Post-diagnostic metformin and statin use and risk of biochemical recurrence in Veterans diagnosed with prostate cancer.

Objective: To evaluate the impact of post-diagnostic metformin or statin use and duration on risk of biochemical recurrence in a racially-diverse cohort of Veterans.

Methods: The population consisted of men diagnosed with prostate cancer in the Veterans Health Administration and treated with either radical prostatectomy or radiation (Full cohort n = 65,759, Black men n = 18,817, White men n = 46,631, Other = 311). The association between post-diagnostic (1) metformin and (2) statin use with biochemical recurrence was assessed using multivariable, time-varying Cox Proportional Hazard Models for the overall cohort and by race. In a secondary analysis, metformin and statin duration were evaluated.

Results: Post-diagnostic metformin use was not associated with biochemical recurrence (multivariable-adjusted hazard ratio [aHR]: 1.01; 95% confidence interval [CI]: 0.94, 1.09), with similar results observed for both Black and White men. However, duration of metformin use was associated with a reduced risk of biochemical recurrence in the cohort overall (HR: 0.94; 95% CI: 0.92, 0.95) as well as both Black and White men. By contrast, statin use was associated with a reduced risk of biochemical recurrence (HR: 0.83; 95% CI: 0.79, 0.88) in the overall cohort as well as both White and Black men. Duration of statin use was also inversely associated with biochemical recurrence in all groups.

Conclusion: Post-diagnostic metformin and statin use have the potential to prevent biochemical recurrence in men diagnosed with prostate cancer.