The vast majority of women diagnosed with early stage breast cancer today can expect to become long-term survivors, not casualties of the disease, according to research published Tuesday in The British Medical Journal.
For those diagnosed with breast cancer, the risk of dying is highest during the first five years after diagnosis. That risk has fallen from 14% in the 1990s to 5% today, a “substantial” improvement, the authors reported. What’s more, 60% of those diagnosed between 2010 and 2015 had a five-year mortality risk as low as 3%.
The findings are “good news for the great majority of women diagnosed with early breast cancer today because their prognosis has improved so much,” the authors said in a news release about the study.
Conclusions were drawn from the data of more than half a million English women diagnosed with early invasive breast cancer from 1993 through 2015. All were treated with surgery, and follow-up data was gathered in 2020.
Why breast cancer deaths are declining
The biology of the disease may have changed over the two decades the study took place due to hormonal changes tied to obesity, the use of hormone replacement therapy, and reproductive factors, the authors noted.
The development of new therapies and the more precise targeting of interventions like surgery and radiotherapy “undoubtedly” contributed to the decrease in mortality during the study, they added.
U.S. cancer deaths have been on the decline for more than three decades—and stayed on the decline, even with the pandemic raging, according to a report released in January from the American Cancer Society.
While American cancer deaths have dropped by a third since 1991, breast cancer diagnoses have risen slowly—by about 0.5% per year—since the mid-2000s, due in part to declines in the fertility rate and increases in obesity, according to the report.
