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New research calls into question the computer technology that helps doctors interpret mammograms. It's supposed to spot breast cancers that a doctor might miss. But a study in this week's New England Journal of Medicine concludes the computer programs don't work as advertised and may do more harm than good.
NPR's Richard Knox has the story.
RICHARD KNOX: The computer programs are supposed to be like having a second opinion on each mammogram. In a darkened room at Beth Israel Deaconess Medical Center in Boston, Dr. Ferris Hall demonstrates how so-called computer aided detection works.
Dr. FERRIS HALL (Beth Israel Deaconess Medical Center, Boston): We're looking at this mammogram now. We're looking at all four views up at once, and I'm going to press a little button here which gives us the computer-aided detection, and lo and behold we can see that there's a circle on three of the images.
KNOX: That means the computer has spotted something the doctor should pay close attention to. The problem is, most of the time it's not a problem.
Dr. HALL: We have to look at one to 2,000 marks on mammograms and dismiss them for every one that marks a cancer. So therein lies the problem, which is that you have to dismiss so many of these marks because they aren't going to be cancer, but it may call your attention to something that you overlooked.
KNOX: Dr. Joanne Elmore and her colleagues wanted to know the bottom line on computer-aided mammography. They collected data from 43 mammography centers in three states to see if those that used the computer technology did better.
Dr. JOANNE ELMORE (Researcher, University of Washington): We had hoped to find that more cancers would be detected, and obviously we do not like missing breast cancers. And unfortunately we did not find that the programs improved the cancer detection rate.
KNOX: Elmore, a researcher at the University of Washington, says radiologists may be overwhelmed by the high numbers of marks that computer programs are putting on mammograms. One thing is clear. Centers that use computer-aided mammography bring many more women back for more studies.
Dr. ELMORE: Their recall rate, they send a woman a letter and say, Dear Mrs. Smith, don't worry, but we'd like you to come back for a few additional tests to make certain you don't have cancer; this recall rate increased by 31 percent.
KNOX: And even though the technology doesn't detect any more cancers, the number of breast biopsies went up 21 percent. Elmore says women should ask whether their hospital or mammography center uses computer-aided detection, as about 40 percent of U.S. centers do. If so, they'd know they have a higher chance of being called back for unnecessary tests.
Dr. ELMORE: Some women do not like the experience of getting called back for additional testing. They find it very stressful. They find it very time-consuming, very expensive, and the idea of possibly also going on to have a biopsy when you don't have cancer is something that they don't want to put up with. Whereas there are other women who may have just had a best friend diagnosed with breast cancer. They want to make certain nothing's missed, and they don't mind putting up with additional testing. I think each woman should make this decision on her own.
KNOX: The new study indicates that computer-aided mammography is doing more harm than good by exposing women to unnecessary tests and anxiety, but Elmore doesn't expect it will cause centers to abandon the technology.
Dr. ELMORE: So many facilities in the United States have already purchased these programs and have been actively using them that we're at the stage where it's hard to make an abrupt u-turn.
KNOX: Ferris Hall, the Boston radiologist, agrees.
Dr. HALL: This is a substantial hit for computer-aided detection, but in no way is it dead.
KNOX: Hall says that's partly because years ago, when computer-aided mammography was new, Medicare and private insurers started paying extra for it. That's one big reason why the technology spread so fast.
Dr. HALL: Many of us got this with the idea that we would help patients and pick up more things, but that wasn't proven. What we did know was we were going to be paid a little more and that we would be keeping up with our neighbors who could advertise and did advertise this as, well, we have computer-aided detection.
KNOX: So the main message of the new study is, doctors who use it need to be more skeptical about it. Richard Knox, NPR News.
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