January 14, 2010
Health care experts confront controversy over new mammography guidelines
When the U.S. Preventive Services Task Force of the Department of Health and Human Services issued new breast cancer screening guidelines in November, the ensuing confusion, alarm and extensive media coverage fueled a national debate over how to interpret the new recommendations.
It’s a controversy that continues to cause confusion among patients, health care professionals and lawmakers.
A month after the new guidelines first made headlines, an interdisciplinary panel of researchers and health care providers gathered Dec. 17 at the UW Health Sciences Center to try to make sense out of the controversy.
Presented by the Institute of Translational Health Sciences at UW Medicine — a cross-institutional organization that includes UW Medicine, Fred Hutchinson Cancer Research Center, Group Health Research Institute and Seattle Children’s — the panel discussion featured five experts who each brought their own perspective to the debate.
Based on data from randomized clinical trials, as well as community data and statistical modeling, the guidelines recommend against routine screening mammography in women 40 to 49 and would scale back screening for women 50 to 74 from annually to every other year. The recommendations question the usefulness of mammography for women 75 and older. They also counsel against clinicians taking the time to teach women to perform breast self-exams, and question the usefulness of clinical breast exams.
The task force said the new guidelines strike a better balance between the benefits of early cancer detection and the unnecessary anxiety and extra costs associated with false positives, which sometimes result from the tests.
Dr. Joann Elmore, UW professor of Medicine and section head of the Division of General Internal Medicine at Harborview Medical Center, served as panel moderator. She said evaluating the efficacy of cancer screening tests “is very challenging. It takes hundreds of thousands of individuals in randomized trials, and you have to follow them forward for 15 to 20 years to look at outcomes.”
Elmore said these latest recommendations indicate “that the benefits are perhaps smaller than we had hoped for, and there are unexpected harms.”
Citing previous recommendations from the task force over the years, Dr. Alfred Berg, UW professor of Family Medicine and immediate past chair of the Preventive Services Task Force, said a historical perspective is key to understanding these latest recommendations.
“This really isn’t much different from previous guidelines,” he said.
In 1989, the task force recommended mammography every 1 to 2 years for all women beginning at age 50 and concluding at approximately age 55. In 1996, the recommendation was for screening every 1 to 2 years for women age 50 to 69. There was insufficient evidence to recommend for or against mammography in younger (40-49) or older (70+) women. In 2002, the task force recommended mammography every 1 to 2 years for women age 40 to 69. But that year’s recommendation also stated, “the precise age at which the benefits from screening mammography justify the potential harms is a subjective judgment and should take into account patient preferences.”
Berg said one source of the confusion is that the principal audience for the recommendations is primary-care clinicians, not patients, insurance companies or government agencies.
“It’s the clinicians — the nurses and doctors — who are seeing the patients and trying to help them decide whether to be screened or not,” Berg said, adding that the challenge is to learn how to take this population based information and put it into a digestible format for patients.
Fellow panelist Dr. Diana Miglioretti, UW affiliate associate professor of Biostatistics and senior investigator with Group Health Research Institute, said the task force first determines whether there is evidence that the screening test reduces morbidity or mortality.
“We can say, for mammography, the answer is yes for women age 40 to 49, but the story doesn’t end there,” she said. After identifying mortality reduction, Miglioretti said the next step is to determine any adverse effects of screening and treatment — and whether the benefits outweigh the harms due to those adverse effects.
Among the adverse effects, or harms, are concerns of the pain associated with a mammogram and fears of a false-positive test result.
“These harms are not hypothetical or unquantifiable,” said Dr. Paul Fishman, UW affiliate associate professor of Health Services and associate investigator at Group Health Research. They are real harms, he said, such as when a healthy woman is called back for a false-positive result and undergoes subsequent unnecessary treatment.
Dr. Connie Lehman, UW professor of Radiology and director of Breast Imaging at Seattle Cancer Care Alliance, said the SCCA is in agreement with the American Cancer Society, which stands by their own recommendation that women 40 and over have a mammogram every year.
“What we at SCCA say to our patients is please get a mammogram every year starting at the age of 40,” she said, adding that the priority “really should be to help patients make more informed decisions.”
Lehman said one of the best resources available to women is the breast cancer consortium, an information source linking the mammographic histories of millions of women to tumor registries. The consortium is a research resource for studies designed to assess the delivery and quality of breast cancer screening and related patient outcomes in the United States.
“We can see how mammography is performing,” she said, “and then use that information to better guide women in making decisions right now on what they should do.”
Lehman said “early detection is how we cure these women — and we cure them with a minimally invasive procedure.” The benefits, she said, are both decreased morbidity and improved survival when women are diagnosed early.
While each of the panelists brought their individual perspective to the breast cancer screening debate, all agreed that one of the challenges of evidence-based medicine is “people can look at the same data and reach different conclusions,” Berg said. “There’s really no way to address that, other than to look under the hood and see how recommendations are actually made.”
Watch an archived video of the hour-long panel discussion at the UWTV Web site.