The Effect of Metformin on Prognosis in Patients With Locally Advanced Gastric Cancer Associated With Type 2 Diabetes Mellitus

Objectives: This study examined the effect of metformin use on the prognosis of gastric cancer patients. Materials and Methods: The study population comprised 2187 patients who underwent curative gastrectomy for the treatment of gastric cancer. They were divided into 3 groups: metformin (n=103), non-metformin (n=139), and non-diabetes mellitus (DM) (n=1945) according to their history of type 2 DM and metformin use. Survival, disease recurrence, and the pathologic stage were analyzed. Results: Overall survival was better in the metformin group than in the non-DM group (P=0.005). Metformin use was an independent prognostic factor of overall survival, cancer recurrence, and peritoneal recurrence. An effect of metformin use was especially notable in patients with T4 or N0 disease. Conclusions: Metformin improves the survival of patients with gastric cancer and type 2 DM.