How is colon cancer diagnosed?Routine screening tests are recommended for patients who have any of the risk factors, which are outlined in Symptoms. A doctor may also order these tests to look for cancer if a patient experiences a change in bowel habits or bleeding from the
All adults more than 50 years old should be screened for colon cancer since regular screening has been shown to reduce colon cancer deaths. People who are at increased risk of developing colon cancer have different screening recommendations than the general public. For example, screening can begin at a younger age; may take place more frequently, and require the use of different procedures. The precise screening recommendations depend on a person's level of risk. Some factors that should prompt more aggressive screening include family history of colon cancer or polyps; a previous personal diagnosis of inflammatory bowel disease, or a previous personal diagnosis of either colon cancer or polyps.
The three screening and diagnostic tests performed most commonly for colon cancer are the following:
Rectal examination: Wearing thin gloves, the doctor puts a greased finger into the rectum and gently feels for lumps. The doctor might also check material collected from the rectum to see if there is any blood in it.
Proctoscopy: The doctor might want to look inside the rectum and lower colon with a special instrument called a sigmoidoscope or a proctosigmoidoscope. This examination, called a proctoscopy or procto examination, finds about half of all colon and rectal cancers. The test is usually done in a doctor's office. The patient usually will feel some pressure but usually does not feel pain.
Colonoscopy: The doctor might also want to look inside the rectum and the entire colon with a special tool called a colonoscope. This test can also be done in a doctor’s office. It too causes some pressure, but usually it does not cause the patient to feel pain.