Breast cancer cases are expected to rise in coming years, according a study by the National Cancer Institute. Researchers predict 40 million American women born between 1946 and 1964 will be at risk of developing post-menopausal breast cancer in the next several years, according to the study, presented in April at the American Association for Cancer Research’s annual meeting.
The study also showed an additional 56 million women in their 20s and 30s will have a substantial risk of premenopausal breast cancer, at 0.4% to 1.5% over a 10-year period.
“Managing this clinical burden will present a huge challenge,” Philip S. Rosenberg, PhD, a senior investigator in the division of cancer epidemiology and genetics at the National Cancer Institute, said in an association news release. “The one silver lining is that we expect fewer [estrogen receptor]–negative tumors, which include the most difficult-to-treat HER2-positive and triple-negative subtypes.”
The study involved looking at data from the National Cancer Institute’s Surveillance, Epidemiology and End Results Program, along with population projections from the U.S. Census Bureau and future projections of breast cancer cases from 2011 to 2030. Researchers credited the wide use and acceptance of mammographies in the U.S. as adding to increasing numbers of invasive and in-situ tumor diagnosis. Cancer in-situ is defined as an early stage of the disease when the cancerous growth or tumor is confined to its original site and has not spread to surrounding tissue or other organs, according to Cancer Treatment Centers of America.
The study predicts the total number of new breast cancer cases classified as invasive and in-situ will increase by about 50%, with 283,000 cases in 2011 to 441,000 in 2030. Although the number of new breast cancer cases among women ages 50 to 69 is predicted to go down from 55% in 2011 to 44% in 2030, the number of breast cancer cases for women ages 70 to 84 is expected to rise from 24% to 35%.
Researchers are not yet sure why estrogen receptor-negative breast cancers are expected to decline in the future. The cite women having children later in life as a possible factor. Have a baby at a young age is one of the risk factors for estrogen receptor-negative tumors, according to the study. They also attributed the projected decline in the more difficult to treat breast cancers to an increase in breast-feeding.
“In sum, our results suggest that although breast cancer overall is going to increase, different subtypes of breast cancer are moving in different directions and on different trajectories,” Rosenberg said in the news release. “These distinct patterns within the overall breast cancer picture highlight key research opportunities that could inform smarter screening and kinder, gentler, and more effective treatment.”