Effect Of Metformin On Survival Outcomes In Estrogen Receptor Positive Breast Cancer Patients With Diabetes

Background:Breast caner and diabetes are major causes of morbidity and mortality worldwide.There are some associations between two diseases. Epidemiology research showed that diabetes is associated with decreased survival in breast cancer patients.Metformin is a traditional drug in diabetes care. The current consensus is that metformin can decrease the risk of breast cancer, associated with better clinical outcomes and is the independent prognosis indicator for breast cancer. Metformin as a traditional drug may become the new drugs for anti-cancer.Aim:Study the association between metformin and the outcomes of ER positive breast cancer with diabetes.To clarify the effect of metformin on the patients’better survival.Method:We reviewed47patients with ER positive breast cancer and diabetes.The correlation between the metformin, age, stage.menopausal status and prognosis were statistically analyzed. The primary endpoint was overall survival (OS). The association of patient survival with metfotmin therapy was evaluated by Kaplan-Meier method. The difference of OS between metformin user and nonuser was analyzed by Log-rank test. The relationships of risk factors to overall survival (e.g. metformin, age, stage,menopausal status) were analyzed using multivariate Cox regression analysis.Results:In47cases,22cases are metformin user and25cases are not. The average survival time of metformin user and nonuser is92.8months (95%CI,76.8-108.8months) and84.3months (95%CI,69.6-99.2months). In Log-rank analysis, there’s no statistically difference (P=0.508). The survival curve suggest that the metformin users trend to have lengthened survival. A Cox regression analysis showed that stage (P<0.05hazard ratio(HR)=2.091,95%CI1.014-4.312) predicted poor survival. But There is no significant association between the age of diagnosis, menopausal status, metformin and OS. They are not the independent prognosis indicator.Conclusions:metformin users are not associated with better clinical outcomes than nonusers in ER positive breast cancer with diabetes patients, but trend to have lengthened survival. The stage of breast cancer but not the age, menopausal status, metformin is the independent prognosis indicator of breast.