Patients with prostate cancer are less likely to develop oesophageal adenocarcinoma: could androgens have a role in the aetiology of oesophageal adenocarcinoma?

Oestrogen receptors: A potential therapeutic target in oesophageal adenocarcinoma?

Oesophageal cancer is the seventh most common cancer in the world and adenocarcinoma is the dominant subtype in Western industrialised nations. The global 5-year relative survival rate for oesophageal adenocarcinoma is 12%. Chemotherapy is a standard treatment offered to patients with both resectable and unresectable disease. However, there are only a few established chemotherapeutic drug options and progress in this area is limited. Recent efforts have focused on targeted molecular therapies. Epidemiological evidence points towards hormonal influences on disease development, particularly sex hormones. Several research studies have demonstrated oestrogen receptor (ER) expression in oesophageal adenocarcinoma tissue, making them a possible option for targeting with ER modulating agents. ERs are also present in laboratory models of the disease and experiments in ER-positive cell lines suggest that ER modulator therapy may be effective. A deeper understanding of the roles of ERα and ERβ in this disease would be valuable for future translation into clinical practice. In this review, we discuss the association between oestrogens and the development of oesophageal adenocarcinoma and the potential to modulate ER signalling networks for therapeutic benefit.

Risk of esophageal and gastric adenocarcinoma in men receiving androgen deprivation therapy for prostate cancer

The aim of this study was to explore the male predominance in esophageal and gastric adenocarcinoma by evaluating the preventive potential of androgen deprivation therapy (ADT). This matched cohort study was based on a national Swedish database of prostate cancer patients in 2006-2013. Prostate cancer patients receiving ADT were the exposed group. Prostate cancer-free men from the general population were randomly selected and matched to the index case by birth year and county of residence, forming the unexposed control group. The participants were followed until a diagnosis of esophageal or gastric cancer, death, emigration, or end of the study period. The risk of esophageal adenocarcinoma, cardia gastric adenocarcinoma, non-cardia gastric adenocarcinoma, and esophageal squamous-cell carcinoma among ADT-exposed compared to unexposed was calculated by multivariable Cox proportional hazard regression. The hazard ratios (HRs) and 95% confidence intervals (CIs) were adjusted for confounders. There was a risk reduction of non-cardia gastric adenocarcinoma among ADT-users compared to non-users (HR 0.49 [95% CI 0.24-0.98]). No such decreased risk was found for esophageal adenocarcinoma (HR 1.17 [95% CI 0.60-2.32]), cardia gastric adenocarcinoma (HR 0.99 [95% CI 0.40-2.46]), or esophageal squamous cell carcinoma (HR 0.99 [95% CI 0.31-3.13]). This study indicates that androgen deprivation therapy decreases the risk of non-cardia gastric adenocarcinoma, while no decreased risk was found for esophageal adenocarcinoma, cardia gastric adenocarcinoma, or esophageal squamous-cell carcinoma.

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.

Associations Between Prediagnostic Concentrations of Circulating Sex Steroid Hormones and Esophageal/Gastric Cardia Adenocarcinoma Among Men

Background

Esophageal adenocarcinoma (EA) and gastric cardia adenocarcinoma (GCA) are characterized by a strong male predominance. Concentrations of sex steroid hormones have been hypothesized to explain this sex disparity. However, no prospective population-based study has examined sex steroid hormones in relation to EA/GCA risk. Thus, we investigated whether prediagnostic circulating sex steroid hormone concentrations were associated with EA/GCA in a nested case-control study drawn from participants in three prospective cohort studies.

Methods

Using gas chromatography-mass spectrometry (GC-MS) and electrochemiluminescence immunoassay, we quantitated sex steroid hormones and sex hormone binding globulin, respectively, in serum from 259 EA/GCA male case participants and 259 matched male control participants from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study, and Cancer Prevention Study II Nutrition Cohort. Multivariable conditional logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for associations between circulating hormones and EA/GCA risk. All statistical tests were two-sided.

Results

Higher concentrations of dehydroepiandrosterone (DHEA) were associated with a 38% decreased risk of EA/GCA (OR per unit increase in log2 DHEA = 0.62, 95% CI = 0.47 to 0.82, Ptrend = .001). Higher estradiol concentrations were associated with a 34% reduced risk of EA/GCA (OR = 0.66, 95% CI = 0.45 to 0.98, Ptrend = .05), and the association with free estradiol was similar. No other associations between baseline hormone concentrations and future EA/GCA risk were observed.

Conclusions

This study provides the first evidence that higher concentrations of circulating DHEA, estradiol, and free estradiol may be associated with lower risks of EA/GCA in men.

Do Sex Hormones Underlie Sex Differences in Cancer Incidence? Testing the Intuitive in Esophageal Adenocarcinoma

Esophageal adenocarcinoma (EA) incidence is 4-8 times higher in men compared with women, yet this imbalance cannot be explained by known risk factors. This issue of The American Journal of Gastroenterology features results from only the second prospective study to assess whether prediagnostic sex steroid hormones underlie sex differences in EA. Xie et al. report that higher concentrations of testosterone and luteinizing hormone were associated with decreased EA risk. While contrary to the long-standing hypothesis that testosterone increases EA risk, these important results lay a foundation for additional studies to further elucidate this intuitive, intriguing, and evolving hypothesis.

Hormonal and reproductive factors and risk of upper gastrointestinal cancers in men: A prospective cohort study within the UK Biobank

Incidence of upper gastrointestinal cancers of the oesophagus and stomach show a strong unexplained male predominance. Hormonal and reproductive factors have been associated with upper gastrointestinal cancers in women but there is little available data on men. To investigate this, we included 219,425 men enrolled in the UK Biobank in 2006-2010. Baseline assessments provided information on hormonal and reproductive factors (specifically hair baldness, number of children fathered, relative age at first facial hair and relative age voice broke) and incident oesophageal or gastric cancers were identified through linkage to U.K. cancer registries. Unadjusted and adjusted hazard ratios (HR) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models. During 8 years of follow-up, 309 oesophageal 210 gastric cancers occurred. There was some evidence that male pattern baldness, was associated with gastric cancer risk (adjusted HR 1.35, 95% CI 0.97, 1.88), particularly for frontal male pattern baldness (adjusted HR 1.52, 95% CI 1.02, 2.28). There was little evidence of association between other hormonal and reproductive factors and risk of oesophageal or gastric cancer, overall or by histological subtype. In the first study of a range of male hormonal and reproductive factors and gastric cancer, there was a suggestion that male pattern baldness, often used as a proxy of sex hormone levels, may be associated with gastric cancer. Future prospective studies that directly test circulating sex steroid hormone levels in relation to upper gastrointestinal cancer risk are warranted.

Association between circulating levels of sex steroid hormones and esophageal adenocarcinoma in the FINBAR Study

Background

Esophageal adenocarcinoma (EA) is characterized by a strong male predominance. Sex steroid hormones have been hypothesized to underlie this sex disparity, but no population-based study to date has examined this potential association.

Methods

Using mass spectrometry and ELISA, we quantitated sex steroid hormones and sex hormone binding globulin, respectively, in plasma from males– 172 EA cases and 185 controls–within the Factors Influencing the Barrett/Adenocarcinoma Relationship (FINBAR) Study, a case-control investigation conducted in Northern Ireland and Ireland. Multivariable adjusted logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for associations between circulating hormones and EA.

Results

Higher androgen:estrogen ratio metrics were associated with increased odds of EA (e.g., testosterone:estradiol ratio OR_{Q4 v. Q1} = 2.58, 95%CI = 1.23–5.43; P_trend = 0.009). All estrogens and androgens were associated with significant decreased odds of EA. When restricted to individuals with minimal to no decrease in body mass index, the size of association for the androgen:estrogen ratio was not greatly altered.

Conclusions

This first study of sex steroid hormones and EA provides tentative evidence that androgen:estrogen balance may be a factor related to EA. Replication of these findings in prospective studies is needed to enhance confidence in the causality of this effect.

The Male Predominance in Esophageal Adenocarcinoma

The incidence of esophageal adenocarcinoma (EAC) has increased rapidly during the past 4 decades in many Western populations, including North America and Europe. The established etiological factors for EAC include gastroesophageal reflux and obesity, Helicobacter pylori infection, tobacco smoking, and consumption of fruit and vegetables. There is a marked male predominance of EAC with a male-to-female ratio in incidence of up to 9:1. This review evaluates the available literature on the reasons for the male predominance, particularly an update on epidemiologic evidence from human studies during the past decade. The striking sex difference does not seem to be explained by established risk factors, given that the prevalence of the etiological factors and the strengths of associations between these factors and EAC risk are similar between the sexes. Sex hormonal factors may play a role in the development of EAC; estrogenic exposures may prevent such development, whereas androgens might increase the risk of EAC. However, continuing research efforts are still needed to fully understand the reasons for the male predominance of EAC.

Polymorphisms in genes in the androgen pathway and risk of Barrett's esophagus and esophageal adenocarcinoma

The strong male predominance in Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC) remains inadequately explained, but sex hormones might be involved. We hypothesized that single nucleotide polymorphisms (SNPs) in the androgen pathway influence risk of developing BE and EAC. This genetic-epidemiological analysis included 14 studies from Australia, Europe and North America. Polymorphisms in 16 genes coding for the androgen pathway were analyzed using a gene-based approach: versatile gene-based test association study. This method evaluates associations between a trait and all SNPs within a specific gene rather than each SNP marker individually as in a conventional GWAS. The data were stratified for sex, body-mass index, waist-to-hip ratio, tobacco smoking and gastroesophageal reflux status. Included were data from 1,508 EAC patients, 2,383 BE patients and 2,170 control participants. SNPs within the gene CYP17A1 were associated with risk of BE in the sexes combined (p = 0.002) and in males (p = 0.003), but not in females separately (p = 0.3). This association was found in tobacco smokers (p = 0.003) and in BE patients without reflux (p = 0.004), but not in nonsmokers (p = 0.2) or those with reflux (p = 0.036). SNPs within JMJD1C were associated with risk of EAC in females (p = 0.001). However, none of these associations replicated in a subsequent sample. Fourteen other genes studied did not reach statistically significant levels of association with BE, EAC or the combination of BE and EAC, after correcting for the number of genes included in the analysis. In conclusion, genetic variants in the androgen-related genes CYP17A1 and JMJD1C might be associated with risk of BE and EAC, respectively, but replication data with larger sample sizes are needed.

Androgen Receptor and Androgen-Responsive Gene FKBP5 Are Independent Prognostic Indicators for Esophageal Adenocarcinoma

BACKGROUND

Esophageal adenocarcinoma is a male-dominant disease, but the role of androgens is unclear.

AIMS

To examine the expression and clinical correlates of the androgen receptor (AR) and the androgen-responsive gene FK506-binding protein 5 (FKBP5) in esophageal adenocarcinoma.

METHODS

Expression of AR and FKBP5 was determined by immunohistochemistry. The effect of the AR ligand 5α-dihydrotestosterone (DHT) on the expression of a panel of androgen-responsive genes was measured in AR-positive and AR-negative esophageal adenocarcinoma cell lines. Correlations in expression between androgen-responsive genes were analyzed in an independent cohort of esophageal adenocarcinoma tissues.

RESULTS

There was AR staining in 75 of 77 cases (97 %), and FKBP5 staining in 49 (64 %), all of which had nuclear AR. Nuclear AR with FKBP5 expression was associated with decreased median survival (451 vs. 2800 days) and was an independent prognostic indicator (HR 2.894, 95 % CI 1.396–6.002, p = 0.0043) in multivariable Cox proportional hazards models. DHT induced a significant increase in expression of the androgen-responsive genes FKBP5, HMOX1, FBXO32, VEGFA, WNT5A, and KLK3 only in AR-positive cells in vitro. Significant correlations in expression were observed between these androgen-responsive genes in an independent cohort of esophageal adenocarcinoma tissues.

CONCLUSION

Nuclear AR and expression of FKBP5 is associated with decreased survival in esophageal adenocarcinoma.

Association between circulating levels of sex steroid hormones and Barrett's esophagus in men: a case-control analysis

BACKGROUND & AIMS

Esophageal adenocarcinoma is believed to result from the progression of gastroesophageal reflux disease to erosive esophagitis and re-epithelialization of the esophagus with a columnar cell population termed Barrett's esophagus (BE). Men develop BE and esophageal adenocarcinoma more frequently than women, yet little is known about the mechanisms of this difference. We assessed whether sex steroid hormones were associated with BE in a male population.

METHODS

We analyzed data from the Barrett's Esophagus Early Detection Case Control Study, based at the Walter Reed National Military Medical Center. Blood samples were collected from 174 men with BE and 213 men without BE (controls, based on endoscopic analysis); 13 sex steroid hormones were measured by mass spectrometry and sex hormone binding globulin was measured by enzyme-linked immunosorbent assay. We also calculated free estradiol, free testosterone, and free dihydrotestosterone (DHT). We used multivariable logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) adjusted for age, race, smoking status, alcohol consumption, body mass index, heartburn, regurgitation, and gastroesophageal symptom score (excluding heartburn and regurgitation).

RESULTS

Levels of free testosterone and free DHT were associated positively with BE risk; patients in the highest quartile for these hormones were most likely to have BE (free testosterone: OR, 5.36; 95% CI, 2.21-13.03; P = .0002; free DHT: OR, 4.25; 95% CI, 1.87-9.66; P = .001). Level of estrone sulfate was associated inversely with BE risk (P for trend = .02). No other hormone was associated with BE risk. Relationships were not modified by age or BMI.

CONCLUSIONS

In an analysis of men, levels of free testosterone and free DHT were significantly associated with BE.

Personal and family history of cancer and the risk of Barrett's esophagus in men

The association between Barrett's esophagus (BE) and a personal or family history of cancer other than gastroesophageal remains unknown. To evaluate the effect of personal and family history of certain cancers and cancer treatments on the risk of BE, we analyzed data from a Veterans Affairs case-control study that included 264 men with definitive BE (cases) and 1486 men without BE (controls). Patients with history of esophageal or gastric cancer were excluded. Patients underwent elective esophagogastroduodenoscopy or a study esophagogastroduodenoscopy concurrently with screening colonoscopy to determine BE status. Personal and family history of several types of cancer was obtained from self-reported questionnaires, supplemented and verified by electronic medical-record reviews. We estimated the association between personal and family history of cancer or radiation/chemotherapy, and BE. Personal history of oropharyngeal cancer (1.5% vs. 0.4%) or prostate cancer (7.2% vs. 4.4%) was more frequently present in cases than controls. The association between BE and prostate cancer persisted in multivariable analyses (adjusted odds ratio 1.90; 95% confidence interval 1.07-3.38, P = 0.028) while that with oropharyngeal cancer (adjusted odds ratio 3.63; 95% confidence interval 0.92-14.29, P = 0.066) was attenuated after adjusting for retained covariates of age, race, gastroesophageal reflux disease, hiatal hernia, and proton pump inhibitor use. Within the subset of patients with cancer, prior treatment with radiation or chemotherapy was not associated with BE. There were no significant differences between cases and controls in the proportions of subjects with several specific malignancies in first- or second-degree relatives. In conclusion, the risk of BE in men may be elevated with prior personal history of oropharyngeal or prostate cancer. However, prior cancer treatments and family history of cancer were not associated with increased risk of BE. Further studies are needed to elucidate if there is a causative relationship or shared risk factors between prostate cancer and BE.

Risk factors for the development of oesophageal adenocarcinoma in Barrett's oesophagus: a UK primary care retrospective nested case-control study

BACKGROUND

Oesophageal adenocarcinoma (OAC) incidence is rising rapidly and prognosis remains poor. Endoscopic surveillance of Barrett's oesophagus (BO) remains controversial.

OBJECTIVE

A nested case-control study was undertaken to evaluate risk factors for progression of BO to OAC, potentially guiding surveillance efforts.

METHODS

The Health Improvement Network database includes general practitioner consultations from 5 million UK subjects. BO subjects with 1-year minimum of follow up were followed until development of OAC or end of time on database. Demographic variables (age, gender, smoking, body mass index) and data on medication considered negatively (aspirin/nonsteroidal anti-inflammatory drugs/proton pump inhibitors) or positively associated (lower oesophageal sphincter-relaxing and asthma drugs) with OAC development were studied. Cox regression analysis-derived hazard ratios with 95% confidence intervals estimated the relative risk for OAC progression.

RESULTS

A total of 3749 BO subjects were studied: 55 developed OAC during 17,743 patient years of follow up, a progression rate of 0.3% per annum. There was 96.7% of the cohort who took proton-pump inhibitors, with no association observed. Increasing age (1.03, 95% CI 1.01-1.05, p = 0.005), male gender (3.06, 95% CI 1.50-6.24, p = 0.002), and having ever smoked (2.36, 95% CI 1.13-4.93, p = 0.023) were associated with progression to OAC, (although smoking lost association on multivariate analysis). Increasing number of drugs used for asthma (2.91, 95% CI 1.10-7.68, p= 0.0314) was also associated.

CONCLUSION

In this nested case-control study of BO, male gender, increasing age, and increasing use of asthma drugs were associated with progression to OAC.

Subjects with prostate cancer are less likely to develop esophageal cancer: analysis of SEER 9 registries database

Esophageal adenocarcinoma (EAC) is five times more common among men. EAC tissue exhibits an increased concentration of androgen receptors. We previously reported lower EAC incidence following prostate cancer (PC), suggesting androgen deprivation therapy may reduce EAC incidence, but were unable to demonstrate reducing incidence of EAC with time (latency effect) that would support a cumulative effect of anti-androgen treatment.The Survival Epidemiology and End Results (SEER9) dataset from 1977–2004 was therefore examined to identify subjects with a first malignant primary of PC.Subjects were followed until second primary cancer diagnosis,death, or time period end. Age- and period-adjusted standardized incidence ratios (SIR) were calculated as an estimate of relative risk of an esophageal second malignant primary. Between 1977 and 2004, 343,538 subjects (following exclusion criteria) developed PC as a first primary malignant tumor, providing 2,014,337 years of follow-up.Subsequently 604 esophageal cancers developed, with 763 expected. The incidence of EAC fell following PC [SIR0.83 (95 % CI 0.74–0.93)] with a latency effect identified with SIR 1.1 3 months to 1 year post-PC, SIR 0.85 1–5 years post-PC, and SIR 0.75 greater than five years post-PC. The incidence of esophageal squamous cell carcinoma (ESCC) after PC was also reduced [SIR, 0.79 (0.69-0.89)],with evidence of a latency effect also seen. There is a reduced risk of developing esophageal cancer, both EAC and ESCC, following PC. Androgen deprivation therapy may contribute, but changes in lifestyle following PC diagnosis and decrease in ESCC incidence are also plausible explanations.

Risk of second primary cancer after treatment for esophageal cancer: a pooled analysis of nine cancer registries

The introduction of new treatments for esophageal cancer including surgery, chemotherapy, radiotherapy, or a combination of these modalities has not only improved patient survival, but may also increase the risk of the second primary cancers. The available evidence is conflicting with most risk estimates based on sparse numbers. Here we estimated standardized incidence ratios (SIRs) of second cancer among 24,557 esophageal cancer survivors (at least 2 months) in the Surveillance, Epidemiology, and End Results (SEER) Program between 1973 and 2007, who had been followed up for median 6.5 years (range 2 months-29.3 years). Second cancer risk was statistically significantly elevated (SIR = 1.34, 95% confidence interval [CI]= 1.25-1.42) among the survivors compared with the general population; the SIRs for cancers of oral and pharynx, stomach, small intestine, larynx, lung and bronchus, thyroid and prostate cancer were 8.64 (95% CI = 7.36-10.07), 2.87 (95% CI = 2.10-3.82), 3.80 (95% CI = 1.82-7.00), 3.19 (95% CI = 2.12-4.61), 1.68 (95% CI = 1.46-1.93), 2.50 (95% CI = 1.25-4.47), and 0.77 (95% CI = 0.65-0.90), respectively. Radiotherapy raised cancer risk of larynx (SIR = 3.98, 95% CI = 2.43-6.14) and thyroid (SIR = 3.57, 95% CI = 1.54-7.03) among all esophageal cancer survivors. For patients who had 5-9 years of follow up after radiotherapy, the SIR for lung cancer was 3.46 (95% CI = 2.41-4.82). Patients with esophageal cancer are at increased risks of second cancers of oral and pharynx, larynx, lung, and thyroid, while at a decreased risk for prostate cancer. These findings indicate that radiotherapy for esophageal cancer patients may increase risk of developing second cancers of larynx, lung, and thyroid. Thus, randomized clinical trials to address the association of radiotherapy and the risk of secondary cancer are warranted.

Hormonal factors and risks of esophageal squamous cell carcinoma and adenocarcinoma in postmenopausal women

The incidences of esophageal adenocarcinoma and squamous cell carcinoma (SCC) are higher in males than in females. We investigated whether female-related hormonal factors are associated with risks of these two types of esophageal cancer. We examined the association between use of hormone therapy (HT) and the risks of esophageal adenocarcinoma and SCC in postmenopausal women enrolled in the Women's Health Initiative (WHI) clinical trials and observational studies. Twenty-three esophageal adenocarcinoma and 34 esophageal SCC cases were confirmed among the 161,080 participants, after a median of 11.82 years of follow-up. Risk of esophageal SCC was lower among HT users (past users: HR = 0.25, 95% CI: 0.06-1.10 in 2 cases; current users: HR = 0.41, 95% CI: 0.18-0.94 in 9 cases). A decreased esophageal SCC risk was observed for current users of estrogen plus progestin (E+P) therapy (HR = 0.25, 95% CI: 0.07-0.86 in 3 cases) but not for current users of estrogen-only therapy (HR = 0.96, 95% CI: 0.28-3.29 in 6 cases). No association was observed between the use of HT and the risk of esophageal adenocarcinoma. No other reproductive or hormonal factors were significantly associated with the risk of either SCC or adenocarcinoma. Current use of E+P therapy was found to be associated with a decreased risk of esophageal SCC, but no association was observed with esophageal adenocarcinoma. To provide more definitive evidence, a pooled analysis of all available studies or a much larger study would be needed.

Hormonal factors and risks of esophageal squamous cell carcinoma and adenocarcinoma in postmenopausal women

The incidences of esophageal adenocarcinoma and squamous cell carcinoma (SCC) are higher in males than in females. We investigated whether female-related hormonal factors are associated with risks of these two types of esophageal cancer. We examined the association between use of hormone therapy (HT) and the risks of esophageal adenocarcinoma and SCC in postmenopausal women enrolled in the Women's Health Initiative (WHI) clinical trials and observational studies. Twenty-three esophageal adenocarcinoma and 34 esophageal SCC cases were confirmed among the 161,080 participants, after a median of 11.82 years of follow-up. Risk of esophageal SCC was lower among HT users (past users: HR = 0.25, 95% CI: 0.06-1.10 in 2 cases; current users: HR = 0.41, 95% CI: 0.18-0.94 in 9 cases). A decreased esophageal SCC risk was observed for current users of estrogen plus progestin (E+P) therapy (HR = 0.25, 95% CI: 0.07-0.86 in 3 cases) but not for current users of estrogen-only therapy (HR = 0.96, 95% CI: 0.28-3.29 in 6 cases). No association was observed between the use of HT and the risk of esophageal adenocarcinoma. No other reproductive or hormonal factors were significantly associated with the risk of either SCC or adenocarcinoma. Current use of E+P therapy was found to be associated with a decreased risk of esophageal SCC, but no association was observed with esophageal adenocarcinoma. To provide more definitive evidence, a pooled analysis of all available studies or a much larger study would be needed.

Sex-specific exposure prevalence of established risk factors for oesophageal adenocarcinoma

BACKGROUND

There is an unexplained male predominance in the incidence of oesophageal adenocarcinoma, and the sex-specific distribution of its risk factors in the general population is not known.

METHODS

A random sample of Swedish citizens aged 40-79 years completed a questionnaire for assessment of the prevalence of five risk factors for oesophageal adenocarcinoma: reflux symptoms, body mass index, tobacco smoking habits, socioeconomic status, and use of non-steroidal anti-inflammatory drugs (NSAIDs). Logistic regression was used to calculate odds ratios (ORs) with 95% confidence intervals (CIs) to evaluate the association of these risk factors, separately and combined, with male sex, with women as reference.

RESULTS

Among 6969 invited people, 4906 (70.4%) completed the questionnaire. Adjusted prevalence estimates showed a negative association with male sex with regard to reflux disease (OR=0.70, 95% CI=0.58-0.84), whereas overweight (OR=1.98, 95% CI=1.72-2.27) and obesity (OR=1.22, 95% CI=1.01-1.47), previous smoking (OR=1.50, 95% CI=1.30-1.72), and no NSAID use (OR=1.35, 95% CI=1.15-1.49) were positively associated.

CONCLUSIONS

Exposure to some but not all established risk factors for oesophageal adenocarcinoma seems to be more common in men than in women, but the differences are small and unlikely to explain the male predominance of this tumour.

The risk of oesophageal cancer is not affected by a diagnosis of breast cancer

Oesophageal adenocarcinoma (OAC) is less common and develops at a later age in women compared with men. Endogenous oestrogen may therefore protect against OAC development. A cohort of women with breast cancer, a tumour commonly treated with oestrogen antagonists, was examined to identify the subsequent risk of developing OAC. Earlier studies have implicated radiotherapy in increasing oesophageal cancer (OC) risk among women with breast cancer. West Midlands Cancer Intelligence Unit data recording cancer diagnosis and treatment information was examined to identify patients with a first malignant primary breast cancer during 1977-2004. Patients were followed until diagnosis of a second primary cancer, death or end of the time period examined. Age-adjusted and period-adjusted standardized incidence ratios (SIR) were calculated as an estimate of relative risk for a second primary OC. Seventy-three thousand six hundred and thirteen women were eligible for the study, providing 486 679 person years at risk for analysis. One hundred and thirty-two second primary OCs were observed, compared with 121 expected (SIR 1.09; 95% confidence interval: 0.91-1.29). Radiotherapy treatment in 37 888 women did not affect the risk of a second primary OC (SIR 1.07; 95% confidence interval: 0.79-1.41). No difference was identified when examined by OC morphology.There was no association between breast cancer and a second primary OC. Radiotherapy that avoids deep irradiation in the treatment of breast cancer, local nodes or recurrence was not associated with an increased risk of developing a second primary OC.

Sex differences in the incidence of gastrointestinal adenocarcinoma in Sweden 1970-2006

BACKGROUND

Oesophageal and gastric adenocarcinoma share a male predominance not seen for other adenocarcinomas of the gastrointestinal tract. These sex differences are not explained by known risk factors. An endogenous factor, such as premenopausal oestrogen exposure, may act protectively in favour of women and might be detected by scrutinising sex ratios and incidence rates stratified by age.

METHODS

The Swedish Cancer Register was used to collect primary oesophageal, gastric cardia, non-cardia gastric, colonic and pancreatic adenocarcinoma cases aged 25-84, during the study period of 1970-2006. Cases were divided into five-year age groups and crude incidence rates and male: female ratios were calculated. Evaluating potential time period effect, the corresponding results from 1970-1986 and 1987-2006 were also derived.

RESULTS

The sex ratio for oesophageal adenocarcinoma ranged from approximately 10:1 to 4:1, presenting a seemingly consistent decline with age. The sex ratio for non-cardia gastric adenocarcinoma, however, increased with age to reach 2:1 at a point one to two decades after menopause, where the ratio levelled off and eventually declined. There was no discernible time period effect concerning any type of adenocarcinoma. The ratios for gastric cardia, colonic and pancreatic adenocarcinoma were stable with age.

CONCLUSION

This study indicates separate patterns of age-dependency of the sex difference in oesophageal and non-cardia gastric adenocarcinoma incidence. The non-cardia gastric adenocarcinoma pattern might be due to a protective effect during premenopausal years for the female population, while the seemingly steady decline in sex ratio in oesophageal adenocarcinoma indicates a mechanism independent of menopause.