In spite of the innumerable scientific articles, editorials, critiques, media debates, NIH consensus conferences, guidelines, and learned international panels assembled to resolve the controversies, many of the original questions remain unresolved. The “true believers” and the “skeptics” remain passionate and largely unmoved.
But politics, advocacy, and public acceptance have tipped the scales, as Handel Reynolds describes in this short (94 pages) but extensively referenced (17 pages) book.
Dr. Reynolds, a breast radiologist and former chief of breast radiology at Indiana University, presents the mammography story as a chronologic mixture of science, politics, advocacy, and the unfortunate attempt to make an imperfect test with insufficient data a simple binary decision for women.
Mammography, first described in the 1930s, developed slowly and was originally used to confirm a suspected diagnosis. But in 1963, Dr. Phillip Strax, whose wife had died of breast cancer at age 39, persuaded the Health Insurance Plan of Greater New York to support a randomized trial of screening mammography—the HIP trial. Sixty-two thousand women aged 40 to 60 were enrolled—half received yearly mammograms and clinical breast exams, and the other half had usual medical care.
The results, published in 1971, showed 40 percent fewer breast cancer deaths in screened women aged 50 to 59. No benefit was seen in the group of those aged 40 to 49. Dr. Reynolds points out that the HIP trial remains the only randomized trial of mammography ever carried out in the United States.
That same year, Congress passed the National Cancer Act, which infused federal funds into the “War on Cancer.” This brought the American Cancer Society together with the National Cancer Institute to initiate the Breast Cancer Detection Demonstration Project (BCDDP), which enrolled 280,000 women age 35 to 65 in an uncontrolled screening program.
Breast cancer diagnoses in both First Lady Betty Ford and Second Lady Happy Rockefeller within two weeks of each other in 1974 accelerated enrollment, although neither was diagnosed by mammography. The BCDDP results were reported in 1981, showing that 41 percent of the cancers were found by mammography alone. In women age 50 to 59, 42 percent were identified by mammography alone; and for those 40 to 49, 19.4 percent were found on mammography alone.
No control group was included, so no information could be gleaned about mortality reduction. The results of the BCDDP were generally consistent with those of the HIP trial and persuaded the believers that screening benefitted all age-included groups and would ultimately show survival benefits.
Widespread screening mammography did identify a large number of heretofore undiagnosed patients with ductal carcinoma-in-situ (DCIS), and this contributed to the so-called “epidemic” of breast cancer seen in the '80s and '90s and mobilized a burgeoning breast cancer advocacy community.
Dr. Reynolds describes that time as a struggle between the true believers (the American Cancer Society and the American College of Radiology) and the skeptics (the U.S. Preventive Services Task Force [USPSTF], the American College of Physicians, and increasingly, the National Cancer Institute).
Two pivotal events accompanied by unambiguous political action and expression of public views solidified mammography screening and superseded any scientific controversy. The first, a 1997 NIH consensus conference reviewing new and updated data from studies from the U.S., Europe, and Canada, noted a 16 percent reduction in cancer mortality in 40-49 year olds but declined to alter its guidelines. A political and public firestorm erupted. In February 1997 the Senate passed a resolution 98-0 suggesting that the National Cancer Advisory Board ask the NCI to reissue its earlier guidelines favoring screening in 40-49 year olds. The NCI complied. This episode, as Dr. Reynolds suggests, “established the primacy of politics over science in the mammography dispute.”
The second event, in 2009, surrounded the decision by the USPSTF to recommend against screening mammography in 40-49 year olds and citing the frequency of overdiagnosis, radiation exposure, pain, anxiety, and false negatives.
Reaction to the decision was swift and unambiguous. Congress, advocates, and true believers in the medical community reacted immediately. A Gallup poll indicated that 76 percent of women disagreed with the decision, and within 48 hours, Secretary Kathleen Sebelius publically disavowed the guidelines. Subsequent legislation built coverage into the Affordable Care Act, and the House passed legislation warning private insurers not to attempt to deny coverage to women age 40-49.
Breast cancer screening has now been widely utilized in the United States for more than 30 years. One would have expected that as the disease is detected earlier, the frequency of advanced disease would decline. However, as Bleyer and Welch point out in the November 22, 2012 issue of the New England Journal of Medicine, “Despite substantial increases in the number of cases of early-stage breast cancer detected, screening mammography has only marginally reduced the frequency of advanced disease. The imbalance suggests substantial overdiagnosis and that screening is having, at best, only a small effect on the rate of death from breast cancer.
The Big Squeeze is an absorbing mix of science, politics, advocacy, and the struggle over imperfect information. The author elects to present the conclusions and reaction to studies rather than the details. There are no comprehensive tables, graphs, or p values. In this reviewer's view, this works well in illuminating the social and political controversy surrounding mammography.
Dr. Reynolds suggests that the scientific debate persists in the medical community because both sides have credible data to support their view. That said, he believes that the politicians and the public have moved on. They support access to mammography for women above 40.
This reader would have hoped that the author might have included more of the information from the European trials; a more thorough discussion of what flaws actually exist in the major studies; the real radiation risks; and the utility of other screening tools as well as the potential for better diagnostic tools for the future. That said, he does use the final chapter to explore the limits of mammography, the malpractice burden, and most importantly, the contributions of DCIS to overdiagnosis and overtreatment of this still poorly understood disease largely discovered through the widespread use of mammography.
This is an illuminating book with a novel perspective on breast cancer screening, written by an accomplished radiologist with a refreshingly balanced view of the controversy. It is valuable for oncologists, and is also an excellent book for patients and the lay public who struggle to make sense out of a complex story, and ultimately have to make their own decisions about mammography.
ILR PRESS, 2012, HARDCOVER, ISBN 978-0-8014-5093-8
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