As reported in JAMA by Kevin C. Oeffinger, MD, of Memorial Sloan Kettering Cancer Center, New York, and colleagues, the American Cancer Society (ACS) has issued an update to its 2003 guideline on breast cancer screening for women at average risk of breast cancer.¹ Robert A. Smith, PhD, of the Cancer Control Department, ACS, is the corresponding author of the JAMA article.

In formulating the updated recommendations, an ACS guideline development group selected the Duke University Evidence Synthesis Group to conduct an independent systematic evidence review of the breast cancer screening literature. The ACS also commissioned the Breast Cancer Surveillance Consortium to update previously published analyses of mammography screening interval and outcomes, and the ACS Surveillance and Health Services Research Program contributed supplementary data on disease burden using Surveillance, Epidemiology, and End Results (SEER) program data.

Average Risk

Women at average risk were defined as those without a personal history of breast cancer, a confirmed or suspected genetic mutation known to be associated with increased risk (eg, BRCA), or a history of radiotherapy to the chest at a young age. The authors acknowledged that there also are women outside of these higher-risk categories who are at higher-than-average risk of breast cancer and for whom mammography screening alone may have reduced effectiveness, including those with significant family histories but who do not have a high probability of carrying identified risk mutations, those with a prior diagnosis of benign proliferative breast disease, and those with significant mammographic breast density.

The investigators noted: “At this time, there are no reliable estimates of the number of women who have one or more of these risk factors; nor are there widely accepted risk-based screening recommendations that differ for women in this intermediate-risk group compared with average-risk women.”

Evidence Synthesis

Key points from the evidence synthesis follow:

• Screening mammography in women aged 40 to 69 years is associated with reduction in breast cancer deaths across a range of study designs; inferential evidence supports breast cancer screening for women aged ≥ 70 years who are in good health.
• Estimates of the cumulative lifetime risk of false-positive examination results are greater if screening begins at younger ages, due to the greater number of mammograms as well as to the higher recall rate for younger women. The quality of evidence for overdiagnosis is not sufficient to estimate a lifetime risk with confidence.
• Analysis of the effects of the screening interval indicates more favorable tumor characteristics when premenopausal women are screened annually vs biennially.
• Evidence does not support routine clinical breast examination as a screening method for women at average risk.

Updated Recommendations

The updated recommendations, designated as strong or qualified, are reproduced here. A strong recommendation indicates consensus that the benefits of adherence to an intervention outweigh the undesirable effects that may result from screening. A qualified recommendation indicates clear evidence of benefit of screening but less certainty about the balance of benefits and harms or about patient values and preferences, factors that could lead to different decisions about screening.

Women with an average risk of breast cancer should undergo regular screening mammography starting at age 45 years. (Strong Recommendation)

1a.      Women aged 45 to 54 years should be screened annually. (Qualified Recommendation)

1b.      Women 55 years and older should transition to biennial screening or have the opportunity to continue screening annually. (Qualified Recommendation)

1c.      Women should have the opportunity to begin annual screening between the ages of 40 and 44 years. (Qualified Recommendation)

Women should continue screening mammography as long as their overall health is good and they have a life expectancy of 10 years or longer. (Qualified Recommendation)

The ACS does not recommend clinical breast examination for breast cancer screening among average-risk women at any age. (Qualified Recommendation)

The authors concluded: “These updated ACS guidelines provide evidence-based recommendations for breast cancer screening for women at average risk of breast cancer. These recommendations should be considered by physicians and women in discussions about breast cancer ­screening.”

They continued:

[T]he ACS recommendations are made in the context of maximizing reductions in breast cancer mortality and reducing years of life lost while minimizing the associated harms among the population of women in the United States. The ACS recognizes that the balance of benefits and harms will be close in some instances and that the spectrum of women’s values and preferences will lead to varying decisions. The intention of this new guideline is to provide both guidance and flexibility for women about when to start and stop screening mammography and how frequently to be screened for breast cancer.” ■

Disclosure: This work was supported by the ACS. For full disclosures of the study authors, visit www.jama.jamanetwork.com.

Reference

1. Oeffinger KC, Fontham ET, Etzioni R, et al: Breast cancer screening for women at average risk: 2015 guideline update from the American Cancer Society. JAMA 314:1599-1614, 2015.