ACS changes breast cancer screening recommendations for women at average risk
Based on the available evidence, the American Cancer Society recommends that women who are at average risk of breast cancer should have regular screening mammography beginning at age 45.
The American Cancer Society (ACS) published new guidance in the Oct. 20 Journal of the American Medical Association on breast cancer screening in average-risk women, changing its recommended starting age for annual screening mammograms from 40 years to 45 years.
The previous ACS guidelines, published in 2003, recommended annual screening mammography for average-risk women beginning at age 40 years, with no upper age limit for women in good health who would be candidates for breast cancer treatment if diagnosed. In addition, clinical breast exams were also previously recommended at least every 3 years for women in their 20s and 30s and preferably annually for asymptomatic women 40 years of age and older.
To update the guidelines, the ACS commissioned a systematic evidence review of the literature, along with a supplemental analysis of mammography registry data. Controlled studies, observational studies published since 2000 that included at least 1,000 average-risk women, and modeling/simulation studies were included in the evidence synthesis (7 reviews; 10 randomized, controlled trials; 72 observational studies; and 1 modeling study). “Average risk” was defined in the evidence synthesis as women who had no personal or family history of breast cancer, no confirmed or suspected genetic mutation that increases breast cancer risk, no previous breast neoplasia, and no history of chest irradiation.
The evidence review looked at the relative benefits, limitations, and harms associated with mammography screening versus no screening in average-risk women age 40 and older, as well as how these factors varied by age, screening interval, and screening history. It also looked at the relative benefits, limitations, and harms associated with different screening intervals in average-risk women and the benefits, limitations, and harms associated with clinical breast examination in average-risk women 20 years of age and older versus no clinical breast examination, as well as how these factors varied by age, screening interval, and rates of mammography participation.
Based on the available evidence, the ACS now recommends that women who are at average risk of breast cancer should have regular screening mammography beginning at age 45 (strong recommendation). Annual screening should be done in those ages 45 to 54 (qualified recommendation), while those 55 years of age and older should either transition to biennial screening or continue annual screening (qualified recommendation). Women should continue mammography screening if they are in overall good health and they are expected to live at least 10 years (qualified recommendation). The ACS does not recommend clinical breast examinations in average-risk women at any age (qualified recommendation). For clinicians, a rating of “strong recommendation” indicates that most individuals should receive the recommended course of action, while a rating of “qualified recommendation” indicates that clinicians should acknowledge that different choices will be appropriate for different patients and that they must help patients arrive at a decision that is consistent with patients' values and preferences.
The guideline authors wrote that the updated recommendations aim to “balance the goal of reducing the burden of breast cancer against the understanding that breast cancer screening is a preventive health intervention applied to the entire eligible population of women, most of whom will not develop breast cancer during their lifetime.” They also noted concern about the “contentious nature” of the breast cancer screening debate and said that it would be more productive to discuss ways to improve mammography screening, such as developing central registries and providing better clinical training and continuing education, as well as ways to increase access to high-quality breast imaging.
The authors of an accompanying editorial pointed out several “striking” aspects of the new guidelines, including the recommendation for annual screening in women ages 45 to 54 and the differences from the 2009 U.S. Preventive Services Task Force (USPSTF) recommendations. The USPSTF currently recommends screening every 2 years for women 50 to 74 years of age and notes that the evidence is insufficient to assess the benefits and harms of clinical breast exams in women age 40 years and older or screening mammography in women age 75 years and older. (The USPSTF is currently updating its recommendations on this topic and has posted draft recommendations online.) The editorialists also noted that the evidence available to help women make decisions about screening mammography is incomplete and that more information is needed on overdiagnosis in particular.
“In the meantime, it is important to remember and emphasize with average-risk women older than 40 years that there is no single right answer to the question ‘Should I have a mammogram?’,” the editorialists wrote. “Instead, women should be supported in estimating and understanding their risk for developing breast cancer and articulating their values and preferences so that clinicians can help them make informed decisions.”