309 Background: Proton pump inhibitors (PPIs) are a commonly prescribed class of medications. Although in-vitro and in-vivo data have shown PPIs to have anti-tumor effects, more recent studies suggest an increased cancer risk in several solid organs. Pantoprazole, a commonly prescribed PPI, has been shown to harbor a protective effect in human prostate cancer (PCa) cells. We aimed to investigate the effect of pantoprazole and other PPIs on PCa-specific death and additional PCa outcomes. Methods: In this retrospective, population-based cohort study, data were incorporated from the Institute for Clinical and Evaluative Sciences to identify all men aged 66 and above with a history of a single negative prostate biopsy between 1994 and 2016. We used multivariable Cox regression models with time-dependent covariates, to assess the effect of PPIs on PCa diagnosis, androgen deprivation therapy (ADT) use, and PCa-specific death. All models included other medications with a putative effect on PCa. All models were adjusted for age, rurality, comorbidity, and year of patient study inclusion. Results: Overall, 21,512 men were included, with a mean follow-up time of 8.06 years (SD 5.44 years). A total of 10,999 patients (51.1%) used a PPI. A total of 5,187 patients (24.1%) were diagnosed with PCa, 2,043 patients (9.5%) were treated with ADT, and 805 patients (3.7%) died from PCa. Pantoprazole was associated with a 3.0% (95% CI 0.3%-6,0%) increased rate of being treated with ADT for every six months of cumulative use, while any use of all other PPIs was associated with a 39.0% (95% CI 18.0%-64.0%) increased PCa-specific mortality. No significant association was found with PCa diagnosis. Conclusions: Upon validation of the potentially negative association of PPIs with PCa outcomes, the expansive use of PPIs may need to be reassessed, especially in PCa patients.
In vitro antibacterial activity of omeprazole and its selectivity for Helicobacter spp. are dependent on incubation conditions.
