The U.S. Preventive Services Task Force (USPSTF) “chose to ignore the science available to them” and brought about “potential damage to women’s health” in its 2009 recommendations for more limited mammography screening, costing an estimated 6,500 deaths in women each year, a study published in the February issue of the American Journal of Roentgenology concluded.
On Nov. 16, 2009, the USPSTF reversed its recommendations for breast cancer screening, calling for biennial mammograms (instead of every one to two years); concluding that insufficient evidence existed to make recommendations to women over 74 years; and saying that women between the ages of 40 and 49 should choose whether to undergo screening based on patient context.
The USPSTF relied on evidence from three major sources, according to R. Edward Hendrick, PhD, of the department of radiology at the University of Colorado-Denver, School of Medicine and Mark A. Helvie, MD, of the department of radiology at the University of Michigan Health System in Ann Arbor. First, the USPSTF relied on random controlled trial data and “harms” based on a report published by the Oregon Evidence-Based Practice Center. The USPSTF also based its recommendations on the National Cancer Institute’s (NCI) Breast Cancer Surveillance Consortium and NCI’s Cancer Intervention and Surveillance Modeling Network.
Hendrick and Helvie criticized the USPSTF, however, for omitting non-random control trials that measured mortality as outcomes and peer-reviewed cost-benefit analyses of mammography compared with other accepted interventions. As the result, Hendrick and Helvie compared the USPSTF recommendations with projected endpoints according to the American Cancer Society (ACS) recommendation of annual screening starting at age 40. The authors used the mean values from the six Cancer Intervention and Surveillance Modeling Network models as well as the Breast Cancer Surveillance Consortium and the Cancer Incidence: Surveillance Epidemiology and End Results studies.
Hendrick and Helvie’s analysis showed that annual screening for women aged 40 to 84 (ACS standards) resulted in a 39.6 percent drop in mortality for women, whereas biennial screening for women 50 to 74 years of age brought about a 23.2 percent reduction in mortality. “Thus, on average, a woman who gets breast cancer has a 71 percent higher probability of not dying from the disease if she follows ACS mammography screening guidelines rather than USPSTF recommendations,” the authors wrote.
These findings translated to 12 lives saved per 1,000 women screened following the ACS recommendations, compared with seven using the USPSTF-recommended regimen. Extrapolating these findings to the nearly 20 million women in the U.S. that will turn 40 in the next ten years, the authors estimated that just fewer than 65,000 women would be saved if following the ACS rather than USPSTF recommendations, assuming 65 percent screening compliance under both sets of recommendations.
According to the researchers, additional screening for women aged 40 to 49 would, on average, result in a false-positive result once every 10 years, a recall for additional imaging once every 12 years and a false-positive biopsy once every 149 years. The authors cited these “harms” as playing a large role in the USPSTF revised recommendations, while pointing out that the “harm can be mitigated if women elect real-time screening interpretation with same-visit diagnostic imaging offered at many U.S. facilities. This option was not mentioned by the USPSTF report.”
Moreover, relating to overestimation of the final harm, the authors argued that the “USPSTF made two fundamental errors in estimating radiation dose (and risk) to the breast. First, they based their estimates of radiation doses on screen-film mammography phantom results rather than on actual average patient exposures…Second,” Hendrick and Helvie continued, “the USPSTF incorrectly combined the mean glandular dose to the left breast to the mean glandular dose to the right breast, doubling their dose estimate.”
The authors said that correct estimations of radiation risk, taken from the Biologic Effects of Ionizing Radiation report, results in approximately one fatality for every 100,000 women.
The authors sharply criticized the USPSTF recommendations, which have generated significant controversy since their release a year ago. “[T]he USPSTF-recommended screening regimen misses 20 to 25 more cancers per 1,000