Prognostic significance of metformin treatment in endometrial cancer: a meta-analysis.

Background: Previous studies suggested that metformin treatment could affect the survival outcomes of endometrial cancer (EC). This meta-analysis aims to investigate the prognostic value of metformin use in patients with EC. Methods: Pubmed and Embase databases were searched from inception to November 2019. We analyzed the association between metformin intake and survival of EC. Summary hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated using the random-effects model. The primary outcome was overall survival (OS) and the secondary outcome was progression-free survival (PFS). Results: A total of eight cohort studies enrolling 6911 participants were eligible for this meta-analysis. For patients with diabetes mellitus (DM), the pooled results showed metformin could significantly improve the OS (HR=0.57, 95% CI 0.42 to 0.78) and PFS (HR=0.61, 95% CI 0.46 to 0.80,). However, no significant difference in OS (HR= 0.79, 95% CI 0.58 to 1.08) and PFS (HR=1.05, 95% CI 0.93 to1.19) was found between the patients with diabetes who used metformin and the subjects without diabetes. Conclusions: This study showed, based on only a limited number of studies, that metformin use was significantly associated a favorable survival outcome with of EC in diabetes patients.