Hong Xu, Yixiang Mao, Kai Chen, Min Tao

Department of Oncology, First Affiliated Hospital ofSoochow University

Objective:Diabetic patients with breast cancerreceiving metformin and neoadjuvant chemotherapy have a higher pathologic completeresponse (pCR) rate than do diabetics not receiving metformin, but findings onsalvage treatment have been inconsistent. We performed a meta-analysis toassess the impact of adding metformin to standard therapy on the prognosis ofbreast cancer patients with diabetes. Method: We searched PubMed, Embase,Web of Science (TS), CNKI, VIP and CBM from inception to January 10, 2015without language restrictions, including references related to metformin,breast cancer, and prognosis. We performed the meta-analysis with use of arandom effects model, hazard ratio (HR), and 95% confidence intervals (95% CIs)as effect measures. Result: A total of 11 studies consisting of 5464breast cancer patients with diabetes were included, which including 2760 patientsin the metformin group, and 2704 patients in the non-metformin therapy group.The meta-analysis showed that metformin could improve the overall (HR: 0.53;95% CI: 0.39-0.71) and cancer specific survival time (HR: 0.89; 95%CI:0.79-1.00) of the breast cancer. Subgroup analysis revealed that metformincould improve overall survival after adjusting hormone receptor by 65% (HR:0.35; 95% CI: 0.15-0.84). Taking metformin after the diagnosis of breast cancermight still prolong the overall survival. Conclusion: The use ofmetformin in standard cancer therapy could improve both overall and cancer-specificsurvival of breast cancer.

Key Words: Metformin  breast cancer metaanalysis