Q&A: CT Colonography

Q: What improvements have been made in screening for colorectal cancer?

A: Let’s face the facts—people don’t enjoy getting screened for colorectal cancer. Perhaps it’s just the thought of what you have to do, or maybe you heard that the tests are complicated and uncomfortable. Less than half of the people in this country who should be screened, actually do it.

That’s too bad, because we could save thousands of lives every year when it comes to colorectal cancer if we did what we already know prevents colorectal cancer or finds it early.

There are a number of ways to get the job done, including tests that look for blood in the stool, colonoscopy, sigmoidoscopy, or, in some instances, barium enema.

Now, a new type of X-ray test called a virtual colonoscopy, or CT colonography (CTC), is being used more often as an alternative to colonoscopy for colon cancer screening. Studies show CTC can find polyps and cancers in the colon. You still have to go through the bowel prep, but you don’t have to be put to sleep to get the test. However, if the doctor finds something in the colon that must be removed or further examined, you will likely have to make another appointment to get a traditional colonoscopy and possibly have a biopsy or a polyp taken out.

Interestingly, there are no long-term studies that show CTC—or colonoscopy, for that matter—actually reduces deaths from colorectal cancer more than, let’s say, the stool blood tests. Still, based on what evidence we do have, the American Cancer Society recently concluded that the test was effective in both preventing colorectal cancer and finding it early, when treatment is most effective.

Unfortunately, the test is still new and isn’t widely available. Many commercial insurers don’t cover it yet, and Medicare hasn’t made a decision if they will pay for the test or whether they even consider it acceptable for colorectal cancer screening.

If you are 50 or older and at average risk for colorectal cancer, talk with your health care professional and determine which test is best for you. But no matter which test you decide on, just do it! It may save your life.

Len Lichtenfeld

, MD

, is deputy medical officer for the American Cancer Society.