American women, and their doctors, have been thrown into a state of confusion by the release of a new study of the likely benefits--and possible harms--of screening mammography among 40-49 year olds. A federal panel--the U.S. Preventive Services Task Force (USPSTF)--analyzed examined recent studies and came to a very different conclusion than they did seven years ago: mammograms for women under 50 should be deferred, and women over 50 need only get the exam every two years.
(The panel also cast doubt on the benefits of clinical breast exams--performed by a doctor--and advised eliminating entirely breast self exams as useless in saving lives from breast cancer).
These recommendations--which have no official force--fly in the face of what I learned in medical school and practiced during my twenty years in internal medicine. If I advised a 45-year old woman to forgo mammogram she was expecting to get, it is most likely she would have made her next appointment with the doctor down the block. Even experienced, conscientious caregivers will have trouble explaining the recommendations to their patients, assuming they understand them themselves.
Won't mammograms detect breast tumors early, thus saving lives and preventing the suffering associated with more extensive procedures for later-stage cancers, people ask? Why is the advisory applicable to 40-somethings while mammograms are still OK for over-50s?
While mammography reduces death from breast cancer equally in both age groups--around 15%--the adverse effects of screening exams cause more harm in the younger group, since their rate of potentially lethal breast cancer is much lower. That is, more young women suffer from the consequences of false positive tests--nodules and calcifications that need to be investigated further--but, most likely, constitute no health risk (sometimes called "incidentalomas" by radiologists). Further, some slow-growing tumors--actual cancers--would never have become a risk to life or health but will need surgical intervention nevertheless, once detected. In their collective wisdom, the USPSTF experts determined that the age cut-off at which the benefit/risk ratio for doing the exams that can lead to such dilemmas is: 50 years.
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The American Cancer Society, the American College of Obstetrics and Gynecology--and many of America's doctors and their patient--strongly disagree. They wonder why the harm done by misleading mammograms is unacceptable for younger women while tolerable for their elders, and they said so in no uncertain terms. Many women have said, in effect: "OK, I heard the experts discussing these statistics--and I still want my annual mammogram." (And of course women with specific higher risk factors should certainly continue to adhere to their doctor's advice on more intensive protocols for early detection.)
Let's be perfectly clear: the new advisory is a population-based policy recommendation and is _not_ meant to be an authoritative mandate to women and doctors. The decision to have--or defer--a mammogram for an under-50 year-old illustrates why there are no "right answers" in the art of medical practice. It remains an intensely personal decision.
Such balancing may well become more frequent in the future, if healthcare reform leads to a tightening of medical expenditures, as is likely. Indeed, the main impact of the new study will be its influence on insurance coverage, since both government and private insurance plans may well take guidance from the USPSTF conclusions and reduce coverage for screening mammograms. Another likely unintended effect will be more women skipping exams, due to confusion and the perception that medical paradigms shift with the wind.
Similar controversies have been rumbling among learned medical bodies over the advisability of cancer screening with PSA for prostate cancer and CT screening for lung cancer among current and former smokers. In both instances, the superficial approach asserts that finding cancer--any cancer, no matter how small or indolent--is worthwhile, and that when it is found, surgical removal is warranted. But careful studies have shown that lives are not necessarily saved by such screenings, and much needless harm can be inflicted when test findings are reflexively pursued. The same caveats need to be applied to screening for breast cancer.
Until we have the technological expertise to discern true, life-threatening abnormalities from benign nodules and slow-growing malignancies of no real threat, the best device for dealing with such calculations is a physician who knows the patient and is willing to be flexible in balancing "best practices" and the individual patients' needs and concerns.
Dr. Gilbert Ross is Medical Director of the American Council on Science and Health (ACSH.org).
