Multilevel factors associated with delays to neoadjuvant chemotherapy among young adults with operable breast cancer.

11091 Background: Breast cancer (BC) rates are increasing in young adults (YAs: age 18-39) and this population may experience unique barriers to treatment initiation. We identified factors associated with treatment initiation delays in a cohort of YAs with operable BC who received neoadjuvant chemotherapy (NACT). Methods: Using the National Cancer Database, we identified YAs diagnosed with non-metastatic BC from 2010-2020 who received NACT. We grouped patients by receptor status and clinical stage: 1) Hormone Receptor positive/HER-2 negative (HR+/HER2-) and were lymph node (LN) LN+; 2) HER-2 positive (HER2+) cT2+ or LN+; and 3) triple negative BC (TNBC) cT2+ or LN+. Primary outcome was delayed treatment initiation, defined as > 60 days from diagnosis date to NACT. Multivariable (MV) logistic regression was used to model factors associated with delay and adjusted for sociodemographic, clinical, and facility-level factors. We also examined factors associated with delays by tumor type. Results: Of 23,078 included patients, 62% were non-Hispanic White (NHW) and 74% had private insurance. By tumor type, 28% (n=6,350) were ER/PR+, 39% (n=8,921) were HER2+, and 34% (n=7,807) had TNBC. Most patients were treated at academic comprehensive cancer programs (ACCP) or comprehensive community cancer programs (CCCP) (40% and 34%). Treatment delays were observed among 7% of patients (n=1,638) across all tumor types. In MV analysis, non-Hispanic Black (NHB) and Hispanic YAs had 2-fold higher odds of delays compared with NHW YAs. YAs with low-income had higher odds of delays compared with higher income (OR=1.41), and YAs with private insurance had lower odds of delays compared with Medicaid (OR=0.54). YAs treated at any non-ACCP facility were less likely to experience delays. The results were similar for each tumor type. Conclusions: While the overall incidence of delays was low, significant racial, ethnic, and institutional-level treatment initiation disparities were observed among YAs receiving NACT for BC. Table: see text