OBJECTIVES:

• Compare the performance characteristics (sensitivity, specificity, and predictive values) of fecal occult blood (FOB) testing and multitarget DNA-based assay panel (MTAP) testing applied to stools and plasma in identifying colorectal cancer.
• Compare the specificity of the MTAP and FOB tests in participants given pretest dietary restrictions vs no pretest dietary restrictions in order to evaluate the necessity of a formal pretest preparation for MTAP.
• Compare the detection rates of colorectal neoplasia using MTAP alone, flexible sigmoidoscopy alone, and combination sigmoidoscopy and FOB testing.
• Determine the causes of MTAP "false-positive" results, (i.e., positive MTAP and negative colonoscopy).
• Determine and compare the pathological and molecular features of colorectal cancer detected vs not detected by the MTAP.

OUTLINE: This is a randomized, multicenter study. Participants are stratified according to age (50-64 [closed to accrual as of 6/5/03] vs 65-80), gender (male vs female), and participating center. Participants are randomized to one of two screening arms.

• Arm I: Participants eat no red meat and take no nonsteroidal anti-inflammatory drugs (NSAIDs) and no vitamin C or multivitamins for 3 days prior to and during stool sample collection. Participants collect stool samples 3 different times and perform fecal occult blood (FOB) test smears from each stool. After each collection, participants ship the whole stool and FOB test smear to their participating center for blinded multitarget DNA-based assay panel (MTAP) testing.
• Arm II: Participants take no vitamin C or multivitamins for 3 days before and during stool sample collection. Participants collect stool samples and FOB test smears and samples are tested as in arm I.

Within 2 months after stool sample collection, participants have their blood drawn for additional MTAP testing and undergo colonoscopy.

PROJECTED ACCRUAL: A total of 4,000 participants (2,000 per arm) will be accrued for this study.

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