Treatment with metformin is associated with higher remission rate in diabetic patients with thyroid cancer

Abstract

Context: Clinical trials demonstrated that metformin increases the efficiency of systemic therapy in cancer patients. Objective:Weexamined whether the efficacy of conventional treatment of differentiated thyroid cancer (DTC) is affected by therapy with metformin in diabetic patients. Design:Wecomparedthe rate of complete response (CR)betweendiabeticswhoweretreated with metformin (group MF+; n = 34) or not treated (group MF+; n = 21) and control nondiabetic patients (group C; n = 185). We also examined the effects of metformin on DTC cells in vitro. Results: The groups were comparable in terms of age, sex, body mass index, diabetes management, frequencies of multifocal tumor growth, extrathyroidal extension, and locoregional and distant metastases. Tumor size was significantly smaller in theMF+group compared with theMF+and C groups (1.37±0.97 vs 2.44±1.49 vs 2.39±1.73 cm, respectively; P=.026).Amultivariate model revealed that extrathyroidal extension (P = .018), distant metastases (P < .0001), and lack of treatment with metformin of diabetics (P