Comparison of Barium Enema, Computed Tomographic Colonography, and Colonoscopy in Detecting Colon Cancer

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