For colorectal cancer patients with type II diabetes, could metformin improve the survival rate? A meta-analysis

Objective: Current research is controversial about whether metformin can improve the survival rate of patients with colon cancer. Therefore, we conducted a meta-analysis to identify the association between metformin and the survival rate of colorectal cancer (CRC) patients with type II diabetes. Methods: We conducted a search in databases including Pubmed, EMBASE and Cochrane Library. All articles were published in the last decade, and the quality of each study was evaluated by the Newcastle-Ottawa Scale. Odds ratios (ORs) and its corresponding 95% confidence intervals (Os) for each study were calculated and summary relative risk estimates with corresponding 95% Cls were generated using the random-effects model. Heterogeneity and publication bias were assessed. Results: Ten articles were included in this meta-analysis. The included articles were all cohort studies. In a pooled analysis of all studies, metformin using was associated with increased overall survival (OS) rate (OR, 0.54; 95% CI, 0.47 to 0.63) and cancer-specific survival (CS) rate (OR 0.59; 95% CI 0.43 to 0.82) of CRC patients with diabetes. We found that the effect of metformin is associated with geographical region through subgroup meta-analysis. Conclusions: Metformin using was associated with an increased OS rate and CS rate of colorectal cancer. (C) 2019 Elsevier Masson SAS. All rights reserved.