Tests for Colorectal Cancer Screening

• The fecal occult blood test (FOBT) - Three consecutive stool specimens are collected at home and sent to a lab, which checks for hidden blood. One study reported a 33% reduction in colorectal cancer incidence among people offered an annual FOBT with follow-up treatment as indicated.
• Flexible sigmoidosity - a flexible, lighted tube (sigmoidoscope) is used to visually inspect the interior of the rectum and colon. Studies have found that deaths from colorectal cancers located within reach of the sigmoidoscope were 59 percent to 79 percent lower among people who underwent this procedure.
• Colonoscopy - a flexible, lighted tube (colonoscope) is used to examine the walls of the rectum and entire colon. If indicated, polyps can be removed or samples of tissue taken to be biopsied. Colonoscopies are used either as a screening test or as a follow-up procedure when another test detects an abnormality.
• Double-contrast barium enema - This test comprises a series of X-rays of the colon and rectum, taken after the patient is given an enema containing barium dye followed by an injection of air into the lower bowel.