Survival advantage associated with metformin usage in hepatocellular carcinoma patients receiving radiotherapy: A propensity score matching analysis

Background: The present study aimed to evaluate the effects of metformin on the clinical outcomes of patients receiving radiotherapy for inoperable hepatocellular carcinoma. Patients and Methods: The medical records of 217 patients treated with stereotactic body or hypofractionated radiotherapy for inoperable hepatocellular carcinoma were reviewed. Patients were divided into the metformin group (n=19) and the nonmetformin group (n=198), including those with diabetes (n=29), and those without (n=169). We performed a propensity score-matching analysis comparing the two groups. Results: In the propensity score-matched cohort (n=76), the overall survival rate of the metformin group was higher than that of the non-metformin group (2-year, 76% vs. 37%, p=0.022). The adjusted Cox proportional hazards model revealed that metformin usage was a significant factor for mortality (adjusted hazard ratio=0.361; 95% confidence interval=0.139-0.935). Conclusion: The use of metformin in patients with hepatocellular carcinoma receiving radiotherapy was associated with higher overall survival.