In the United States, breast cancer mortality rates dropped every year for women across all age groups between 1989 and 2010, but after that, the trend stalled for those younger than 40 years.
"It's clear that mortality rates in women under 40 are no longer decreasing," lead author R. Edward Hendrick, PhD, clinical professor from the Department of Radiology at the University of Colorado School of Medicine, in Aurora, Colorado, stated in a press release. "I estimate that in two to three years, the mortality rate will be increasing significantly in these women."
The findings were published online February 9 in Radiology.
The authors speculate that the findings may be related to recommendations for mammography screening.
For their study, the authors analyzed National Center for Health Statistics data for 1969–2017 and delay-adjusted invasive breast cancer incidence rates from the Surveillance, Epidemiology, and End Results program.
They found that breast cancer mortality rates decreased significantly by 1.5% to 3.4% per year for all age groups from 1989–2010, and by 1.2% to 2.2% per year after 2010 for those aged 40–79 years.
However, the rates increased after 2010 by a nonsignificant 2.8% per year for women aged 20–29 years and 0.3% per year for those aged 30–39 years.
Distant-stage breast cancer incidence rates increased by more than 4% per year after the year 2000 in women aged 20–39 years.
"Our hope is that these findings focus more attention and research on breast cancer in younger women and what is behind this rapid increase in late-stage cancers," Hendrick stated in the press release.
He and his colleagues speculate that the contrast between the upward trend in women younger than 40 and the downward trend in older women highlights the value of mammography and may reflect the benefits of regular screening, which is not currently recommended for women younger than 40 who are not at high risk for breast cancer.
However, other groups, including the American College of Radiology and the Society for Breast Imaging, support starting annual mammograms at age 40 years.
An expert who was approached for comment noted that the incidence of breast cancer increases with age.
It is more common in women as they age, so screening recommendations do not include women younger than 40 unless they are at very high risk for breast cancer, noted Joann G. Elmore, MD, MPH, professor of medicine at the David Geffen School of Medicine, the University of California, Los Angeles.
"The majority of deaths due to breast cancer are in women over age 40. The breast cancer mortality rates per 100,000 as shown [in this study] are ~3 patients/100,000 for the under 40 age group, ~30/100,000 in the 40–69 age group, and ~80/100,000 in the 70 and above age group," she pointed out.
Elmore was a coauthor of an editorial regarding the 2019 evidence-based guidance statement from the American College of Physicians (ACP). That guidance, which was endorsed by the United States Preventive Services Task Force, recommended screening every other year for average-risk women aged 50–74 years, as reported by Medscape Medical News at the time.
In their editorial, Elmore and coauthor Christoph Lee, MD, of the University of Washington, Seattle, applauded the ACP's approach but stressed that the guidance is not a perfect product and does not "clearly illuminate the full path ahead for every woman."
Breast cancer screening guidelines continue to evolve, they said. They concluded that "[p]hysicians are left to use their best judgment based on available research and expert recommendations."
Radiology. Published online February 9, 2021. Full text
Sharon Worcester is a reporter for MDedge News, part of the Medscape Professional Network.
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Cite this: Breast Cancer Mortality in Under 40s Resparks Screening Debate - Medscape - Mar 04, 2021.