Your doctor will review your symptoms and examine your abdomen and rectum. A sample of a bowel movement will be tested for blood.

Procedures called sigmoidoscopy or colonoscopy let your doctor look at the inside of the colon and rectum. For both procedures your doctor inserts a slim, flexible, lighted tube through your anus and looks at the inside of your colon and rectum. Your doctor may remove a small piece of tissue that looks abnormal to test for cancer (a test called a biopsy). Colorectal cancer is common enough that colonoscopy after the age of 50 is recommended as a routine screening procedure.

Another test you might have is a double-contrast barium enema. In this procedure fluid that contains barium is put into your colon. X-rays are then taken that show the inside of your colon. If the X-ray images show a polyp or cancer, you will need to have a colonoscopy to get a sample of tissue (biopsy) for lab tests.

If cancer is found, you will have lab tests and X-rays to check for spread of the cancer to other parts of your body.