The American Cancer Society (ACS) announced this week in the Journal of the American Medical Association that it revised long-standing breast cancer screening guidelines. The organization now recommends women ages 45 to 54 – who have average breast cancer risk – get a mammogram once per year. Starting at age 55, women should get a mammogram once every other year and should continue as long as they are healthy. In addition, the ACS no longer recommends clinical breast exams for women who are symptom free.
But other medical groups, including the American College of Radiology and the Society for Breast Imaging, are not adopting the new guidelines. Instead, they’re encouraging patients to receive mammograms once each year starting at the age of 40 – the ACS’s previous recommendations.
“The new ACS guidelines are based on a systematic evidence review of breast cancer screening literature including randomized controlled trials, more recent observational studies, and simulations,” said Douglas Yee, MD, director of the Masonic Cancer Center, University of Minnesota. “It is admirable that newer observational studies were included, since the randomized trials that are foundational to the ACS guidelines are now over 30 years old.”
The new breast screening recommendations contain a fundamental assumption that all women are at the same risk and will all have the same outcomes if they develop breast cancer, Yee notes. However, risk varies greatly from person to person.
Research shows that cancers have many molecular subtypes, each with different biology and prognosis. Doctors can use different therapies based on the breast cancer’s subtype to make treatment far more effective. This highly individualized treatment is called “precision” medicine and catching cancer early is extremely helpful when tailoring treatments.
“Researchers agree, screening yearly saves more lives than screening less often than yearly, by catching cancers earlier,” according to Tim Emory, M.D., director of Breast Imaging at the Masonic Cancer Center. “But researchers don’t agree whether yearly screening is worth it.”
Paradoxically, while women with high risk get breast cancer much more often than those of average risk, most breast cancers are found in women with average risk”, said Emory. “Ideally, we would like to know which women will get breast cancer, screen them, and leave everybody else alone. But we are not there yet.”
With more research into risk assessment and screening technology, experts at the Masonic Cancer Center believe “precision” prevention strategies will follow the concept of “precision” medicine – including the use of breast imaging. “For example, we know these guidelines are completely inappropriate for women with an inherited BRCA mutation and even mammography alone may not be sufficient for this high risk population,” Yee said.
Emory adds, “Screening is a personal choice. If women want to minimize their chance of dying from breast cancer and they are willing to put up with the inconveniences of more frequent screening, then they should get yearly mammography beginning at age 40. But screening less often, for example by following the new ACS guidelines, is certainly better than no screening at all.”
Talk to your primary care provider, assess your risk factors, and determine a screening plan that’s right for you.
For more from Dr. Emory, read his recent Star Tribune article.