FDA Cites Drawbacks of Whole Body CT Scanning
FDA Patient Safety News: Show #6, July 2002

Lots of people are interested these days in whole-body CT scanning, where healthy people can walk in and be screened for a variety of disease conditions. This type of screening is being widely promoted, and it's had great deal of coverage in the press. Here's some information you may want to pass along to your patients.

Proponents of whole body CT screening claim that it enables people without symptoms to find out as early as possible about diseases they may have, so that they can get early treatment. They cite peace of mind as another benefit - that is, the comfort in finding out that the scan has not detected a disease.

But there are serious drawbacks to whole body CT screening for healthy persons, and the FDA is recommending that people consider those drawbacks before they decide to have one of these scans.

First of all, no manufacturer has submitted data to the FDA that demonstrate that this kind of screening is safe and effective. Statements by facilities that perform these scans that imply that the FDA has somehow "approved" or "cleared" or "certified" CT devices for screening are simply not true.

There's also the issue of false positives and false negatives. False positive results, in which the scan indicates abnormalities that don't exist, can lead to more tests and medical procedures, some of those carry their own hazards. And ironically, instead of providing peace of mind, they induce needless anxiety. False negative results, in which the scan fails to pick up an abnormality, can lead to a false sense of security, and they cause an inappropriate peace of mind - which can be dangerous because it can prevent the person from getting proper diagnosis. The point to remember is that these whole body CT scans we don't have good data on how often these false positives and false negatives occur.

And last but not least, these whole body scans deliver a radiation dose much larger than most conventional diagnostic x-ray procedures. And that brings up its own long-term health hazard. The principal radiation risk from medical x-rays, including CT, is the possibility of slightly increasing the probability of developing cancer later in life. For a patient with a real medical need, the benefit of the x-ray procedure far outweighs the risk, even when the radiation dose is relatively high. But with these whole body CT scans, where the benefit is doubtful, the potential harm from the radiation may be greater than the presumed benefit from the scan.

FDA isn't the only organization concerned about this issue. The American College of Radiology, the American College of Cardiology, and the American Heart Association do not recommend whole body CT screening for healthy, asymptomatic people.

Here's what the ACR had to say in a recent press release:

The American College of Radiology at this time, does not believe there is sufficient scientific evidence to justify recommending total body CT screening for patients with no symptoms or a family history suggesting disease. To date there is no evidence that total body CT screening is cost effective or is effective in prolonging life. The ACR is concerned that this procedure will lead to the discovery of numerous findings that will not ultimately affect patients' health, but will result in increased patient anxiety, unnecessary follow-up examinations and treatments and wasted expense.

Bear in mind that CT scans are a valuable and proven diagnostic tool when used to help detect and diagnose specific diseases in patients who have symptoms. The concern here is using these devices for screening in healthy, asymptomatic people. The bottom line is to think twice before undergoing whole body CT scans, because the harm may outweigh the benefit.

Additional Information:

Brochure: Full-Body CT Scans - What You Need to Know.

Whole Body Scanning Using Computed Tomography (CT). April 17, 2002.

FDA Patient Safety News is available at www.fda.gov/psn