Barium enema x-ray or colonoscopy methods are used to detect colon cancer once it is suspected to be present. In barium enema x- ray method, x-ray of the colon and rectum of the patient is taken after giving enema which is white liquid containing barium. If there are tumors present, they will appear as dark shadow in the x-ray. Colonoscopy is considered to be more accurate test for confirming the presence of colon cancer. Here a tube is inserted into the rectum of the patient to view the entire colon from inside.
Before the colonoscopy test, the colon must be empty. The doctor removes polyps from the colon which are then sent to the laboratories for detection of cancer. This test will help the doctor to know whether there is any bleeding in the colon or any kind of inflammation. Air is pumped in the colon to enlarge it so that the doctor can get clear view of what is present in colon. Time for this examination is around 30 minutes. Since sedative is given at the time of examination, it will take some time for you to come out of its effect.