The Radiation Oncology-Biology Integration Network (ROBIN) Molecular Characterization Trial (MCT) of Standard Short Course Radiotherapy for Rectal Cancer

Eligible patients will receive short course radiation therapy (scRT) of 25Gy over 5 days (fractions) for their localized rectal cancer. Research bloods stool and tissue will be collected at three time points: Baseline, end of radiation therapy and at surgery.

Subjects are expected to undergo total mesenteric Excision(TME) even if subjects have achieved complete response by imaging.TME is a specific surgical technique used in the treatment of rectal cancer in which the bowel with the tumor is entirely removed along with surrounding fat and lymph nodes.