Design: Prospective, randomized controlled clinical trial Setting: at Minia University Hospital and Minia Oncology Institute. Condition: Colorectal cancer.
To be eligible for participation, patients must meet the following criteria:
1. Histologically confirmed diagnosis of rectal adenocarcinoma.
2. Age starting from 18 and older.
3. Eastern Cooperative Oncology Group (ECOG) performance status of 0-2.
4. Adequate organ function (renal, hepatic, and hematological)
5. Signed informed consent.
Patients will be randomized into two groups:
Group A: Patients will receive standard chemoradiotherapy(CRT).
Group B: Patients will self-administer 1000mg of metformin twice daily by mouth:
1. beginning 1-2 weeks before standard CRT.
2. during standard CRT.
3. until 30 days after the end of standard CRT.