Metformin use may improve outcomes in men with localized prostate cancer (PCa) treated with external-beam radiation (EBRT), according to researchers.
Daniel E. Spratt, MD, and collaborators at Memorial Sloan-Kettering Cancer Center in New York, analyzed data from 2,901 consecutive PCa patients undergoing EBRT, of whom 157 were taking metformin, 162 were diabetics not taking metformin, and 2,582 were non-diabetic controls. After a median follow-up of 8.7 years, the 10-year PCa-specific mortality (PCSM) actuarial rates were 2.7%, 21.9%, and 8.2% for the metformin users, the diabetic non-metformin group, and the nondiabetics, respectively. Compared with the diabetic non-metformin group, the metformin users were twice as likely to be alive without PSA recurrence and 3.7 times as likely to be alive and free of distant metastases, the researchers reported online in European Urology. Metformin users were 5.1 times less likely die from PCa.
In addition, metformin use was independently and significantly associated with a nearly 15-fold decreased likelihood of the development of castration-resistant PCa in patients experiencing biochemical failure.