In addition, about 25 percent of the drop was attributed to improved mammography screening and about 29 percent to better treatment of metastatic breast cancer, meaning cancer that has spread.
The findings used analysis of observational and clinical trial data from four models within the federally funded Cancer Intervention and Surveillance Modeling Network that track breast cancer screenings and treatments. Using modeling, the researchers were able to take into account changes in breast cancer incidence over time.
The 58 percent reduction figure represents “what the mortality would have been estimated to be in 2019 if no improvements [in screenings and treatments] had been made” in the 44 years examined, said Jennifer Caswell-Jin, the study’s lead author and an assistant professor of oncology at Stanford Medicine.
Without modeling, data shows that the mortality rate declined by 44 percent from 1975 to 2019, from 48 deaths per 100,000 women in 1975 to 27 per 100,000 women in 2019.
An editorial accompanying the research noted that, despite the “overall progress in reducing breast cancer mortality, reductions have not been equally distributed across all patient populations,” adding that rural, Black and uninsured patients are still “at greatest risk of dying from breast cancer.”
The American Cancer Society ranks breast cancer as the most common cancer among U.S. women (aside from skin cancers) and the second-leading cause of cancer deaths among women, following lung cancer.
This article is part of The Post’s “Big Number” series, which takes a brief look at the statistical aspect of health issues. Additional information and relevant research are available through the hyperlinks.
