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

Therapeutic Strategies and Potential Actions of Female Sex Steroid Hormones and Their Receptors in Colon Cancer Based on Preclinical Studies

Several epidemiological studies have reported that the use of female sex steroid hormones could reduce the risk of colon cancer (CRC). This review summarizes the available data related to estradiol (E2) and progesterone (P4) single and dual treatments in CRC male and female in vitro and in vivo models, mainly from preclinical studies, alongside their potential molecular mechanisms. Most of the studies showed that E2 exogenous treatment and/or reactivation of its beta receptor (ERβ) significantly inhibited cell proliferation, induced cell cycle arrest, and promoted apoptosis by modulating several molecular pathways. Likewise, the inhibition of ERα receptors produced similar antitumorigenic actions, both in vivo and in vitro, suggesting that E2 could have dual opposing roles in CRC that are dependent on the expression profile of its nuclear receptors. The available studies on P4 are scarce, and the results revealed that in vitro and in vivo treatments with natural and synthetic progesterone were also associated with promising tumoricidal actions. Nevertheless, the combination of E2 with P4 showed enhanced anticancer activities compared with their monotherapy protocols in male–female cell lines and animals. Collectively, the studies suggested that the female sex steroid hormones could provide a novel and effective therapeutic strategy against 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.

Association of Endogenous Pregnenolone, Progesterone, and Related Metabolites with Risk of Endometrial and Ovarian Cancers in Postmenopausal Women: The BFIT Cohort

BACKGROUND

Postmenopausal pregnenolone and/or progesterone levels in relation to endometrial and ovarian cancer risks have been infrequently evaluated. To address this, we utilized a sensitive and reliable assay to quantify prediagnostic levels of seven markers related to endogenous hormone metabolism.

METHODS

Hormones were quantified in baseline serum collected from postmenopausal women in a cohort study nested within the Breast and Bone Follow-up to the Fracture Intervention Trial (B∼FIT). Women using exogenous hormones at baseline (1992-1993) were excluded. Incident endometrial (n = 65) and ovarian (n = 67) cancers were diagnosed during 12 follow-up years and compared with a subcohort of 345 women (no hysterectomy) and 413 women (no oophorectomy), respectively. Cox models with robust variance were used to estimate cancer risk.

RESULTS

Circulating progesterone levels were not associated with endometrial [tertile (T)3 vs. T1 HR (95% confidence interval): 1.87 (0.85-4.11); P _trend = 0.17] or ovarian cancer risk [1.16 (0.58-2.33); 0.73]. Increasing levels of the progesterone-to-estradiol ratio were inversely associated with endometrial cancer risk [T3 vs. T1: 0.29 (0.09-0.95); 0.03]. Increasing levels of 17-hydroxypregnenolone were inversely associated with endometrial cancer risk [0.40 (0.18-0.91); 0.03] and positively associated with ovarian cancer risk [3.11 (1.39-6.93); 0.01].

CONCLUSIONS

Using sensitive and reliable assays, this study provides novel data that endogenous progesterone levels are not strongly associated with incident endometrial or ovarian cancer risks. 17-hydroxypregnenolone was positively associated with ovarian cancer and inversely associated with endometrial cancer.

IMPACT

While our results require replication in large studies, they provide further support of the hormonal etiology of endometrial and ovarian cancers.

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.

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.

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.

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.

Energy balance and gastrointestinal cancer: risk, interventions, outcomes and mechanisms

Obesity increases the risk of multiple gastrointestinal cancers and worsens disease outcomes. Conversely, strong inverse associations have emerged between physical activity and colon cancer and possibly other gastrointestinal malignancies. The effect of weight loss interventions - such as modifications of diet and/or physical activity or bariatric surgery - remains unclear in patients who are obese and have gastrointestinal cancer, although large clinical trials are underway. Human intervention studies have already shed light on potential mechanisms underlying the energy balance-cancer relationship, with preclinical models supporting emerging pathway effects. Central to interventions that reduce obesity or increase physical activity are pluripotent cancer-preventive effects (including reduced systemic and adipose tissue inflammation and angiogenesis, altered adipokine levels and improved insulin resistance) that directly interface with the hallmarks of cancer. Other mechanisms, such as DNA repair, oxidative stress and telomere length, immune function, effects on cancer stem cells and the microbiome, could also contribute to energy balance effects on gastrointestinal cancers. Although some mechanisms are well understood (for instance, systemic effects on inflammation and insulin signalling), other areas remain unclear. The current state of knowledge supports the need to better integrate mechanistic approaches with preclinical and human studies to develop effective, personalized diet and exercise interventions to reduce the burden of obesity on gastrointestinal cancer.

Intracrine Regulation of Estrogen and Other Sex Steroid Levels in Endometrium and Non-gynecological Tissues; Pathology, Physiology, and Drug Discovery

Our understanding of the intracrine (or local) regulation of estrogen and other steroid synthesis and degradation expanded in the last decades, also thanks to recent technological advances in chromatography mass-spectrometry. Estrogen responsive tissues and organs are not passive receivers of the pool of steroids present in the blood but they can actively modify the intra-tissue steroid concentrations. This allows fine-tuning the exposure of responsive tissues and organs to estrogens and other steroids in order to best respond to the physiological needs of each specific organ. Deviations in such intracrine control can lead to unbalanced steroid hormone exposure and disturbances. Through a systematic bibliographic search on the expression of the intracrine enzymes in various tissues, this review gives an up-to-date view of the intracrine estrogen metabolisms, and to a lesser extent that of progestogens and androgens, in the lower female genital tract, including the physiological control of endometrial functions, receptivity, menopausal status and related pathological conditions. An overview of the intracrine regulation in extra gynecological tissues such as the lungs, gastrointestinal tract, brain, colon and bone is given. Current therapeutic approaches aimed at interfering with these metabolisms and future perspectives are discussed.

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.

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.

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.

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.

Obesity and Colorectal Cancer

There is strong evidence that modifiable lifestyle factors such as obesity play a key role in colorectal carcinogenesis. Epidemiologic data have consistently reported a positive association between obesity and colorectal cancer. The relative risk associated with general obesity (as assessed by BMI) is higher in men than in women and for cancer of the colon than for cancer of the rectum. Abdominal obesity (as assessed by waist circumference (WC) or waist-to-hip ratio) is associated with an increased risk of colorectal cancer in both sexes, with stronger associations for cancer of the colon than for cancer of the rectum. Plausible biological mechanisms include insulin resistance, hyperinsulinemia, chronic inflammation, altered levels of growth factors, adipocytokines and steroid hormones. In addition to its effect on colorectal cancer incidence, obesity may play a role in colorectal cancer recurrence, treatment outcomes and survival. Understanding the effects of childhood and adolescent obesity and weight change over the life course in relation to future risk of colorectal cancer is incomplete but essential for targeted preventive recommendations. This chapter summarizes the current evidence on the relationship between obesity and colorectal cancer and colorectal adenoma, a common precursor lesion.