Improved outcomes among breast cancer patients with more frequent mammography screening.
e19146 Background: Guidelines for optimal frequency of screening mammography (annual, biennial, never/choice of patient) vary by professional society, due to mixed or insufficient evidence regarding its benefits and harms. Little evidence exists on the impact of screening frequency, rather than any screening, on health outcomes. In this study, we measured differences in cancer stage at diagnosis, treatment rendered, mortality, and cost of treatment for women with different numbers of screenings prior to breast cancer diagnosis. Methods: Utilizing administrative claims, we identified 25,492 women aged 44 or older with various numbers of mammographic screening ≥ 11 months apart during the four years prior to their incident breast cancer diagnosis from 2010 to 2018. Outcomes were assessed during the six months following diagnosis. Regression models were used to compare women with differing numbers of mammograms (0, 1, 2, 3, or 4/5), adjusting for demographic characteristics and baseline comorbidities. Results: More screenings were associated with less advanced cancer at diagnosis, higher rates in lumpectomy and radiation, lower rates in mastectomy and chemotherapy, lower costs and mortality within 6 months post diagnosis (Table). Results were similar in a subgroup with only women aged 44-49 at diagnosis (not shown). Conclusions: Increased frequency of screening mammography is associated with earlier breast cancer stage at diagnosis, less toxic and invasive treatment, lower mortality, and lower cost, including for women under age 50. [Table: see text]