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Metformin and prostate cancer mortality: a meta-analysis

Konrad Hermann Stopsack, David R. Ziehr, Jennifer R. Rider, Edward L. Giovannucci

Cancer Causes & Control, 2015

9,186 participants · 74 citations

Abstract

PURPOSE: Observational studies report conflicting results on the association between metformin exposure and prostate cancer outcomes. This meta-analysis summarizes studies reporting overall survival, prostate cancer-specific mortality, and biochemical recurrence.

METHODS: PubMed and Embase were systematically reviewed to identify studies investigating the association between metformin use and clinical endpoints among men with prostate cancer while taking confounding by diabetes diagnosis into account. Pooled risk estimates (hazard ratios, HRs) and 95 % confidence intervals (CIs) were calculated using random-effects models. Sensitivity analyses for quality components and factors for heterogeneity were conducted.

RESULTS: Of 549 articles identified, nine retrospective cohort studies representing 9,186 patients were included. There was significant heterogeneity between studies, and studies differed in quality. Metformin use was associated with improved overall survival in studies with clear risk window definition (HR 0.88, 95 % CI 0.86-0.90, p < 0.001) and in studies with potential immortal time bias (HR 0.52, 95 % CI 0.41-0.65, p < 0.001). No significant association with prostate cancer-specific mortality was detected (HR 0.76, 95 % CI 0.44-1.31, p = 0.33). Metformin use was associated with a decreased risk of biochemical recurrence (HR 0.79, 95 % CI 0.63-1.00, p = 0.047).

CONCLUSIONS: This meta-analysis suggests a benefit of metformin in men with diabetes and prostate cancer.…

How strong is the evidence?

Evidence Hub reads this as a meta-analysis, done in people. Its evidence level is 1 of 5 (Highest · pooled evidence). Pooled evidence from several studies sits at the top of the evidence pyramid. Reported size: 9,186 participants or records.

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