A new study finds a small but statistically significant increase in the rate of advanced breast cancer in women 25 to 39 years of age, raising questions about what may be causing the apparent increase.
The study was led by Rebecca H. Johnson, M.D., of Seattle Children’s Hospital and University of Washington, Seattle, and appears in the Journal of the American Medical Association. Researchers looked at breast cancer incidence and age in three U.S. National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) registries.
They found that since 1976, there has been a steady increase in the incidence of distant disease breast cancer in 25- to 39-year-old women, from 1.53 per 100,000 in 1976 to 2.90 per 100,000 in 2009. While the increase in relative risk is high, the researchers note that this is an absolute difference of 1.37 cases per 100,000, or 2.07 percent per year over the 34-year interval, a relatively small increase. Importantly though, the trend continues, indicating the need for further study and monitoring.
Len Lichtenfeld, M.D., deputy chief medical officer, had this to say about the study.
“This study makes the important observation—not previously documented—that the incidence of advanced breast cancer at the time of diagnosis has been significantly increasing over time in women between the ages of 25 and 39, and appears to be accelerating in recent years. Although the numbers of women impacted are small, we must never forget that for these women, their loved ones, friends, colleagues and communities, this is a devastating event.
“If the trend continues to increase over time, we cannot predict what will happen over the next ten or twenty years. As a result, it is important we continue research to understand what is contributing to this observation. Although the study’s authors and other experts—including those from the American Cancer Society—may have some thoughts, the reality is that at this point we do not have the facts to answer the question as to cause. Some reasonable areas for investigation may include childhood obesity, environmental exposures and delayed childbearing among others.
“It is important to point out that this increase is only in the diagnosis of advanced disease, not in localized or regional stages of breast cancer in women under age 40. And of particular importance is that there is nothing in this study that suggests routine breast cancer screening for women in this age group at average risk is either appropriate or justified.
“If there is a message for young women as a result of this study, it is that they should always be aware of changes in their breasts, and consult a health care professional if they discover such changes. For health care professionals, it is important to remember being under the age of 40 does not mean that a woman cannot develop breast cancer. Therefore, changes in the breast should be carefully evaluated.”
You can find comprehensive information on breast cancer, its risks, and the latest trends on the Detailed Guide at cancer.org.