MADISON, WI—Metformin, a commonly used drug for patients with Type 2 diabetes mellitus (DM), has shown promise in helping to treat prostate cancer (PCa), according to a new study.

The report in the Journal of Urology posited that metformin plus androgen deprivation therapy (ADT) might be beneficial in combination. To do that, a research team from the William S. Middleton Memorial Veterans Hospital and the University of Wisconsin-Madison performed a retrospective cohort of patients with advanced PCa.1

The investigators used the national VA database to identify all men diagnosed with PCa between 2000-2008 who were treated with ADT with follow-up through May of 2016. Excluded from the study were patients who had received ADT for six months or less or who had undergone the therapy concurrent with localized radiation.

In the cohort after exclusions were 87,344 patients divided into three cohorts: 61% were no DM, 22% were DM no metformin, and 17% were DM on metformin. Hazard ratios were calculated for overall survival (OS), skeletal-related events (SRE) and cancer-specific survival (CSS).

Results indicated that OS showed improved survival in DM on metformin (HR 0.82, 95% CI 0.78-0.86) vs. DM no metformin (HR 1.03, 95% CI 0.99-1.08) with no DM as referent group.

In addition, the study team noted, research revealed HR 0.82 (95% CI 0.72-0.93) for DM on metformin, while Cox proportional hazards analysis for CSS showed improved survival in DM on metformin (HR 0.70, 95% CI 0.64-0.77) vs. DM with no metformin (HR 0.93, 95% CI 0.85- 1.00), using no DM as a referent group.

“Metformin use in veterans with PCa receiving ADT is associated with improved oncologic outcomes,” study authors concluded. “This association should be evaluated in a prospective clinical trial.”

1. Richards KA, Liou JI, Cryns VL, Downs TM, Abel EJ, Jarrard DF. Metformin Use Is Associated with Improved Survival in Patients with Advanced Prostate Cancer on Androgen Deprivation Therapy. J Urol. 2018 Jun 22. pii: S0022-5347(18)43412-X. doi: 10.1016/j.juro.2018.06.031. [Epub ahead of print] PubMed PMID: 29940252.