Colorectal Cancer Screening

What is colorectal cancer screening?

Colorectal cancer screening is a check for cancer of the rectum and colon (large intestine).

Why is it important?

Colorectal cancer is the second leading cause of cancer deaths in the US. It is often found too late for a cure. This does not always have to be the case. When found in the early stages, colorectal cancer can often be cured by surgery. If you have screening tests, the cancer can be found in its early stages before it causes symptoms.

If you have a parent, brother, or sister who has had polyps or cancer in the colon, you may be at an increased risk for polyps or cancer. Polyps are growths inside the bowel that sometimes become cancerous. Your healthcare provider may want to screen you for colorectal cancer at an earlier age and more often than people with no family history of these problems. When polyps are found early, they can be removed before they become cancerous.

What are the signs of colorectal cancer?

See your healthcare provider right away if you notice any of these symptoms of possible colorectal cancer:

• rectal bleeding, which might show up as blood on toilet paper, in the toilet bowl, or in bowel movements
• a change in your bowel movements, especially if you have bouts of constipation that alternate with bouts of diarrhea
• pain in your lower abdomen that doesn't go away or that comes back often
• a feeling of discomfort or the urge to move your bowels when there is no stool present.

What are the screening tests?

Tests used to screen for colorectal cancer are:

• FOBT (fecal occult blood test) or FIT (fecal immunochemical test). This is a lab test of a sample of bowel movement (stool) for traces of blood. The test may be done in your healthcare provider's office. However, more often your provider will give you 3 test cards and ask you to collect tiny samples of stool at home on 3 different days. You will put the samples on the cards and return the cards to your provider's office. The samples will be tested to see if any blood is present.

  This test is relatively easy and does not cost much. However, many things can affect its accuracy. Also, things other than cancer can cause blood in the stool. When the FOBT finds blood, more tests need to be done to look for the cause.

  Eating certain foods before this test may lead to incorrect results. For 2 days before your stool is tested, don't eat turnips, horseradish, or red meat. Also, do not take vitamin C, iron supplements, or anti-inflammatory medicines, such as ibuprofen or aspirin, for 2 to 3 days before the test. If you have been taking these medicines daily, ask your provider if you should stop them for a few days before your test. Never stop your medicines without first asking your provider.

  The FIT is the same procedure as the FOBT except a different chemical is used to test the stool samples. This chemical is more specific than the FOBT chemical. For the FIT you do not have to avoid some foods or medicines before you collect the stool samples. Ask your healthcare provider about the specific instructions for your test.

• Flexible sigmoidoscopy. The healthcare provider inserts a slim, flexible, lighted tube called a sigmoidoscope into your rectum. The provider looks at your rectum and the lower part of your colon with the scope. Because this exam looks at just the lower part of the bowel, not all colorectal cancers or polyps can be seen.
• Colonoscopy. After giving you a sedative to relax you, the healthcare provider inserts a scope called a colonoscope into your rectum. This tool is longer than the sigmoidoscope. With it the provider can see most or all of the colon to check for polyps and cancer.

  If a sigmoidoscopy or colonoscopy finds an abnormal area in the rectum or colon, the healthcare provider can use the scope to remove a sample of tissue for lab tests. This is called a biopsy. Sometimes the entire abnormal area can be removed with the scope. If an abnormal area is too large to take out with the scope and it needs to be removed, surgery will be needed.

• Virtual colonoscopy is a way to look at the colon and screen for cancer without putting a scope into the colon. It is a CT scan done with special techniques to look for polyps in the colon and rectum. It is not yet widely available and it has not been shown to be as accurate as actual colonoscopy. If an abnormality, such as a polyp, is seen with the virtual colonoscopy, then a regular colonoscopy needs to be done.
• Double-contrast barium enema. After an X-ray is taken to make sure that your intestines are free of stool, a lubricated tube is inserted into your anus. Barium, which is a fluid that can be seen on X-rays, is passed through the tube into your rectum and colon. Air is pumped into the colon so it is easier for your provider to see any abnormal areas. The flow of barium in the colon can be seen with a fluoroscope, which is a special X-ray machine that can show movement. Other names for this test are air contrast barium enema, lower gastrointestinal (GI) exam, and lower GI.

When should I have screening tests for colorectal cancer?

If you are 50 or older and have an average risk of colon cancer, it is generally recommended that you:

• Have your stool checked for blood (FOBT or FIT) once a year.
• Have your first sigmoidoscopy or colonoscopy at age 50 and then
• Have another sigmoidoscopy every 5 years or colonoscopy every 10 years.

A virtual colonoscopy (computed tomographic colonoscopy) or barium enema may be done every 5 years instead of colonoscopy or sigmoidoscopy.

If you have not recently had a colonoscopy and the results from any of the other tests are positive, then you will need to have a colonoscopy to make sure no cancer is present.

If you have a higher than normal risk for colorectal cancer, ask your healthcare provider when and how often you should be tested for colorectal cancer. You may need to start testing before you are 50.

You may have a higher risk of colorectal cancer if you have:

• a history of colon polyps or previous colorectal cancer
• a history of chronic inflammatory bowel disease, such as Crohn's disease
• a parent, brother, or sister who has had colorectal cancer
• a family history of colon cancer diagnosed before age 50
• a family history of one of the known hereditary colorectal cancers.