• Overall survival [ Designated as safety issue: No ]
• Toxicity [ Designated as safety issue: Yes ]
• Correlation of tumor biologic characteristics with survival [ Designated as safety issue: No ]

• Overall survival
• Toxicity
• Correlation of tumor biologic characteristics with survival

RATIONALE: Drugs used in chemotherapy, such as oxaliplatin, leucovorin, and fluorouracil, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Monoclonal antibodies, such as bevacizumab, can block tumor growth in different ways. Some block the ability of tumor cells to grow and spread. Others find tumor cells and help kill them or carry tumor-killing substances to them. Bevacizumab may also stop the growth of tumor cells by blocking blood flow to the tumor. Giving combination chemotherapy together with bevacizumab after surgery may kill any remaining tumor cells or prevent the cancer from coming back. Sometimes, after surgery, the tumor may not need additional treatment until it progresses. In this case, observation may be sufficient. It is not yet known whether giving combination chemotherapy together with bevacizumab is more effective than combination chemotherapy alone or observation only in treating colon cancer.

PURPOSE: This randomized phase III trial is studying oxaliplatin, leucovorin, fluorouracil, and bevacizumab to see how well they work compared to oxaliplatin, leucovorin, and fluorouracil or observation only in treating patients who have undergone surgery for stage II colon cancer.

OBJECTIVES:

Primary

• Compare the 3-year disease-free survival of patients with resected stage II colon cancer at high risk for recurrence treated with oxaliplatin, leucovorin calcium, and fluorouracil with vs without bevacizumab.

Secondary

• Compare the overall survival of patients treated with these regimens.
• Compare the toxicity profiles of these regimens in these patients.
• Correlate tumor biologic characteristics with survival of patients treated with these regimens.

OUTLINE: This is a randomized study. Patients are stratified according to disease stage (IIA vs IIB) and microsatellite stability (MSS) (stable vs low-grade instability [MSI-L]). Patients with disease that is at high risk for microsatellite instability (MSI) and loss of heterozygosity (LOH) at chromosome 18q are randomized to 1 of 2 treatment arms (arms I and II). Patients with disease that is at low risk for MSI and 18q LOH are assigned to arm III.

• Arm I: Patients receive oxaliplatin IV over 2 hours and leucovorin calcium IV over 2 hours on day 1. Patients also receive fluorouracil IV bolus followed by fluorouracil IV continuously over 46 hours beginning on day 1. Treatment repeats every 2 weeks for 12 courses in the absence of disease progression or unacceptable toxicity.
• Arm II: Patients receive oxaliplatin, leucovorin calcium, and fluorouracil as in arm I and bevacizumab IV over 30-90 minutes on day 1. Treatment repeats every 2 weeks for 12 courses in the absence of disease progression or unacceptable toxicity. Patients then receive bevacizumab alone for 12 additional courses in the absence of disease progression or unacceptable toxicity.
• Arm III: Patients undergo observation only. Patients are followed every 3 months for 1-2 years, every 6 months for 3 years, and then annually for up to 10 years from study entry.

PROJECTED ACCRUAL: A total of 3,610 patients will be accrued for this study within 5.8 years.

• Biological: bevacizumab
  Given IV
• Drug: fluorouracil
  Given IV
• Drug: leucovorin calcium
  Given IV
• Drug: oxaliplatin
  Given IV
• Other: clinical observation
  No intervention

• Active Comparator: Arm I
  Patients receive oxaliplatin IV over 2 hours and leucovorin calcium IV over 2 hours on day 1. Patients also receive fluorouracil IV bolus followed by fluorouracil IV continuously over 46 hours beginning on day 1. Treatment repeats every 2 weeks for 12 courses.
  Interventions:

  • Drug: fluorouracil
  • Drug: leucovorin calcium
  • Drug: oxaliplatin
• Experimental: Arm II
  Patients receive oxaliplatin, leucovorin calcium, and fluorouracil as in arm I and bevacizumab IV over 30-90 minutes on day 1. Treatment repeats every 2 weeks for 12 courses in the absence of disease progression or unacceptable toxicity. Patients then receive bevacizumab alone for 12 additional courses.
  Interventions:

  • Biological: bevacizumab
  • Drug: fluorouracil
  • Drug: leucovorin calcium
  • Drug: oxaliplatin
• No Intervention: Arm III
  Patients undergo observation only.
  Intervention: Other: clinical observation

DISEASE CHARACTERISTICS:

• Histologically confirmed adenocarcinoma of the colon

  • Stage II disease (pT3, pT4a-b, N0, M0)

    • At least 8 lymph nodes must have been evaluated

• Meets 1 of the following criteria:

  • High risk for microsatellite instability (MSI) and loss of heterozygosity (LOH) at chromosome 18q

    • Microsatellite stable (MSS) with 18q LOH
    • MSI-low grade (MSI-L) with 18q LOH

  • Low risk for MSI and 18q LOH

    • MSS with retention of 18q alleles
    • MSI-L with retention of 18q alleles
    • MSI-high grade (MSI-H) with retention of 18q alleles
    • MSI-H without retention of 18q alleles
    • MSI-H with 18q status uninformative

• Distal extent of tumor must be ≥ 12 cm from the anal verge by endoscopy or surgical examination

  • If tumor is located beyond sigmoid colon and centimeter distance is unavailable, include anatomic region of the colon (e.g., right colon, transverse colon, hepatic flexure, descending colon, or cecum)

• Has undergone surgical resection of the tumor between the past 28-60 days

  • Must have had a complete resection (R0 resection)
• No history of isolated, distant, or noncontiguous intra-abdominal metastases
• Patients with synchronous tumors or appendiceal tumors are ineligible
• Hereditary non-polyposis colorectal cancer allowed
• Paraffin-embedded tumor specimen (one with normal mucosa and one from the resection tumor) available

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• ECOG 0-2

Life expectancy

• Not specified

Hematopoietic

• Absolute granulocyte count ≥ 1,500/mm^3*
• Platelet count ≥ 100,000/mm^3*
• No significant bleeding unrelated to tumor within the past 6 months* NOTE: *For patients with high-risk disease only

Hepatic

• Bilirubin normal (unless due to Gilbert's disease or similar syndrome)*
• Alkaline phosphatase (AP) < 2.5 times upper limit of normal (ULN)*
• AST < 1.5 times ULN*

• PT INR > 1.5* allowed provided the following criteria are met:

  • Patient is on full-dose anticoagulants
  • INR in range (usually 2-3) on a stable dose of warfarin or low molecular weight heparin
  • No active bleeding or pathological condition associated with a high risk of bleeding unrelated to primary colon tumor
• No systemic hepatic disease* NOTE: *For patients with high-risk disease only

Renal

• Creatinine ≤ 1.5 times ULN*
• Urine protein:creatinine ratio < 1.0* OR
• Urine protein < 1 gm on 24-hour urine collection*
• No systemic renal disease* NOTE: *For patients with high-risk disease only

Cardiovascular

• History of hypertension allowed provided blood pressure < 150/90 mm Hg while on a stable regimen of anti-hypertensive therapy*
• No New York Heart Association class III or IV cardiac disease*
• No symptomatic arrhythmia*
• No history of transient ischemic attack*
• No history of cerebrovascular accident*
• No symptomatic peripheral vascular disease*
• No arterial thromboembolic events within the past 12 months*
• No unstable angina within the past 12 months*
• No myocardial infarction within the past 12 months*
• No other systemic cardiovascular disease* NOTE: *For patients with high-risk disease only

Other

• Not pregnant or nursing*
• Negative pregnancy test*
• Fertile patients must use effective contraception during and for 3 months after completion of study treatment*
• No active gastroduodenal ulcer by endoscopy*
• No complete obstruction or perforation of the bowel
• No history of inflammatory bowel disease
• No prior or concurrent malignancy except for nonmelanoma skin cancer, carcinoma in situ of the cervix, breast cancer in situ, treated non-pelvic cancer from which the patient has been disease-free for > 5 years, or history of breast cancer (without evidence of disease) and remain on hormonal therapy for > 5 years
• No other nonmalignant systemic disease that would preclude study compliance*
• No psychiatric or addictive disorder or other condition that would preclude study participation*
• No serious or non-healing wound, skin ulcer, or bone fracture*
• No peripheral neuropathy ≥ grade 2*
• No significant traumatic injury within the past 4 weeks*
• No known allergy to platinum compounds NOTE: *For patients with high-risk disease only

PRIOR CONCURRENT THERAPY:

Biologic therapy

• Not specified

Chemotherapy

• Not specified

Endocrine therapy

• Not specified

Radiotherapy

• No prior radiotherapy for this cancer

Surgery

• See Disease Characteristics
• More than 28 days since prior major surgery or open biopsy*
• More than 7 days since prior core biopsy or other minor procedure except placement of a vascular access device* NOTE: *For patients with high-risk disease only

Other

• No prior systemic therapy for this cancer NOTE: *For patients with high-risk disease only