Radiosensitizing Effects of Metformin on Ionizing Irradiation: An Overview of Animal and Clinical Studies

Abstract

Radiation therapy is the most common modality to treat various types of cancers. The use of radiosensitizers as an adjuvant therapy to increase the sensitivity of tumors against radiation and to improve the efficiency of radiotherapy has risen over the past years. Metformin, the first-line drug in type two diabetes has attracted the researcher’s attention because of its anti-cancer and anti-proliferative properties and many studies have been conducted to investigate the radiosensitization effects of metformin in different types of malignancies. This review aims to gather the existing evidence of radiosensitizing effects of metformin in animal and clinical studies. Various databases like PubMed, Scopus, and Google Scholar were searched over a period of 35 years for this review. The results include 54 studies on the radiosensitization effect of metformin in in-vivo and clinical conditions including breast, colorectal, prostate, lung, liver, and other cancers. This review shows that metformin in animal and clinical studies appears to be a potential radiosensitizer for many types of cancers. However, further investigations are needed to determine whether metformin can be used as a radiosensitizer in adjuvant radiotherapy.