Capecitabine and Oxaliplatin or Standard Follow-Up Care in Treating Patients Who Have Undergone Surgery for Locally Advanced Rectal Cancer

DISEASE CHARACTERISTICS:

• Histologically confirmed adenocarcinoma of the rectum

  • Within 15 cm of the anal verge
  • Locally advanced disease

• Underwent complete resection of primary tumor within the past 12 weeks

  • ypT0-4, N0-2 with definitive histology at surgery
  • Circumferential resection margin > 1 mm
  • No gross evidence of residual disease

• Received neoadjuvant fluoropyrimidine-based chemoradiotherapy with ≥ 45 Gy planned total radiation dose, given in 1 of the following fashions:

  • Prolonged fluorouracil IV during radiotherapy
  • Low-dose leucovorin calcium and fluorouracil (days 1-5 and 29-33) concurrently with radiotherapy
  • Oral capecitabine concurrently with radiotherapy
• No evidence of metastatic disease

PATIENT CHARACTERISTICS:

• WHO performance status 0-1
• Absolute neutrophil count ≥ 1,500/mm³
• Platelet count ≥ 100,000/mm³
• Creatinine clearance ≥ 50 mL/min
• Bilirubin ≤ 1.25 times upper limit of normal (ULN)
• AST and ALT ≤ 1.25 times ULN
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception during and for ≥ 3 months after completion of study treatment
• No known dihydropyrimidine dehydrogenase deficiency
• No hypersensitivity to platinum compounds
• No preexisting peripheral neuropathy ≥ grade 1
• No lack of physical integrity of the upper gastrointestinal tract
• No malabsorption syndrome

• No other serious uncontrolled medical condition or concurrent medical illness that would compromise life expectancy and/or preclude study compliance, including any of the following:

  • Serious uncontrolled infections
  • Significant cardiac disease (e.g., uncontrolled angina, congestive heart failure, cardiomyopathy, or arrhythmias) or myocardial infarction within the past 12 months
  • Interstitial pneumonia or symptomatic lung fibrosis
• No other malignancies except adequately treated in situ carcinoma of the cervix or basal cell or squamous cell carcinoma of the skin, unless disease-free for ≥ 10 years
• No history of uncontrolled seizures, CNS disorders, or psychiatric disability that would preclude study compliance

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics

• No prior chemotherapy exceeding 6 weeks in duration

  • Prior chemotherapy given as part of neoadjuvant treatment (i.e., chemoradiotherapy) may last a maximum of 11-12 weeks
• No prior oxaliplatin
• Prior mitomycin C, irinotecan hydrochloride, or cetuximab allowed
• No concurrent warfarin, antiviral agents, or phenytoin