A group of experts says most people over age 75 do not need routine tests for colon cancer. The advice is part of a report from the U.S. Preventive Services Task Force. This independent group offers advice to doctors on preventive care and testing. The new report was published November 4 in the journal Annals of Internal Medicine. It also says there's still not enough proof that two new tests for colon cancer are effective. The tests are CT colonoscopy, also called "virtual colonoscopy," and DNA stool tests.

By Mary Pickett, M.D.
Harvard Medical School

What Is the Doctor's Reaction?

Colon cancer is the third most common cancer in the United States for both men and women.

Doctors say you should get tested for colon cancer starting at age 50. Tests for large groups of people without symptoms are known as screening.

This year, two groups have updated their advice on colon cancer screening. They are the American Cancer Society and the U.S. Preventive Services Task Force. The cancer society report also came from the U.S. Multi-Society Task Force on Colorectal Cancer and the American College of Radiology. It was issued several months ago. The U.S. Preventive Services Task Force guideline was published today.

These groups did not give exactly the same advice. Both, however, gave a variety of options.

Colonoscopy is the favorite test for colon cancer screening. It is very effective in finding colon cancer. If the test finds a growth called a polyp, the polyp can be removed at the same time.

The new task force report left several options off its list. It said we need more evidence before we know for sure that the tests are effective.

The task force said you can stop having colon cancer screening after age 75. At this age, you have a limited life expectancy. This reduces the value of finding cancer in an early stage.

Colon cancer screening is useful because it can find cancer before it has spread to lymph nodes. Early treatment can cure about 9 out of 10 people. If colon cancer is allowed to reach a more advanced stage, it usually can't be cured. Colon cancer is the second leading cause of cancer death in the United States.

Colon cancer screening also can prevent cancer. Some of the screening tests can find polyps. Colon cancer often begins on the surface of a polyp. Removing the polyps helps to prevent colon cancer.

What Changes Can I Make Now?

More than 4 out of 10 people over 50 have had a colonoscopy. If you are over 50 and you have not been screened, choose one of the tests below and arrange to have it done. Here are the options that both expert groups recommend:

• Colonoscopy every 10 years -- The entire colon is examined with a camera at the end of a thin, flexible "scope."



• Fecal occult blood testing (FOBT) every year -- This test detects blood from the esophagus, stomach, small intestines and colon. If it finds blood, a colonoscopy is needed to find the source of bleeding and see if it is cancer. Both expert groups say your doctor should use a modern "high sensitivity" FOBT test.



• Flexible sigmoidoscopy every 5 years, plus fecal occult blood testing -- The doctor uses a camera at the end of a thin, flexible scope to look at the lower one-third of the colon. This test costs less than a colonoscopy. You also don't need drugs to make you drowsy. If the test finds polyps, a colonoscopy is needed to remove them.

The American Cancer Society also says the tests below are reasonable choices. The task force does not recommend them:

• Double-contrast barium enema every 5 years -- The rectum is filled with X-ray contrast dye through a tube. X-rays are used to look inside the colon. If polyps are found, a colonoscopy is needed to remove them.



• CT colonography (virtual colonoscopy) every 5 years -- The rectum is filled with X-ray contrast dye through a tube. Computed tomography (CT), a form of X-ray, is used to look inside the colon. If polyps are found, a colonoscopy is needed to remove them.



• Fecal immunochemical test (FIT) every year -- Three stool samples are tested for "human hemoglobin," which is in fresh blood. If the test finds blood, it usually means there's bleeding from the colon. A colonoscopy is needed to find the source of blood.



• Stool DNA test -- It's unclear how often this is needed. An entire bowel movement must be packed in ice and tested. Certain genes can be found in cell fragments in the stool if cancer is present. This test is new. It's not as reliable as some of the other methods.

What Can I Expect Looking to the Future?

Colon cancer is the second leading cause of cancer death in the United States. Screening for colon cancer saves lives. Colon cancer screening is one of the most sensible ways you can protect your health.

Some insurance plans require patients to pay for a portion of the test. Some people decide to wait until they have better insurance. If this is a problem for you, choose a less costly option such as yearly stool testing. Change in the U.S. health care system may be on the political horizon. Still, waiting for better insurance is a bad screening plan.