Q&A: CT Scans and Cancer Risk

Q: Do CT scans increase the risk of cancer?

Recent articles in the Archives of Internal Medicine have once again pointed out that CT scans, also known as computed tomography, are not necessarily without risk. As noted in one of the reports, published last December, it is possible that 29,000 future cancer diagnoses and 14,500 cancer deaths in the U.S. may be related to having had a CT scan in 2007.

Since their introduction into clinical practice in the 1970s, CT scans, which use much higher radiation doses than a regular X-ray, have become more routine for diagnosing a disease, or to just “be sure nothing is wrong.” Some experts feel they are being overused and as a substitute for taking the time to perform an adequate history and physical, and having a discussion with the patient. But in other circumstances—such as in emergency departments nationwide—a CT scan is the fastest and best way to be certain what is happening with a very ill person.

So what do you do if your doctor recommends you have a CT scan?

If you are a cancer patient, getting repeated CT scans may be a routine and accepted part of your treatment program, although the frequency of scans should be carefully considered. But if you don’t have cancer or another serious illness, it is perfectly OK to ask the doctor whether you really need the scan, and whether the results will likely cause a change in your treatment.

Of course, doctors sometimes recommend CT scans because they are afraid they might miss a serious underlying condition that might not be suspected based on the history, physical, and laboratory studies. Good communication between health care professionals and their patients can go a long way to determine whether you really need a CT scan.

Like many things in life, nothing is free of risk. With CT scans, we need to understand that the risks from the radiation are real and not inconsequential.

So if you really need the scan, get it. But if the scan is just being done to “make sure,” talk with your doctor about whether another approach may be just as effective and less risky.

—Len Lichtenfeld, MD, is deputy chief medical officer for the American Cancer Society