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.