USPSTF Proposes Breast Cancer Screening Changes

Jennifer Middleton, MD, MPH
Posted on May 22, 2023

Earlier this month, the United States Preventive Services Task Force (USPSTF) released a draft recommendation statement for new breast cancer screening guidelines. The most significant change would be a new grade B recommendation for “biennial screening mammography for women 40 to 74 years of age.” The USPSTF notes that these recommendations apply to “cisgender women and all other persons assigned female at birth (including transgender men and nonbinary persons) 40 years or older at average risk of breast cancer.” These recommendations not only differ significantly from the 2016 USPSTF breast cancer screening guidelines, which gave a grade C recommendation for the screening of average risk women 40 to 49 years of age, but also from current recommendations from the American Cancer Society (begin annual screening for all at 45 years of age, though consider beginning at 40 years of age) and the National Comprehensive Cancer Network (begin annual screening at 40 years of age).  Notably, though, the most recent AAFP recommendations align with the 2016 USPSTF’s, and the American College of Obstetricians and Gynecologists’ most recent recommendations are also similar to the 2016 USPSTF’s (offer at 40 years of age, begin biannually no later than 50 years of age). Although these conflicting guidelines have been confounding patients and clinicians alike for some time, this latest USPSTF iteration is unlikely to quell the debate regarding ideal breast cancer screening practices.

The USPSTF reviewed an updated systematic review and a modeling study to reach its new recommendations. The systematic review has yet to be published, but the manuscript draft is available to download at the USPSTF website. The review examined the various strategies regarding when to begin screening, when to stop screening, how often to screen, and what modalities to use. The authors sought studies of asymptomatic, average risk women in highly developed countries and included both “randomized trials and nonrandomized studies of interventions (NRSI):”

We did not find evidence of lower breast cancer mortality or risk of progression to advanced cancer in eligible studies comparing different breast cancer screening strategies. There were downstream consequences (e.g., more false-positive results and biopsy) with supplemental screening. Regular mammography screening is associated with reduced breast cancer mortality for women ages 50 to 69, based on trials conducted over 20 years ago, and longer term followup from the trials has not altered these conclusions.

This systematic review noted that most studies were performed in “White European” populations and called out the need for additional research to address the glaring disparities in diagnosis and outcomes for Black women in the United States.

The systematic review, then, did not explicitly support changing the 2016 USPTSF grade C recommendation for screening women between 40 to 49 years of age; the USPSTF instead cited its modeling study’s conclusions and the increasing prevalence of breast cancer in younger women to justify this change. The modeling report is also yet to be published but can be downloaded from the USPSTF website.  It details the use of six sophisticated “microsimulation and analytic models ... in a hypothetical cohort of average-risk US 40-year-old female persons” and found that “[s]trategies with biennial screening, start ages at 40 or 45, and cessation age 79 resulted in greater incremental gains in mortality reduction per mammogram compared with most strategies involving annual screening, start age 50, and/or cessation age 74.”

Unfortunately, the breast cancers that occur in premenopausal persons (which is most of the most controversial 40 to 49 years of age group) tend to be more aggressive, diagnosed at a later stage, and result in early mortality. If breast cancers in younger persons are, in fact, “etiologically distinct from breast cancers arising in older women,” then the USPSTF’s assumption that increasing screening in younger persons will result in improved outcomes just as it does for older women may be questionable. (In fairness, the models in the modeling study did use age-adjusted data regarding cancer outcomes in their analyses, but not all of the models treated survival rates similarly.)

Assuming that the USPTSF draft statement is approved, the AAFP will likely soon decide whether to endorse it. Less controversial, hopefully, will be the USPSTF’s call to action to increase study of the disparities in outcomes among Black women, which must lead to interventions to reverse the effects of structuralized racism that underlie this and so many other health inequities. While we await the AAFP’s decision, this excellent AFP editorial by evidence-based medicine experts and former USPSTF members Drs. Ebell and Lin outlines practical strategies for “Counseling Women About Breast Cancer Screening" considering the continued disagreements among organizations, and Table 3 from the 2021 AFP article on “Breast Cancer Screening: Common Questions and Answers” provides a comprehensive overview of the USPSTF, AAFP, ACS, ACOG, NCCN, and the American College of Radiology guidelines.