Metabolic syndrome and risk of prostate cancer: a systematic review and meta-analysis

INTRODUCTION: Emerging evidence supports the hypothesis that metabolic syndrome is associated with cancer pathogenesis. In particular regarding prostate cancer, observational studies from various settings report different results. This systematic review and meta-analysis aimed to provide a quantitative estimate of the association between metabolic syndrome in prostate cancer, in particular Gleason Score >6, accounting for different study designs. EVIDENCE ACQUISITION: Systematic research of available literature in English language until 2020 was conducted through in Embase, Medline, Cochrane Library and NIH Registry of Clinical Trials. For each study, information regarding the study design, the population, the definition of metabolic syndrome, data relating to prostate cancer were collected, the association between MetS and outcome of interest was determined by calculating the generic inverse variance with random effects method. EVIDENCE SYNTHESIS: In the final sample 19 studies were included with total of 114,329 patients, 29.4% met the criteria for metabolic syndrome. We report a significant association between metabolic syndrome and prostate cancer in cross-sectional studies (OR=1.30; 95% CI: 1.13-1.49) and for patients with clinically significant prostate cancer (OR=1.56; 95% CI: 1.23 1.99). Association between metabolic syndrome and prostate cancer combining all studies, in cohort studies and case control studies was not significant. CONCLUSIONS: Growing evidence support the association between metabolic syndrome and prostate cancer, bias derived from observational studies might conceal further findings.