A tube reaching the full length of the colon is placed through the rectum into the colon. The tube links to a video camera and display. By looking at the video image, the physician can look for polyps or unusual-looking tissue throughout the entire colon. Then, using a wire loop that goes through the tube, the physician can remove polyps or tissue, which can then be examined in a lab for signs of cancer. An enema of a chalky substance opens and partly fills up the colon.
Air is added to expand the colon.
Then, x-rays are taken and examined. Digital Rectal Examination. Used in concert with the other tests described above, a digital rectal examination is performed by a doctor or nurse, who insert a lubricated gloved finger into the rectum to feel for lumps or abnormal areas.