Cancer Risk From CAT Scans: Why You Shouldn't Worry

While new research points to imaging's cancer risk, one doctor urges calm.


July 20, 2007 — -- A recent study published in the Journal of the American Medical Association concluded that the use of a newer and faster type of CAT scan (also known as computerized tomography or CT) can increase a patient's potential risk of cancer when used to image the heart or the major vessels around it.

This risk -- which applies particularly to breast and lung cancer cases -- is greater for young female patients.

Researchers found, for example, that a 20-year-old woman's potential risk of developing cancer was as great as one in 114 for a single scan of the heart and aorta -- the major artery leading from the heart. In comparison, the risk for an 80-year-old was about one in 3,000.

CAT scans are used for far more than diagnosing heart problems. They have been used increasingly over the last few years for many illnesses and injuries.

CAT scans are reportedly performed some 62 million times a year, and their popularity is on the rise.

As one example, the number of CT examinations of the cervical spine performed in the emergency room has increased nearly 500 percent in recent years, while emergency room traffic has only increased by a small fraction of that.

So do these new study findings mean that we should stop using CAT scans to image the heart?

No, they don't.

Heart disease is the leading killer of both women and men in the United States, and CAT scanning is an important tool we use to diagnose heart disease effectively so we can treat it.

That said, physicians and patients should be very aware of the potential risks that CAT scans can pose, and take care to determine whether it's the best diagnostic tool in a given case.

While the new CAT scan examinations are quick and relatively painless -- often all a patient must endure is the placement of an IV -- there are other methods by which we can diagnose heart problems, including imaging examinations such as ultrasound or magnetic resonance imaging (or MRI), that do not use radiation.

Additional methods include stress tests, in which a doctor evaluates blood flow to the heart through various methods of monitoring. Because the information from these different studies can vary, the type or order of heart imaging examinations depends on what the doctor is trying to see.

Risks should be taken into consideration, such as radiation dose for young women. For example, a young woman with chest pain, who also has a family history of breast cancer, might not be the best candidate for CAT scanning, as opposed to an 80-year-old man with the same symptoms.

What can you do about this? CAT scans should only be used following discussion with your physician and should only be performed at reputable facilities with staff who are experts in performing these types of scans.

It is also now possible for people to pay out of pocket for CAT scans with the intent of achieving peace of mind about what is going on inside their bodies. I cannot stress enough that these CAT scans should not be taken lightly; they are not to be used in order to simply be sure everything is "OK."

When you or a loved one has symptoms such as chest pain that might warrant a heart CAT scan, I encourage you to ask questions about what kinds of tests are available to evaluate your symptoms and if a CAT scan is the best choice.

In the end, you should remember that in certain cases a CAT scan will be the best option to accurately diagnose your condition, provide immediate and lifesaving information, and get you on the road to treatment.

I have no doubt that CAT scans will remain very important diagnostic tools for many illnesses and injuries, including heart disease. They offer a highly detailed look inside a patient's body that cannot always be duplicated by other diagnostic tools.

But this study and others like it remind us that there are potential risks that need to be considered. We must continue an open dialogue -- patient to physician and physician to physician -- so that we can do our best to reliably diagnose disease without exposing patients to undue risk at the hands of our own diagnostic equipment.

Dr. Donald Frush is director of the division of pediatric radiology at Duke University Medical Center in Durham, N.C.