AACR 2015: U.S. Breast Cancer Cases Expected to Increase by as Much as 50% by 2030
The total number of breast cancer cases in the United States is forecast to be 50% greater in 2030 than it was in 2011, when invasive and in situ or screening-detected cancers are counted together. This increase is predicted to be driven mostly by a marked increase in cases of estrogen receptor–positive tumors, and cases in women older than 70, according to research presented at the AACR Annual Meeting 2015, held April 18 to 22 in Philadelphia (Abstract 3699).
“Managing this clinical burden will present a huge challenge,” said Philip S. Rosenberg, PhD, Senior Investigator in the Division of Cancer Epidemiology and Genetics at the National Cancer Institute (NCI). “The silver lining is that we expect fewer estrogen receptor–negative tumors, which include the most difficult-to-treat HER2-positive and triple-negative subtypes.”
According to Dr. Rosenberg, during the next several decades, 40 million American women who were born between 1946 and 1964 will face high absolute risks for postmenopausal breast cancer, which for the average woman is estimated to be 2% to 4% over a 10-year period. An additional 56 million women, most of them currently in their 20s and 30s, will be at substantial risk of premenopausal breast cancer, averaging 0.4% to 1.5% over a 10-year period.
Study Details
With this study, Dr. Rosenberg and colleagues wanted to estimate the future incidence and burden of new cases of breast cancer according to in situ, invasive, and estrogen receptor status, in order to help the oncology community develop a proactive roadmap to optimize prevention and treatment strategies.
To do this, the researchers used nationally representative cancer surveillance data from the NCI Surveillance, Epidemiology, and End Results Program, population projections produced by the Census Bureau, and mathematic forecasting models to project the future numbers of breast cancer cases in the United States from 2011 to 2030. Because screening mammography is well accepted in the United States, the researchers forecast rising numbers of both invasive and in situ tumor diagnoses, which are almost entirely detected via screening mammography.
Breast Cancer’s Predicted Trajectory
The total number of new breast cancer cases classified as invasive and in situ is expected to increase by about 50%, from 283,000 in 2011, to 441,000 in 2030. Dr. Rosenberg and colleagues forecast that although the proportion of new breast cancer cases among women ages 50 to 69 is expected to decrease from 55% in 2011, to 44% in 2030, the proportion of cases in women ages 70 to 84 is expected to increase from 24% to 35%.
Data from the study forecast that the proportion of estrogen receptor–positive invasive cancers will remain at about 63%; the proportion of estrogen receptor–positive in situ cancers—most of which are detected through screening mammography—will increase from 19% to 29%.
In contrast, the researchers forecast that the proportion of estrogen receptor–negative cancers, both invasive and in situ, will decrease from 17% of all tumors in 2011, to 9% in 2030. “The reasons for this decline remain unclear, but there are intriguing clues. For example, early age at first birth in the absence of breast-feeding is a particularly strong risk factor for early onset of estrogen receptor–negative tumors. We know that in recent years, women have been delaying births and breast-feeding more often, both of which might partly explain the decline in this type of breast cancer,” Dr. Rosenberg explained.
“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,” Dr. Rosenberg said. “These distinct patterns within the overall breast cancer picture highlight key research opportunities that could inform smarter screening and kinder, gentler, more effective treatment.”
This research was supported by the Intramural Research Program of the National Institutes of Health.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
