As the wait continues for improved breast screening methods, better understanding of associated harms, enhanced strategies for identification of high-risk patients, and tools to assist patients and clinicians in incorporating these factors into their decisions should be research priorities, according to a review published on April 2 by the Journal of the American Medical Association.
Both the medical community and the media have become involved in the controversy that surrounds mammography policy and practice. Currently, the U.S. Preventive Services Task Force (USPSTF) recommends that women under the age of 50 make individualized decisions to undergo the screening.
However, “The central issue for clinicians, which is infrequently addressed in the medical literature, is how to individualize mammography recommendations and foster informed decisions by patients,” wrote the review’s authors, Lydia E. Pace, MD, MPH, and Nancy L. Keating, MD, MPH, both of Brigham and Women’s Hospital in Boston. “To accomplish this, clinicians must assess a patient’s individual risk for breast cancer, effectively communicate the risks and benefits of screening, identify how a patient’s characteristics might modify those risks and benefits, and elicit patients’ personal preferences and values.”
Pace and Keating sought to determine several major clinical aims in their review, including: the benefit of mammography screening and how it varies by age and patient risk; the harms of screening; what is already known about incorporating individual characteristics into breast cancer screening recommendations; and how patients are best supported in making informed decisions about mammography.
The authors searched MEDLINE from 1960 to 2014 in order to answer their questions. In addition to MEDLINE, they also manually searched reference lists of key articles retrieved, selected reviews, meta-analyses, and practice recommendations. The level of evidence was then rated using the American Heart Association guidelines.
Findings revealed that mammography was associated with a 19 percent overall reduction in breast cancer mortality. Women between the ages of 40 and 50 who underwent ten years of annual mammograms had a cumulative risk of 61 percent for a false-positive result. Approximately 19 percent of the cancers diagnosed during that time period were not clinically apparent without screening.
Pace and Keating discovered that the screening’s net benefit depended immensely on baseline breast cancer risk and should be included in screening decisions. Despite their scarcity in clinical practice, decision aids could potentially help patients combine information about risks and benefits with their own values and priorities.
“Although better data are needed to estimate the magnitude of overdiagnosis, the risks of mammography screening are significant, decreasing the net benefit of screening,” wrote the authors. “The net benefit is less for younger women, who have a lower absolute risk of breast cancer and greater risk of false-positive findings, and with annual screening, which increases false-positive findings and would also be expected to increase overdiagnosis.”
While the researchers believe that some challenges associated with mammography can be fixed with future research and improved use of decision aids, they still assert the need for better screening tests.
“Until better screening methods are available, improved understanding of these harms, enhanced strategies to identify the highest-risk patients, and tools to help patients and clinicians incorporate these in their decisions should be research priorities,” they concluded.
In an associated editorial published on April 2 by JAMA, authors Joann G. Elmore, MD, MPH, of the University of Washington School of Medicine in Seattle and Barnett S. Kramer, MD, MPH, of the National Cancer Institute in Bethesda, Md., reinforce these ideas. They wrote, “People make decisions based on facts and also values and preferences. A shared decision-making discussion that only focuses on data is not complete. Physicians must find a way to discuss an individual patient’s values and personal philosophies regarding health care in a neutral and nonjudgmental manner.”
They went on, “This decision should start with facts, and Pace and Keating have provided an excellent summary of the risks and benefits. Women considering screening mammography should receive all the information they need, and their preferences should be respected.”
The review, however, has not been warmly embraced by all thus far. In a statement released by the American College of Radiology on April 1, entitled, “JAMA Article Breast Cancer Screening Recommendations Potentially Deadly for Many Women,” the organization stated: “The American College of Radiology (ACR) and Society of Breast Imaging (SBI) agree with statements made by Pace and Keating, in their recent article published in JAMA, that women should discuss mammography with their doctor and breast cancer diagnosis and treatment may one day be more individualized. However, at present, breast cancer screening based primarily on risk—as discussed in the JAMA article—would miss the overwhelming majority of breast cancers present in women and result in thousands of unnecessary deaths each year.”
The ACR continued: “To arrive at their recommendations, the JAMA article authors also placed too much emphasis on the obsolete and low lifesaving benefit of mammography claimed in outdated or discredited studies.” They then cited several recent studies that confirm the benefits of mammography in reducing breast cancer deaths. The statement concluded, “Mammography can detect cancer early when it’s most treatable and can be treated less invasively—which not only saves lives, but helps preserve quality of life.”