Inclusion Criteria

DISEASE CHARACTERISTICS:

- Average risk of colorectal cancer and meets the following criteria:

- More than 1 year since prior fecal occult blood test

- More than 10 years since prior structural colorectal evaluation (i.e.,
colonoscopy, colon x-ray, or sigmoidoscopy)

- More than 1 month since prior overt rectal bleeding (hematochezia or melena)

- More than 5 years since prior aerodigestive cancer

- No prior colorectal resection

- No contraindications to colonoscopy

- No high-risk conditions for colorectal cancer, such as the following:

- Familial adenomatous polyposis

- Hereditary nonpolyposis colorectal cancer syndrome

- Other hereditary cancer syndromes

- Prior colorectal cancer or adenoma

- Inflammatory bowel disease

- Two or more first-degree relatives with colorectal cancer

PATIENT CHARACTERISTICS:

Age:

- 65 to 80

Performance status:

- Not specified

Menopausal status:

- Postmenopausal, with the following qualifications:

- No menstrual period within the past year

- On regular hormone replacement therapy

- Underwent surgical intervention

Life expectancy:

- Not specified

Hematopoietic:

- No coagulopathy

Hepatic:

- Not specified

Renal:

- Not specified

Cardiovascular:

- No serious cardiopulmonary disease

Pulmonary:

- See Cardiovascular

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- Not specified

Chemotherapy:

- More than 3 months since prior chemotherapy

Endocrine therapy:

- Not specified

Radiotherapy:

- Not specified

Surgery:

- See Disease Characteristics

Other:

- No concurrent therapeutic nonsteroidal anti-inflammatory drugs except prophylactic
aspirin (≤ 325 mg/day)

- Concurrent cyclo-oxygenase-2 inhibitors (e.g., celecoxib and rofecoxib) allowed

- No concurrent anticoagulants