Postmenopausal levels of endogenous sex hormones and risk of colorectal cancer

The increased risk of colorectal cancer in the women who underwent hysterectomy from the South Korean National Health Insurance Database

BACKGROUND

Several population-based studies and observational studies have shown that oophorectomy is associated with an increased risk of colorectal cancer (CRC), and hormone replacement therapy has been associated with a reduction in the risk of colorectal cancer. This study was carried out to investigate whether hysterectomy, which may affect the levels of female hormones, is associated with a risk of cancer of the specific gastrointestinal tract.

METHODS

This population-based retrospective cohort study was conducted using insurance data provided by the Health Insurance Review and Assessment Service (HIRA) from January 1, 2007, to December 31, 2020. The hysterectomy group included 40- to 59-year-old women who underwent hysterectomy with uterine leiomyoma or uterine endometriosis from January 1, 2011, to December 31, 2014. The control group included women aged 40 to 59 years who visited medical institutions for medical examination from January 1, 2011 to December 31, 2014.

RESULTS

The hysterectomy and non-hysterectomhy groups comprised 66,204 and 89,768 subjects, respectively. The median ages in the non-hysterectomy group and hysterectomy group were 48 (range: 43-53) and 46 (range: 44-49) years, respectively. In the unadjusted results of the analysis, all colorectal cancer (CRC) increased in the hysterectomy alone group (HR 1.222, 95% confidence interval (CI) 1.016-1.47, p = 0.033), sigmoid colon cancer increased in the hysterectomy alone group (HR 1.71, 95% CI 1.073-2.724, p = 0.024), and rectal cancer increased in the hysterectomy with adnexal surgery group (HR 1.924, 95% CI 1.073-2.724, p = 0.002). The adjusted results showed that all CRC increased in the hysterectomy alone group (HR 1.406, 95% CI 1.057-1.871, p = 0.019), colon cancer increased in the hysterectomy alone group (HR 1.523, 95% CI 1.068-2.17, p = 0.02), and rectal cancer increased in the hysterectomy with adnexal surgery group (HR 1.933, 95% CI 1.131-3.302, p = 0.016). The all-cause mortality of GI cancer increased in the hysterectomy alone group (HR 3.495, 95% CI 1.347-9.07, p = 0.001).

CONCLUSIONS

This study showed that the risk of all CRC increased in women who underwent hysterectomy compared with women who did not. In particular, the risk of rectal cancer was significantly higher in the women who underwent hysterectomy with adnexal surgery than in the controls. There was no association between hysterectomy and other GI cancers.

Prognostic Value of Combined Hematological/Biochemical Indexes and Tumor Clinicopathologic Features in Colorectal Cancer Patients—A Pilot Single Center Study

Colorectal cancer (CRC) is a significant public health problem. There is increasing evidence that the host’s immune response and nutritional status play a role in the development and progression of cancer. The aim of our study was to examine the prognostic value of clinical markers/indexes of inflammation, nutritional and pathohistological status in relation to overall survival and disease free-survival in CRC. The total number of CRC patients included in the study was 111 and they underwent laboratory analyses within a week before surgery. Detailed pathohistological analysis and laboratory parameters were part of the standard hospital pre-operative procedure. Medical data were collected from archived hospital data. Data on the exact date of death were obtained by inspecting the death registers for the territory of the Republic of Serbia. All parameters were analyzed in relation to the overall survival and survival period without disease relapse. The follow-up median was 42 (24−48) months. The patients with the III, IV and V degrees of the Clavien–Dindo classification had 2.609 (HR: 2.609; 95% CI: 1.437−4.737; p = 0.002) times higher risk of death. The modified Glasgow prognostic score (mGPS) 2 and higher lymph node ratio carried a 2.188 (HR: 2.188; 95% CI: 1.413−3.387; p < 0.001) and 6.862 (HR: 6.862; 95% CI: 1.635−28.808; p = 0.009) times higher risk of death in the postoperative period, respectively; the risk was 3.089 times higher (HR: 3.089; 95% CI: 1.447−6.593; p = 0.004) in patients with verified tumor deposits. The patients with tumor deposits had 1.888 (HR: 1.888; 95% CI: 1024−3481; p = 0.042) and 3.049 (HR: 3.049; 95% CI: 1.206−7.706; p = 0.018) times higher risk of disease recurrence, respectively. The emphasized peritumoral lymphocyte response reduced the risk of recurrence by 61% (HR: 0.391; 95% CI: 0.196−0.780; p = 0.005). Standard perioperative laboratory and pathohistological parameters, which do not present any additional cost for the health system, may provide information on the CRC patient outcome and lay the groundwork for a larger prospective examination.

Estrogen concentration and estrogen receptor-β expression in postmenopausal colon cancer considering patient/tumor background

PURPOSE

A large number of studies have suggested an inhibitory role of estrogens against colorectal cancer (CRC), but persistent controversy exists. CRC characteristics are affected by sex, age, and tumor locus, suggesting the need for a systematic study considering these factors. The purpose of this study was to verify the difference in the pathobiological role of estrogens in CRC according to patient/tumor backgrounds.

METHODS

Surgical specimens from 116 postmenopausal women (≥ 70 years/o, n = 74; < 70 years/o, n = 42) were studied. Estrogen receptor-β (ER-β), the main ER in the colorectal epithelium, was immunohistochemically examined. The concentrations of estradiol (E2) and estrone (E1) were examined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). These factors were compared according to the tissue type (cancerous or non-cancerous), patients' age, tumor backgrounds (locus, histology, pathological stage, status of mismatch repair protein = MMR), and clinical outcome.

RESULTS

ER-β-positivity, higher E2 concentration, deficient-MMR, and medullary/mucinous histology (Med/Muc) were closely related to right-sided tumors in women who were aged ≥ 70 years /o (R-Ca ≥ 70) and also closely related to each other. ER-β reduction compared with non-cancerous counterparts was observed only in left-sided tumors of patients < 70 years /o (L-Ca < 70), non-Med/Muc, or proficient-MMR tumors.

CONCLUSION

The present results suggest that estrogens do not suppress, but rather promote, R-Ca ≥ 70, Med/Muc, or deficient-MMR tumors, whereas estrogens suppress L-Ca < 70, non-Med/Muc, or proficient-MMR tumors, confirming the difference in pathobiological role of estrogens in postmenopausal colon cancer according to the patients' age and tumor background. This may at least partly explain the controversy regarding the association between estrogens and CRC.

Endogenous Circulating Sex Hormone Concentrations and Colon Cancer Risk in Postmenopausal Women: A Prospective Study and Meta-Analysis

Background

Observational studies have consistently reported that postmenopausal hormone therapy use is associated with lower colon cancer risk, but epidemiologic studies examining the associations between circulating concentrations of endogenous estrogens and colorectal cancer have reported inconsistent results.

Methods

We investigated the associations between circulating concentrations of estrone, estradiol, free estradiol, testosterone, free testosterone, androstenedione, dehydroepiandrosterone (DHEA), progesterone, and sex hormone-binding globulin (SHBG) with colon cancer risk in a nested case-control study of 1028 postmenopausal European women (512 colon cancer cases, 516 matched controls) who were noncurrent users of exogenous hormones at blood collection. Multivariable conditional logistic regression models were used to compute odds ratios and 95% confidence intervals to evaluate the association between circulating sex hormones and colon cancer risk. We also conducted a dose-response meta-analysis of prospective studies of circulating estrone and estradiol with colorectal, colon, and rectal cancer risk in postmenopausal women. All statistical tests were 2-sided.

Results

In the multivariable model, a nonstatistically significantly positive relationship was found between circulating estrone and colon cancer risk (odds ratio per log2 1-unit increment = 1.17 [95% confidence interval = 1.00 to 1.38]; odds ratioquartile4-quartile1  = 1.33 [95% confidence interval = 0.89 to 1.97], P trend  = .20). Circulating concentrations of estradiol, free estradiol, testosterone, free testosterone, androstenedione, DHEA, progesterone, and SHBG were not associated with colon cancer risk. In the dose-response meta-analysis, no clear evidence of associations were found between circulating estradiol and estrone concentrations with colorectal, colon, and rectal cancer risk.

Conclusion

Our observational and meta-analysis results do not support an association between circulating concentrations of endogenous sex hormones and colon or rectal cancer in postmenopausal women.

Circulating Levels of Testosterone, Sex Hormone Binding Globulin and Colorectal Cancer Risk: Observational and Mendelian Randomization Analyses

BACKGROUND

Epidemiologic studies evaluating associations between sex steroid hormones and colorectal cancer risk have yielded inconsistent results. To elucidate the role of circulating levels of testosterone, and sex hormone-binding globulin (SHBG) in colorectal cancer risk, we conducted observational and Mendelian randomization (MR) analyses.

METHODS

The observational analyses included 333,530 participants enrolled in the UK Biobank with testosterone and SHBG measured. HRs and 95% confidence intervals (CI) were estimated using multivariable Cox proportional hazards models. For MR analyses, genetic variants robustly associated with hormone levels were identified and their association with colorectal cancer (42,866 cases/42,752 controls) was examined using two-sample MR.

RESULTS

In the observational analysis, there was little evidence that circulating levels of total testosterone were associated with colorectal cancer risk; the MR analyses showed a greater risk for women (OR per 1-SD = 1.09; 95% CI, 1.01-1.17), although pleiotropy may have biased this result. Higher SHBG concentrations were associated with greater colorectal cancer risk for women (HR per 1-SD = 1.16; 95% CI, 1.05-1.29), but was unsupported by the MR analysis. There was little evidence of associations between free testosterone and colorectal cancer in observational and MR analyses.

CONCLUSIONS

Circulating concentrations of sex hormones are unlikely to be causally associated with colorectal cancer. Additional experimental studies are required to better understand the possible role of androgens in colorectal cancer development.

IMPACT

Our results from large-scale analyses provide little evidence for sex hormone pathways playing a causal role in colorectal cancer development.See related commentary by Hang and Shen, p. 1302.

Sex Hormone and Colorectal Cancer: The Knowns and Unknowns

Sex hormones have been suggested as a contributor to gender disparity in incidence and mortality of colorectal cancer, but previous observational studies on endogenous sex hormones and colorectal cancer risk have led to contradictory results. Leveraging the large-scale UK biobank resource, Dimou and colleagues performed both observational and Mendelian randomization (MR) analyses to investigate the association of serum testosterone and sex hormone binding globulin concentrations with the risk of colorectal cancer. Although the findings provide little evidence for independent roles of the hormones in colorectal cancer, further interrogation of possible mediating effects of sex hormones on the causal pathways of colorectal cancer could deepen our understanding of colorectal cancer etiology and improve tailored prevention. While MR analysis is useful for inferring causality in observational studies, the current null results should be interpreted with caution because of insufficient statistical power and predefined assumptions of linearity. Moreover, given the widespread use of testosterone supplementation in older men to restore age-related decline of endogenous concentrations, large and long-term randomized controlled trials are required to clarify the effect of testosterone on colorectal cancer risk, which would provide critical evidence for health decision making.See related article by Dimou et al., p. 1336.

An approach to classifying occupational exposures to endocrine disrupting chemicals by sex hormone function using an expert judgment process

Endocrine disrupting chemicals (EDCs) are exogenous substances that interfere with the endocrine system and cause adverse effects. We aimed to classify the effects of 24 known EDCs, prevalent in certain occupations, according to four modes of action (estrogenic, antiestrogenic, androgenic, and/or antiandrogenic). A literature search, stratified into four types of literature was conducted (namely: national and international agency reports; review articles; primary studies; ToxCast^TM). The state of the evidence of each EDC on sex hormone function was summarized and reviewed by an expert panel. For each mode of action, the experts evaluated the likelihood of endocrine disruption in five categories: "No", "Unlikely", "Possibly", "Probably", and "Yes". Seven agents were categorized as "Yes," or having strong evidence for their effects on sex hormone function (antiandrogenic: lead, arsenic, butylbenzyl phthalate, dibutyl phthalate, dicyclohexyl phthalate; estrogenic: nonylphenol, bisphenol A). Nine agents were categorized as "Probable," or having probable evidence (antiandrogenic: bis(2-ethylhexyl)phthalate, nonylphenol, toluene, bisphenol A, diisononyl phthalate; androgenic: cadmium; estrogenic: copper, cadmium and; anti-estrogenic: lead). Two agents (arsenic, polychlorinated biphenyls) had opposing conclusions supporting both "probably" estrogenic and antiestrogenic effects. This synthesis will allow researchers to evaluate the health effects of selected EDCs with an added level of precision related to the mode of action.

Endogenous Progestogens and Colorectal Cancer Risk among Postmenopausal Women

BACKGROUND

The role of progestogens in colorectal cancer development is poorly characterized. To address this, our group developed a highly sensitive assay to measure concentrations of seven markers of endogenous progestogen metabolism among postmenopausal women.

METHODS

The markers were measured in baseline serum collected from postmenopausal women in a case-cohort study within the breast and bone follow-up to the fracture intervention trial (B∼FIT). We followed women not using exogenous hormones at baseline (1992-1993) for up to 12 years: 187 women with incident colorectal cancer diagnosed during follow-up and a subcohort of 495 women selected on strata of age and clinical center. We used adjusted Cox regression models with robust variance to estimate risk for colorectal cancer [hazard ratios (HR), 95% confidence intervals (CI)].

RESULTS

High concentrations of pregnenolone and progesterone were not associated with colorectal cancer [quintile(Q)5 versus Q1: pregnenolone HR, 0.71, 95% CI, 0.40-1.25; progesterone HR, 1.25; 95% CI, 0.71-2.22]. A trend of increasing risk was suggested, but statistically imprecise across quintiles of 17-hydroxypregnenolone (Q2 to Q5 HRs, 0.75-1.44; P _trend, 0.06).

CONCLUSIONS

We used sensitive and reliable assays to measure multiple circulating markers of progestogen metabolism. Progestogens were generally unassociated with colorectal cancer risk in postmenopausal women.

IMPACT

Our findings are consistent with most prior research on circulating endogenous sex hormones, which taken together suggest that sex hormones may not be major drivers of colorectal carcinogenesis in postmenopausal women.

Endogenous sex steroid hormones and colorectal cancer risk: a systematic review and meta-analysis

Preclinical data suggest that endogenous sex steroid hormones may be implicated in colorectal cancer (CRC) development, however, findings from epidemiological studies are conflicting. The aim of this systematic review and meta-analysis was to investigate the associations between endogenous concentrations of sex hormones and CRC risk. PubMed and Scopus were searched until June 2020 for prospective studies evaluating the association between pre-diagnostic plasma/serum concentrations of estradiol, testosterone and sex-hormone binding globulin (SHBG) and CRC risk. Summary relative risks (RRs) and 95% confidence intervals (CIs) were estimated using the inverse-variance weighted random-effects model based on the DerSimonian-Laird estimator. Eight studies were included in the meta-analysis after evaluating 3,859 non-duplicate records. Four of the eight studies had a nested case-control design, one study was a case-cohort and the rest three studies were cohort studies, and they included on average 295 cases (range:48-732) and 2,105 controls. No associations were found for endogenous sex steroid hormones in men or post-menopausal women with CRC risk, with evidence for substantial heterogeneity observed among women. Findings from this meta-analysis do not support presence of associations between pre-diagnostic concentrations of testosterone, estradiol and SHBG with incident CRC risk in men and post-menopausal women.

Circulating Sex Hormones Are Associated With Gastric and Colorectal Cancers but Not Esophageal Adenocarcinoma in the UK Biobank

INTRODUCTION

Gastrointestinal cancers show an unexplained male predominance, but few prospective studies have investigated sex hormones and gastrointestinal cancer risk. This study aimed to determine the impact of circulating sex hormones on risk of esophageal, gastric, and colorectal cancers in men and women.

METHODS

We included 219,425 men and 147,180 women from the UK Biobank. Sex hormones were quantified using chemiluminescent immunoassay. Gastrointestinal cancers were identified from cancer registry linkages. Sex hormone concentrations and risk of gastrointestinal cancers were investigated using Cox proportional hazards regression.

RESULTS

During the 10 years of follow-up, 376 esophageal adenocarcinoma, 108 esophageal squamous cell carcinoma, and 333 gastric and 2,868 colorectal cancer cases were identified. Increased hazard ratios (HRs) were found for sex hormone-binding globulin (SHBG) and risk of gastric cancer in men (Q4 vs Q1 HR 1.43, 95% confidence interval [CI] 0.95-2.17, Ptrend = 0.01). Free testosterone was inversely associated with esophageal squamous cell carcinoma in women (Q4 vs Q1 HR 0.32, 95% CI 0.11-0.98, Ptrend = 0.05). For colorectal cancer, SHBG was associated with a reduced risk among men (Q4 vs Q1 HR 0.89, 95% CI 0.77-1.03, Ptrend = 0.04) and free testosterone concentrations was associated with a reduction in risk among women (Q4 vs Q1 HR 0.80, 95% CI 0.66-0.97, Ptrend = 0.01). No associations were found for esophageal adenocarcinoma.

DISCUSSION

In this large prospective investigation of prediagnostic sex hormones and risk of gastrointestinal cancers, men with higher SHBG concentrations had higher gastric, yet lower colorectal, cancer risks, whereas women with higher free testosterone levels had a lower risk of esophageal squamous cell carcinoma and colorectal cancer.

Plasma sex hormones and risk of conventional and serrated precursors of colorectal cancer in postmenopausal women

BACKGROUND

Sex hormones have been suggested to play a role in colorectal cancer (CRC), but their influence on early initiation of CRC remains unknown.

METHODS

We retrospectively examined the associations with risk of CRC precursors, including conventional adenomas and serrated polyps, for plasma estrone, estradiol, free estradiol, testosterone, free testosterone, sex hormone-binding globulin (SHBG), and the ratio of estradiol to testosterone among 5404 postmenopausal women from the Nurses' Health Study I and II. Multivariable logistic regression was used to calculate the odds ratio (OR) and 95% confidence intervals (CI). Given multiple testing, P < 0.005 was considered statistically significant.

RESULTS

During 20 years of follow-up, we documented 535 conventional adenoma cases and 402 serrated polyp cases. Higher concentrations of SHBG were associated with lower risk of conventional adenomas, particularly advanced adenomas (multivariable OR comparing the highest to the lowest quartile, 0.40, 95% CI 0.24-0.67, P for trend < 0.0001). A nominally significant association was found for SHBG with lower risk of large serrated polyps (≥ 10 mm) (OR, 0.47, 95% CI 0.17-1.35, P for trend = 0.02) as well as free estradiol and free testosterone with higher risk of conventional adenomas (OR, 1.54, 95% CI 1.02-2.31, P for trend = 0.03 and OR, 1.33, 95% CI 0.99-1.78, P for trend = 0.03, respectively).

CONCLUSIONS

The findings suggest a potential role of sex hormones, particularly SHBG, in early colorectal carcinogenesis.

Serial endometrial thickness and risk of non-endometrial hormone-dependent cancers in postmenopausal women in UK Collaborative Trial of Ovarian Cancer Screening

OBJECTIVE

Estrogen is a well-established risk factor for various cancers. It causes endometrial proliferation, which is assessed routinely as endometrial thickness (ET) using transvaginal ultrasound (TVS). Only one previous study, restricted to endometrial and breast cancer, has considered ET and the risk of non-endometrial cancer. The aim of this study was to explore the association between baseline and serial ET measurements and nine non-endometrial hormone-sensitive cancers, in postmenopausal women, using contemporary statistical methodology that attempts to minimize the biases typical of endogenous serial data.

METHODS

This was a cohort study nested within the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS). In the ultrasound arm of UKCTOCS, 50639 postmenopausal women, aged 50-74, underwent annual TVS examination, of whom 38 105 had a valid ET measurement, no prior hysterectomy and complete covariate data, and were included in this study. All women were followed up through linkage to national cancer registries. The effect of ET on the risk of six estrogen-dependent cancers (breast, ovarian, colorectal, bladder, lung and pancreatic) was assessed using joint models for longitudinal biomarker and time-to-event data, and Cox models were used to assess the association between baseline ET measurement and these six cancers in addition to liver cancer, gastric cancer and non-Hodgkin's lymphoma (NHL). All models were adjusted for current hormone-replacement therapy (HRT) use, body mass index, age at last menstrual period, parity and oral contraceptive pill use.

RESULTS

The 38 105 included women had a combined total of 267 567 (median, 8; interquartile range, 5-9) valid ET measurements. During a combined total of 407 838 (median, 10.9) years of follow-up, 1398 breast, 351 endometrial, 381 lung, 495 colorectal, 222 ovarian, 94 pancreatic, 79 bladder, 62 gastric, 38 liver cancers and 52 NHLs were registered. Using joint models, a doubling of ET increased significantly the risk of breast (hazard ratio (HR), 1.21; 95% CI, 1.09-1.36; P = 0.001), ovarian (HR, 1.39; 95% CI, 1.06-1.82; P = 0.018) and lung (HR, 1.25; 95% CI, 1.02-1.54; P = 0.036) cancers. There were no statistically significant associations between ET and the remaining six cancers.

CONCLUSION

Postmenopausal women with high/increasing ET on TVS are at increased risk of breast, ovarian and lung cancer. It is important that clinicians are aware of these risks, as TVS is a common investigation. © 2019 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Endogenous sex hormones and colorectal cancer survival among men and women

Although previous studies have suggested a potential role of sex hormones in the etiology of colorectal cancer (CRC), no study has yet examined the associations between circulating sex hormones and survival among CRC patients. We prospectively assessed the associations of prediagnostic plasma concentrations of estrone, estradiol, free estradiol, testosterone, free testosterone and sex hormone-binding globulin (SHBG) with CRC-specific and overall mortality among 609 CRC patients (370 men and 239 postmenopausal women not taking hormone therapy at blood collection) from four U.S. cohorts. Multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazard regression. We identified 174 deaths (83 CRC-specific deaths) in men and 106 deaths (70 CRC-specific deaths) in women. In men, higher circulating level of free testosterone was associated with lower risk of overall (the highest vs. lowest tertiles, HR = 0.66, 95% CI, 0.45-0.99, p_trend = 0.04) and possibly CRC-specific mortality (HR = 0.73, 95% CI, 0.41-1.29, p_trend = 0.27). We generally observed nonsignificant inverse associations for other sex steroids, and a positive association for SHBG with CRC-specific mortality among male patients. In women, however, we found a suggestive positive association of estrone with overall (HR = 1.54, 95% CI, 0.92-2.60, p_trend = 0.11) and CRC-specific mortality (HR = 1.96, 95% CI, 1.01-3.84, p_trend = 0.06). Total estradiol, free estradiol and free testosterone were generally suggestively associated with higher risk of mortality among female patients, although not statistically significant. These findings implicated a potential role of endogenous sex hormones in CRC prognosis, which warrant further investigation.

Lifestyle and dietary environmental factors in colorectal cancer susceptibility

Colorectal cancer (CRC) incidence changes with time and by variations in diet and lifestyle, as evidenced historically by migrant studies and recently by extensive epidemiologic evidence. The worldwide heterogeneity in CRC incidence is strongly suggestive of etiological involvement of environmental exposures, particularly lifestyle and diet. It is established that physical inactivity, obesity and some dietary factors (red/processed meats, alcohol) are positively associated with CRC, while healthy lifestyle habits show inverse associations. Mechanistic evidence shows that lifestyle and dietary components that contribute to energy excess are linked with increased CRC via metabolic dysfunction, inflammation, oxidative stress, bacterial dysbiosis and breakdown of gut barrier integrity while the reverse is apparent for components associated with decreased risk. This chapter will review the available evidence on lifestyle and dietary factors in CRC etiology and their underlying mechanisms in CRC development. This short review will also touch upon available information on potential gene-environment interactions, molecular sub-types of CRC and anatomical sub-sites within the colorectum.

Circulating sex hormone levels and colorectal cancer risk in Japanese postmenopausal women: The JPHC nested case-control study

Previous epidemiological studies evaluated endogenous sex hormone levels and colorectal cancer (CRC) risk have yielded inconsistent results. Also, it is unknown if consumption of dietary isoflavones may influence the endogenous sex hormones and CRC relationships. We conducted a nested case-control study within the JPHC Study Cohort II wherein 11,644 women provided blood samples at the 5-year follow-up survey. We selected two matched controls for each case from the cohort (185 CRC cases and 361 controls). Multivariable conditional logistic regression was used to estimate odds ratios (ORs), 95% confidence intervals (CIs) for the association between circulating sex hormone levels and CRC risk. Comparing extreme tertiles, circulating testosterone levels were positively associated with CRC risk (OR = 2.10, 95% CI = 1.11-3.99, p for trend = 0.03). Levels of estradiol, SHBG, and progesterone were not associated with CRC risk. In a subgroup analysis by dietary isoflavone intake, SHBG levels were positively associated with CRC risk among those with low total isoflavone intake (p for trend = 0.03), with a statistically nonsignificant inverse association among those with high total isoflavone intake (p for trend = 0.22; p for interaction = 0.002). Endogenous levels of testosterone were positively associated with CRC among postmenopausal women. The association of endogenous SHBG with CRC development may be altered by the level of dietary isoflavone intake.

Estradiol reference intervals in women during the menstrual cycle, postmenopausal women and men using an LC-MS/MS method

BACKGROUND

For optimal medical decision-making, harmonized reference intervals for estradiol for different ages and both sexes are needed. Our aim was to establish reference intervals using a highly accurate and traceable LC-MS/MS method and to compare these with reference intervals in literature.

METHODS

Estradiol was measured in serum obtained daily during the menstrual cycle of 30 healthy premenopausal women and in serum of 64 men and 33 postmenopausal women. The accuracy of our LC-MS/MS method was demonstrated by a method comparison with the CDC reference method.

RESULTS

Our LC-MS/MS method was traceable to the reference method. Estradiol reference interval during the early follicular phase (days -15 to -6) was 31-771 pmol/L; during the late follicular phase (days -5 to -1) 104-1742 pmol/L; during the LH peak (day 0) 275-2864 pmol/L; during the early luteal phase (days +1 to +4) 95-1188 pmol/L; during mid luteal phase (days +5 to +9) 151-1941 pmol/L; during late luteal phase (days +10 to +14) 39-1769 pmol/L. The reference interval for men was 12-136 pmol/L and for postmenopausal women <26 pmol/L.

CONCLUSIONS

The established estradiol reference intervals can be used for all traceable LC-MS/MS methods for medical-decision making.

Obesity and the Risk of Gastrointestinal Cancers

Obesity is a risk factor for all major gastrointestinal cancers. With the rapid increase in the prevalence of obesity worldwide, this link could lead to an elevated burden of cancers of the digestive system. Currently, three main mechanisms explaining the link between excess adiposity and gastrointestinal cancer risk are being considered, including altered insulin signaling, obesity-associated chronic low-grade inflammation, and altered sex hormone metabolism, although new potential mechanisms emerge. This review is aimed to present our current knowledge on biological mechanisms involved in adiposity-related gastrointestinal carcinogenesis supported by results collected in epidemiological studies.

Reproductive factors, obesity and risk of colorectal cancer in a cohort of Asian women

BACKGROUND

This study evaluated reproductive factors and obesity in relation to colorectal cancer (CRC) in Asian women.

METHODS

The study cohort comprised 28191 women who were recruited between 1994 and 1997. During 18 years of prospective follow-up, 404 and 212 women developed colon cancer (CC) and rectal cancer (RC) respectively. Cox proportional hazards regression was used.

RESULTS

Menstrual factors were not related to the risk of CRC, CC and RC. Gravidity and parity were not associated with CRC or RC, but women who were ever pregnant had a HR of 1.87 (95%CI 1.12-3.14) compared to those never pregnant, and parous women had a HR of 1.79 (95% CI 1.10-2.92) compared to nulliparous women for CC. Use of oral contraceptives and hormone replacement therapy were not associated with CRC, CC or RC. Compared to women with normal BMI, women who were obese had HRs of 1.39 (95%CI 1.12-1.74) and 1.64 (95%CI 1.24-2.16) for CRC and CC respectively. No increased risk was seen for RC. Adjusted for BMI, for colonic cancer, women in the highest quartile for Waist Circumference had a HR of 2.14 (95%CI 1.42-3.25) compared to the lowest quartile, for Waist Hip Ratio, a HR of 1.74 (95%CI 1.30-2.34), and for Waist-Height ratio, a HR of 1.80 (1.26-2.57). None of these measures were significantly associated with RC.

CONCLUSIONS

Obesity is positively associated with CC but not RC, and abdominal obesity exerts an independent effect. Reproductive factors had at best a weak effect on CC and RC.

Type 2 diabetes and risk of colorectal cancer in two large U.S. prospective cohorts

Background

Previous studies have shown a positive association between type 2 diabetes (T2D) and colorectal cancer (CRC) risk. However, it is uncertain whether this association differs by duration of T2D or sex. We thus investigated the associations of T2D and its duration with the risk of incident CRC.

Methods

We followed 87,523 women from the Nurses’ Health Study (1980–2012) and 47,240 men from the Health Professionals Follow-up Study (1986–2012). Data on physician-diagnosed T2D was collected at baseline with a questionnaire and updated biennially. Cox regression models were used to estimate multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs).

Results

We documented 3000 CRC cases during up to 32 years of follow-up. Among men, T2D was associated with increased risk of CRC compared to those without T2D (HR: 1.42; 95% CI: 1.12–1.81). This positive association persisted in sensitivity analyses by excluding CRC identified within 1 year of diabetes diagnosis and patients with T2D who used hypoglycaemic medications. Among women, T2D was positively, but not statistically significantly, associated with CRC risk (HR: 1.17; 95% CI: 0.98–1.39).

Conclusions

Our findings support that T2D was associated with a moderately higher risk of developing CRC in men; a weaker, nonsignificant positive association was observed in women.

Adiposity and gastrointestinal cancers: epidemiology, mechanisms and future directions

Excess adiposity is a risk factor for several cancers of the gastrointestinal system, specifically oesophageal adenocarcinoma and colorectal, small intestine, pancreatic, liver, gallbladder and stomach cancers. With the increasing prevalence of obesity in nearly all regions of the world, this relationship could represent a growing source of cancers of the digestive system. Experimental and molecular epidemiological studies indicate important roles for alterations in insulin signalling, adipose tissue-derived inflammation and sex hormone pathways in mediating the association between adiposity and gastrointestinal cancer. The intestinal microbiome, gut hormones and non alcoholic fatty liver disease (NAFLD) also have possible roles. However, important gaps remain in our knowledge. For instance, our understanding of how adiposity throughout the life course is related to the risk of gastrointestinal cancer development and of how obesity influences gastrointestinal cancer prognosis and survival is limited. Nonetheless, the increasing use of state-of-the-art analytical methods (such as omics technologies, Mendelian randomization and MRI) in large-scale epidemiological studies offers exciting opportunities to advance our understanding of the complex relationship between adiposity and gastrointestinal cancers. Here, we examine the epidemiology of associations between obesity and gastrointestinal cancer, explore potential mechanisms underlying these relationships and highlight important unanswered research questions.

Mendelian randomisation study of age at menarche and age at menopause and the risk of colorectal cancer

Background

Substantial evidence supports an association between use of menopausal hormone therapy and decreased colorectal cancer (CRC) risk, indicating a role of exogenous sex hormones in CRC development. However, findings on endogenous oestrogen exposure and CRC are inconsistent.

Methods

We used a Mendelian randomisation approach to test for a causal effect of age at menarche and age at menopause as surrogates for endogenous oestrogen exposure on CRC risk. Weighted genetic risk scores based on 358 single-nucleotide polymorphisms associated with age at menarche and 51 single-nucleotide polymorphisms associated with age at menopause were used to estimate the association with CRC risk using logistic regression in 12,944 women diagnosed with CRC and 10,741 women without CRC from three consortia. Sensitivity analyses were conducted to address pleiotropy and possible confounding by body mass index.

Results

Genetic risk scores for age at menarche (odds ratio per year 0.98, 95% confidence interval: 0.95–1.02) and age at menopause (odds ratio 0.98, 95% confidence interval: 0.94–1.01) were not significantly associated with CRC risk. The sensitivity analyses yielded similar results.

Conclusions

Our study does not support a causal relationship between genetic risk scores for age at menarche and age at menopause and CRC risk.

Significance of intratissue estrogen concentration coupled with estrogen receptors levels in colorectal cancer prognosis

Dysregulation of estrogen related pathways is implicated colorectal cancer (CRC) development. However, significance of intratissue concentration of estrone (E1) and 17β-estradiol (E2) in relation to estrogen receptor (ESR) expression level was not addressed so far. Herein, we measured E1 and E2 intratissue concentration using liquid chromatography electrospray ionization tandem mass spectrometry (ESI LC/MS) and mRNA levels of ESR1 and ESR2 using RT-qPCR in cancerous and histopathologically unchanged tissue from 75 and 110 CRC patients, respectively. The obtained results were associated with clinicopathological factors, expression of estrogen dependent genes (CTNNB1, CCND1) and prognostic significance. We found no statistically significant differences in E1 or E2 concentration between cancerous tissue and histopathologically unchanged counterparts. Moreover, mRNA levels of ESR1 and ESR2 were significantly decreased in cancerous tissue compared with histopathologically unchanged (p=0.00001). Log rank analysis revealed no benefit of low E1 to E2 ratio, high E1, E2 concentration or ESR1, ESR2 mRNA level for patients’ overall (OS) and disease free survival (DFS). Interestingly, we have observed that patients with low ESR1 mRNA level coupled with low E1 intratissue concentration had a significant decrease in DFS compared with group of patients with high ESR1 mRNA level and high E1 concentration (HR=0.16, 95% CI 0.02-1.05; p=0.06). Furthermore, patients with low E1 concentration and low ESR1 transcript had significantly higher CTNNB1 and CCND1 mRNA level compare with subgroup with high level of both grouping factors. Our study indicates a potential value of estrogen intratissue concentration and its receptor expression level for CRC patients’ prognosis.

Estrogen Activation by Steroid Sulfatase Increases Colorectal Cancer Proliferation via GPER

CONTEXT

Estrogens affect the incidence and progression of colorectal cancer (CRC), although the precise molecular mechanisms remain ill-defined.

OBJECTIVE

The present study investigated prereceptor estrogen metabolism through steroid sulphatase (STS) and 17β-hydroxysteroid dehydrogenase activity and subsequent nongenomic estrogen signaling in human CRC tissue, in The Cancer Genome Atlas colon adenocarcinoma data set, and in in vitro and in vivo CRC models. We aimed to define and therapeutically target pathways through which estrogens alter CRC proliferation and progression.

DESIGN, SETTING, PATIENTS, AND INTERVENTIONS

Human CRC samples with normal tissue-matched controls were collected from postmenopausal female and age-matched male patients. Estrogen metabolism enzymes and nongenomic downstream signaling pathways were determined. CRC cell lines were transfected with STS and cultured for in vitro and in vivo analysis. Estrogen metabolism was determined using an ultra-performance liquid chromatography-tandem mass spectrometry method.

PRIMARY OUTCOME MEASURE

The proliferative effects of estrogen metabolism were evaluated using 5-bromo-2'-deoxyuridine assays and CRC mouse xenograft studies.

RESULTS

Human CRC exhibits dysregulated estrogen metabolism, favoring estradiol synthesis. The activity of STS, the fundamental enzyme that activates conjugated estrogens, is significantly (P < 0.001) elevated in human CRC compared with matched controls. STS overexpression accelerates CRC proliferation in in vitro and in vivo models, with STS inhibition an effective treatment. We defined a G-protein-coupled estrogen receptor (GPER) proproliferative pathway potentially through increased expression of connective tissue growth factor in CRC.

CONCLUSION

Human CRC favors estradiol synthesis to augment proliferation via GPER stimulation. Further research is required regarding whether estrogen replacement therapy should be used with caution in patients at high risk of developing CRC.

Effect of nonylphenol on the regulation of cell growth in colorectal cancer cells

Nonylphenol (NP) is a well-known endocrine-disrupting chemical (EDC), which can enhance the progression of cancer by functioning as an estrogen‑like factor. In the present study, the effects of different concentrations of NP on COLO205 colorectal cancer (CRC) cells were examined. The results of flow cytometric analysis revealed that NP significantly decreased the proportion of cells in the G0/G1 phase in a dose‑dependent manner, which was accompanied by a marginal increase in the proportions of cells in S and G2/M phases. NP did not induce apoptosis, whereas estradiol (E2) did induce apoptosis. To elucidate the mechanisms underlying the action of NP on COLO205 cells, the transcriptional levels of extracellular signal‑regulated kinase (ERK)1, ERK2 and phosphoinositide 3‑kinase (PI3K) were assessed using reverse transcription‑quantitative polymerase chain reaction analysis. The expressions levels of ERK1, ERK2 and PI3K were increased by treatment with NP in a dose‑dependent manner. On examining protein levels, the expression of PI3K p38 was increased by NP and E2, and the expression of ERK1/2 was increased by NP. The phosphorylation of the ERK protein was significantly increased by treatment with NP at a high concentration (10‑4 M; P<0.01), but significantly decreased by E2 (P<0.01). Two key proteins in the transforming growth factor (TGF)β pathway (c‑Fos and SnoN) were selected for analysis using western blot analysis in the COLO205 cells treated with NP and E2. The expression levels of c‑Fos and SnoN were significantly increased by treatment with E2 (10‑7 M; P<0.01) and NP (10‑7‑10‑4 M; P<0.01). Taken together, these results indicated that NP affected the development of CRC via the ERK signaling pathway and TGFβ pathway.

Reproductive and menstrual factors and colorectal cancer incidence in the Women's Health Initiative Observational Study

BACKGROUND

Reproductive and menstrual factors have been evaluated as surrogates for long-term hormonal exposures in several prospective studies of colorectal cancer, yet findings have been conflicting.

METHODS

The relation of reproductive and menstrual factors (self-reported via a reproductive history questionnaire) with incident colorectal cancer was investigated among women enrolled in the Women's Health Initiative Observational Study (WHI-OS), a longitudinal cohort of 93 676 postmenopausal women (aged 50-79 years at enrolment) in which 1149 incident cases of colorectal cancer occurred over a median follow-up of 11.9 years. Multivariable Cox proportional hazards models that included established colorectal cancer risk factors were constructed to examine the association of colorectal cancer incidence with reproductive and menstrual factors.

RESULTS

Having had two children (vs nulliparous: hazard ratio (HR)=0.80, 95% confidence interval (CI): 0.64-0.99) was inversely associated with colorectal cancer risk. Compared with never users, ever use of oral contraceptives was associated with lower colorectal cancer risk (HR=0.74, 95% CI: 0.63-0.86); however, no relationship was observed for duration of oral contraceptives use (4 years vs 1 year: HR=0.94, 95% CI: 0.67-1.32). None of the remaining reproductive and menstrual factors was associated with colorectal cancer incidence.

CONCLUSIONS

Parity and prior use of oral contraceptives were associated with lower colorectal cancer risk in this cohort of postmenopausal women.

Menopausal Hormone Therapy, Age, and Chronic Diseases: Perspectives on Statistical Trends

The release of the Women's Health Initiative (WHI) study in 2002 was a shock to the medical community. Hormone therapy (HT) had generally been considered to be highly beneficial for postmenopausal women since it was the gold standard for relief of menopausal symptoms (hot flashes, night sweats, vaginal atrophy) and it was thought to protect women from osteoporosis, heart disease, and cognitive decline and to generally improve quality of life. However, WHI showed a statistically significant increase in a number of disease states, including breast cancer, cardiovascular disease, and stroke. One problem with the WHI study was that the average age of women in the study was 63, which is considerably older than the age at which most women enter menopause (about 51). The timing hypothesis attempts to rationalize the effect of age on response to HT and risk of various diseases. The data suggests that younger women (50-60) may be protected from heart disease with only a slight increase in breast cancer risk. In contrast, older women (>65) are more susceptible to breast cancer and heart disease and should avoid HT. This Perspective on Statistical Trends evaluates the current data on HT and risk for chronic diseases as a function of age.

Risk of colorectal cancer with hysterectomy and oophorectomy: A systematic review and meta-analysis

BACKGROUND

Colorectal cancer (CRC) is the second most commonly diagnosed cancer worldwide in females. Sex hormones may play a protective effect in CRC pathogenesis. Ovarian sex steroid levels are reduced in premenopausal women after hysterectomy. Prospective studies have revealed an 80% decrease in serum oestradiol levels after bilateral oophorectomy in premenopausal women. We aimed to elucidate the relationship between hysterectomy or oophorectomy and risk of CRC.

METHODS

We estimated relative risk (RR) and 95% confidence intervals (95% CIs) with the meta-analysis. Cochran's Q test and Higgins I² statistic were used to check for heterogeneity. Subgroup and sensitivity analyses were performed as were Egger's and Begg's tests and the "trim-and-fill" method for publication bias analysis.

RESULTS

Risk of CRC was increased 30% for women undergoing oophorectomy relative to the general population and 24% with hysterectomy relative to no surgery. The risk was increased 22% with hysterectomy with bilateral salpingoo-ophorectomy as compared with simple hysterectomy. On subgroup analysis, risk of rectal cancer was increased 28% and colon cancer 19% with hysterectomy. Europeans seem to be sensitive to the risk of CRC, with 27% increased risk after hysterectomy. The risk of CRC after oophorectomy gradually increased with age at oophorectomy. The risk was greater with bilateral oophorectomy, with 36% increased risk, than unilateral oophorectomy, with 20% increased risk. Risk was increased 66% with time since oophorectomy 1-4 years as compared with 5-9 and ≥ 10 years.

CONCLUSIONS

Risk of CRC was increased for women undergoing hysterectomy or oophorectomy. Women with susceptibility genes for ovarian cancer or metrocarcinoma should choose oophorectomy or hysterectomy. For women not at high risk for these cancers, oophorectomy or hysterectomy should not be recommended for increasing the subsequent risk of CRC.

Prognostic impact of lymph node dissection is different for male and female colon cancer patients: a propensity score analysis in a multicenter retrospective study

PURPOSE

Colon cancers in male and female patients are suggested to be oncologically different. The aim of this study is to elucidate the prognostic impact of lymph node dissection (LND) in male and female colon cancer patients.

METHODS

A total of 5941 stage I-III colon cancer patients who were curatively operated on during the period from 1997 to 2007 were retrospectively studied. Cancer-specific survival (CSS) was individually compared between for male and female patients treated with D3, D2, and D1 LND. Background differences of the patients were matched using propensity scores.

RESULTS

D3, D2, and D1 LND were performed in 3756 (63 %), 1707 (29 %), and 478 (8 %), respectively, and more extensive LND was indicated for younger patients and more advanced disease. D2 LND was significantly associated with decreased cancer-specific mortality compared to D1 LND in male patients (HR 0.54, 95 % CI 0.32-0.89, p = 0.04), but not in female patients. D3 LND did not correlate to an improved prognosis compared to D2 LND both in male and female patients.

CONCLUSIONS

D2 LND was associated with an improved CSS in male, but not female colon cancer patients, compared to D1 LND. This suggested that colon cancer in male and female patients might be oncologically different, and that the prognostic impact of the extent of surgical intervention for colon cancer might therefore be different between sexes.

Progesterone receptor activation is required for folic acid-induced anti-proliferation in colorectal cancer cell lines

Previously, we demonstrated that folic acid (FA) could inhibit proliferation of colorectal cancer cell lines through activating the folate receptor (FR)α/cSrc/ERK1/2/NFκB/p53 pathway and anti-COLO-205 tumor growth in vivo. Since we recently also demonstrated that female sex hormones could affect the FA's action in regulating endothelial cell proliferation and migration, the aim of this study was to investigate the effect of progesterone (P4) on the FA-induced anti-proliferation in colorectal cancer cells. Treatment with FA significantly reduced the proliferation of the P4 receptor (PR)-positive colon cancer cell lines, COLO-205, HT-29 and LoVo, but did not significantly affect the proliferation of the PR-negative colon cancer cell lines, HCT116 and DLD-1. Pre-treatment with Org 31710, a PR specific antagonist, abolished the FA-induced proliferation inhibition and activation in the signaling pathway involved in regulating proliferation inhibition in these PR positive colorectal cancer cell lines. The involvement of PR in the FA-induced activation of cSrc and up-regulations in cell cycle inhibitory proteins (p21, p27 and p53) was confirmed by knock-down of PR expression using the siRNA technique. Importantly, we show direct protein interaction between FR and PR in COLO-205. Moreover, treatment with FA induced PR activation in COLO-205. Taken together, these data suggest that FA induced proliferation inhibition in colon cancer cells through activation of PR. This finding might explain some of the controversies of FA's effects on cancer growth and provide valuable reference for clinical applications of FA in treating colorectal cancer.

Inverse associations of dietary fiber and menopausal hormone therapy with colorectal cancer risk in the Multiethnic Cohort Study

In the Multiethnic Cohort Study, we previously reported that dietary fiber intake was inversely associated with colorectal cancer risk in men only. In women, the inverse relationship was weaker and appeared to be confounded by menopausal hormone therapy (MHT). We re-examined this observation with a greatly increased power. Using Cox proportional hazards models, we analyzed data from 187,674 participants with 4,692 cases identified during a mean follow-up period of 16 years. In multivariable-adjusted models, dietary fiber intake was inversely associated with colorectal cancer risk in both sexes: HR = 0.73, 95% CI: 0.61-0.89 for highest vs. lowest quintile, ptrend  = 0.0020 in men and HR = 0.76, 95% CI: 0.62-0.91, ptrend  = 0.0067 in women. Postmenopausal women who ever used MHT had a 19% lower risk of colorectal cancer (95% CI: 0.74-0.89) compared with MHT never users. In a joint analysis of dietary fiber and MHT, dietary fiber intake was associated with a lower colorectal cancer risk in MHT never users (HR = 0.75, 95% CI: 0.59-0.95, ptrend  = 0.045), but did not appear to further decrease the colorectal cancer risk of MHT ever users (ptrend  = 0.11). Our results support the overall protective roles of dietary fiber and MHT against colorectal cancer and suggest that dietary fiber may not lower risk further among women who ever used MHT. If confirmed, these results would suggest that MHT and dietary fiber may share overlapping mechanisms in protecting against colorectal cancer.

Risk of Colorectal Cancer After Ovarian Stimulation for In Vitro Fertilization

BACKGROUND & AIMS

Apart from lifestyle factors, sex hormones also seem to have a role in the etiology of colorectal cancer. This raises interest in the possible effects of fertility drugs, especially because the use of ovarian stimulation for in vitro fertilization (IVF) has strongly increased over the past decades.

METHODS

In 1996, a nationwide cohort study was set up to examine cancer risk in a population that included 19,158 women who received ovarian stimulation for IVF (IVF group) and 5950 women who underwent subfertility treatments other than IVF (non-IVF group). Cancer incidence was ascertained through linkage with the Netherlands Cancer Registry. Colorectal cancer risk in the IVF group was compared with those in the general population and in the non-IVF group.

RESULTS

After a median follow-up of 21 years, 109 colorectal cancers were observed. Compared with the general population, risk of colorectal cancer was not increased in the IVF group (standardized incidence ratio, 1.00; 95% confidence interval [CI], 0.80-1.23), and was significantly decreased in the non-IVF group (standardized incidence ratio, 0.58; 95% CI, 0.36-0.88). Women in the IVF group had a significant increase in risk compared with women in the non-IVF group (multivariable-adjusted hazard ratio, 1.80; 95% CI, 1.10-2.94). No trend emerged with more IVF cycles or more ampules of gonadotropins administered. Colorectal cancer risk did not increase with longer follow-up periods.

CONCLUSIONS

Although women who receive ovarian stimulation for IVF do not have an increased risk for colorectal cancer compared with the general population, findings from our nationwide cohort study indicate that their risk is increased compared with women who received subfertility treatments other than IVF. Further research is warranted to examine whether ovarian stimulation for IVF contributes to development of colorectal cancer.

Population-based analysis of colorectal cancer risk after oophorectomy

BACKGROUND

The development of colorectal cancer is influenced by hormonal factors. Oophorectomy alters endogenous levels of sex hormones, but the effect on colorectal cancer risk is unclear. The aim of this cohort study was to examine colorectal cancer risk after oophorectomy for benign indications.

METHODS

Women who had undergone oophorectomy between 1965 and 2011 were identified from the Swedish Patient Registry. Standard incidence ratios (SIRs) and 95 per cent confidence intervals for colorectal cancer risk were calculated compared with those in the general population. Stratification was carried out for unilateral and bilateral oophorectomy, and hysterectomy without specification of whether the ovaries were removed or not. Associations between the three oophorectomy options and colorectal cancer risk in different locations were assessed by means of hazard ratios (HRs) and 95 per cent confidence intervals calculated by Cox proportional hazards regression modelling.

RESULTS

Of 195 973 women who had undergone oophorectomy, 3150 (1·6 per cent) were diagnosed with colorectal cancer at a later date (median follow-up 18 years). Colorectal cancer risk was increased after oophorectomy compared with that in the general population (SIR 1·30, 95 per cent c.i. 1·26 to 1·35). The risk was lower for younger age at oophorectomy (15-39 years: SIR 1·10, 0·97 to 1·23; 40-49 years: SIR 1·26, 1·19 to 1·33; P for trend < 0·001). The risk was highest 1-4 years after oophorectomy (SIR 1·66, 1·51 to 1·81; P < 0·001). In the multivariable analysis, women who underwent bilateral oophorectomy had a higher risk of rectal cancer than those who had only unilateral oophorectomy (HR 2·28, 95 per cent c.i. 1·33 to 3·91).

CONCLUSION

Colorectal cancer risk is increased after oophorectomy for benign indications.

Increased risk of colorectal cancer in patients diagnosed with breast cancer in women

BACKGROUND

Epidemiological studies have shown a potential association between sex hormones and colorectal cancer. The risk of colorectal cancer in breast cancer patients who may have been exposed to increased levels of endogenous sex hormones and/or exogenous sex hormones (e.g. anti-hormonal therapy) has not been thoroughly evaluated.

METHODS

Using the National Swedish Cancer Register we established a population-based prospective cohort of breast cancer patients in women diagnosed in Sweden between 1961 and 2010. Subsequent colorectal cancers were identified from the same register. Standardized incidence ratios (SIRs) and 95% confidence intervals (95%CIs) were used to estimate the risk of colorectal cancer after a diagnosis of breast cancer. The association between breast cancer therapy and risk of colorectal cancer was evaluated in a subcohort of breast cancer patients treated in Stockholm between 1977 and 2007. Hazard ratios (HRs) and 95%CIs were estimated using Cox regression models.

RESULTS

In a cohort of 179,733 breast cancer patients in Sweden, 2571 incident cases of colorectal cancer (1008 adenocarcinomas in the proximal colon, 590 in the distal colon and 808 in the rectum) were identified during an average follow-up of 9.68 years. An increased risk of colorectal adenocarcinoma was observed in the breast cancer cohort compared with that in the general population (SIR=1.59, 95%CI: 1.53, 1.65). Adenocarcinoma in the proximal colon showed a non-significantly higher SIR (1.72, 95%CI: 1.61, 1.82) compared with the distal colon (1.46, 95%CI: 1.34, 1.58). In the subcohort of 20,171 breast cancers with available treatment data, 299 cases with colorectal cancers were identified. No treatment-dependent risk of colorectal cancer was observed among the breast cancer patients.

CONCLUSION

An increased risk of colorectal adenocarcinoma - especially in the proximal colon - was observed in the breast cancer cohort. Breast cancer treatment did not alter this risk.

A Prospective Evaluation of Endogenous Sex Hormone Levels and Colorectal Cancer Risk in Postmenopausal Women

BACKGROUND

Postmenopausal hormone therapy use has been associated with lower colorectal cancer risk in observational studies. However, the role of endogenous sex hormones in colorectal cancer development in postmenopausal women is uncertain.

METHODS

The relation of colorectal cancer risk with circulating levels of estradiol, estrone, free (bioactive) estradiol, progesterone and sex hormone-binding globulin (SHBG) was determined in a nested case-control study of 1203 postmenopausal women (401 case patients and 802 age and race/ethnicity-matched control patients) enrolled in the Women's Health Initiative Clinical Trial (WHI-CT) who were not assigned to the estrogen-alone or combined estrogen plus progestin intervention groups. We used multivariable-adjusted conditional logistic regression models that included established colorectal cancer risk factors. All statistical tests were two-sided.

RESULTS

Comparing extreme quartiles, estrone (odds ratio [OR]q4-q1 = 0.44, 95% confidence interval [CI] = 0.28 to 0.68, P trend = .001), free estradiol (ORq4-q1 = 0.43, 95% CI = 0.27 to 0.69, P trend ≤ .0001), and total estradiol (ORq4-q1 = 0.58, 95% CI = 0.38 to 0.90, P trend = .08) were inversely associated with colorectal cancer risk. SHBG levels were positively associated with colorectal cancer development (OR[q4-q1] = 2.30, 95% CI = 1.51 to 3.51, P trend ≤ .0001); this association strengthened after further adjustment for estradiol and estrone (ORq4-q1 = 2.50, 95% CI = 1.59 to 3.92, P trend < .0001). Progesterone was not associated with colorectal cancer risk.

CONCLUSION

Endogenous estrogen levels were inversely, and SHBG levels positively, associated with colorectal cancer risk, even after control for several colorectal cancer risk factors. These results suggest that endogenous estrogens may confer protection against colorectal tumorigenesis among postmenopausal women.

Estrogen and cancers of the colorectum, breast, and lung in postmenopausal women

As estrogens play an important role in maintaining physiological function in various organs, the estrogen decrease after menopause is thought to cause various diseases frequently observed in postmenopausal or elderly women. With the aging of society and a decrease in infectious or vascular diseases, neoplasms have now become the most frequent cause of death in Japan. Cancers of the colorectum, breast, and lung have been rapidly increasing both in incidence and death, especially among postmenopausal women. Interestingly, all three of these cancers are associated with estrogens. In premenopausal women, ovarian estrogens plays major roles in the female reproductive organs through the classic estrogen receptor, ER-α. In postmenopausal women, however, estrogens produced/activated by peripherally localized estrogen-metabolizing enzymes such as aromatase, which converts androgen into estrogens, are thought to play physiologically and pathobiologically important roles in various organs through second ER, namely ER-β, distributing systemically. In this article, the association of estrogens with these cancers in postmenopausal or elderly women are reviewed, especially focusing on the role of ER-β and peripheral estrogen metabolism. The possibility of prevention or treatment of these diseases through estrogenic control is also discussed.

Estrogen Metabolites Are Not Associated with Colorectal Cancer Risk in Postmenopausal Women

BACKGROUND

A potential protective role for estrogen in colon carcinogenesis has been suggested based on exogenous hormone use, but it is unclear from previous studies whether endogenous estrogens are related to colorectal cancer risk. These few prior studies focused on parent estrogens; none evaluated effects of estrogen metabolism in postmenopausal women.

METHODS

We followed 15,595 women (ages 55-80 years) enrolled in the Breast and Bone Follow-up to the Fracture Intervention Trial (B∼FIT) who donated blood between 1992 and 1993 for cancer through December 2004. A panel of 15 estrogen metabolites (EM), including estradiol and estrone, were measured in serum from 187 colorectal cancer cases and a subcohort of 501 women not using exogenous hormones at blood draw. We examined EM individually, grouped by pathway (hydroxylation at the C-2, C-4, or C-16 position) and by ratios of the groupings using Cox proportional hazards regression models.

RESULTS

No significant associations were seen for estrone (HRQ4 vs. Q1 = 1.15; 95% CI, 0.69-1.93; Ptrend = 0.54), estradiol (HRQ4 vs. Q1 = 0.98; 95% CI, 0.58-1.64; Ptrend > 0.99), or total EM (the sum of all EM; HRQ4 vs. Q1 = 1.35; 95% CI, 0.81-2.24; Ptrend = 0.33). Most metabolites in the 2-, 4-, or 16-pathway were unrelated to risk, although a borderline trend in risk was associated with high levels of 17-epiestriol.

CONCLUSION

Circulating estrogens and their metabolites were generally unrelated to colorectal cancer risk in postmenopausal women.

IMPACT

Additional studies are needed to understand how exogenous estrogen may prevent colorectal cancer.

Benefit of primary tumor resection in stage IV colorectal cancer with unresectable metastasis: a multicenter retrospective study using a propensity score analysis

PURPOSE

Retrospective studies have shown that primary tumor resection improves the prognosis of patients with colorectal cancer (CRC) with unresectable metastasis (mCRC). The aim of this study was to investigate the prognostic impact of primary tumor resection in various subgroups of mCRC patients.

METHODS

A total of 1982 patients with mCRC from January 1997 to December 2007 were retrospectively evaluated. The impact of primary tumor resection on cancer-specific survival (CSS) was analyzed using propensity score analysis to mitigate selection bias. Covariates in the models for propensity scores included treatment period, age, gender, tumor location, depth, lymph node metastasis, number of metastatic organs, and carcinoembryonic antigen (CEA) levels.

RESULTS

Among the whole patient population, primary tumor resection significantly improved CSS [hazard ratio (HR) 0.46, 95% confidence interval (CI) 0.32-0.66, p < 0.01]. However, primary tumor resection did not significantly improve CSS in the following subgroups: patients treated in the first 5 years of the study (HR 0.56, 95% CI 0.28-1.13, p = 0.08), patients aged >65 years (HR 0.72, 95% CI 0.36-1.42, p = 0.31), female patients (HR 0.60, 95% CI 0.31-1.17, p = 0.13), patients with right-sided colon cancer (HR 0.68, 95% CI 0.39-1.20, p = 0.17), and patients without nodal involvement (HR 0.54, 95% CI 0.25-1.17, p = 0.09).

CONCLUSIONS

Our study suggests that primary tumor resection improves the survival of patients with mCRC. However, the prognostic benefit is different among patient subpopulations.

Evaluating estradiol levels in male patients with colorectal carcinoma

BACKGROUND

Globally more than 1 million people suffer from colorectal cancer (CRC) per annum, resulting in about 0.5 million deaths. The role of estrogen in CRC is being researched with great interest; expression of estrogen receptors (alfa and beta) is being explored.

AIMS AND OBJECTIVE

Our objective was to compare the serum estradiol levels in diagnosed male patients of CRC, with age-matched controls; and to study the estradiol levels across the different stages of CRC.

SETTING AND DESIGN

A cross-sectional study was conducted from January, 2012 to March, 2013 at a tertiary care hospital in north India.

MATERIALS AND METHODS

Fifty one male preoperative CRC patients were enrolled along with 50 age-matched male controls. Ethical approval and informed written consent from each participant were duly obtained. CRC patients were staged as per TNM (T- Tumour, N- Node, M- Metastasis; I, II, III and IV) criteria. Serum estradiol level was measured by Chemiimmunofluroscence method (normal = 11.6 - 41.2 pg/ml).

STATISTICAL ANALYSIS USED

We used student's t test and ANOVA (analysis of variance) to analyse the data (SPSS version 17.0, SPSS, Inc., Chicago, Illinois) Result: The mean serum estradiol level among CRC patients (43.4, sd=27.1) was significantly more than that among controls (mean=24.7, sd=17.5), (p<0.0001). Across the four TNM stages of CRC patients, mean estradiol level was highest in Stage II (55.9, sd=15.5); followed by Stages III (44.1, sd=24.9), IV (36.3, sd=30.0) and I (26.4, sd=38.8). However, significant difference was obtained only between Stages I and II.

CONCLUSION

Our study revealed increased levels of serum estradiol in Indian male CRC patients. Further research is warranted to corroborate this finding, and to understand the role of estradiol across different TNM stages of CRC.

Analgesic use and patterns of estrogen metabolism in premenopausal women

Analgesic use has been hypothesized to reduce the risk of some cancers, with inverse associations between analgesics and colon cancer, and suggestive inverse associations for breast cancer. Estrogen metabolites (EM) have genotoxic and estrogenic potential; genotoxicity may differ by hydroxylation pathway. Analgesic use may impact patterns of estrogen metabolism; effects of analgesics on disease risk could be mediated through these patterns. We conducted a cross-sectional study among 603 premenopausal women in the Nurses' Health Study II. Frequency of aspirin, non-aspirin nonsteroidal anti-inflammatory drugs (NSAIDs), and acetaminophen use was reported via questionnaire; average frequency in 1997 and 1999 was calculated. Women provided urine samples between 1996 and 1999, collected during the mid-luteal phase of the menstrual cycle. Urinary EM were quantified using high-performance liquid chromatography-tandem mass spectrometry. We observed no association between analgesic use and estradiol, estrone, or specific pathways of estrogen metabolism. Women reporting more frequent aspirin use had lower methylated 2-catechols (e.g., 2-hydroxyestrone-3-methyl ether, 2+ days/week vs. non-use: 0.95 vs. 1.21 pmol/mg creatinine; p difference = 0.01, p trend = 0.07). Non-aspirin NSAID use was positively associated with 17-epiestriol (4+ days/week vs. non-use: 2.48 vs. 1.52 pmol/mg creatinine; p difference = 0.01, p trend = 0.11). Acetaminophen use was positively associated with total EM (2+ days/week vs. non-use: 236 vs. 198 pmol/mg creatinine; p difference = 0.02, p trend = 0.11), 2-hydroxyestrone-3-methyl ether (1.6 vs. 1.1 pmol/mg creatinine; p difference < 0.01, p trend = 0.02), and 16α-hydroxyestrone (17 vs. 12 pmol/mg creatinine; p difference = 0.01, p trend = 0.05). This study provides the first assessment of analgesic use and patterns of estrogen metabolism in women. While we observed some associations between analgesics and individual EM, no clear patterns emerged.

Raloxifene and antiestrogenic gonadorelin inhibits intestinal tumorigenesis by modulating immune cells and decreasing stem-like cells

Studies suggest that estrogen plays a contributing role in colorectal cancer. This project examined the preventive effects of raloxifene, a selective estrogen receptor modulator (SERM), and gonadorelin, an antiestrogenic drug, in female Apc(Min/+) mouse intestinal tumorigenesis. Six-week-old Apc(Min/+)mice were fed diet containing 1 ppm raloxifene or control diet. Gonadorelin (150 ng/mouse) was injected subcutaneously into one treatment group. Intestinal tumors were evaluated for tumor multiplicity and size. Mice treated with raloxifene and gonadorelin showed colon tumor inhibition of 80% and 75%, respectively. Both drugs significantly inhibited small intestinal tumor multiplicity and size (75%-65%, P < 0.0001). Raloxifene and gonadorelin showed significant tumor inhibition with 98% and 94% inhibition of polyps >2 mm in size. In mice fed with raloxifene or injected with gonadorelin, tumors showed significantly reduced proliferating cell nuclear antigen expression (58%-65%, P < 0.0001). Raloxifene treatment decreased β-catenin, cyclin D1, laminin 1β, Ccl6, and stem-like cells (Lgr 5, EpCAM, CD44/CD24), as well as suppressed inflammatory genes (COX-2, mPGES-1, 5-LOX,). Gonadorelin showed significant decrease in COX-2, mPGES-1, iNOS, and stem-like cells or increased NK cells and chemokines required for NK cells. Both drugs were effective in suppressing tumor growth albeit with different mechanisms. These observations show that either suppression of estrogen levels or modulation of estrogen receptor dramatically suppresses small intestinal and colonic tumor formation in female Apc(Min/+) mice. These results support the concept of chemoprevention by these agents in reducing endogenous levels of estrogen or modulating ER signaling.

Chemopreventive efficacy of raloxifene, bexarotene, and their combination on the progression of chemically induced colon adenomas to adenocarcinomas in rats

Estrogen receptor (ER)-β signaling is associated positively in colon tumor progression, whereas downregulation or loss of function of retinoid X receptor (RXR)-α occurs in colon tumors. The chemopreventive efficacies of the estrogen antagonist raloxifene and the selective RXR agonist bexarotene were tested individually and in combination, during promotion and progression stages of colon tumorigenesis. Colon tumors were induced in male F344 rats with azoxymethane and at early adenoma stage, groups of rats (36 or 45 per group) were fed diets containing raloxifene (1.5 or 3 ppm), bexarotene (50 or 100 ppm), or their low-dose combinations for 40 weeks. Raloxifene or bexarotene alone significantly suppressed colon adenocarcinoma formation in terms of multiplicities (mean ± SE): control, 3.59 ± 0.25; 1.5 ppm raloxifene, 2.51 ± 0.29 (P < 0.004); 3 ppm raloxifene, 2.14 ± 0.28 (P < 0.0001); 50 ppm bexarotene, 2.25 ± 0.32 (P < 0.001); 100 ppm bexarotene, 2.1 ± 0.27 (P < 0.0001); and 1.5 ppm raloxifene + 50 ppm bexarotene, 1.57 ± 0.21 (P < 0.0001). The low-dose combination caused significant (56%) inhibition of adenocarcinomas as compared with control diet fed rats. Tumors exposed to raloxifene, bexarotene and/or the combination showed significant suppression of proliferating cell nuclear antigen, cyclin D1, and β-catenin with an increased apoptotic cells (3-fold) and p21 expression (3.8-fold) as compared tumors of rats fed control diet. The combination of low doses of raloxifene and bexarotene significantly suppressed the progression of colonic adenomas to adenocarcinomas and may be useful for colon cancer prevention and/or treatment in high-risk individuals.

Increased risk of colon cancer in men in the pre-diabetes phase

BACKGROUND

Historically, studies exploring the association between type 2 diabetes mellitus (DM) and cancer lack accurate definition of date of DM onset, limiting temporal analyses. We examined the temporal relationship between colon cancer risk and DM using an electronic algorithm and clinical, administrative, and laboratory data to pinpoint date of DM onset.

METHODS

Subjects diagnosed with DM (N = 11,236) between January 1, 1995 and December 31, 2009 were identified and matched at a 5∶1 ratio with 54 365 non-diabetic subjects by age, gender, smoking history, residence, and diagnosis reference date. Colon cancer incidence relative to the reference date was used to develop Cox regression models adjusted for matching variables, body mass index, insurance status, and comorbidities. Primary outcomes measures included hazard ratio (HR) and number needed to be exposed for one additional person to be harmed (NNEH).

RESULTS

The adjusted HR for colon cancer in men before DM onset was 1.28 (95% CI 1.04-1.58, P = 0.0223) and the NNEH decreased with time, reaching 263 at DM onset. No such difference was observed in women. After DM onset, DM did not appear to alter colon cancer risk in either gender.

CONCLUSIONS

Colon cancer risk is increased in diabetic men, but not women, before DM onset. DM did not alter colon cancer risk in men or women after clinical onset. In pre-diabetic men, colon cancer risk increased as time to DM onset decreased, suggesting that the effects of the pre-diabetes phase on colon cancer risk in men are cumulative.

Oestrogen and colorectal cancer: mechanisms and controversies

AIM

The role of oestrogen metabolism and action in colorectal cancer (CRC) is controversial. An extensive review of the current literature, encompassing epidemiological evidence, systemic and peripheral oestrogen concentrations, 17β-hydroxysteroid dehydrogenase (17β-HSD) and aromatase in CRC, steroid sulphatase (STS)/oestrone sulphotransferase (EST) and in vitro and in vivo genomic effects was therefore undertaken.

METHODS

A literature search (key words: colorectal cancer, oestrogen, oestrogen receptor, 17β-HSD, STS, organic anion transporter) was performed using Embase, Medline, and Pubmed and papers were evaluated on scientific relevance on an individual basis.

RESULTS

Epidemiological data highlights that premenopausal women, or postmenopausal women taking hormone replacement therapy, are significantly less likely than males to develop CRC. This implies that oestrogen signalling is most likely involved in CRC physiology and aetiology. Little is known about oestrogen metabolism in the colon. However, the expression of 17β-HSD, STS, and EST, enzymes involved in oestrogen metabolism, have shown prognostic significance. Evidence also suggests that protective effects are modulated through oestrogen receptor beta, although which metabolite of oestrogen, oestradiol (E2) or oestrone (E1), is more active remains undefined. To complicate matters, the changes in the peripheral ratios of these enzymes, oestrogens and receptors most likely influences CRC progression.

CONCLUSION

Epidemiological evidence, now supported by in vitro and in vivo studies, strongly associates oestrogen action and metabolism with CRC. Initially protective against CRC, once developed, results suggests that oestrogens increase proliferation. Consequently, hormone-ablation therapy, already successful against breast and prostate cancer, may be effective against CRC.

Colorectal cancer risk associated with hormone use varies by expression of estrogen receptor-β

The risk of colorectal cancer is reduced among users of oral contraceptives or menopausal hormone therapy, but associations with reproductive characteristics that are markers of a woman's endogenous hormone milieu have not been consistently observed. To help understand possible mechanisms through which exogenous and endogenous hormonal exposures are involved in colorectal cancer, we assessed the risk of these malignancies according to tumor expression of estrogen receptor-β (ESR2). In a population-based study of postmenopausal women (503 cases and 721 controls matched for sex and age), immunohistochemical expression of ESR2 was determined in 445 cases of incident colorectal cancer. Unconditional logistic regression was used in case-case analyses to assess heterogeneity between risk associations according to ESR2 status and in case-control analyses to estimate associations separately for ESR2-negative and ESR2-positive tumors. For ESR2-positive tumors but not ESR2-negative tumors, colorectal cancer risk significantly decreased with duration of oral contraceptive use [per five-year increments OR ESR2-positive, 0.87, 95% confidence interval (CI), 0.77-0.99; OR ESR2-negative, 1.02, 95% CI, 0.91-1.15; Pheterogeneity = 0.07] and with duration of menopausal hormone therapy use (per five-year increments OR ESR2-positive, 0.84, 95% CI, 0.74-0.95; OR ESR2-negative, 0.94, 95% CI 0.84-1.05; Pheterogeneity = 0.06). Significant heterogeneity according to ESR2 expression was found for the association with current use of menopausal hormone therapy (<0.5 years ago; Pheterogeneity = 0.023) but not for associations with reproductive factors. In conclusion, our results suggest that hormone use decreases risk for ESR2-positive but not ESR2-negative colorectal cancer.

Association between sex hormones and colorectal cancer risk in men and women

BACKGROUND & AIMS

There is observational and clinical evidence that indicates that sex hormones affect development of colorectal cancer in men and women. However, the relationship between endogenous sex hormone levels and colorectal cancer is unclear.

METHODS

We collected data on lifestyle, medical history, and diet (through 2008), along with blood samples, from the Nurses' Health Study, the Women's Health Study, the Health Professional Follow-up Study, and the Physicians' Health Study II. We measured plasma levels of estrone, estradiol, testosterone, sex hormone binding globulin (SHBG), and C-peptide among 730 women (293 cases of colorectal cancer and 437 healthy individuals as controls) and 1158 men (439 colorectal cancer cases and 719 controls) and used unconditional logistic regression to estimate relative risks (RRs) and 95% confidence intervals. All statistical tests were 2-sided.

RESULTS

Total testosterone, SHBG, and the ratio of estradiol to testosterone were associated with colorectal cancer in men after adjustments for matching and risk factors for colorectal cancer, including body mass index and plasma levels of C-peptide. The RRs in the highest relative to the lowest quartile were 0.62 for testosterone (95% confidence interval, 0.40-0.96), 0.65 for SHBG (95% confidence interval, 0.42-0.99), and 2.63 for the ratio (95% confidence interval, 1.58-4.36) (P values for trend ≤ .02). However, in women, only the ratio of estradiol to testosterone was (inversely) associated with colorectal cancer after adjustments for all factors (RR, 0.43; 95% confidence interval, 0.22-0.84; P value for trend = .03).

CONCLUSIONS

On the basis of combined data from 4 population studies, there appears to be an association between levels of sex hormones and colorectal cancer risk in men. There also appears to be an inverse association between the ratio of estradiol to testosterone and colorectal cancer in postmenopausal women.

Influence of Obesity and Related Metabolic Alterations on Colorectal Cancer Risk

Obesity and related metabolic alterations have been implicated to play a role in colorectal cancer risk. The metabolic syndrome, as assessed according to current international definitions by the key components, abdominal obesity, dyslipidemia, elevated blood pressure, and abnormal glucose metabolism, is associated with colorectal cancer. Recent studies suggest that abdominal obesity and abnormal glucose metabolism may primarily account for this association. Visceral adipose tissue is physiologically more active than subcutaneous adipose tissue and generates hormones and cytokines with inflammatory, metabolic, and direct carcinogenic potential, which may directly or indirectly increase colorectal cancer risk. Current evidence suggests that obesity acts as a risk factor for colorectal cancer by several mechanisms, including chronic low-grade inflammation, hyperinsulinemia, as well as alterations in insulin-like growth factor and adipokine concentrations. Metabolic biomarkers reflecting these processes may not only provide clues for etiological understanding of colorectal carcinogenesis but also might be an alternative way to define an "obesity phenotype" that is relevant for colorectal cancer development.

Gender, anthropometric factors and risk of colorectal cancer with particular reference to tumour location and TNM stage: a cohort study

Background

It remains unclear whether the increased risk of colorectal cancer (CRC) associated with obesity differs by gender, distribution of fat, tumour location and clinical (TNM) stage. The primary aim of this study was to examine these associations in 584 incident colorectal cancer cases from a Swedish prospective population-based cohort including 28098 men and women.

Methods

Seven anthropometric factors; height, weight, bodyfat percentage, hip circumference, waist circumference, BMI and waist-hip ratio (WHR) were categorized into quartiles of baseline anthropometric measurements. Relative risks of CRC, total risk as well as risk of different TNM stages, and risk of tumours located to the colon or rectum, were calculated for all cases, women and men, respectively, using multivariate Cox regression models.

Results

Obesity, as defined by all anthropometric variables, was significantly associated with an overall increased risk of CRC in both women and men. While none of the anthropometric measures was significantly associated with risk of tumour (T)-stage 1 and 2 tumours, all anthropometric variables were significantly associated with an increased risk of T-stage 3 and 4, in particular in men. In men, increasing quartiles of weight, hip, waist, BMI and WHR were significantly associated with an increased risk of lymph node positive (N1 and N2) disease, and risk of both non-metastatic (M0) and metastatic (M1) disease. In women, there were no or weak associations between obesity and risk of node-positive disease, but statistically significant associations between increased weight, bodyfat percentage, hip, BMI and M0 disease. Interestingly, there was an increased risk of colon but not rectal cancer in men, and rectal but not colon cancer in women, by increased measures of weight, hip-, waist circumference and bodyfat percentage.

Conclusions

This study is the first to show a relationship between obesity, measured as several different anthropometric factors, and an increased risk of colorectal cancer of more advanced clinical stage, in particular in men. These findings suggest that risk of CRC differs according to the method of characterising obesity, and also according to gender, location, and tumour stage.