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

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. 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). 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. 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.