Chemotherapy Alone or Chemotherapy Plus Radiation Therapy in Treating Patients With Locally Advanced Rectal Cancer Undergoing Surgery

DISEASE CHARACTERISTICS:

• Diagnosis of rectal adenocarcinoma
• Radiologically measurable or clinically evaluable disease
• For this patient, the standard treatment recommendation in the absence of a clinical trial would be combined-modality, neoadjuvant chemoradiation followed by curative-intent surgical resection

• Candidate for sphincter-sparing surgical resection prior to neoadjuvant therapy according to the primary surgeon

  • No patient for whom primary surgeon indicates need for abdominoperineal (APR) at baseline

• Clinical stage T2N1, T3N0, T3N1 (stage IIA, IIIA, or IIIB)

  • Clinical staging should be estimated based on the combination of the following assessments: physical exam by the primary surgeon, CT scan of the chest/abdomen/pelvis, and either a pelvic MRI or an ultrasound (ERUS)

    • Clinical stage N2 disease is to be estimated as four or more lymph nodes that are ≥ 10 mm
    • No clinical T4 tumors

• Preoperative proctoscopy with tumor tissue evident between 5 and 12 cm from the anal verge, inclusive

  • No evidence that tumor is adjacent to (defined as within 3 mm of) the mesorectal fascia on pre-operative MRI or ERUS/pelvic CT scan
• No tumor causing symptomatic bowel obstruction

PATIENT CHARACTERISTICS:

• ECOG performance status 0, 1, or 2
• Absolute neutrophil count (ANC) ≥ 1,500/mm³
• Platelets ≥ 100,000/mm³
• Hemoglobin > 8.0 g/dL
• Total bilirubin ≤ 1.5 times upper limit of normal (ULN)
• AST and ALT ≤ 3 times ULN
• Creatinine ≤ 1.5 times ULN
• Not pregnant or nursing
• Negative pregnancy test
• Patient of child-bearing potential is willing to employ adequate contraception
• Willing to return to enrolling medical site for all study assessments
• No other invasive malignancy ≤ 5 years prior to registration; exceptions are colonic polyps, non-melanoma skin cancer, or carcinoma-in-situ of the cervix
• No co-morbid illnesses or other concurrent disease that, in the judgment of the clinician obtaining informed consent, would make the patient inappropriate for entry into this study or interfere significantly with the proper assessment of safety and toxicity of the prescribed regimens

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics
• No chemotherapy within 5 years prior to registration (hormonal therapy is allowable if the disease-free interval is ≥ 5 years)
• No prior pelvic radiation