DISEASE CHARACTERISTICS:

• History of ≥ 1 surgically resected adenomatous polyp of the colon measuring ≥ 3 mm within the past 5 years

• Screening colonoscopy performed within the past 6 months

  • All polyps must have been removed during colonoscopy, pathologically examined, and archived
• No prior surgical resection removing > 40 cm of the colon
• No personal or family history of familial polyposis or hereditary non-polyposis colon cancer

PATIENT CHARACTERISTICS:

Age

• 40 to 80

Performance status

• SWOG 0-1

Life expectancy

• Not specified

Hematopoietic

• Hematocrit ≥ 35%
• WBC ≥ 4,000/mm³
• Platelet count ≥ 100,000/mm³

Hepatic

• Bilirubin ≤ 2.0 mg/dL
• AST and ALT ≤ 2 times normal

Renal

• Creatinine ≤ 1.5 mg/dL
• Urine protein ≤ 1+*
• Urine casts 0-3*
• Urine WBC and RBC count 0-5 cells* NOTE: *By urinalysis

Gastrointestinal

• No history of inflammatory bowel disease

• No gastric or duodenal ulcers within the past 12 months

  • Gastric or duodenal ulcers that were adequately treated > 24 months ago are allowed
• No symptomatic gastric or duodenal ulcers

Other

• Not pregnant or nursing
• Negative pregnancy test
• Must have regional geographic stability over the next 36 months

• Pure tone audiometry evaluation normal

  • Patients with ≥ 20 dB of uncorrectable hearing loss (for age) of any 2 contiguous frequencies are not allowed
• No invasive malignancy within the past 5 years except adequately treated nonmelanoma skin cancer, level I (or Breslow < 0.76 mm) cutaneous melanoma, Duke's A colon cancer, stage I cervical cancer, or stage 0 chronic lymphocytic leukemia
• No severe metabolic disorder
• No other significant acute or chronic disease that would preclude study participation
• No history of abnormal wound healing or repair
• No conditions that would confer risk of abnormal wound healing or repair
• No history of allergy to NSAIDs or eflornithine

PRIOR CONCURRENT THERAPY:

Biologic therapy

• Not specified

Chemotherapy

• No concurrent chemotherapy

Endocrine therapy

• No concurrent corticosteroids on a regular or predictable intermittent basis

Radiotherapy

• No concurrent radiotherapy

Surgery

• See Disease Characteristics

Other

• Concurrent calcium supplements (≤ 1,000 mg/day) allowed
• Concurrent aspirin for cardiovascular prophylaxis (i.e., 81 mg/day) allowed
• Concurrent lipid-lowering drugs (i.e., high-dose statins) allowed
• No other concurrent nonsteroidal anti-inflammatory drugs (NSAIDs) on a regular or predictable intermittent basis
• No concurrent anticoagulants on a regular or predictable intermittent basis
• No concurrent treatment for gastric or duodenal ulcers