Mammography screening and improved treatments have prevented between 384,000 and 614,500 breast cancer deaths since 1989, according to a study published in Cancer.
“Recent reviews of mammography screening have focused media attention on some of the risks of mammography screening, such as callbacks for additional imaging and breast biopsies, downplaying the most important aspect of screening — that finding and treating breast cancer early saves women’s lives,” R. Edward Hendrick, PhD, visiting clinical professor of radiology at University of Colorado School of Medicine, said in a press release. “Our study provides evidence of just how effective the combination of early detection and modern breast cancer treatment have been in averting breast cancer deaths.”
Hendrick and colleagues reviewed age-adjusted female breast cancer mortality rates and population data from the SEER database to estimate the number of breast cancer deaths avoided since 1989 as a result of screening mammography — which became widely available in the mid-1980s — and improved treatments.
The researchers used four assumptions regarding background morality rates (without screening mammography and improved treatment) to estimate deaths prevented for women aged 40 to 84 years. They calculated the number of deaths averted by multiplying the difference between background and SEER-reported mortality rates for each 5-year age group by the U.S. population of women in that age group.
The investigators used SEER data to approximate annual and cumulative breast cancer deaths prevented in 2012 and 2015 and extrapolated SEER data to estimate deaths avoided in 2018.
They found that the number of single-year breast cancer deaths and reductions in breast cancer mortality ranged from 20,860 to 33,842 (38.6%-50.5%) in 2012; 23,703 to 39,415 (41.5%-54.2%) in 2015; and 27,083 to 45,726 (45.3%-58.3%) in 2018.
Cumulative breast cancer deaths prevented since 1989 ranged from 237,234 to 370,402 in 2012, from 305,934 to 483,435 in 2015, and from 384,046 to 614,484 in 2018.
Hendrick noted that only about half of U.S. women aged older than 40 years are regularly screened with mammography.
“The best possible long-term effect of our findings would be to help women recognize that early detection and modern, personalized breast cancer treatment saves lives, and to encourage more women to get screened annually starting at age 40,” he said in the press release.
Advances in research do not negate the need for screening mammography, according to study co-author Mark A. Helvie, MD, professor of radiology and director of the breast imaging division at University of Michigan Rogel Cancer Center.
“While we anticipate new scientific advances that will further reduce breast cancer deaths and morbidity, it is important that women continue to comply with existing screening and treatment recommendations,” Helvie said in the press release. – by Jennifer Byrne
Disclosures: Hendricks reports a consultant role for GE Healthcare for work outside the current study. Helvie reports institutional research grants from GE Healthcare and IBM Watson for work outside the current study. The other author reports no relevant financial disclosures.