Postmenopausal hormone use and risk of large-bowel cancer

Association of Radiation and Procarbazine Dose With Risk of Colorectal Cancer Among Survivors of Hodgkin Lymphoma

Importance

Hodgkin lymphoma (HL) survivors have higher rates of colorectal cancer, which may be associated with subdiaphragmatic radiation therapy and/or alkylating chemotherapy. Although radiation dose-response associations with breast, lung, stomach, pancreatic, and esophageal cancer after HL have been demonstrated, the association of radiation therapy with colorectal cancer remains unclear.

Objective

To quantify the rate of colorectal cancer according to radiation dose to the large bowel and procarbazine dose among HL survivors.

Design, Setting, and Participants

A nested case-control study examined 5-year HL survivors at 5 hospital centers in the Netherlands. Participants had been diagnosed with HL in 1964 to 2000, when they were 15 to 50 years of age, and were followed for a median of approximately 26 years. Survivors of HL who developed colorectal cancer and survivors who were selected as controls were individually matched on sex, age at HL diagnosis, and date of HL diagnosis. Data were analyzed from July 2021 to October 2022.

Exposures

Mean radiation doses to the large bowel were estimated by reconstructing individual radiation therapy treatments on representative computed tomography data sets.

Main Outcomes and Measures

Excess rate ratios (ERRs) were modeled to evaluate the excess risk associated with each 1-gray increase in radiation dose, and potential effect modification by procarbazine was explored.

Results

The study population included 316 participants (mean [SD] age at HL diagnosis, 33.0 [9.8] years; 221 [69.9%] men), 78 of whom were HL survivors who developed colorectal cancer (cases) and 238 who did not (controls). The median (IQR) interval between HL and colorectal cancer was 25.7 (18.2-31.6) years. Increased colorectal cancer rates were seen for patients who received subdiaphragmatic radiation therapy (rate ratio [RR], 2.4; 95% CI, 1.4-4.1) and those who received more than 8.4 g/m2 procarbazine (RR, 2.5; 95% CI, 1.3-5.0). Overall, colorectal cancer rate increased linearly with mean radiation dose to the whole large bowel and dose to the affected bowel segment. The association between radiation dose and colorectal cancer rate became stronger with increasing procarbazine dose: the ERR per gray to the whole bowel was 3.5% (95% CI, 0.4%-12.6%) for patients who did not receive procarbazine, and increased 1.2-fold (95% CI, 1.1-1.3) for each 1-g/m2 increase in procarbazine dose.

Conclusions and Relevance

This nested case-control study of 5-year HL survivors found a dose-response association between radiation therapy and colorectal cancer risk, and modification of this association by procarbazine. These findings may enable individualized colorectal cancer risk estimations, identification of high-risk survivors for subsequent screening, and optimization of treatment strategies.

Hormone Replacement Therapy After Breast Cancer: It Is Time

ABSTRACT

This article reviews the decades of evidence supporting the reproducible benefits of HRT for menopausal symptom control, improved cardiac health, prevention of hip fracture, reduction in the risk and pace of cognitive decline, and enhanced longevity. It quantifies the increased risk of thromboembolism associated with oral, though not transdermal, HRT. It evaluates the repeated claims that HRT is associated with an increased risk of breast cancer development, and, when administered to breast cancer survivors, an increased risk of breast cancer recurrence. Twenty-five studies of HRT after a breast cancer diagnosis, published between 1980 and 2013, are discussed, as are the 20 reviews of those studies published between 1994 and 2021. Only 1 of the 25 studies, the HABITS trial, demonstrated an increased risk of recurrence, which was limited to local or contralateral, and not distant, recurrence. None of the studies, including HABITS, reported increased breast cancer mortality associated with HRT. Even in the HABITS trial, the absolute increase in the number of women who had a recurrence (localized only) associated with HRT administration was 22. It is on the basis of these 22 patients that HRT, with its demonstrated benefits for so many aspects of women's health, is being denied to millions of breast cancer survivors around the world.

Risk of de novo cancer after premenopausal bilateral oophorectomy

BACKGROUND

Hysterectomy is one of the most frequent gynecologic surgeries in the United States. Women undergoing hysterectomy are commonly offered bilateral oophorectomy for ovarian and breast cancer prevention. Although bilateral oophorectomy may dramatically reduce the risk of gynecologic cancers, some studies suggested that bilateral oophorectomy may be associated with an increased risk of other types of cancer, such as lung cancer and colorectal cancer. However, the results are conflicting.

OBJECTIVE

To study the association between bilateral oophorectomy and the risk of subsequent cancer of any type.

STUDY DESIGN

This population-based cohort study included all premenopausal women who underwent bilateral oophorectomy for a nonmalignant indication before the age of 50, between January 1, 1988 and December 31, 2007 in Olmsted County, Minnesota, and a random sample of age-matched (±1 year) referent women who did not undergo bilateral oophorectomy. Women with cancer before oophorectomy (or index date) or within 6 months after the index date were excluded. Time-to-event analyses were performed to assess the risk of de novo cancer. Cancer diagnosis and type were confirmed using medical record review.

RESULTS

Over a median follow-up of 18 years, the risk of any cancer did not significantly differ between the 1562 women who underwent bilateral oophorectomy before natural menopause and the 1610 referent women (adjusted hazard ratio, 0.82; 95% confidence interval, 0.66-1.03). However, women who underwent bilateral oophorectomy had a decreased risk of gynecologic cancers (adjusted hazard ratio, 0.15; 95% confidence interval, 0.06-0.34) but not of nongynecologic cancers (adjusted hazard ratio, 0.99; 95% confidence interval, 0.78-1.26). In particular, the risk of breast cancer, gastrointestinal cancer, and lung cancer did not differ between these 2 cohorts. Use of estrogen therapy through the age of 50 years in women who underwent bilateral oophorectomy did not modify the results.

CONCLUSION

Women who underwent bilateral oophorectomy before menopause have a reduced risk of gynecologic cancer but not of other types of cancer including breast cancer. Women at average risk of ovarian cancer should not consider bilateral oophorectomy for the prevention of breast cancer or other nongynecologic cancers.

Hormone replacement therapy in relation to the risk of colorectal cancer in women by BMI: a multicentre study with propensity score matching

BACKGROUND

Epidemiological evidence about hormone replacement therapy and colorectal carcinogenesis by demographic and clinical traits remains unclear. We aimed to assess this postulated association in a large multicentre study and further explore the modification effect by BMI and others.

METHODS

We retrospectively collected records of women diagnosed with colorectal cancer (CRC) at the age of 50 years and older during 2014-2017 and their HRT dispensing prior to CRC diagnosis in three tertiary hospitals in China. CRC cases were matched with controls at a ratio of 1:3 using nearest neighbour propensity scores matching to better control for the remaining imbalance between groups, which generated a total of 824 cases with 2472 controls.

RESULTS

Our study confirmed the inversed association between colorectal cancer risk and hormone replacement therapy (OR, 0.62; 95% CI, 0.54-0.75), which was more prominent among women having multiple HRT dispenses (OR, 0.60; 95% CI, 0.52-0.76). Furthermore, significant associations were consistently observed for the short-term (OR, 0.69; 95% CI, 0.57-0.88), middle-term (OR, 0.51; 95% CI, 0.41-0.66), and long-term HRT users (OR, 0.70; 95% CI, 0.43-0.90). Estrogen-related regimen reduced CRC risk more than progestogen-only. We, for the first time, found that the modifying effect of BMI on HRT use and CRC risk was in different ways when BMI was categorized by a medium level of 27.

CONCLUSION

Our findings mainly suggest that there might be a different mechanism for the reversed association between HRT and colorectal tumorigenesis by BMI level, providing thoughts on clinical treatment of CRC.

Steroid Sulphatase and Its Inhibitors: Past, Present, and Future

Steroid sulphatase (STS), involved in the hydrolysis of steroid sulphates, plays an important role in the formation of both active oestrogens and androgens. Since these steroids significantly impact the proliferation of both oestrogen- and androgen-dependent cancers, many research groups over the past 30 years have designed and developed STS inhibitors. One of the main contributors to this field has been Prof. Barry Potter, previously at the University of Bath and now at the University of Oxford. Upon Prof. Potter’s imminent retirement, this review takes a look back at the work on STS inhibitors and their contribution to our understanding of sulphate biology and as potential therapeutic agents in hormone-dependent disease. A number of potent STS inhibitors have now been developed, one of which, Irosustat (STX64, 667Coumate, BN83495), remains the only one to have completed phase I/II clinical trials against numerous indications (breast, prostate, endometrial). These studies have provided new insights into the origins of androgens and oestrogens in women and men. In addition to the therapeutic role of STS inhibition in breast and prostate cancer, there is now good evidence to suggest they may also provide benefits in patients with colorectal and ovarian cancer, and in treating endometriosis. To explore the potential of STS inhibitors further, a number of second- and third-generation inhibitors have been developed, together with single molecules that possess aromatase–STS inhibitory properties. The further development of potent STS inhibitors will allow their potential therapeutic value to be explored in a variety of hormone-dependent cancers and possibly other non-oncological conditions.

Hormone Replacement Therapy and Colorectal Cancer Incidence and Mortality in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial

INTRODUCTION

Hormone replacement therapy has been shown to reduce colorectal cancer incidence, but its effect on colorectal cancer mortality is controversial. The objective of this study was to determine the effect of hormone replacement therapy on survival from colorectal cancer.

PATIENTS AND METHODS

We performed a secondary analysis of data from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, a large multicenter randomized trial run from 1993 to 2001, with follow-up data recently becoming mature. Participants were women aged 55 to 74 years, without recent colonoscopy. Data from the trial were analyzed to evaluate colorectal cancer incidence, disease-specific mortality, and all-cause mortality based on subjects' use of hormone replacement therapy at the time of randomization: never, current, or former users.

RESULTS

A total of 75,587 women with 912 (1.21%) incident colorectal cancers and 239 associated deaths were analyzed, with median follow-up of 11.9 years. Overall, 88.6% were non-Hispanic white, and < 10% had not completed high school. The never-user group was slightly older than the current or former user groups (average, 63.8 vs. 61.4 vs. 63.3 years; P < .001). Almost one-half (47.1%) of the current users had undergone hysterectomy, compared with 21.6% of never-users and 34.0% of former users (P < .001). Adjusted colorectal cancer incidence in current users compared to never-users was lower (hazard ratio [HR], 0.81; 95% confidence interval [CI], 0.69-0.94; P = .005), as was death from colorectal cancer (HR, 0.63; 95% CI, 0.47-0.85; P = .002) and all-cause mortality (HR, 0.76; 95% CI, 0.72-0.80; P < .001).

CONCLUSIONS

Hormone replacement therapy is associated with a reduced risk of colorectal cancer incidence and improved colorectal cancer-specific survival, as well as all-cause mortality.

Diabetes Mellitus and Site-specific Colorectal Cancer Risk in Korea: A Case-control Study

Objectives:

Previous large-scale cohort studies conducted in Korea have found a positive association between diabetes mellitus (DM) and colorectal cancer (CRC) in men only, in contrast to studies of other populations that have found significant associations in both men and women.

Methods:

A total of 1070 CRC cases and 2775 controls were recruited from the National Cancer Center, Korea between August 2010 and June 2013. Self-reported DM history and the duration of DM were compared between cases and controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by binary and polytomous logistic regression models.

Results:

DM was associated with an elevated risk of CRC in both men (OR, 1.47; 95% CI, 1.13 to 1.90) and women (OR, 1.92; 95% CI, 1.24 to 2.98). This association remained when we controlled for age, body mass index, alcohol consumption, and physical activity level. In sub-site analyses, DM was associated with distal colon cancer risk in both men (multivariate OR, 2.04; 95% CI, 1.39 to 3.00) and women (multivariate ORs, 1.99; 95% CI, 1.05 to 3.79), while DM was only associated with rectal cancer risk in women (multivariate OR, 2.05; 95% CI, 1.10 to 3.82). No significant association was found between DM and proximal colon cancer risk in either men (multivariate OR, 1.45; 95% CI, 0.88 to 2.41) or women (multivariate OR, 1.79; 95% CI, 0.78 to 4.08).

Conclusions:

Overall, DM was associated with an increased risk of CRC in Koreans. However, potential over-estimation of the ORs should be considered due to potential biases from the case-control design.

The sharp decline of beta estrogen receptors expression in long-lasting ulcerative-associated carcinoma

OBJECTIVE

Colorectal carcinoma is an important cause of death in inflammatory bowel diseases, thus requiring surveillance for dysplasia in long-standing ulcerative colitis (UC). Females show a lower incidence probably related to hormonal factors; therefore, a role of estrogen receptors (ERs) has been supposed in carcinoma-associated colitis (CAC) development. Our aim was to identify ER beta/alpha expression in long-lasting pancolitis through each grade of dysplasia to carcinoma and, furthermore, to investigate the simultaneous epithelial apoptosis/proliferation.

MATERIALS AND METHODS

Forty-eight patients affected by long-lasting pancolitis were retrospectively investigated. Samples were divided into four groups: UC, low-grade dysplasia/high-grade dysplasia (UC-HGD), and CAC. Normal colon samples were used as controls. ER-beta, ER-alpha, Ki-67, and TUNEL expression (labeling/H index) were evaluated by immunohistochemistry.

RESULTS

ER-beta expression revealed an impressive reduction in CAC (10.4 ± 5.1; p < 0.001) compared to controls and UC (34.3 ± 3.1 and 26.8 ± 7.8, respectively), meanwhile ER-beta level in LGD (29.4 ± 3.7) was comparable to UC. As far ER-beta/ER-alpha mean value ratio revealed a progressive reduction. Ki67 demonstrated a progressive significant increase from UC until CAC (37.9 ± 6.4 < 45.7 ± 6.2 < 60.6 ± 5.2 < 71.1 ± 5.1; p < 0.001). Apoptotic index (TUNEL) revealed a strong fall in UC-HGD and CAC.

CONCLUSIONS

ER-beta fall could be considered as a biomarker of UC-dysplasia progression. It occurs in HGD and overt neoplasia, while in LGD shows a normal expression. At the moment, we are unable to use this tool in the clinical practice to predict tumor progression, but it would be appropriate to encourage ER expression investigations in large samples for the interesting perspectives of application.

Trends of postmenopausal estrogen plus progestin prevalence in the United States between 1970 and 2010

OBJECTIVE

To estimate long term trends in estrogen-progestin prevalence for the U.S. female population by year and age.

METHODS

We integrated data on oral estrogen-progestin use from the National Health and Nutrition Examination Survey 1999-2010 with data from the National Prescription Audit 1970-2003. Distributions of estrogen-progestin by age from the National Health and Nutrition Examination Survey were applied to the prescription data, and calibration and interpolation procedures were used to generate estrogen-progestin prevalence estimates by single year of age and single calendar year for 1970-2010.

RESULTS

Estimated prevalence of oral estrogen-progestin was below 0.5% in the 1970s, began to rise in the early 1980s, and almost tripled between 1990 and the late 1990s. The age-adjusted prevalence for women aged 45-64 years peaked at 13.5% in 1999 with highest use among 57-year-old women (23.2%). Prevalence of estrogen-progestin use declined dramatically in the early 2000s with only 2.7% of women aged 45-64 years using estrogen-progestin in 2010, which is comparable to prevalence levels in the mid-1980s.

CONCLUSION

The dramatic rise and fall of estrogen-progestin use over the past 40 years provides an illuminating case study of prescription practices before, during, and after the development of evidence regarding benefits and harms.

LEVEL OF EVIDENCE

: II.

Associations of hormone replacement therapy and oral contraceptives with risk of colorectal cancer defined by clinicopathological factors, beta-catenin alterations, expression of cyclin D1, p53, and microsatellite-instability

Background

Postmenopausal hormone therapy (HRT) and oral contraceptive (OC) use have in several studies been reported to be associated with a decreased colorectal cancer (CRC) risk. However, data on the association between HRT and OC and risk of different clinicopathological and molecular subsets of CRC are lacking. The aim of this molecular pathological epidemiology study was therefore to evaluate the associations between HRT and OC use and risk of specific CRC subgroups, overall and by tumour site.

Method

In the population-based prospective cohort study Mamö Diet and Cancer, including 17035 women, 304 cases of CRC were diagnosed up until 31 December 2008. Immunohistochemical expression of beta-catenin, cyclin D1, p53 and MSI-screening status had previously been assessed in tissue microarrays with tumours from 280 cases. HRT was assessed as current use of combined HRT (CHRT) or unopposed oestrogen (ERT), and analysed among 12583 peri-and postmenopausal women. OC use was assessed as ever vs never use among all women in the cohort. A multivariate Cox regression model was applied to determine hazard ratios for risk of CRC, overall and according to molecular subgroups, in relation to HRT and OC use.

Results

There was no significantly reduced risk of CRC by CHRT or ERT use, however a reduced risk of T-stage 1–2 tumours was seen among CHRT users (HR: 0.24; 95% CI: 0.09-0.77).

Analysis stratified by tumour location revealed a reduced overall risk of rectal, but not colon, cancer among CHRT and ERT users, including T stage 1–2, lymph node negative, distant metastasis-free, cyclin D1 - and p53 negative tumours.

In unadjusted analysis, OC use was significantly associated with a reduced overall risk of CRC (HR: 0.56; 95% CI: 0.44-0.71), but this significance was not retained in adjusted analysis (HR: 1.05: 95% CI: 0.80-1.37). A similar risk reduction was seen for the majority of clinicopathological and molecular subgroups.

Conclusion

Our findings provide information on the relationship between use of HRT and OC and risk of clinicopathological and molecular subsets of CRC.

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.

Endocrine and metabolic changes in human aging

Numerous alterations in hormonal secretion occur with aging. In general, these tend towards a disintegration of the normal cyclic secretory patterns resulting in lower total circulating levels. In addition, declines in receptors and postreceptor function further decreases the ability of the hormonal orchestra to maintain coordinated function throughout the organism. Clues to some of these age-related changes in humans may come from the study of simpler organisms where regulatory systems are known to modulate the aging process. In particular, the interactions among the environment, hormones, and insulin receptor genes have led to new insights into the genetic control of longevity and the development of syndrome X.

Association of estrogen receptor beta variants and serum levels of estradiol with risk of colorectal cancer: a case control study

Background

Endogenous estrogens may play a vital role in colorectal tumorigenesis. Estrogen receptor beta is the predominant subtype which mediates the biological effect of estrogens, while loss of expression of estrogen receptor beta has been indicated as a common step in the development of colorectal cancer (CRC). Epidemiological studies have revealed several functional polymorphisms of estrogen receptor beta (ESR2) for cancer risk, but relevant study in CRC is limited, particularly in men. This study aimed to investigate the association of circulating estradiol and variations of ESR2 with CRC risk in men.

Methods

We initiated a case–control study consisting of 390 patients with CRC and 445 healthy controls in men only. We genotyped ESR2 single nucleotide polymorphisms (SNPs) rs1256049 and rs4986938 and measured serum estradiol concentration using chemilluminescence immunoassay. Multivariable logistic regression model was performed to evaluate the associations between these variables and CRC risk.

Results

ESR2 rs1256049 CT/TT genotypes were associated with reduced risk of CRC (odds ratio [OR], 0.7, 95% confidence interval [CI], 0.5–1.0), while rs4986938 CT/TT genotypes were associated with increased risk of CRC (OR, 1.5, 95% CI, 1.0–2.1). In addition, the CRC risk increased with the number of risk genotypes of these two SNPs in a dose–response manner (P_trend, 0.003). Specifically, subjects carrying risk genotypes of both SNPs had the highest risk of CRC (OR, 2.0, 95% CI, 1.3–3.3.). Moreover, serum estradiol concentration alone was associated with risk of CRC in men (OR, 1.2, 95% CI, 1.0–1.3). However, individuals presenting both rs4986938 CT/TT genotypes and high level of serum estradiol had a high risk of CRC (OR, 2.3, 95% CI, 1.4–3.9), compared with those presenting CC genotype and low level of serum estradiol. The similar joint results were not observed for SNP rs1256049.

Conclusions

These results suggest that endogenous estrogen and genetic variations in ESR2 may individually, or more likely jointly, affect CRC risk in male Han Chinese population, while larger studies are needed to validate our findings.

Postmenopausal hormone therapy is associated with a reduced risk of colorectal cancer lacking CDKN1A expression

Experimental studies have shown that estrogen- or progesterone-activated signaling leads to growth inhibition effects on colon cancer cells through the upregulation of several cell-cycle regulators. However, epidemiologic studies evaluating hormone therapy use and colorectal cancer risk by the status of cell-cycle regulators are lacking. In this study, we used data from the prospective Nurses' Health Study to evaluate whether the association between hormone therapy use and colorectal cancer risk differs by the molecular pathologic status of microsatellite instability (MSI) and expression of cell-cycle-related tumor biomarkers, including CDKN1A (p21, CIP1), CDKN1B (p27, KIP1), and TP53 (p53) by immunohistochemistry. Duplication Cox regression analysis was used to determine an association between hormone therapy use, cancer risk, and specific tumor biomarkers in 581 incident colon and rectal cancer cases that occurred during 26 years of follow-up among 105,520 postmenopausal women. We found a difference between hormone therapy use and colorectal cancer risk according to CDKN1A expression (P(heterogeneity) = 0.01). Current hormone therapy use was associated with a reduced risk for CDKN1A-nonexpressed [multivariate relative risk (RR), 0.61; 95% confidence interval (CI), 0.46-0.82] but not for CDKN1A-expressed (RR, 1.32; 95% CI, 0.76-2.31) tumors. The lower risk for CDKN1A-nonexpressed but not for CDKN1A-expressed cancers was also present among current users of estrogen-alone therapy. We found no significant difference in the relations between hormone therapy use and cancer risk according to MSI, CDKN1B, or TP53 status. Together, our molecular pathological epidemiology findings suggest a preventive effect of hormone therapy against colorectal carcinogenesis that depends, in part, on loss of cyclin-dependent kinase inhibitor CDKN1A.

Diets and hormonal levels in postmenopausal women with or without breast cancer

The role of diet in breast cancer (BC) risk is unclear. Fiber could reduce BC risk, through the enterohepatic circulation of estrogens. We examined the relationship between diet and sex hormones in postmenopausal women with or without BC. Thirty-one postmenopausal women (10 omnivores, 11 vegetarians, and 10 BC omnivores) were recruited. Dietary records (5 days) and hormone levels (3 days) were evaluated on 4 occasions over 1 yr. Vegetarians showed a lower fat/fiber ratio, a higher intake of total and cereal fiber (g/d)/body weight (kg), a significantly lower level of plasma estrone-sulfate, estradiol, free-estradiol, free-testosterone, and ring D oxygenated estrogens, and a significantly higher level of sex-hormone-binding-globulin than BC subjects. Fiber was consumed in slightly larger amounts by omnivores than by BC subjects. Omnivores had significantly lower plasma testosterone and estrone-sulfate but higher sex-hormone-binding-globulin than BC subjects. No difference was found for the urinary 16-oxygenated estrogens. However, the 2-MeO-E1/2-OH-E1 ratio was significantly lower in omnivores than in BC group. This ratio is positively associated with the fat/fiber ratio. In conclusion, testosterone may contribute to causing alterations in the levels of catechol estrogens and 16-oxygenated estrogens. The fat/fiber ratio appears to be useful in evaluating dietary effects on estrogen metabolism.

Menopausal hormone therapy and risk of gastrointestinal cancer: nested case-control study within a prospective cohort, and meta-analysis

Use of menopausal hormone therapy (HT) has been associated with reduced risk of colorectal cancer; evidence for its effect on other gastrointestinal cancers is limited. We conducted a nested case-control study within a UK cohort, and meta-analyses combining our results with those from published studies. Our study included women aged 50+ in the UK General Practice Research Database (GPRD): 1,054 with oesophageal, 750 with gastric and 4,708 with colorectal cancer, and 5 age- and practice-matched controls per case. Relative risks (RRs) and 95% confidence intervals (CIs) for cancer in relation to prospectively-recorded HT prescriptions were estimated by conditional logistic regression. Women prescribed HT had a reduced risk of oesophageal cancer (adjusted RR for 1+ vs. no HT prescriptions, 0.68, 95% CI 0.53-0.88; p = 0.004), gastric cancer (0.75, 0.54-1.05; p = 0.1) and colorectal cancer (0.81, 0.73-0.90; p < 0.001). There were no significant differences in cancer risk by HT type, estimated duration of HT use or between past and current users. In meta-analyses, risks for ever vs. never use of HT were significantly reduced for all three cancers (summary RR for oesophageal cancer, 0.68, 0.55-0.84, p < 0.001; for gastric cancer, 0.78, 0.65-0.94, p = 0.008; for colorectal cancer, 0.84, 0.81-0.88, p < 0.001). In high-income countries, estimated incidence over 5 years of these three cancers combined in women aged 50-64 was 2.9/1,000 in HT users and 3.6/1,000 in never users. The absolute reduction in risk of these cancers in HT users is small compared to the HT-associated increased risk of breast cancer.

The effect of estrogen vs. combined estrogen-progestogen therapy on the risk of colorectal cancer

Studies suggest that estrogen therapy (ET) and combined estrogen-progestogen therapy (EPT) may have different associations with colorectal cancer (CRC) risk, but data are conflicting. Prior meta-analyses did not distinguish between ET and EPT. We conducted a meta-analysis to summarize the relative risks (RR) of CRC due to ET versus EPT among peri- or postmenopausal women. From a total of 2,661 articles, four randomized controlled trials, eight cohort and eight case-control studies were included. Variables assessed included study characteristics, duration and recency of menopausal hormone therapy (HT) use, method of assessment of HT use, outcome definition and its ascertainment method. RRs were synthesized by random-effects models. We found that EPT ever use was associated with a decreased risk of CRC (RR 0.74, 95% CI 0.68-0.81), and so was ET ever use (RR 0.79, 95% CI 0.69-0.91). While current use of ET was associated with a significantly reduced risk of CRC (RR 0.70, 95% CI 0.57-0.85), former use was not (RR 0.86, 95%CI 0.67-1.11). Recency did not significantly modify the association between EPT and CRC risk. EPT former use was associated with a lower RR of CRC compared to ET former use (p = 0.008) but no such difference was observed between EPT and ET current use (p = 0.12). Overall, we found consistent evidence supporting the association between EPT and CRC risk reduction, regardless of recency. While literature for the association between ET and CRC risk is heterogeneous, our analyses suggest only current use of ET is associated with a decreased CRC risk.

Menopausal hormone therapy and risk of colorectal cancer in the European Prospective Investigation into Cancer and Nutrition

Menopausal hormone therapy (HT) may influence colorectal cancer risk. A total of 136,275 postmenopausal women from the European Prospective Investigation into Cancer and Nutrition were followed for an average of 9 years, during which time 1,186 colorectal cancers were diagnosed. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox proportional hazards models stratified by center and age, and adjusted for body mass index, smoking, diabetes, physical activity and alcohol consumption. Compared to never use of HT at study enrollment, current use of estrogen-only (HR, 1.02; 95% CI, 0.79-1.31) or estrogen plus progestin (HR, 0.94; 95% CI, 0.77-1.14) was not significantly associated with the risk of colorectal cancer, and these associations did not vary by recency, duration, route of administration, regimen or specific constituent of HT. Our results show no significant association of estrogen-only or estrogen plus progestin therapy with colorectal cancer risk.

Risk of second primary colorectal cancer among colorectal cancer cases: a population-based analysis

BACKGROUND

Patients with history of colorectal cancer (CRC) are at increased risk for developing a second primary colorectal cancer (SPCRC) as compared to the general population. However, the degree of risk is uncertain. Here, we attempt to quantify the risk, using data from the large population-based California Cancer Registry (CCR).

MATERIALS AND METHODS

We analyzed the CCR data for cases with surgically-treated colon and rectal cancer diagnosed during the period 1990-2005 and followed through up to January 2008. We excluded those patients diagnosed with metastatic disease and those in whom SPCRC was diagnosed within 6 months of the diagnosis of the primary CRC. Standardized incidence ratios (SIR) with 95% confidence intervals (CI) were calculated to evaluate risk as compared to the underlying population after taking into account age, sex, ethnicity, and time at risk.

RESULTS

The study cohort consisted of 69809 cases with colon cancer and 34448 with rectal cancer. Among these patients there were 1443 cases of SPCRCs. The SIR for developing SPCRC was higher in colon cancer survivors (SIR=1.4; 95% CI: 1.3 to 1.5) as compared to the underlying population. The incidence of SPCRC was also higher in females (SIR=1.5; 95% CI: 1.3 to 1.6) and Hispanics (SIR=2.0; 95% CI: 1.7 to 2.4) with primary colon cancer. The SIR for developing an SPCRC was higher only among those whose initial tumor was located in the descending colon (SIR=1.6; 95% CI: 1.3 to 2.0) and proximal colon (SIR=1.4; 95% CI: 1.3 to 1.6).

CONCLUSIONS

Our results confirm that CRC patients, especially females and Hispanics, are at a higher risk of developing SPCRC than the general population. Differential SPCRC risk by colorectal tumor subsite is dependent on gender and ethnicity, underscoring the heterogeneous nature of CRC.

Pre-diagnostic NSAID use but not hormone therapy is associated with improved colorectal cancer survival in women

Background:

Non-steroidal anti-inflammatory drugs (NSAIDs) and hormone therapy (HT) independently decrease the risk of colorectal cancer. However, their role in altering survival after a colorectal cancer diagnosis is not well established.

Methods:

We examined the association between the use of these common medications before diagnosis and colorectal cancer survival among women in western Washington State diagnosed with incident colorectal cancer from 1997 to 2002. Cases were ascertained using the Surveillance, Epidemiology and End Results cancer registry; mortality follow-up was completed through linkages to the National Death Index. Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

Results:

We observed no overall association between colorectal cancer survival and pre-diagnostic NSAID use. However, when stratified by tumour sub-site, NSAID use was associated with a reduced risk of colorectal cancer mortality for women diagnosed with proximal (HR=0.55; 95% CI: 0.32–0.92), but not distal or rectal (HR=1.32; 95% CI: 0.83–2.10) tumours. The usage of HT was not associated with colorectal cancer survival overall or by tumour sub-site.

Conclusion:

Usage of NSAIDs before diagnosis may be associated with improved colorectal cancer survival among women diagnosed with proximal tumours. The usage of HT does not appear to have a function in altering colorectal cancer mortality.

High levels of acute phase proteins and soluble 70 kDa heat shock proteins are independent and additive risk factors for mortality in colorectal cancer

Recently, we reported that high soluble Hsp70 (sHsp70) level was a significant predictor of mortality during an almost 3-year-long follow-up period in patients with colorectal cancer. This association was the strongest in the group of <70-year-old female patients as well as in those who were in a less advanced stage of the disease at baseline. According to these observations, measurement of the serum level of sHsp70 is a useful, stage-independent prognostic marker in colorectal cancer, especially in patients without distant metastasis. Since many literature data indicated that measurement of C-reactive protein (CRP) and other acute phase proteins (APPs) may also be suitable for predicting the mortality of patients with colorectal cancer, it seemed reasonable to study whether the effect of sHsp70 and other APPs are related or independent. In order to answer this question, we measured the concentrations of CRP as well as of other complement-related APPs (C1 inhibitor, C3, and C9) along with that of the MASP-2 complement component in the sera of 175 patients with colorectal cancer and known levels of sHsp70, which have been used in our previous study. High (above median) levels of CRP, C1 esterase inhibitor (C1-INH), and sHsp70 were found to be independently associated with poor patient survival, whereas no such association was observed with the other proteins tested. According to the adjusted Cox proportional hazards analysis, the additive effect of high sHsp70, CRP, and C1-INH levels on the survival of patients exceeded that of high sHsp70 alone, with a hazard ratio (HR) of 2.83 (1.13-70.9). In some subgroups of patients, such as in females [HR 4.80 (1.07-21.60)] or in ≤70-year-old patients [HR 11.53 (2.78-47.70)], even greater differences were obtained. These findings indicate that the clinical mortality-prediction value of combined measurements of sHsp70, CRP, and C1-INH with inexpensive methods can be very high, especially in specific subgroups of patients with colorectal cancer.

Selectively targeting estrogen receptors for cancer treatment

Estrogens regulate growth and development through the action of two distinct estrogen receptors (ERs), ERα and ERβ, which mediate proliferation and differentiation of cells. For decades, ERα mediated estrogen signaling has been therapeutically targeted to treat breast cancer, most notably with the selective estrogen receptor modulator (SERM) tamoxifen. Selectively targeting ERs occurs at two levels: tissue selectivity and receptor subtype selectivity. SERMs have been developed with emphasis on tissue selectivity to target ER signaling for breast cancer treatment. Additionally, new approaches to selectively target the action of ERα going beyond ligand-dependent activity are under current investigation. As evidence of the anti-proliferative role of ERβ accumulates, selectively targeting ERβ is an attractive approach for designing new cancer therapies with the emphasis shifted to designing ligands with subtype selectivity. This review will present the mechanistic and structural features of ERs that determine tissue and subtype selectivity with an emphasis on current approaches to selectively target ERα and ERβ for cancer treatment.

The association between a functional CYP1A1 polymorphism and colorectal neoplasia risk in post menopausal women

BACKGROUND

The impact of estrogen on risk of colorectal neoplasia is uncertain. Carriers of the AA and CA genotype allele of the C4887A polymorphism of the CYP1A1 gene have enhanced estrogen metabolism relative to carriers of the CC genotype.

AIMS

This study examined whether this genetic marker of enhanced estrogen catabolism segregated with colorectal neoplasia (CRN) in postmenopausal women.

METHODS

We enrolled hormone negative postmenopausal women having screening or surveillance colonoscopy. Demographic and medical data were gathered. Blood was collected and analyzed for CYP1A1 polymorphisms of the C4887A allele by PCR-RFLP. Colonoscopy and pathology data were gathered from hospital databases.

RESULTS

One hundred sixty-eight women were enrolled in the study. Twenty-one subjects (12.5%) carried at least one A allele, and 147 subjects (87.5%) carried the CC alleles for the C4887A polymorphism of the CYP1A1 gene. Seventy subjects (41.7%) had CRN and 98 subjects (58.3%) did not have CRN. Of the subjects who carried the A allele, 57% had CRN as compared to 39% of those who carried the CC allele; the association was not statistically significant (P = 0.16). In a multivariate logistic regression analysis, age, BMI, current tobacco use, and first degree relative with CRN were independent risk factors for CRN but the C4887A polymorphisms remained not statistically significant (P = 0.35).

CONCLUSIONS

Carriers of the A allele of the C4887A polymorphism have enhanced estrogen catabolism and lower free estradiol. Our results suggest, however, that inherent estrogen metabolism as determined by C4887A polymorphisms is not associated with CRN risk.

Hormone replacement therapy, oral contraceptive use, and distal large bowel cancer: a population-based case-control study

OBJECTIVES

Lower incidence rates of distal large bowel cancer in women when compared with men support the protective role of female hormones. We aimed to determine the associations between hormone replacement therapy, oral contraceptive use, and distal large bowel cancer.

METHODS

We conducted a population-based case-control study of incident distal large bowel cancer in North Carolina between 2001 and 2006. Data on hormone replacement therapy, oral contraceptive use, demographics, and risk factors were obtained through in-person interviews. Odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between oral contraceptive use, hormone replacement therapy, and distal large bowel cancer were estimated through unconditional logistic regression models overall, by duration of use, and within strata of race.

RESULTS

There were a total of 443 women with distal large bowel cancer and 405 controls. Ever use of hormone replacement therapy was strongly associated with a reduced risk of distal large bowel cancer (OR 0.52, 95% CI 0.38-0.72). Further reduction of distal large bowel cancer risk occurred with increased duration of use (<4 years (OR 0.77, 95% CI 0.44-1.35), 4-8 years (OR 0.64, 95% CI 0.37-1.10), 9-14 years (OR 0.47, 95% CI 0.27-0.81), and >or=15 years (OR 0.34, 95% CI 0.20-0.58)). Ever use of oral contraceptives was not associated with reduced incidence of distal large bowel cancer (OR 0.95, 95% CI 0.67-1.34) nor was duration of use. There were no differences by race.

CONCLUSIONS

Hormone replacement therapy is associated with a lower risk of distal large bowel cancer. This risk is further reduced with increased duration of use. Hormone replacement therapy may be partially responsible for the reduced incidence of distal large bowel cancer in women compared with men.

Smoking, gender, and ethnicity predict somatic BRAF mutations in colorectal cancer

Approximately 5% to 15% of all colorectal cancers (CRC) have an activating BRAF somatic mutation, which may be associated with a distinct risk profile compared with tumors without BRAF mutations. Here, we measured the prevalence and epidemiologic correlates of the BRAF V600E somatic mutation in cases collected as a part of a population-based case-control study of CRC in northern Israel. The prevalence of BRAF V600E was 5.0% in this population, and the mutation was more likely to be found in tumors from cases who were of Ashkenazi Jewish descent [odds ratio (OR), 1.87; 95% confidence interval (95% CI), 1.01-3.47], female (OR, 1.97; P = 1.17-3.31), and older (73.8 years versus 70.3 years; P < 0.001). These results were similar when restricting to only tumors with microsatellite instability. Whether smoking was associated with a BRAF somatic mutation depended on gender. Although men were less likely to have a tumor with a BRAF somatic mutation, men who smoked were much more likely to have a tumor with a somatic BRAF mutation (OR(interaction), 4.95; 95% CI, 1.18-20.83) than women who never smoked. We note the strong heterogeneity in the reported prevalence of the BRAF V600E mutation in studies of different ethnicities, with a lower prevalence in Israel than other Western populations but a higher prevalence among Jewish than non-Jewish Israeli cases. Epidemiologic studies of CRC should incorporate somatic characteristics to fully appreciate risk factors for this disease.

Serum level of soluble 70-kD heat shock protein is associated with high mortality in patients with colorectal cancer without distant metastasis

Many findings indicate that measuring the serum concentration of soluble 70-kD heat shock protein (soluble HSP70) may provide important information in cardiovascular, inflammatory, and pregnancy-related diseases; however, only scarce data are available in cancer. Therefore, using a commercial ELISA kit, we measured soluble HSP70 concentration in the sera of 179 patients with colorectal cancer. We investigated the relationship between soluble HSP70 concentration and mortality, during 33.0 (24.4-44.0) months long follow-up. High (>1.65 pg/ml, median concentration) soluble HSP70 level was a significant (hazard ratio: 1.88 (1.20-2.96, p = 0.005) predictor of mortality during the follow-up period. When we compared the soluble HSP70 levels in patients with non-resected primary tumors as compared to those who were recruited into the study 4-6 weeks after the tumor resection they were found to be significantly (p = 0.020) higher in the former group. Since the patients with non-resected primary tumors had also distant metastasis and died early, we limited the further analysis to 142 patients with no distant metastasis at the beginning of the follow-up. This association remained significant even after multiple Cox-regression analysis had been performed to adjust the data for age and sex (p = 0.028); age, sex, and TNM-T stage (p = 0.041); age, sex, and TNM-N stage (p = 0.021); age, sex, and histological grade (p = 0.023); or age, sex, and tumor localization (p = 0.029). Further analysis showed that the significant association between high HSP70 levels and poor survival is in the strongest in the group of <70-year-old female patients (HR: 5.52 (2.02-15.15), p = 0.001), as well as in those who were in a less advanced stage of the disease at baseline. These novel findings indicate that the serum level of soluble HSP70 might prove a useful, stage-independent prognostic marker in colorectal cancer without distant metastasis.

Menopausal hormone therapy use and risk of invasive colon cancer: the California Teachers Study

Results from epidemiologic studies of hormone therapy use and colon cancer risk are inconsistent. This question was investigated in the California Teachers Study (1995-2006) among 56,864 perimenopausal or postmenopausal participants under 80 years of age with no prior colorectal cancer by using Cox proportional hazards regression. Incident invasive colon cancer was diagnosed among 442 participants. Baseline-recent hormone therapy users were at 36% lower risk for colon cancer versus baseline-never users (baseline-recent users: relative risk (RR) = 0.64, 95% confidence interval (CI): 0.51, 0.80). Results did not differ by formulation. Estimated risk was lower among baseline-recent hormone therapy users with increasing duration between 5 and 15 years of use (RR = 0.49, 95% CI: 0.35, 0.68), but the trend did not persist in the longest duration group, more than 15 years of use (RR = 0.69, 95% CI: 0.52, 0.92; P(trend) = 0.60). Long-term recreational physical activity, obesity, regular use of nonsteroidal antiinflammatory medications, and daily alcohol intake did not modify these effects; baseline-recent use was more strongly associated with colon cancer risk among women with a family history of colorectal cancer (P(heterogeneity) = 0.04). Baseline-recent hormone therapy use was inversely associated with invasive colon cancer risk among perimenopausal and postmenopausal women in the California Teachers Study.

Colorectal cancer incidence and postmenopausal hormone use by type, recency, and duration in cancer prevention study II

The Women's Health Initiative randomized trials showed a reduction in colorectal cancer risk with the use of estrogen plus progesterone (E + P), but not with estrogen alone (E-only), after intervention periods <7 years. Using data from the Cancer Prevention Study II Nutrition Cohort, we examined associations of colorectal cancer risk with E-only and E + P, including analyses by recency and duration of hormone use. During 13.2 years of follow-up, 776 cases of invasive colorectal cancer occurred among 67,412 postmenopausal women participants. Cox proportional hazards models were used to estimate multivariate-adjusted relative risks (RR) and 95% confidence intervals (95% CI) of colorectal cancer for current and former hormone users according to hormone type and duration of use. Relative to women who never used postmenopausal hormones, current, but not former, use of E-only was associated with a reduced risk of colorectal cancer (RR 0.76; 95% CI, 0.59-0.97). Among current E-only users, duration of use was inversely and linearly associated with risk (P(trend) = 0.01). Use of E-only for <5 years was not associated with reduced risk, whereas use for >or=20 years was associated with a 45% reduction in risk (RR, 0.55; 95% CI, 0.36-0.86). There were no statistically significant associations between E + P and colorectal cancer risk. Our results suggest a strong inverse association of long-term use of E-only with colorectal cancer risk, underscoring the importance of collecting data on duration of hormone use in epidemiologic studies of postmenopausal hormones and risk of disease.

Gender disparities in metastatic colorectal cancer survival

PURPOSE

Previous studies have shown that estrogen prevents colon cancer in postmenopausal women, indicating a role in colorectal cancer carcinogenesis and tumor progression. We investigated the interactions between sex, age, ethnicity, and year of diagnosis on overall survival (OS) in patients with metastatic colorectal cancer (MCRC).

EXPERIMENTAL DESIGN

We screened 52,882 patients with MCRC from 1988 to 2004, using the Surveillance Epidemiology and End Results registry. Age at diagnosis, sex, ethnicity, tumor location, year of diagnosis, OS, and cancer-specific survival were evaluated using Cox proportional hazards model. The models were adjusted for marital status, tumor site, tumor differentiation, and treatment with radiation and/or surgery.

RESULTS

We observed that younger women (18-44 years old) with MCRC lived longer than younger men (17 months versus 14; P < 0.0001, log-rank test). In contrast, older women (55 years and older) had significantly worse OS than older men (7 months versus 9; P < 0.0001, log-rank test). In multivariate analysis, we found that gender discrepancies have widened in recent years; young women diagnosed after 2000 have improved cancer-specific survival, compared to men (hazard ratio, 0.778; 95% confidence interval, 0.669-0.904), but those diagnosed before 2000 benefit less (hazard ratio, 0.931; 95% confidence interval, 0.821-1.056).

CONCLUSION

As one of the largest data sets analyzed to establish that younger women with MCRC survive longer than younger men, hormonal status not only seems to play an important role in the development and pathogenesis of colorectal cancer but also may be of prognostic significance. These data warrant further studies to determine the role of estrogen in colorectal cancer.

Reprint of Are all estrogens the same?

This paper focuses on the question whether different estrogens (E) have different qualitative pharmacodynamic effects when used by women for contraception, Hormone Replacement Therapy (HRT) or prevention of osteoporosis. In this context estrogens have been defined as the estrogen agonists estradiol (E2), estrone (E1), estriol (E3), conjugated equine estrogens (CEE), diethylstilbestrol (DES) and ethinylestradiol (EE). Selective Estrogen Receptor Modulator's (SERM's) have been excluded from this analysis primarily because of lack of comparative (clinical) data with estrogen agonists. A major problem when addressing the issue of comparability of estrogen agonists is the lack of data from head-to-head estrogen-only comparative studies. Comparative studies have been performed almost exclusively with estrogen agonists combined with a series of different progestogens (P), that have been added to protect the uterus from endometrial hyperplasia. Since progestogens are known to exhibit different intrinsic pharmacodynamic properties and interactions with estrogens, it is impossible to judge which role the estrogen plays when qualitative differences between different combined E/P preparations are observed. In summary, no convincing evidence has been found that the estrogens mentioned differ qualitatively. Obviously quantitative differences are present due to differences in e.g. receptor affinity, metabolism (half life) and route of administration (transdermal/vaginal). Since DES has been discarded for human use due to teratogenicity, EE used in all combined E/P oral contraceptives is the most potent estrogen agonist available at present. In HRT, E2 and CEE are equally effective for the treatment of hot flushes and urogenital atrophy and superior to any other treatment option. For long-term treatment to prevent osteoporosis and even for short-term HRT, estrogen agonists are heavily debated recently because of a small increased risk of breast cancer, that has been known for a long time already. Well informed and individualised choice of treatment seems the appropriate solution.

Chemoprevention of colorectal neoplasia by estrogen: potential role of vitamin D activity

Postmenopausal hormone replacement therapy lowers colon cancer incidence. In humans, the mechanism is unknown, but animal models suggest that it may involve activation of the vitamin D receptor (VDR) pathway. The aims of our study were to determine whether estrogen intervention affects global gene expression in rectal mucosal biopsies and whether vitamin D-related genes are affected. Estradiol was given to raise serum estradiol to premenopausal levels in 10 postmenopausal women under close nutritional control. Primary end points were expression of VDR, CYP24A1, CYP27B1, and E-cadherin in rectal mucosa by reverse transcription-PCR and examining response to estradiol by genome-wide arrays. Responses in gene expression in rectal biopsies to estrogen were determined in each subject individually and compared with a human estrogen response gene array database and a custom array in vitro-generated database. Cluster analysis showed that subjects maintained their overall gene expression profile and that interindividual differences were greater than intraindividual differences after intervention. Eight of 10 subjects showed significant enrichment in estrogen-responsive genes. Gene array group analysis showed activation of the VDR pathway and down-regulation of inflammatory and immune signaling pathways. Reverse transcription-PCR analysis showed significant up-regulation of VDR and E-cadherin, a downstream target of vitamin D action. These data suggest that the chemopreventive action of hormone replacement therapy on colon neoplasia results, at least in part, from changes in vitamin D activity. Evaluation of gene arrays is useful in chemopreventive intervention studies in small groups of subjects.

Menopausal hormone therapy and risk of colorectal cancer

We evaluated colorectal cancer risk associated with the duration and recency of specific menopausal hormone therapy formulations (i.e., unopposed estrogen versus estrogen plus progestin) and regimens (i.e., sequential versus continuous estrogen plus progestin use) among 56,733 postmenopausal women participating in the Breast Cancer Detection Demonstration Project follow-up study. Hormone therapy use and other risk factors were ascertained through telephone interviews and mailed questionnaires from 1979 to 1998. The final cancer group included 960 women who were identified from self-report, medical records, state registry data, and the National Death Index. Poisson regression was used to generate multivariable rate ratios (RR) and 95% confidence intervals (95% CI). We observed a decreased risk of colorectal cancer among ever users of unopposed estrogen therapy (RR, 0.83; 95% CI, 0.70-0.99). Among estrogen users, the largest reduced risk was observed for current users (RR, 0.75; 95% CI, 0.54-1.05) and users of >or=ten years duration (RR, 0.74; 95% CI, 0.56-0.96). We found a reduced risk among users of estrogen plus progestin therapy (RR, 0.78; 95% CI, 0.60-1.02), with sequential regimen users (progestin <15 days per cycle) having the largest risk reduction (RR, 0.64; 95% CI, 0.43-0.95). Past users of >or=5 years ago (RR, 0.55; 95% CI, 0.32-0.98) had the largest risk reduction. In this study, estrogen plus progestin use, especially sequential regimen use, was associated with the largest overall reduction of colorectal cancer risk.

Prospective cohort study of soy food intake and colorectal cancer risk in women

BACKGROUND

Soy and some of its constituents, such as isoflavones, have been shown to have cancer-inhibitory activities in experimental studies. Data from epidemiologic studies linking usual soy food intake with colorectal cancer are limited and inconsistent.

OBJECTIVE

The objective was to investigate whether soy food intake is associated with colorectal cancer risk.

DESIGN

We prospectively examined 68,412 women aged 40-70 y and free of cancer and diabetes at enrollment. Usual soy food intake was assessed at baseline (1997-2000) and reassessed during the first follow-up (2000-2002) through in-person interviews with a validated food-frequency questionnaire. We excluded the first year of observation to minimize lifestyle changes related to preclinical disease.

RESULTS

During a mean follow-up of 6.4 y, 321 incident colorectal cancer cases were identified. After adjustment for potential confounding factors, total soy food intake was inversely associated with colorectal cancer risk. Each 5-g/d increment in intake of soy foods as assessed by dry weight [equivalent to approximately 1 oz (28.35 g) tofu/d] was associated with an 8% reduction in risk (95% CI: 3%, 14%). Women in the highest tertile of intake had a multivariate relative risk of 0.67 (95% CI: 0.49, 0.90) compared with those in the lowest tertile (P for trend = 0.008). This inverse association was primarily confined to postmenopausal women. Similar results were also found for intakes of soy protein and isoflavones.

CONCLUSION

This prospective study suggests that consumption of soy foods may reduce the risk of colorectal cancer in postmenopausal women.

Hormone therapy in relation to survival from large bowel cancer

Epidemiologic studies of hormone therapy (HT) and colorectal cancer incidence consistently show an inverse association; however, few studies have considered prediagnostic use of HT on mortality among colorectal cancer patients. We evaluated the relationship of HT and survival among a population-based cohort of women with large bowel cancer. Cases (n=1,297) were newly diagnosed with invasive cancer of the colon or rectum, aged 40-74 years at diagnosis, who were identified by Wisconsin's statewide registry (1988-1991; 1997-2001) for two case-control studies. Information on HT use and other colorectal cancer risk factors was collected by standardized interview. There were 507 deaths (274 of these attributable to colorectal cancer) over 8.4 years of follow-up through December 2005. Hormone use was not associated with colorectal cancer mortality (adjusted hazard rate ratio=1.09, confidence interval=0.81-1.47). Colorectal cancer specific mortality was not associated with HT when considered separately by preparation type. Stage did not modify this relationship. Long-term HT was weakly positively associated with increased mortality after diagnosis of proximal colon, but not distal colon cancer. Because we detected no differences in survival among users of HT compared to non-users, the results suggest that HT use may affect only the incidence of some colorectal tumors.

Conjugated equine estrogens and colorectal cancer incidence and survival: the Women's Health Initiative randomized clinical trial

BACKGROUND

In separate Women's Health Initiative randomized trials, combined hormone therapy with estrogen plus progestin reduced colorectal cancer incidence but estrogen alone in women with hysterectomy did not. We now analyze features of the colorectal cancers that developed and examine the survival of women following colorectal cancer diagnosis in the latter trial.

PARTICIPANTS AND METHODS

10,739 postmenopausal women who were 50 to 79 years of age and had undergone hysterectomy were randomized to conjugated equine estrogens (0.625 mg/d) or matching placebo. Colorectal cancer incidence was a component of the monitoring global index of the study but was not a primary study endpoint. Colorectal cancers were verified by central medical record and pathology report review. Bowel exam frequency was not protocol defined, but information on their use was collected.

RESULTS

After a median 7.1 years, there were 58 invasive colorectal cancers in the hormone group and 53 in the placebo group [hazard ratio, 1.12; 95% confidence interval (95% CI), 0.77-1.63]. Tumor size, stage, and grade were comparable in the two randomization groups. Bowel exam frequency was also comparable in the two groups. The cumulative mortality following colorectal cancer diagnosis among women in the conjugated equine estrogen group was 34% compared with 30% in the placebo group (hazard ratio, 1.34; 95% CI, 0.58-3.19).

CONCLUSIONS

In contrast to the preponderance of observational studies, conjugated equine estrogens in a randomized clinical trial did not reduce colorectal cancer incidence nor improve survival after diagnosis.

Estrogens, phytoestrogens and colorectal neoproliferative lesions

Epidemiological and experimental studies suggest a protective role of estrogens against colorectal cancer. This effect seems to be mediated by their binding to estrogen receptor beta (ER-beta), one of the two estrogen receptors with high affinity for these hormones. Very recently, the demonstration of an involvement of ER-beta in the development of adenomatous polyps of the colon has also been documented, suggesting the use of selective ER-beta agonists in primary colorectal cancer prevention. Phytoestrogens are plant-derived compounds that structurally and functionally act as estrogen-agonists in mammals. They are characterized by a higher binding affinity to ER-beta as compared to estrogen receptor alpha (ER-alpha), the other estrogen receptor subtype. These biological characteristics explain why the administration of phytoestrogens does not produce the classical side effects associated to estrogen administration (cerebro- and cardio-vascular accidents, higher incidence of endometrial and breast cancer) and makes these substances ideal candidates for the prevention of colorectal cancer.

Leptin concentrations, leptin receptor polymorphisms, and colorectal adenoma risk

Obesity has been shown to be associated with an increased risk of both colorectal cancer and adenomatous polyps. One mechanism underlying this relationship may involve the growth-promoting effects of the circulating hormones associated with obesity, such as leptin. We conducted a gastroenterology clinic-based, case-control study to evaluate the relationship between circulating leptin concentrations and colorectal adenoma risk; in addition, we evaluated the relationship between leptin receptor polymorphisms and adenoma risk. Individuals with adenomas (n = 157) and colonoscopy-negative controls (n = 191), who had a clinically indicated colonoscopy, were recruited from a large health maintenance organization in the Seattle metropolitan area from 1999 to 2003. Odds ratios and 95% confidence intervals were obtained using logistic regression, adjusting for age at diagnosis, body mass index, family history of colorectal cancer, smoking history, nonsteroidal anti-inflammatory drug use, physical activity, and, among women, menopausal status and postmenopausal hormone use. Among men, those in the highest tertile of leptin concentrations had a 3.3-fold (95% confidence interval, 1.2-8.7) increased adenoma risk compared with those in the lowest tertile (P trend = 0.01). There were no associations between leptin concentrations and adenoma risk in women. There were no associations of leptin receptor genotypes or haplotypes and adenoma risk. The results of this study suggest that, in men, leptin may be associated with risk of colorectal adenomas.

Molecular markers and targets for colorectal cancer prevention

Colorectal cancer is the third most prevalent cancer in the world. If detected at an early stage, treatment often might lead to cure. As prevention is better than cure, epidemiological studies reveal that having a healthy diet often protects from promoting/ developing cancer. An important consideration in evaluating new drugs and devices is determining whether a product can effectively treat a targeted disease. There are quite a number of biomarkers making their way into clinical trials and few are awaiting the preclinical efficacy and safety results to enter into clinical trials. Researchers are facing challenges in modifying trial design and defining the right control population, validating biomarker assays from the biological and analytical perspective and using biomarker data as a guideline for decision making. In spite of following all guidelines, the results are disappointing from many of the large clinical trials. To avoid these disappointments, selection of biomarkers and its target drug needs to be evaluated in appropriate animal models for its toxicities and efficacies. The focus of this review is on the few of the potential molecular targets and their biomarkers in colorectal cancers. Strengths and limitations of biomarkers/surrogate endpoints are also discussed. Various pathways involved in tumor cells and the specific agents to target the altered molecular biomarker in biomolecular pathway are elucidated. Importance of emerging new platforms siRNAs and miRNAs technology for colorectal cancer therapeutics is reviewed.

Long-term use of progestogens: colon adenoma and colon carcinoma

Colon cancer is the second most common cancer in women in the Western world and there is a trend towards an increasing risk. Colon adenoma is a potential precursor for colon cancer. Adenoma and carcinoma of the colon seem to be influenced by estrogens and progesterone/progestins. This is related to the presence of estrogen and progesterone receptors, with apparently higher concentrations in colon cancers than in adenomas. Epidemiological data and the finding of a significant reduction in colon cancer risk related to hormone replacement therapy (HRT), and in particular the length of HRT intake, indicate that progesterone/progestins have a preventive effect. This has not been shown with postmenopausal estrogen replacement therapy (ERT) alone. Furthermore, the recurrence rate of adenoma appears to be reduced, and the survival of colon cancer patients improved, with HRT; such effects have not been documented with ERT.

Soy product consumption and the risk of colon cancer: a prospective study in Takayama, Japan

The relationship of the intake of soy products and the incidence of colon cancer was prospectively evaluated in a population-based cohort study in Japan. The total intake of soy products and isoflavones in a daily diet was estimated from a validated questionnaire administered at the baseline. The participation rate of the questionnaire was 92.0%. The participants were followed from 1992 to 2000, and colon cancer diagnoses were identified at the main hospitals in the study area. In the analysis, 13,894 men and 16,327 women were included. The medians for energy-adjusted soy product intake were 85.52 g/day for men and 79.60 g/day for women. During follow-up, 111 men and 102 women were diagnosed with colon cancer. A Cox-proportional hazard model was applied to assess the risk of colon cancer incidence. Among women, the risk was reduced with an increased soy product consumption; the hazard ratio in the highest tertile was 0.56 (95% CI 0.34-0.92) compared as the lowest tertile (trend: P=0.04), after adjusting for multiple potential confounders. Among men, no significant association was observed. Our results exhibited the weak benefit of soy foods only among women. Further research to confirm our results may be beneficial.

Estrogen plus progestin use, microsatellite instability, and the risk of colorectal cancer in women

Current users of postmenopausal hormones (PMH) have approximately 30% to 40% lower risk of colorectal cancer (CRC), although associations with specific types of hormones have been inconsistent. Further, it is not clear whether some tumor types have a different risk. We conducted a case-control study to examine the relationship between PMH and CRC. Cases (n = 1,004), ages 50 to 74 years, were identified from the Surveillance Epidemiology and End Results registry in Washington from 1998 to 2002; controls (n = 1,062) were randomly selected from population lists. Case tissue samples were obtained for microsatellite instability (MSI) analyses. Interviews collected risk-factor data for CRC, including detailed information on PMH. Multivariable logistic regression models estimated odds ratios (OR) and 95% confidence intervals (95% CI). Current use of any PMH was associated with a 20% reduction in CRC risk (95% CI 0.6-0.9). This reduction in risk was limited to women who had taken estrogen plus progestin (EP) preparations only (OR = 0.6, 95% CI 0.5-0.9); there was no association with estrogen-only (E alone) use (OR = 0.9, 95% CI 0.7-1.1). For women with MSI-low or MSI-stable tumors, there was a statistically significant 40% reduction in CRC risk associated with EP use (95% CI 0.4-0.9); there was no clear association with MSI-high tumors. EP use was associated with a decreased risk of CRC; however, there seemed to be no association with E alone data that are consistent with the recent Women's Health Initiative findings. Progestin may enhance the estrogenic effect of conjugated estrogen so the combination may be more biologically active in the colon than E alone.

Lack of evidence for effect modification by estrogen of association between body mass index and colorectal cancer risk among postmenopausal women

OBJECTIVE

Previous studies of the association between body mass index (BMI) and colorectal cancer among women found increased risk only among women who were premenopausal or used hormone replacement therapy (HRT). These results led to the hypothesis that BMI may increase risk more strongly among women with higher levels of circulating estrogen. We examined the association between BMI and colorectal cancer incidence by use of HRT, and number of postmenopausal years without HRT, a measure of duration of exposure to lower levels of estrogen.

METHODS

During follow-up from 1992-2003, 814 incident colorectal cancer cases were identified among 73,842 postmenopausal women in the Cancer Prevention Study-II Nutrition Cohort. Information on BMI and other risk factors was obtained from questionnaires completed at enrollment in 1992-1993 and during follow-up. Hazard ratios were calculated using proportional hazards modeling.

RESULTS

The association between BMI and colorectal cancer incidence was similar among never-users of HRT (hazard ratio 1.13, 95% confidence interval 1.02-1.25 per 5-unit increase in BMI) and current-users of HRT (hazard ratio 1.08, 95% confidence interval 0.92-1.27 per 5-unit increase in BMI). Among women not currently using HRT, the association between BMI and colorectal cancer did not differ by postmenopausal years without HRT.

CONCLUSIONS

Our results do not support the hypothesis that BMI increases risk of colorectal cancer more strongly among women with higher levels of estrogen.