Radiation warnings ignored

Radiation warnings

Urgent warnings by government experts about the risks of routinely using powerful CT scans to screen patients for colon cancer were ignored by the Food and Drug Administration, according to agency documents and interviews with agency scientists.

After staying quiet for a year, the scientists say they plan to make their concerns public at a meeting of experts on Tuesday called by the FDA to discuss how to protect patients from unnecessary radiation exposures. The two-day meeting is part of a growing reassessment of the risks of routine radiology.

The average lifetime dose of diagnostic radiation has increased sevenfold since 1980, driven in part by the increasing popularity of CT scans. Such scans can deliver the radiation equivalent of 400 chest X-rays.

An estimated 70 million CT (for computed tomography) scans are performed in the US every year, up from three million in the early 1980s, and as many as 14,000 people may die every year of radiation-induced cancers as a result, researchers estimate.

The use of CT scans to screen healthy patients for cancer is particularly controversial. In colon cancer screening for instance, the American College of Radiology as well as the American Cancer Society have endorsed CT scans, in a procedure often called a virtual colonoscopy, while the American College of Gastroenterology recommends direct examinations in which doctors use a camera on a flexible tube, The New York Times reports.

Growing battle

Growing awareness of the risks of scanning led FDA scientists several years ago to begin demanding more and better information from manufacturers to prove that their devices actually were effective for such clinical applications as cancer screening and mapping blood flows in the brain.

But agency managers responded that suddenly changing the rules for the devices would be inappropriate and unfair to manufacturers.

The battle between the two sides intensified over a push by some device manufacturers and radiologists to use CT scans routinely to screen healthy patients for lung, colon and other cancers. At stake was another rapid increase in radiation exposures and scans worth hundreds of millions of dollars annually.

For patients, navigating the debate can be difficult because doctors, patient advocacy groups and manufacturers often endorse positions that are in their economic self-interest. Radiologists, who often own and use CT machines, for instance, often endorse their use; while gastroenterologists, who often own and use camera scopes, often favor their own methods. Patient groups often get financing from drug and device makers, or physician-specialty groups.

Jodie Humphries

Jodie Humphries graduated from Bath Spa University with a BA Hons in Creative Writing in 2008. She has worked for GDS Publishing for the digital group since July 2009. She has previous experience with writing for the web, running her own website since April 2007.

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