Efficacy of metformin therapy in patients with cancer: a meta-analysis of 22 randomised controlled trials
Jie Wen, Zhenjie Yi, Yuyao Chen, Jing Huang, Xueyi Mao, Liyang Zhang, Yu Zeng, Quan Cheng, Wenrui Ye, Zhixiong Liu, Fangkun Liu, Jingfang Liu
Abstract
BACKGROUND: To investigate whether metformin monotherapy or adjunctive therapy improves the prognosis in patients with any type of cancer compared to non-metformin users (age ≥18). METHODS: Databases (Medline, Embase, and the Cochrane Central Register of Controlled Trials) and clinical trial registries ( ClinicalTrials.gov ; the World Health Organization International Clinical Trials Registry Platform) were screened for randomized, controlled trials (RCT) reporting at least progression-free survival (PFS) and/or overall survival (OS). Main outcome measures included hazard ratios (HR), and combined HRs and 95% confidence intervals (CI) were calculated using random-effects models. RESULTS: = 33%) for patients with cancer between the metformin and control groups. Subgroup analyses demonstrated that metformin treatment was associated with a marginally significant improvement in PFS in reproductive system cancers (HR 0.86, 95% CI 0.74-1.00) and a significantly worse PFS in digestive system cancers (HR 1.45, 95% CI 1.03-2.04). The PFS or OS was observed consistently across maintenance dose, diabetes exclusion, median follow-up, risk of bias, and combined antitumoral therapies. CONCLUSION: Metformin treatment was not associated with cancer-related mortality in adults compared with placebo or no treatment. However, metformin implied beneficial effects in the PFS of the patients with reproductive system cancers but was related to a worse PFS in digestive system cancers. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration number CRD42022324672.