Meta-analysis of metabolic syndrome and prostate cancer

BACKGROUND: Metabolic syndrome (MetS) and prostate cancer (PCa) are highly prevalent conditions worldwide. Current evidence suggests the emerging hypothesis that MetS could play a role in the development and progression of several neoplasms. The aims of this study are to evaluate the impact of MetS and MetS factors on PCa incidence, on the risk of high-grade PCa and to analyze the role of MetS and single MetS components on the development of aggressive PCa features. METHODS: A systematic literature search and analysis on PubMed, EMBASE, Cochrane and Academic One File databases until September 2015 was performed by 2 independent reviewers to evaluate the associations between MetS and PCa incidence, and between MetS and high-grade PCa incidence (bioptical Gleason Score⩾8, Prognostic Group 4-5 according to the novel prostate cancer grading system). Also the association between MetS and individual MetS components with pathological Gleason Score⩾8, extra-capsular extension, seminal vesicle invasion, positive surgical margins and biochemical recurrence (defined as two consecutive PSA values ⩾0.2 ng ml-1 after radical prostatectomy) was evaluated. RESULTS: 24 studies were selected including a total of 132 589 participants of whom 17.35% had MetS. There was a slight association between MetS and PCa incidence (odds ratio (OR)=1.17 (1.00-1.36), P=0.04) and between high-grade PCa and MetS (OR= 1.89 (1.50-2.38), P<0.0001) but the studies were statistically heterogeneous. No association was found between MetS components and PCa risk except for hypertension. MetS was significantly associated with pathologic Gleason Score⩾8 (OR= 1.77 (1.34-2.34); P<0.01), extra-capsular extension (OR=1.13 (1.09-1.18); P<0.01), seminal vesicle invasion (OR=1.09 (1.07-1.12); P<0.01), positive surgical margins (OR=1.67 (1.47-1.91); P<0.01) and biochemical recurrence (OR=1.67 (1.04-2.69); P<0.01). CONCLUSIONS: The presence of MetS is associated with worse oncologic outcomes in men with PCa, in particular with more aggressive tumor features, and biochemical recurrence.