Abstract 4341: Regional disparities in time to treatment for breast conserving surgery and mastectomy in women with early-stage breast cancer

BACKGROUND: Although several studies have reported regional differences in type of surgery performed for early-stage breast cancer (ESBCa), no research has examined geographic trends in time from diagnosis to surgical treatment (TtS), a quality measure for early-stage breast cancer care. Given evidence for improved survival outcomes of expedited TtS, we assessed how TtS for both breast conserving surgery (BCS) and mastectomy (MAST) has changed over time within region. METHODS: IBM® MarketScan® claims data were used to select women diagnosed with non-metastatic invasive ESBCa from January 2012 to March 2018. Eligibility criteria included: 1) absence of other cancers 2) ≥ 6 months of continuous insurance enrollment pre- and post- diagnosis 3) treatment with BCS or MAST within 6 months. Days elapsed between diagnosis and first surgery was the dependent variable. Region-specific quantile regression models of median TtS were estimated, which included a vector of patient- and community-level covariates. RESULTS: A total of 57,299 women met the inclusion criteria. Among those receiving MAST (n=18,825), 11% had neoadjuvant chemotherapy and 40% had adjuvant chemotherapy. In the BCS cohort (n=38,474), 4% had neoadjuvant chemotherapy, 28% had adjuvant chemotherapy, and 25% had adjuvant radiation therapy. As expected, receipt of neoadjuvant chemotherapy prolonged TtS by 116-128 days (p