A former Food and Drug Administration scientist said his job was eliminated after he raised concerns about the risks of radiation exposure from high-grade medical scanning.
Dr. Julian Nicholas said at a public hearing that he and other FDA staffers "were pressured to change their scientific opinion" after they opposed the approval of a CT scanner for routine colon cancer screening. Nicholas said that he objected to exposing otherwise healthy patients to the cancer risks of radiation.
After FDA officials pushed ahead with plans to clear the device, Nicholas, now a physician at the Scripps Clinic in San Diego, said he and eight other staffers raised their concerns with the division's top director Dr. Jeffrey Shuren last September. The device apparently is still under review.
"Scientific and regulatory review process for medical devices was being distorted by managers who were not following the laws," Nicholas said. A month later Nicholas' position was terminated, he said.
Nicholas does not think there was undue influence by the manufacturer in his ouster, but that his more cautious stance was in opposition to that of FDA higher-ups.
The allegations about suppression of scientific dissent come at an inopportune time for the agency.
The FDA announced an effort to improve scanning safety in February after three California hospitals reported hundreds of acute radiation overdoses last year, with many patients reporting lost hair and skin redness.
FDA medical reviewer Dr. Robert Smith, a colleague of Nicholas, said he hoped the FDA would learn a lesson from Nicholas' testimony.
"Science must not be ignored, suppressed, or distorted as that endangers the public," Smith told the audience.
Smith, who still works for the agency, supported Nicholas' conclusion that CT scanning for colon cancer should be rejected on safety grounds.
As a reviewer of medical device applications, Nicholas repeatedly rejected a manufacturers' request to market a CT scanner specifically for colon cancer screening. According to Nicholas, between 1.5 and 2 percent of cancers are caused by CT scanning, and he did not want to see scanning used when a conventional colonoscopy could be used instead.
CT scans provide detailed, three-dimensional images of the body, but at a cost — one CT chest scan carries as much radiation as nearly 400 chest X-rays, according to the FDA.
In a June 2009 letter to senior managers, Nicholas stressed that patients should be warned of the radiation risks of CT scanning.
"I hope you understand that the failure to include a warning on the label will mean that patients will undoubtedly develop abdominal cancer and leukemia," Nicholas wrote "It may not happen tomorrow, but yes, sadly it will happen."
Nicholas said he was ridiculed by agency managers for "raising the bugaboo of radiation."
Medical experts are somewhat divided over the usefulness of the so-called virtual colonoscopy, which was designed as a less-invasive alternative to colonoscopy.
The American Cancer Society and the American College of Radiology endorse the procedure for its potential to boost screening for colon cancer, the country's second leading cancer killer.
But some insurers and the government's own Medicare program refuse to pay for the procedure, questioning its effectiveness and the rationale of exposing healthy patients to radiation.
Supporters of the procedure say that virtual colonoscopies use low levels of radiation that don't threaten older patients who get colonoscopies. Radiation exposure that causes cancer accumulates over a lifetime, making younger people the most at risk population for screening.
CT scans became popular because they offer a quick, relatively cheap way to get an almost surgical view of the body. Doctors are free to use them as they choose, but FDA approval for specific indications allows companies to tout those uses in marketing materials.
The average American's radiation exposure has nearly doubled in the last three decades, largely due to CT tests, according to the FDA.
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