The U.S. Preventive Services Task Force is planning to update its breast cancer screening guidelines, which were last issued in 2016. For transparency, it has released the draft research plan it will use for formulating the update, and this draft plan is open for comment until Feb. 17.
However, an expert in breast screening has taken issue with the whole plan.
Daniel Kopans, MD, professor of radiology at Harvard Medical School and founder of the Breast Imaging Division at Massachusetts General Hospital, Boston, argues that previous USPSTF guidelines on breast cancer screening “have been based on flawed analyses of scientific data” and the research plan, as outlined, perpetuates this.
He has also objected, yet again, to the USPSTF panel not having any experts in breast screening on the panel.
Writing in a commentary on Aunt Minnie, a radiology website, he warns about the dangers of not listening to experts: “The COVID-19 pandemic has demonstrated the tragic consequences that result from ignoring science, evidence, and the analysis and advice of experts while being guided by inexpert advice.”
Controversy over previous guidelines
The current USPSTF guidelines on breast cancer screening, which were issued in 2016, were largely unchanged from the previous guidelines that had been issued in 2009. They recommended mammography screening every 2 years for women 50-74 years of age but said that women aged 40-49 should make individual decisions about screening in partnership with their doctors.
The guidance on younger women was met with severe criticism from many experts, as previously reported by this news organization, and the every-2-year interval has also been questioned.
The American College of Radiology and Society of Breast Imaging both recommend annual mammograms starting at age 40.
In the update the USPSTF is now planning, it has an opportunity to “revisit the group’s flawed decision in 2009” about not recommending screening for women in their 40s, argues Dr. Kopans.
But to do that, a number of factors need to be addressed to present a fair and impartial review of the science and evidence in favor of breast screening, he continues, while worrying the draft plan, as currently outlined, will not do so.
One big problem, he argues, is that USPSTF, in its draft plan, has not included statistical models from the U.S. National Cancer Institute and Cancer Intervention and Surveillance Modeling Network to project the potential outcomes of various screening protocols. These NCI/CISNET models all predict that the most lives are saved by annual screening starting at age 40, he points out.
Without these models, the USPSTF will be “guessing in their predictions,” he argues.
Second, even though a reduction in advanced-stage disease is a potentially useful “surrogate endpoint,” Dr. Kopans points out that it is still crucial to remember that women diagnosed at all stages of breast cancer die of the disease. “It has been shown that reducing the size of cancers within stages is also a major benefit from screening that reduces deaths,” he says.
Third, he contends in his commentary that there is a “false claim that the background incidence of breast cancer has not increased over time.” Dr. Kopans says this has been the primary source of misinformation that has been used to promote “the false concepts of massive overdiagnosis” as well as a “false claim that there has not been a reduction in advanced cancers.”
To emphasize his point, Dr. Kopans explains that data clearly demonstrate that the baseline incidence of breast cancer has steadily risen by 1%-1.3% per year, going back at least 80 years. This increase predates screening, which didn’t really begin until the mid-1980s.
“If the correct increasing baseline is used, not only is there no apparent ‘overdiagnosis’ of invasive cancers, but it appears that there has been a major reduction in the incidence of invasive cancers,” he writes. “By using the correct baseline incidence and extrapolation, it is also clear that there has been a major reduction in the rate of advanced cancers.”
To date, there have not been any randomized controlled trials comparing screening intervals (for example, annual vs. every second or third year). But based on the CISNET models, Dr. Kopans emphasized that annual screening is estimated to provide the greatest reduction in deaths. “All women ages 40-74 should be encouraged to be screened every year,” he says.
A version of this article first appeared on Medscape.com.