Chemotherapy, Radiation Therapy, and Surgery in Treating Patients With Locally Advanced Rectal Cancer

Inclusion Criteria: * Histologically confirmed, locally advanced, non-metastatic primary T3 or T4 primary adenocarcinoma of the rectum * No evidence of tumor outside of the pelvis including liver metastases, peritoneal seeding, or metastatic inguinal lymphadenopathy * No intra-operative radiotherapy (IORT) or brachytherapy will be allowed * The distal border of the tumor must be at or below the peritoneal reflection, defined as within 12 centimeters of anal verge by proctoscopic examination * Transmural penetration of tumor through the muscularis propria must be demonstrated by either of the following: * CT scan plus endorectal ultrasound or * MRI * Tumors must be defined prospectively by the surgeon as clinically resectable or not; clinically resectable tumors will be defined by the surgeon as mobile and completely resectable with negative margins based on the routine examination of the non-anesthetized patient; before pre-op treatment, the surgeon should estimate and record the type of resection anticipated: APR, LAR, or LAR/coloanal anastomosis * The tumor may be clinically fixed or initially not completely resectable, clinical stage T4, N0-2, M0 based on the presence of at least one of the following criteria: * Clinically fixed tumors on rectal examination with tumor adherent to the pelvic sidewall or sacrum * Sciatica attributed to sacral root invasion with CT scan/MRI evidence of the lack of clear tissue plane will be considered evidence of fixation * Hydro…