CI), 1.23-2.79 for >40 pack-years versus nonsmokers; P(trend) = 0.03], and there was an increased risk of MSI-H CRC with increasing duration of smoking (OR, 1.94; 95% CI, 1.09-3.46 for >30 years of smoking versus nonsmokers). Alcohol intake was associated with a modest increase in risk for CRC overall (OR, 1.21; 95% CI, 1.03-1.44 for 12+ drinks per week versus nondrinkers), with more marked increases in risk for MSI-L CRC (OR, 1.85; 95% CI, 1.06-3.24) and rectal cancer (OR, 1.48; 95% CI, 1.08-2.02).

CONCLUSIONS

We found associations between cigarette smoking and increased risks of rectal cancer and MSI-H CRC. Alcohol intake was associated with increased risks of rectal cancer and MSI-L CRC. These results highlight the importance of considering tumor phenotype in studies of risk factors for CRC.

Abstract B128: Change in use of folic acid-containing supplements after a diagnosis of colorectal cancer

B128

Background

The B vitamin folate affects colorectal carcinogenesis through effects on nucleotide synthesis and possibly DNA methylation. Animal models and epidemiologic evidence suggest that folate from diet and supplements can prevent the development of colorectal cancer (CRC), but that high folate intake after adenomas or cancer are established may accelerate progression or recurrence. The chemotherapeutic agent 5-fluorouracil inhibits thymidylate synthase, a folate-metabolizing enzyme, and the effect of folate intake on treatment efficacy is unknown. Supplement use and folate intake are high among adults in the U.S., particularly with food supply fortification, and higher still among cancer patients and survivors. However, few studies have addressed use of folic acid-containing supplements (FAS) among colorectal cancer patients, how use changes after diagnosis, and what factors determine changes in FAS use.

Methods

The Colon Cancer Family Registry (CCFR) is a multicenter study of colorectal cancer cases, their family members and controls, recruited since 1998 at six sites in the United States, Australia and Canada. The current analysis includes 1,092 CRC cases with epidemiologic data available from questionnaires administered at enrollment, asking about supplement use and other risk factors before diagnosis, and from follow-up questionnaires about 5 years later. Baseline characteristics for cases who began using FAS (including multivitamins) after diagnosis were compared to those for cases who used FAS neither before nor after diagnosis. We used logistic regression models to evaluate associations between age, sex, CCFR site, race, education, income, lifetime exercise, smoking, body mass index, and diet and change in FAS use, adjusting each model for age, sex and site, when appropriate.

Results

FAS use before CRC diagnosis was 35.4%, while 55.1% of cases used FAS after diagnosis. Women were more likely to begin FAS use after diagnosis (OR 1.60, 95% CI 1.17-2.19). Current smokers were less likely than nonsmokers to begin FAS use (OR 0.63, 95% CI 0.40-0.97), as were those consuming more red meat (OR 0.38, 95% CI 0.21-0.70 for those in the highest versus lowest intake categories, ptrend=0.012). Subjects with higher fruit intake were more likely to begin FAS use (OR 1.95, 95% CI 1.16-3.30 for highest versus lowest intake, ptrend=0.013). We also observed a suggestive association between lifetime physical activity and change in FAS use for active versus less active subjects (OR 1.48, 95% CI 1.01-2.16), though there was no trend with increasing levels of physical activity (ptrend=0.27). Finally, we found that residents of non-U.S. countries were less likely to begin FAS use (OR 0.57, 95% CI 0.33-0.96 for Ontario, Canada and OR 0.21, 95% CI 0.11-0.38 for Australia). Conclusions: Our analysis showed substantial increases in the use of folic acid-containing supplements after diagnosis with colorectal cancer in CCFR participants, especially among women, U.S. residents, nonsmokers, and those who consumed more fruit and less meat. This study begins to characterize CRC patients likely to be using FAS, and suggests that its use is widespread. This finding is notable given evidence that folate may accelerate progression of colorectal cancer, and the unknown effect that FAS intake may have on the efficacy of cancer treatment and on survival.

Citation Information: Cancer Prev Res 2008;1(7 Suppl):B128.

Colon Cancer Family Registry: an international resource for studies of the genetic epidemiology of colon cancer

BACKGROUND

Family studies have served as a cornerstone of genetic research on colorectal cancer.

MATERIALS AND METHODS

The Colorectal Cancer Family Registry (Colon CFR) is an international consortium of six centers in North America and Australia formed as a resource to support studies on the etiology, prevention, and clinical management of colorectal cancer. Differences in design and sampling schemes ensures a resource that covers the continuum of disease risk. Two separate recruitment strategies identified colorectal cancer cases: population-based (incident case probands identified by cancer registries; all six centers) and clinic-based (families with multiple cases of colorectal cancer presenting at cancer family clinics; three centers). At this time, the Colon CFR is in year 10 with the second phase of enrollment nearly complete. In phase I recruitment (1998-2002), population-based sampling ranged from all incident cases of colorectal cancer to a subsample based on age at diagnosis and/or family cancer history. During phase II (2002-2007), population-based recruitment targeted cases diagnosed before the age of 50 years are more likely attributable to genetic factors. Standardized protocols were used to collect information regarding family cancer history and colorectal cancer risk factors, and biospecimens were obtained to assess microsatellite instability (MSI) status, expression of mismatch repair proteins, and other molecular and genetic processes.

RESULTS

Of the 8,369 case probands enrolled to date, 2,602 reported having one or more colorectal cancer-affected relatives and 799 met the Amsterdam I criteria for Lynch syndrome. A large number of affected (1,324) and unaffected (19,816) relatives were enrolled, as were population-based (4,108) and spouse (983) controls. To date, 91% of case probands provided blood (or, for a few, buccal cell) samples and 75% provided tumor tissue. For a selected sample of high-risk subjects, lymphocytes have been immortalized. Nearly 600 case probands had more than two affected colorectal cancer relatives, and 800 meeting the Amsterdam I criteria and 128, the Amsterdam II criteria. MSI testing for 10 markers was attempted on all obtained tumors. Of the 4,011 tumors collected in phase I that were successfully tested, 16% were MSI-high, 12% were MSI-low, and 72% were microsatellite stable. Tumor tissues from clinic-based cases were twice as likely as population-based cases to be MSI-high (34% versus 17%). Seventeen percent of phase I proband tumors and 24% of phase II proband tumors had some loss of mismatch repair protein, with the prevalence depending on sampling. Active follow-up to update personal and family histories, new neoplasms, and deaths in probands and relatives is nearly complete.

CONCLUSIONS

The Colon CFR supports an evolving research program that is broad and interdisciplinary. The greater scientific community has access to this large and well-characterized resource for studies of colorectal cancer.

Pathology features in Bethesda guidelines predict colorectal cancer microsatellite instability: a population-based study

BACKGROUND & AIMS

The revised Bethesda guidelines for Lynch syndrome recommend microsatellite instability (MSI) testing all colorectal cancers in patients diagnosed before age 50 years and colorectal cancers diagnosed in patients between ages 50 and 59 years with particular pathology features. Our aim was to identify pathology and other features that independently predict high MSI (MSI-H).

METHODS

Archival tissue from 1098 population-based colorectal cancers diagnosed before age 60 years was tested for MSI. Pathology features, site, and age at diagnosis were obtained. Multiple logistic regression was performed to determine the predictive value of each feature, as measured by an odds ratio (OR), from which a scoring system (MsPath) was developed to estimate the probability a colorectal cancer is MSI-H.

RESULTS

Fifteen percent of tumors (162) were MSI-H. Independent predictors were tumor-infiltrating lymphocytes (OR, 9.1; 95% confidence interval [CI], 5.9-14.1), proximal subsite (OR, 4.7; 95% CI, 3.1-7.3), mucinous histology (OR, 2.8; 95% CI, 1.7-4.8), poor differentiation (OR, 1.9; 95% CI, 1.2-3.1), Crohn's-like reaction (OR, 1.9; 95% CI, 1.2-2.9), and diagnosis before age 50 years (OR, 1.9; 95% CI, 1.3-2.9). MsPath score >or=1.0 had a sensitivity of 93% and a specificity of 55% for MSI-H.

CONCLUSIONS

The probability an individual colorectal cancer is MSI-H is predicted well by the MsPath score. There is little value in testing for DNA mismatch repair loss in tumors, or for germline mismatch repair mutations, for colorectal cancers diagnosed in patients before age 60 years with an MSPath score <1 (approximately 50%). Pathology can identify almost all MSI-H colorectal cancers diagnosed before age 60 years.

Antibacterial properties and toxicity of Atuna racemosa extract depend on kernel maturity

Through data mining a historic herbal text, we identified Atuna racemosa-Raf. as a plant with alleged antibacterial properties. We have shown that these purported antibacterial properties are most prominent in the kernel of the nut of the plant. While working with traditional healers in Samoa during a botanical collection trip, we identified a range of maturity stages of the kernel. Here we show that the antibacterial properties are different at different stages of kernel maturity, and that the immature kernels have a lower minimal inhibitory concentration (MIC) than the mature kernels. Additionally, we show there is a negative correlation between the antibacterial properties and cytotoxic properties (a stronger antibiotic is less cytotoxic), suggesting there are two separate compounds with disparate characteristics. These findings have implications for the use of this natural product as an antibiotic and chemotherapeutic agent.

A prospective study of anthropometric and clinical measurements associated with insulin resistance syndrome and colorectal cancer in male smokers

Type 2 diabetes mellitus shares risk factors for and has shown a positive association with colorectal cancer. Anthropometric measures (height, weight, and body mass index (weight (kg)/height (m)(2)) and metabolic abnormalities associated with insulin resistance syndrome (IRS) (abnormalities in measured blood pressure, high density lipoprotein (HDL) cholesterol, and total cholesterol) were prospectively evaluated for associations with incident colon (n = 227), rectal (n = 183), and colorectal (n = 410) cancers diagnosed between 1985 and 2002 in 28,983 Finnish male smokers from the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. Cox proportional hazards models were used to calculate hazard ratios and 95% confidence intervals. In comparison with the lowest quintile, the highest quintile of body mass index was significantly associated with colorectal cancer (hazard ratio (HR) = 1.70, 95% confidence interval (CI): 1.01, 2.85; p-trend = 0.01), particularly colon cancer. Subjects with a cluster of three IRS-related conditions (hypertension, body mass index >/=25 kg/m(2), and HDL cholesterol level <40 mg/dl (<1.55 mmol/liter)), compared with those with fewer conditions, had a significantly increased risk of colorectal cancer (HR = 1.40, 95% CI: 1.12, 1.74), particularly colon cancer (HR = 1.58, 95% CI: 1.18, 2.10), but not rectal cancer. These results support the hypothesis that the significant association observed between IRS-defining metabolic abnormalities and colorectal cancer is determined primarily by adiposity.

Can Complementary and Alternative Medicine Clinical Cancer Research Be Successfully Accomplished? The Mayo Clinic–North Central Cancer Treatment Group Experience

Some critics question whether research on complementary and alternative modalities for patients with cancer can be done efficiently in traditional clinical settings. This article reviews a program of complementary medicine research that has been done in a traditional clinical setting over the past 30 years. Trials using complementary therapies for both symptom management and cancer treatment done by the Mayo Clinic and the North Central Cancer Treatment Group are reviewed. Twenty-seven studies have been developed using complementary therapies, addressing such issues as mucosal and epidermal toxicity, hot flashes, lymphedema, anorexia and cachexia, insomnia, cognitive dysfunction, fatigue, and cancer treatment. Nineteen of them have been completed and have had results published in peer-reviewed clinical journals, whereas two manuscripts are in press. Two other trials have recently completed accrual, and the data are being analyzed so that manuscripts can be prepared. In addition, four clinical trials are actively accruing patients. The data presented in this article demonstrate that complementary and alternative medicine research can be done in a scientifically sound manner. Well-designed and adequately powered studies can be implemented, and large numbers of patients can be accrued. The resulting research evaluations can be published in peer-reviewed medical journals.

Insulin, glucose, insulin resistance, and pancreatic cancer in male smokers

CONTEXT

Obesity, diabetes mellitus, and glucose intolerance have been associated with increased pancreatic cancer risk; however, prediagnostic serum insulin concentration has not been evaluated as a predictor of this malignancy.

OBJECTIVE

To investigate whether prediagnostic fasting glucose and insulin concentrations and insulin resistance are associated with subsequent incidence of exocrine pancreatic cancer in a cohort of male smokers.

DESIGN, SETTING, AND PARTICIPANTS

A case-cohort prospective study within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (1985-1988) cohort of 29,133 male Finnish smokers ages 50 to 69 years. The study included 400 randomly sampled subcohort control participants and 169 incident pancreatic cancer cases that occurred after the fifth year of follow-up. All participants were followed up through December 2001 (up to 16.7 years of follow-up).

MAIN OUTCOME MEASURES

Incident exocrine pancreatic cancer identified from the Finnish Cancer Registry.

RESULTS

After adjusting for age, smoking, and body mass index, higher baseline fasting serum concentrations of glucose, insulin, and insulin resistance were positively associated with pancreatic cancer. The presence of biochemically defined diabetes mellitus (glucose, > or =126 mg/dL [> or =6.99 mmol/L]) and insulin concentration in the highest vs lowest quartile both showed a significant 2-fold increased risk (hazard ratio [HR], 2.13; 95% confidence interval [CI], 1.04-4.35; and HR, 2.01; 95% CI, 1.03-3.93; respectively). There were significant interactions for all the biomarker exposures by follow-up time, such that the positive associations were stronger among the cases that occurred more than 10 years after baseline (highest vs lowest quartile: glucose, HR, 2.16; 95% CI, 1.05-4.42; P for trend = .02; insulin, HR, 2.90; 95% CI, 1.22-6.92; P for trend = .005; and insulin resistance, HR, 2.71; 95% CI, 1.19-6.18; P for trend = .006).

CONCLUSIONS

These results support the hypothesis that exposure to higher insulin concentrations and insulin resistance predicts the risk of exocrine pancreatic cancer.

Insulin-like growth factor (IGF)-1, IGF-binding protein-3, and pancreatic cancer in male smokers

To investigate whether insulin-like growth factor (IGF)-1 and IGF-binding protein-3 (IGFBP-3) are prospectively associated with exocrine pancreatic cancer, we conducted a nested case-control study within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study cohort of 29,133 male Finnish smokers, aged 50-69 years. To avoid the potential influence of subclinical cancer on IGF-1 and IGFBP-3, all subjects in this study were alive without clinical evidence of cancer during their 5th year of the cohort follow-up. Four hundred randomly selected cohort controls and 93 incident pancreatic adenocarcinoma cases that occurred between their 5th follow-up year through 1997 (i.e., up to 12.7 years of follow-up) were included in this study. Concentrations of IGF-1 and IGFBP-3 were measured in serum samples obtained at baseline using ELISA. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models, adjusted for confounders. Neither IGF-1, IGFBP-3, nor the IGF-1:IGFBP-3 molar ratio was significantly associated with pancreatic cancer: highest compared to lowest tertile, OR = 0.67, 95% CI 0.37-1.21, P trend = 0.17; OR = 0.70, 95% CI 0.38-1.27, P trend = 0.12; and OR = 0.85, 95% CI 0.50-1.46, P trend = 0.54, respectively. Our results do not support the hypothesis that serum IGF-1 and IGFBP-3 concentrations are associated with pancreatic cancer risk among male smokers. Further studies are necessary to evaluate these associations in other populations.

Insulin-Like Growth Factor (IGF)-1, IGF-Binding Protein-3, and Pancreatic Cancer in Male Smokers

To investigate whether insulin-like growth factor (IGF)-1 and IGF-binding protein-3 (IGFBP-3) are prospectively associated with exocrine pancreatic cancer, we conducted a nested case-control study within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study cohort of 29,133 male Finnish smokers, aged 50–69 years. To avoid the potential influence of subclinical cancer on IGF-1 and IGFBP-3, all subjects in this study were alive without clinical evidence of cancer during their 5th year of the cohort follow-up. Four hundred randomly selected cohort controls and 93 incident pancreatic adenocarcinoma cases that occurred between their 5th follow-up year through 1997 (i.e., up to 12.7 years of follow-up) were included in this study. Concentrations of IGF-1 and IGFBP-3 were measured in serum samples obtained at baseline using ELISA. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models, adjusted for confounders. Neither IGF-1, IGFBP-3, nor the IGF-1:IGFBP-3 molar ratio was significantly associated with pancreatic cancer: highest compared to lowest tertile, OR = 0.67, 95% CI 0.37–1.21, P trend = 0.17; OR = 0.70, 95% CI 0.38–1.27, P trend = 0.12; and OR = 0.85, 95% CI 0.50–1.46, P trend = 0.54, respectively. Our results do not support the hypothesis that serum IGF-1 and IGFBP-3 concentrations are associated with pancreatic cancer risk among male smokers. Further studies are necessary to evaluate these associations in other populations.