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

RATIONALE: Screening tests may help doctors detect cancer cells early and plan more effective treatment for cancer. New diagnostic procedures such as computed tomographic colonography may provide a less invasive method of identifying patients who have colon cancer. PURPOSE: Diagnostic and screening trial to compare the effectiveness of barium enema, computed tomographic colonography, and colonoscopy in detecting of colon cancer.