Patients who have received prior pelvic radiotherapy Prior pelvic radiotherapy or prostatectomy Previous pelvic radiotherapy Clinically large pelvic masses reaching above the umbilicus Pelvic organ prolapse greater than stage II Prior reconstructive pelvic surgery involving mesh for prolapse Histological or cytological confirmation of locally recurrent or metastatic rectal adenocarcinoma\r\n* Note: Patients with locally recurrent/persistent disease within the pelvis after primary therapy (chemotherapy, surgery, and/or radiotherapy) are eligible\r\n* Note: Patients who have had prior pelvic radiotherapy with a total dose of =< 54 Gy are eligible\r\n* Note: Patients with or without metastatic disease (excluding untreated central nervous system [CNS] metastasis), with primary pelvic disease or pelvic recurrence are eligible\r\n* Note: Patients with pelvic disease that is potentially resectable or unresectable are eligible Eligible patients should not have had previous pelvic radiotherapy, chemotherapy or surgery for prostate cancer Any size pelvic lymphadenopathy if it is thought to be a contributor to concurrent hydronephrosis Previous pelvic RT Prior pelvic radiotherapy Patients with any prior chemotherapy or radiotherapy for pelvic malignancy Candidate for pelvic or pelvic-inguinal radiotherapy and concurrent chemotherapy; patients undergoing preoperative chemoradiotherapy are excluded Patient with any prior chemotherapy or radiotherapy for pelvic malignancy Patient with any prior chemotherapy or radiotherapy for pelvic malignancy Completion of pelvic radiotherapy treatment for this current rectal cancer or any prior pelvic radiotherapy (e.g., prior prostate or cervical cancer therapy). Prior pelvic radiotherapy No prior pelvic radiotherapy Any previous pelvic radiotherapy Patients must not have received pelvic radiotherapy as treatment for primary or recurrent disease within 1 year of the first dose of study treatment. Subject who has undergone a prior pelvic anastomosis. Patients must be planned to receive whole pelvic radiotherapy to a total dose of 45 Gy or greater Patients who received prior pelvic radiotherapy for any indication History of any major rectal or pelvic surgery or radiotherapy Previous pelvic radiotherapy that would prevent prostate/seminal vesicle (SV) irradiation Previous pelvic radiotherapy Refuses or is unable to have pelvic MRI Subjects who have had previous pelvic radiotherapy or have had chemotherapy or surgery for prostate cancer Prior history of pelvic radiotherapy Any size pelvic lymphadenopathy if it is thought to be a contributor to concurrent hydronephrosis E 03. Prior isotope therapy, whole pelvic radiotherapy, or radiotherapy to >30% of bone marrow. Patients must not have undergone a prior partial cystectomy for invasive bladder cancer; patients must not have received any prior pelvic surgery that would obviate a complete extended lymphadenectomy (e.g. aorto-femoral/iliac bypass) or for whom the surgeon feels that their ability to perform a standard or extended pelvic node dissection would be compromised Pelvic osseous tumors ANY SIZE Acute pelvic inflammatory disease Has received and completed a course of pelvic radiotherapy ? 6 months prior to LAR surgery (Day 0). Candidate for pelvic, pelvic-inguinal, or extended field radiotherapy with or without concurrent chemotherapy; patients undergoing preoperative or adjuvant chemotherapy are excluded Patients with any prior pelvic surgery Patients with prior history of pelvic fractures or hip replacement Participants with a history of pelvic irradiation; or chemotherapy or radiotherapy within the preceding 14 days Patients must have had a pelvic MRI within 28 days prior to the initiation of treatment Prior breast, chest or pelvic radiotherapy Patients undergoing pelvic exenteration Radiotherapy within 28 days and abdominal/pelvic radiotherapy within 60 days prior to Day 1 of Cycle 1 Prior pelvic RT Known or suspected active pelvic infection Willingness to undergo pelvic radiotherapy Contraindications to radiotherapy (including active inflammatory bowel disease or prior pelvic radiation therapy [XRT]) Extra-pelvic metastasis on any imaging or biopsy. No prior pelvic radiotherapy Prior hip replacement or other major pelvic surgery Prior history of pelvic radiotherapy Past history of pelvic radiotherapy subjects with any contraindication to pelvic radiotherapy including, but not limited to, previous pelvic radiotherapy or brachytherapy No prior pelvic radiation therapy Any prior pelvic radiation Patients who have received prior pelvic radiation or cytotoxic chemotherapy Previous pelvic radiation for prostate cancer. Plans for pelvic radiation while participating in the study Previous pelvic radiation for prostate cancer. Previous pelvic radiation Patients with any prior pelvic radiation therapy. Radiation therapy =< 28 days prior to registration; Note: patients with prior pelvic radiation therapy > 54 Gy are ineligible Radiation therapy to more than 25% of the bone marrow; whole pelvic radiation is considered to be over 25% Radiation therapy to more than 25% of the bone marrow; whole pelvic radiation is considered to be over 25% Prior pelvic radiation Previous pelvic radiation affecting >= 25% of the bone marrow; patients who received whole pelvic radiation are excluded Patients who had pelvic radiation within 12 months Radiation therapy to more than 25% of the bone marrow; whole pelvic radiation is considered to be over 25% Previous pelvic radiation for prostate cancer Previous chemotherapy or pelvic radiation therapy No prior pelvic radiation Previous pelvic radiation for any reason. Prior pelvic radiation Any therapeutic pelvic radiation Subjects must not have had prior pelvic radiation therapy History of prior pelvic radiation therapy No prior pelvic radiation therapy or chemotherapy Previous systemic chemotherapy (for any cancer) or pelvic radiation therapy Previous pelvic radiation for bladder or prostate cancer if performed < 12 months prior to enrollment into the study No previous history of pelvic radiation Patients with a history of prior whole pelvic radiation Pelvic radiation therapy Patients who have received prior pelvic radiation Radiation therapy to more than 25% of the bone marrow; whole pelvic radiation is considered to be over 25% Prior history of pelvic radiation therapy Previous pelvic radiation for prior cancer Previous pelvic radiation therapy Prostate pelvic radiation within the past 12 months Prior pelvic radiation therapy An oncology research protocol requiring full pelvic radiation (i.e., 4-field box technique) Patient must not have had radiation therapy to more than 25% of the bone marrow; whole pelvic radiation is considered to be over 25% History of pelvic radiation Patients must be considered able to tolerate systemic chemotherapy and pelvic radiation therapy Previous pelvic radiation therapy Radiation therapy to more than 25% of the bone marrow (note: whole pelvic radiation is considered to be over 25%) Have had previous radiation of the pelvic area Radiation therapy to more than 25% of the bone marrow; whole pelvic radiation is considered to be over 25% No prior radiation to bladder or pelvic region Radiation therapy to more than 25% of the bone marrow; whole pelvic radiation is considered to be over 25% Patients with any prior history of whole pelvic radiation therapy (WPRT) Patients who have had previous pelvic radiation treatment Radiation therapy to more than 25% of the bone marrow; whole pelvic radiation is considered to be over 25% History of pelvic radiation Prior pelvic radiation Prior pelvic radiation for any reason History of pelvic or rectal radiation therapy Patients who have received any prior pelvic radiation therapy in the area of the tumor that precludes the delivery of a curative dose of pelvic radiation Prior pelvic radiation Patients who are referred with pelvic symptoms, a known pelvic mass, or a history of prior radiation, will be excluded from this investigation Prior pelvic surgery or radiation History of prior pelvic radiation Prior history of pelvic radiation Has received prior pelvic radiation therapy Previous pelvic irradiation, prostate brachytherapy, or bilateral orchiectomy Patients who have received previous vaginal, pelvic, or abdominal irradiation Prior pelvic or abdominal radiation Patients who have received previous vaginal, pelvic, or abdominal irradiation Prior history of abdominal irradiation; patients who have received prior pelvic radiation for colorectal cancer are eligible; however, prior radiation treatment plans must be reviewed prior to enrollment Patients who have had pelvic or abdominal radiation therapy. Previous pelvic irradiation, prostate brachytherapy Previous pelvic irradiation, prostate brachytherapy, or bilateral orchiectomy History of abdominal/pelvic radiation therapy Previous pelvic irradiation, prostate brachytherapy, or bilateral orchiectomy Previous pelvic radiation or prostate brachytherapy Patients who have received previous pelvic or abdominal radiation, cytotoxic chemotherapy, or previous therapy of any kind for this malignancy or any pelvic or abdominal radiation for any prior malignancy Received prior chemotherapy for any abdominal or pelvic tumor. Subject with an active abdominal or pelvic infection at the operation site. All subjects must have a radiographic assessment (chest or abdominal/pelvic CT or MRI) within 28 days prior to registration but do not need to have measurable disease. Patients who have received previous vaginal, pelvic, or abdominal irradiation For abdominal or pelvic irradiation: active inflammatory bowel disease Patients with a history of pelvic or abdominal radiotherapy; Previous pelvic irradiation, prostate brachytherapy Large pelvic or intra-abdominal masses History of previous abdominal or pelvic radiation therapy Prior abdominal or pelvic RT History of prior abdominal or pelvic radiation Patients with prior abdominal or pelvic surgery Major abdominal or pelvic surgery within the past 6 months Subjects with previous pelvic or abdominal radiation therapy;