Watchful Waiting for Complete Responders to Therapy in Rectal Cancer

The purpose of this project is to determine if in a selected group of patients, at higher risk of wound dehiscence and other complications, treatment by local excision and management by a "watchful waiting" or an initial "non-operative management" approach, with an offer of radical resection only to those patients whose tumors demonstrate "regrowth" will maintain acceptable local control and overall survival rate for the whole cohort.

Inclusion Criteria: 1. Age ≥ 18 years 2. Diagnosis of rectal invasive adenocarcinoma 3. Tumor in the low rectum lying \< 4 cm from the anal verge 4. Clinical stage T3/N0-N1M0. 5. Patients with low T2 who will need abdominal perineal resection are also eligible. Exclusion Criteria: 1. Age less than 18 years 2. Other forms of cancer 3. Tumors \>= 4 cm from the anal verge 4. Tumors of other clinical stages than listed above