Several types of laboratory and clinical tests and examinations are used to diagnose colon and rectal cancer. MostPurple Gloves are relatively simple and painless, though some patients do experience minor discomfort requiring mild anesthetics. The tests include:
- Digital rectal examination - The doctor inserts a lubricated, gloved finger into the rectum to feel for abnormal areas or masses.
- Fecal occult or hemoccult blood test - A small amount of stool is placed on a plastic slide or special paper and examined under a microscope for minute traces of blood.
- Sigmoidoscopy - The doctor uses a thin lighted tube called a sigmoidscope to look inside the rectum and lower colon for polyps, tumors or other abnormalities.
- Colonoscopy - A long instrument, similar to the sigmoidscope, is used to examine the inside of the entire colon for tumors and abnormal tissue. This procedure allows the doctor to see much further into the bowel than the sigmoidscope.
- Lower GI Series - This test is used to obtain an x-ray of the colon and rectum. It is sometimes called a barium enema because of the white, chalky substance given to patients prior to the x-ray. The barium outlines the colon and rectum on the x-rays to help the doctor see tumors or other abnormal tissue. The doctor may also expand the colon by gently pumping air during the test to look for small tumors.
If a polyp or tumor is found during colonoscopy or sigmoidoscopy, the doctor may remove all or part of it through the scope so that it can be examined under a microscope for the presence of cancer cells. This procedure is called a biopsy Because colon and rectal cancer risk increases as we age and is easily detected through sigmoidoscopy and/or colonoscopy, cancer experts recommend the tests be done every three to five years after age 50, and earlier and more frequently for those people with a strong family history of the disease.