DISEASE CHARACTERISTICS:

• One of the following must be present:

  • At least 1 positive fecal occult blood test within the past 6 months

  • Iron deficiency anemia, defined as:

    • Hemoglobin less than 13 g/dL (males)
    • Hemoglobin less than 12 g/dL (females)
    • Ferritin less than 45 g/dL
  • Episode of bright red blood per the rectum

  • Family history of colon cancer or adenoma

    • One first-degree relative diagnosed with colon cancer or adenoma at age 60 or under OR
    • Two first-degree relatives diagnosed with colon cancer or adenoma at any age

• No active gastrointestinal hemorrhage, including any of the following:

  • Reported or witnessed hematemesis
  • Melenic stools
  • Melenemesis
  • Multiple episodes of hematochezia within the past 2 months

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• Not specified

Life expectancy:

• Not specified

Hematopoietic:

• See Disease Characteristics

Hepatic:

• Not specified

Renal:

• Not specified

Cardiovascular:

• No myocardial infarction or cerebrovascular accident within the past 6 weeks

Pulmonary:

• No respiratory failure within the past 6 weeks

Other:

• No serious medical disorder (e.g., sepsis) within the past 6 weeks
• Weight less than 300 pounds

• Willing and able to undergo endoscopic or radiologic procedures

  • No need for special precautions in performing endoscopic procedures (e.g., antibiotic prophylaxis or complicated anticoagulation reversal)
• No prisoners
• Not pregnant
• Negative pregnancy test
• Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• Not specified

Endocrine therapy:

• Not specified

Radiotherapy:

• Not specified

Surgery:

• Not specified

Other:

• No other concurrent clinical trial participation involving drugs, medical devices, and/or biologics