Changes to the US Preventive Services Task Force Screening Guidelines and Incidence of Breast Cancer

In this cohort study, in situ breast cancer decreased since 2009, consistent with decreasing use of screening mammography since the 2009 guideline changes, but this decrease did not appear to have translated to more advanced breast cancer stages at diagnosis or decreases in the proportion of cases treated with partial mastectomy. Further research is needed to understand the long-standing increase in localized invasive breast cancer and the decrease in regional invasive breast cancer observed during the past 20 years in the context of decreased breast cancer screening.