Breast cancer death rates declined almost 40 percent between 1989 and 2015, averting 322,600 deaths, the American Cancer Society reported Tuesday.
Breast cancer death rates increased by 0.4 percent per year from 1975 to 1989, according to the study. After that, mortality rates decreased rapidly, for a 39 percent drop overall through 2015. The report, the latest to document a long-term reduction in breast-cancer mortality, attributed the declines to both improvements in treatments and to early detection by mammography.
Deanna Attai, a breast cancer surgeon at the University of California at Los Angeles who was not involved in the study, said the advances in treatment included much better chemotherapy regimens — developed in the 1980s and refined ever since — that are administered post-surgery to reduce the risk of recurrence. Other improvements have included tamoxifen, an anti-estrogen agent that was approved in the late 1970s; Herceptin, a drug used to treat tumors with a higher-than-normal level of a protein called HER2 and drugs called aromatase inhibitors.
More recently, more sophisticated targeted treatments are being used to treat cancer that has spread beyond the breast.