The Association Between Mammography Screening Frequency and Breast Cancer Treatment and Outcomes: A Retrospective Cohort Study.

Abstract

Guidelines for optimal frequency of screening mammography vary by professional society. Sparse evidence exists on the association between screening frequency and breast cancer treatment options. The main objective was to examine differences in cancer treatment rendered for U.S. women with different numbers of screenings prior to breast cancer diagnosis. Cancer stage at diagnosis and health care cost were assessed in secondary analyses. This IRB-exempt retrospective study used administrative claims data to identify women aged 44 or older with various numbers of mammographic screenings ≥11 months apart, during the four years prior to incident breast cancer diagnosis from January 2010 to December 2018. Outcomes were assessed over the six months following diagnosis. Generalized linear regression models were used to compare women with differing numbers of mammograms, adjusting for patient characteristics. Claims data review identified 25 492 women who met inclusion criteria. There was a stepwise improvement in each of these screening categories such that women with four screenings, compared to women with only one screening, experienced higher rates of lumpectomy (70% vs 55%) and radiation therapy (48% vs 36%), lower rates of mastectomy (27% vs 34%) and chemotherapy (28% vs 36%), less stage 3 or 4 cancer at diagnosis (15% vs 29%), and lower health care costs within six months postdiagnosis (P < 0.001). Results were similar in a subgroup limited to women aged 44 to 49 at diagnosis. Potential benefits of more frequent screening include less aggressive treatment and lower health care costs among women who develop breast cancer.