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Do Yearly Mammograms Save Women's Lives?

Controversial new recommendations on breast cancer prevention have caused a stir in the women's health community. But do yearly mammograms really change death rates?
 
 
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EDITOR'S NOTE: Since this article was written, Health and Human Services Secretary Kathleen Sebelius hasyielded to the uproargenerated by new guidelines from the U.S. Preventative Services Task Force, and essentially urged women to ignore the committee's recommendations, and continue with their yearly mammograms, and monthly self-examinations.

The new recommendation from the U.S. Preventative Services Task Force that women under 50 should not undergo routine mammography is generating a lot of controversy -- it is a direct challenge to the strong message women have been receiving for two decades that they should have yearly screening starting at age 40. The task force also recommends that women age 50-74 have a mammogram every two years (rather than yearly) and finds that there is little benefit in screening women over 74 at all.

To the experts who have been questioning the benefits of mammography for several years, these recommendations are no surprise -- and they are welcome. The World Health Organization, and many European countries where the government pays for routine mammography screening, already follow these guidelines. But how is this news playing in Peoria?

The initial reaction from many health professionals, breast cancer survivors and advocates has been outrage and anger, with many insisting that women's health will be compromised if these recommendations are implemented. Still others see the new guidelines as evidence that the government is using comparative-effectiveness studies to justify rationing care. Leading this onslaught are some key members of the cancer establishment: The American Cancer Society, The American College of Radiology and the National Cancer Institute.

Dr. Otis W. Brawley, chief medical officer of the ACS, released this statement in response to the Preventative Task Force report: "As someone who has long been a critic of those overstating the benefits of screening, I use these words advisedly: this is one screening test I recommend unequivocally, and would recommend to any woman 40 and over, be she a patient, a stranger, or a family member."

Dr. Carol H. Lee, chair of the American College of Radiology Breast Imaging Commission, launched a blistering attack on the Preventative Services Task Force recommendations, calling them  "unfounded" and "incredibly flawed," saying that, if adopted, they will "result in many needless deaths." Furthermore, says Lee, they  "seem to reflect a conscious decision to ration care." Lee's organization, of course, has reason to worry about the long-term effects of this report; the American College of Radiology estimates that $3.3 billion was spent on mammograms in the last year alone.

In reality, the mission of the Preventative Services task force is to provide evidence-based recommendations and treatment guidelines for clinicians -- they are not charged with rationing care. Appointed by the Department of Health and Human Services, they are an independent group of 16 experts who specialize in prevention and primary care. True to their mission, the task force members were quite thorough in their research. According to the New York Times "in order to formulate its guidelines, the task force used new data from mammography studies in England and Sweden and also commissioned six groups to make statistical models to analyze the aggregate data."

These six independent groups -- located at academic medical centers -- were comprised of researchers from CISNET, the National Cancer Institute-funded Cancer Intervention and Surveillance Modeling Network. Each group used their own model to examine 20 screening strategies with different starting and stopping ages and intervals. Modeling estimates the lifetime impact (outcomes including benefits and harms) of breast cancer screening mammography.

Their findings were remarkably consistent. In the Times article, Donald A. Berry, a statistician at the University of Texas M. D. Anderson Cancer Center and head of one of the modeling groups says, "The models were the only way to answer questions like how much extra benefit do women get if they are screened every year."

‘We said, essentially with one voice, very little," Dr. Berry said. "So little as to make the harms of additional screening come screaming to the top."

In fact, the CISNET analysis showed that screening every other year in women over 50 maintains almost all of the benefit of annual screening with only half the number of false-positives.

To summarize their other findings, the task force panel determined that the "harms" or risks of yearly mammography screening for women under 50 outweighed its benefits. These risks include anxiety, false positives that lead to surgical biopsies and over-diagnosis (and over-treatment) of precancerous lesions that would never progress or might disappear on their own. The group found that in women 40-49, 1,904 women must be screened for 10 years before one cancer death is prevented. That ratio drops to 1 death prevented for 1,300 women age 50-59 screened, and 1 for 377 for women 60 to 69 years old. 

I've written about the overuse of mammography and the many studies that back up the task force's recommendations here and here in previous posts. It's an issue that has gained traction in recent months, and despite rejection of the new recommendations by some prominent cancer groups, there are others, like the National Breast Cancer Coalition, who support them -- or at least see the guidelines as important tools for helping women make informed decisions about their care. They are too important to be shrugged off as outliers.

The massive campaign to screen early and screen regularly has become so much a part of our culture that it is very difficult to accept an alternative view. Change will not come easily -- and by necessity, it must be gradual. Women have been told for the last 20 years that they should have yearly mammograms starting at age 40. They have been told by countless magazine articles and public health campaigns to conduct self-exams in the shower -- another screening technique the Preventative Task Force no longer recommends.

Through all of these entreaties -- along with the powerful anecdotes from survivors who credit mammography with saving their lives -- women have been made to believe that screening is the same as prevention. Those ideas are hard to dislodge, says Nancy Berlinger, a research scholar at The Hastings Center who has written about comparative effectiveness studies and cancer treatment. "Apart from not smoking, there are not a lot of things you can do to prevent cancer. The idea of a test like mammography as a kind of safety belt, something that provides personal protection against cancer, is very strong." The worry, she says, is that if you take away mammograms, "you leave nothing but fear in its place."

For now, it is unlikely that women will lose insurance coverage for mammography screening anytime soon. The Centers for Medicare and Medicaid Services announced that the new guidelines will not change how the agency covers mammograms for Medicare patients. And the Wall Street Journal reports that Susan Pisano, spokeswoman for America's Health Insurance Plan, an industry trade group, "anticipates mammogram coverage will continue even for those who fall outside the new guidelines' target age range. What may change, she says, are insurers' aggressive outreach efforts to get women to get their screening, such as the reminder postcards they used to receive about getting their annual mammogram."

There is a larger concern here that goes beyond mammography. As evidence has grown that the benefits of some screening tests have been oversold and that there are significant risks involved in widespread use of the techniques, the response from the cancer establishment has been to forcefully dismiss the findings. Could it be that entrenched interests -- in screening, surgery, chemotherapy and other treatments associated with diagnosing more and more cancers -- are impeding scientific evidence? Will we see this same dismissal of comparative effectiveness data when it comes to prostate cancer screening and treatment, cholesterol-lowering drugs, diabetes treatments or other high-cost, high-profit health interventions?

It will take some time for the public and practitioners to really digest the Preventative Task Force's mammography recommendations. The Mayo Clinic, for example, an organization that prides itself on using comparative effectiveness studies to drive clinical practice, characterized the new guidelines as "interesting" but Dr. Sandhya Pruthi, director of the Mayo Clinic Breast Clinic, said "the current practice is to continue with annual screening mammography for women over age 40."

Some practitioners say that the recommendations should be used as a starting point for deeper conversations between women and their doctors about what makes the most sense for them personally. Screening, like treatment for breast cancer, is not a one-size-fits all endeavor. If a woman has a genetic propensity for breast cancer, has close family members who have been diagnosed with the disease or has already had a bout with cancer, she will probably want to receive regular screening, even in her 40s. But for the rest of us, our risks and benefits need to be carefully reconsidered depending on age, lifestyle and comfort level with the stress of false positives, for example.

In the end, the Preventative Task Force mammography recommendations are supported by strong data and good science. The study authors do not have conflicts of interest and despite charges from some critics, they are not connected to the government and did not have rationing of health care resources as their underlying mission. Therefore it seems short-sighted and counter-productive for groups like the American Cancer Society to so forcefully dismiss the recommendations out of hand. Instead, why not use them as the first step in advancing a changing view of breast cancer screening and the real risks and benefits involved. It's only by accepting these shortcomings that we can truly focus on developing better methods for detecting early tumors, better methods for distinguishing lesions that will progress from those that won't, and eventually, giving women a better "safety belt" to use against the threat of breast cancer.

Naomi Freundlich is a patient advocate at the Century Foundation who writes regularly for HealthBeat.