Investigation of the Radiation Protection Effect of Metformin Against Complications Caused by Radiation Therapy in Patients with Prostate Cancer: Randomized Clinical Trial

External-Beam Radiation Therapy (EBRT) is one of the most important treatments for prostate cancer. Metformin is a multifunctional drug that can control complications following radiotherapy.  This double-blind, randomized clinical trial was conducted on patients with prostate cancer candidates for EBRT. Patients were randomly assigned to two groups receiving oral Metformin (n=20) or placebo (n=20). The incidence of acute complications was investigated using radiation therapy oncology group acute complications criteria.  There was no significant change in the number of blood cells before and after treatment in the two groups (p<0.05). The micronuclei number in both groups showed a significant increase during radiotherapy, immediately and one month later (p<0.001). There was no significant difference in number of micronuclei between the two groups (p<0.05). The frequency of urinary complications ≥ grade 2 in the metformin group was lower (p=0.005). There was no significant difference in the incidence of gastrointestinal complications ≥ grade 2 between the metformin and placebo groups (p=0.5).  It is recommended that further studies on Metformin as a radioprotective agent in prostate cancer patients who are candidates for radiotherapy be carried out. This research project was registered in the clinical trial center (IRCT: IRCT20211213053377N1).