Are proton pump inhibitors associated with postmenopausal malignancies?

USA: A new study published in Cancer Epidemiology Biomarkers & Prevention suggests that proton pump inhibitors (PPIs) usage did not contribute to increased risk of breast or endometrial cancer and was found to have an inverse, dose-responsive relationship with colorectal cancer risk in postmenopausal women.

Proton pump inhibitors work by inhibiting fatty acid synthase (FAS), an enzyme that is essential for lipogenesis, energy balance, and cancer cell viability. T J Ballinger and colleagues undertook this study to assess the relationship between PPI usage and the risk of three prevalent obesity-related malignancies in women: colorectal, postmenopausal breast, and endometrial cancer.

This study comprised 124,931 postmenopausal women who participated in the Women's Health Initiative (WHI) epidemiological study and clinical trials and completed a year 3 follow-up evaluation. Prescription and over-the-counter usage of PPI and/or histamine 2 receptor antagonists (H2RA) were investigated at baseline and year 3 to identify possible effects of FAS inhibition by PPI rather than just acid suppression. Cases of incident cancer were judged by a physician. Multivariable hazard ratios (HR) and 95 percent confidence intervals (CI) for relationships between PPI and/or H2RA consumption and cancer incidence after year 3 were estimated using Cox proportional hazard regression models.