Mammography in the News
Medscape Today Medical News
February 3, 2011 — A new analysis is poised to reignite the debate that has been raging over the value of mammography in women younger than 50 years of age.
There was a furor when the revised US Preventative Service Task Force (USPSTF) recommendations for breast cancer screening were released in November 2009. The most notable changes were to advise against routine screening mammograms for women 40 to 49 years of age, to change the screening interval from 1 to 2 years in women 50 years and older, and to end screening at 74 years.
The updated guidelines became mired in controversy as soon as they were published, as previously reported byMedscape Medical News. A number of organizations, including the American Cancer Society (ACS), the American College of Radiology, and the American College of Obstetricians and Gynecologists, recommended that physicians and patients continue to follow earlier guidelines.
|Dr. Edward Hendrick|
Now, a study published in the February issue of the American Journal of Radiology that analyzed the same data as the USPSTF has come up with very different results.
R. Edward Hendrick, PhD, clinical professor of radiology at the University of Colorado School of Medicine in Denver, and Mark Helvie, MD, director of breast imaging at the University of Michigan Comprehensive Cancer Center in Ann Arbor, found that beginning screening at a younger age and at more frequent intervals can save more lives.
|Dr. Mark Helvie|
“What is most important is to save the most lives,” Dr. Hendrick told Medscape Medical News, “not to do the fewest mammograms. If you want to save the most lives, then doing annual mammograms from age 40 to 84 years clearly is superior.”
According to the analysis, women who receive annual mammograms starting at age 40 can significantly reduce the risk of dying from breast cancer by 71%. This is in contrast to women who follow the USPSTF recommendations, who had a 23.2% reduction in mortality.
Lower Mortality With Earlier Screening
Dr. Hendrick and Dr. Helvie used 6 model scenarios of screening mammography that were created by the Cancer Intervention and Surveillance Modeling Network, which is the same modeling data used by the USPSTF. They compared mortality reduction for women who followed the 2009 USPSTF recommendations with that for women who followed the ACS recommendations (annual screening beginning at age 40).
“In their summary paper, the USPSTF did not do any averaging over the 6 models,” explained Dr. Hendrick. In our analyses, we selected a model that was “somewhere in the middle, but it wasn’t an average over the 6.”
When the USPSTF looked at any of these modeling data, they chose the point on the graph when it first begins to turn over in terms of mortality reduction per mammogram done. “That was biennial screening beginning at age 50,” he said.
In contrast, the authors of new analysis averaged the 6 models and found that for women 40 to 84 years, annual screening conveyed an estimated 39.6% reduction in mortality (range over the 6 models, 29.4% to 54%). This was compared with biennial screening at 50 to 74 years, which showed an estimated mortality reduction of 23.2% (range, 20% to 28%).
They found that approximately 12 lives per 1000 women screened would be saved with annual screening beginning at age 40, whereas with the USPSTF-recommended screening regimen, an estimated 7 lives per 1000 women screened would be saved. Overall, the ACS screening guidelines would result in 5 more lives per 1000 women saved than the USPSTF screening guidelines.
Overemphasis of Harms
The USPSTF also overemphasized the potential harms of screening mammography, explained Dr. Hendrick.
You can’t really compare having a call back for additional testing to dying of breast cancer.
“You can’t really compare having a call back for additional testing to dying of breast cancer,” he said. “They were comparing something with mild implications to something with huge implications. They looked at the potential harms of screening without looking at lives saved from a proper perspective.”
The actual number of false-positive tests is also actually quite low, Dr. Hendrick noted. For a woman 40 to 49 years who receives annual screening, a false-positive test will occur once every 10 years on average. She will be recalled for additional imaging once every 12 years and undergo a false-positive biopsy once every 149 years. A missed malignancy will happen once every 1000 years.
In the USPSTF report, the harms of unnecessary recall for additional imaging were emphasized, the authors note. However, “this harm can be mitigated if women elect real-time screening interpretation with same-visit diagnostic imaging offered at many [American] facilities, . . . but this option was not mentioned by the USPSTF report.”
May Dissuade Payors
Because the new recommendations were made by a federal panel, they do have an effect on healthcare decisions, Dr. Hendrick said.
In fact, the guidelines could have dissuaded some women from having a screening mammography, and could influence reimbursement from Medicare, Medicaid, and private payors, he added.
The USPSTF recommendations have done potential damage to women’s health.
“The USPSTF recommendations have done potential damage to women’s health by failing to seize the singular opportunity to both improve mammography in the United States and to increase screening mammography compliance,” say the authors.
Dr. Hendrick reports being a consultant to GE Healthcare and serving on the medical advisory boards of the Koning Corporation and Bracco, both of which develop and manufacture diagnostic imaging systems. Dr. Helvie reports receiving grant support from GE Healthcare.
AJR Am J Roentgenol. 2011;196:W112-W116. Abstract