Racial Differences in Prostate Cancer Aggressiveness and Metformin

Metformin, an inexpensive FDA approved diabetes drug, has been recently re-purposed as a treatment for prostate cancer. It has been associated with a reduced incidence of prostate cancer and improved prostate cancer outcomes. 

Recent questions have risen asking whether race modifies the association between metformin use and prostate cancer aggressiveness.  To gain a better understanding of this issue the association between metformin use and prostate cancer aggressiveness was examined separately in Black Americans (Blacks) and White Americans (Whites).

The study population consisted of 305 Black and 195 White men with prostate cancer and self-reported diabetes from the North Carolina-Louisiana Prostate Cancer Project. High-aggressive prostate cancer was defined using a composite measure of Gleason score, prostate-specific antigen (PSA), and clinical staging. Multivariable logistic regression was used to assess the association between metformin use and high-aggressive prostate cancer at diagnosis, separately among Whites and Blacks, with adjustment for age, screening history, site, education, insurance, and body mass index.

Metformin use was associated positively with high-aggressive prostate cancer in Blacks (OR 2.01; 95% CI 1.05, 3.83). By contrast, a weak inverse association between metformin use and high-aggressive prostate cancer was found in Whites (OR 0.80, 95% CI 0.34, 1.85).

The association between metformin use and prostate cancer aggressiveness may be modified by race. When deciding if Metformin is an appropriate drug you need to consider your race.

Cancer causes & control : CCC. 2018 Sep 28 [Epub ahead of print]

Saira Khan, Jianwen Cai, Matthew E Nielsen, Melissa A Troester, James L Mohler, Elizabeth T H Fontham, Laura Farnan, Bettina F Drake, Andrew F Olshan, Jeannette T Bensen

By Joel T Nowak