Is Trichomonas vaginalis a Risk Factor for Prostate Cancer? A Systematic Review and Meta‐analysis.

Clinical studies have shown that patients exposed to the protozoan Trichomonas vaginalis (TV) may present an increased risk to develop prostate cancer (PCa). However, since data from other studies and meta-analyses did not provide so far univocal results this issue remains controversial. In this systematic review, we examined the current molecular, cellular and clinical evidence in favor or against a possible association between TV prostatitis and the incidence of PCa. Electronic database search, title/abstract screening and full-text reading yielded a total of 17 clinical articles and meta-analyses and 12 articles showing the results of preclinical investigations. Preclinical evidence points to the involvement of TV in proliferative disorders in prostate cells, involving an array of immune cell mediators. Five clinical case-control studies documented a significantly increased odds for PCa in patients with a positive TV serostatus, whereas seven other studies showed nonsignificant results. Our meta-analysis including 12 studies retrieved up to June 1, 2021, did not evidence a significant association between a positive TV serostatus and PCa of any grade (odds ratio [OR], 1.14; 95% confidence interval [CI]: 0.84–1.53). Moreover, we could not find a significant association between advanced/lethal PCa and TV exposure (OR, 1.18; 95% CI: 0.70–2.00). In conclusion, the association between a positive TV serostatus and PCa remains uncertain. Studies focused on a large sample of documented cases of symptomatic, clinical TV chronic prostatitis are warranted to make a conclusive statement in this regard.