Study of Short Course Radiation Therapy for Elderly Patients With Rectal Cancer

Inclusion Criteria: * 70 years or older at time of diagnosis * No restrictions on gender or ethnicity * Ability and willingness to make follow up appointments * Pathologic diagnosis of rectal cancer * Presentation could be symptomatic or asymptomatic * T1-T3 primary rectal adenocarcinoma as determined on TRUS, CT, or MRI pelvis * Peri-rectal node positive allowed * Inability to tolerate radical surgery, as judged by geriatric oncology or surgeon and tumor board OR patient refusal of surgery * Inability to receive chemoradiation therapy, defined as concurrent chemotherapy and radiation doses of 45-50.4 Gy, as judged by radiation, medical, or geriatric oncology * Patients with dementia eligible if Health Care Proxy (HCP) is available and supportive of follow up schedule Exclusion Criteria: * Age under 70 years of age * Ability and desire to receive definitive surgical intervention * Ability and desire to receive concurrent chemoradiation therapy