MAMMOGRAMS: Study Finds High Number Of False Positives
Nearly half of the women who undergo an annual mammography for breast cancer will experience at least one false alarm over a period of 10 years -- leading almost one in every five of these women to undergo an unnecessary biopsy, according to a study in today's New England Journal of Medicine. Of the 2,400 women ages 40 to 69 enrolled in Massachusetts-based Harvard Pilgrim Health Care whose cases the researchers studied, one third "had abnormal tests results requiring additional evaluation, even though no breast cancer was present." Extrapolating from these findings, the University of Washington and Harvard University researchers estimate that "16 million women would have at least one false positive mammogram and 7 million would have at least one false positive clinical breast examination." In financial terms, this means that for every $100 spent on screening, "an additional $33 was spent to evaluate the false positive results." Dr. Joann Elmore, the lead author of the study, and her colleagues conclude that better techniques are needed "to decrease false positive results while maintaining high sensitivity" necessary for correctly diagnosing early signs of breast cancer (4/16 issue).
The number of false alarms that the researchers found "is about twice as high as previous 'guesstimates,'" according to Barnett Kramer, a cancer screening expert at the National Cancer Institute (Rubin, USA Today, 4/16). But the study "confirms what doctors and many of their patients have long known: that although regular mammograms are the most effective way to detect breast cancer early and thereby save lives, they also cause needless fear," the San Francisco Chronicle reports (Perlman, 4/16). The Washington Post reports that the study "highlights an enormous underappreciated emotional toll being exacted upon women, many of whom must endure weeks or even months of worry that they may have cancer before finally learning that they do not." Elmore said, "We've been spending so much time looking at accuracy and efficacy and reducing mortality (with breast cancer screening), but we haven't been looking at the big picture, which includes the problems that come with false positives." George Annas, professor of health law at the Boston University School of Public Health, noted that many doctors believe "false positives are painless. But people always imagine the worst. These women go through hell. And we haven't taken these costs into account at all as we should" (Weiss, 4/16).
In order to squelch the "psychological sequelae" that misdiagnosed women face, the study's authors write that physicians and other health care providers need to do a better job of relaying the information to women, ensuring that they understand the risks and benefits (NEJM, 4/16 issue). "Women shouldn't be surprised if one of those test results requires more follow-up. If they just understand that this is a part of screening, they will be less concerned when it happens," said Harvard University Medical School Professor Dr. Suzanne Fletcher, one of the co-authors (Kong, Boston Globe, 4/16). An accompanying editorial in today's NEJM highlights the need for better communication. Dr. Harold Sox of the Dartmouth-Hitchcock Medical Center writes, "Women rely principally on their personal physicians for guidance and recommendations and for help in reaching a decision. Those who counsel women about screening mammography should learn the facts and convey them accurately. ... We should tell our patients what may happen, listen to them and help them decide" (4/16 issue).
Don't Worry, Be Happy
Other experts believe the study "overstated the risks of breast cancer screening," the Post reports. Stephen Feig, director of breast imaging at Thomas Jefferson University Hospital, said "[f]ollow-up tests are invaluable for ensuring that a breast is normal and for finding nascent cancers before they spread." He agreed that undergoing additional tests might prompt "some anxiety," but said that "the anxiety is very slight" (4/16). ABC's Dr. Tim Johnson reported, "If you start lowering the degree of suspicion, trying to make the rate of false positives lower, you could run the risk of the opposite direction -- that is saying there is no cancer when in fact there is." He said doctors "tend to err on the side of safety and that will bring some false positives." Adding further clarity to Johnson's report, ABC's Peter Jennings said, "In other words, don't be frightened by today's headlines" ("World News Tonight," ABC, 4/15). The cancer institute's Kramer also steered away from becoming overalarmed by the study. "Women need to be aware of both the positive potentials of mammography and the downsides, because there are some, just like there are with any other medical technology," he said (Maugh, Los Angeles Times, 4/16).
Don't Sue Me
Breast cancer screening experts point out that "the U.S. malpractice system places great pressure on American radiologists to, if anything, overdiagnose breast cancer, so as not to be blamed later for missing a nascent tumor," the Post reports. "The single biggest source of malpractice suits for radiologists is for missing a breast cancer," said one of the study's co-authors, Dr. Philip Arena, who called for more "one-stop" screening clinics where women could be re-tested immediately after a mammography finds a possible problem (4/16). Massachusetts General Hospital's Dr. Daniel Kopans criticized the study, noting that "the estimated risk of a false positive that leads to biopsy -- a much narrower definition of 'false positive' -- is less than one in five after a woman has had 10 mammograms, rather than the one-in-two risk based on the study's broader definition" (Boston Globe, 4/16). Emory University's Dr. William Wood said, "The feeling of most of us who treat breast cancer is we would rather err on inconveniencing some of our patients to save the lives of others, than to try to and minimize inconvenience and lose a few lives to do it" ("World Today," CNN, 4/15). The Los Angeles Times further reports that the study is "unlikely to change recommendations by the American Cancer Society and the National Cancer Institute that women have a mammogram every other year in their 40s and every year after they reach 50" (4/16).