IRCT20170728035349N2 IRCT 2022-01-15 Zanjan University of Medical Sciences Evaluation of Metformin impact on the downstaging of rectal cancer patients undergoing neo-adjuvant chemo-radiotherapy Evaluation of Metformin impact on the downstaging of rectal cancer patients undergoing neo-adjuvant chemo-radiotherapy 2022-01-29 anticipated 40 Complete https://irct.ir/trial/60949 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Used, Assignment: Parallel, Purpose: Treatment, Randomization description: Patients are randomly assigned to two groups: metformin recipients (group M) and placebo recipients (group P). For this purpose, random block methods with size 2 will be used and the random sequence of this allocation will be generated by STATA16 software, Blinding description: Due to the ambiguity of this study (patients and physicians prescribing the drug are not aware of the main drug and placebo), metformin 500 mg and placebo were indefinitely given to the patient at the end of each radiotherapy session and Its consumption is ensured. 3 Rectal Cancer. Intervention 1: Intervention group: 20 patients in the intervention group receive one metformin 500 tablet daily from Tehran Daroo Company at the same time with 28 sessions of chemoradiotherapy. Intervention 2: Control group: One placebo daily with 28 sessions of chemoradiotherapy. No - There is not a plan to make this available Justification or reason for not sharing IPD is There is no more information.