Combination Chemotherapy and Bevacizumab With or Without Radiation Therapy in Treating Patients With Locally Advanced Rectal Cancer

DISEASE CHARACTERISTICS:

• Histologically or pathologically confirmed adenocarcinoma of the rectum
• Clinical stage T1, N1; T2, N1; T3, N0; or T3, N1 by endorectal ultrasonography (ERUS)
• No bulky N2 disease by either ERUS or MRI
• No primary fixed or unresectable (clinical stage T4) rectal cancer or recurrent colorectal cancer limited to the pelvis
• Primary unresectable rectal cancer is defined as a primary rectal tumor which on the basis of either physical exam, ERUS or pelvic MRI is deemed to be adherent or fixed to adjacent pelvic structures
• Must be a candidate for all of the following:
• Neoadjuvant chemoradiotherapy
• Systemic therapy with fluorouracil, leucovorin calcium, oxaliplatin (FOLFOX), and bevacizumab
• Complete surgical resection via low anterior resection prior to administration of any therapy
• No low-lying tumors deemed to require an abdominal perineal resection
• No large or bulky tumors that require a diverting colostomy or placement of an endorectal stent prior to treatment initiation
• No clinical evidence of metastatic disease

PATIENT CHARACTERISTICS:

• ECOG performance status 0-2
• Absolute neutrophil count ≥ 1,500/mm^3
• Platelet count > 150,000/mm^3
• Hemoglobin > 8.0 g/dL
• Creatinine ≤ 1.5 times upper limit of normal
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception during and for 4 weeks after completion of study therapy
• No other malignancy within the past 5 years except adequately treated basal cell or squamous cell skin cancer or carcinoma in situ of the cervix
• No arterial thrombotic event within the past 6 months, including stable or unstable angina, myocardial infarction (MI), or cerebral vascular accident (CVA)
• Deep venous thrombosis, pulmonary embolus, MI, CVA, atrial fibrillation, or any other conditions occurring more than 6 months ago allowed provided patient is on stable doses of anticoagulant therapy
• No other medical or psychiatric condition or disease that would preclude study therapy

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics
• No prior chemotherapy or surgery for rectal cancer
• No prior pelvic radiotherapy
• No other concurrent experimental therapy, including any of the following:
• Chemotherapy
• Radiotherapy
• Hormonal therapy
• Antibody therapy
• Immunotherapy
• Gene therapy
• Vaccine therapy
• Angiogenesis inhibitors
• Matrix metalloprotease inhibitors
• Thalidomide
• Anti-vascular endothelial growth factor/Flk-1 monoclonal antibody
• Any other experimental drugs