Factors associated with delays in receipt of neoadjuvant chemotherapy in patients with operable breast cancer.

126 Background: Delays in neoadjuvant chemotherapy initiation (NACTI) after breast cancer (BC) diagnosis have been associated with worse outcomes. We evaluated incidence and predictors of delays of NACTI among high clinical risk patients treated with NACT on a national level. Methods: We conducted a retrospective cohort study using the National Cancer Database. Eligibility included age ≥18 years, diagnosis of non-metastatic BC between 1/1/2010 – 12/31/2020, who were treated with NACT within 180 days of diagnosis. Patients who received neoadjuvant endocrine therapy were excluded. Time to chemotherapy (TTC) in days was recorded. Patients were categorized into sub-cohorts 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+. Multivariable logistic regression, adjusted for demographic, socioeconomic and tumor characteristics, was used to identify characteristics associated with delays > 60 days from diagnosis to NACTI. Multiple imputation was used for missing data. Results: We identified 145,697 eligible patients, 74% were White, 18% were Black, 3.3% were Asian, and 4.6% were Other/Unknown. Across all racial categories, 9.2% were Hispanic. Median age at diagnosis was 52 years (range 18-90), median TTC was 32 days (range 0-180), and 10% had a delay > 60 days. There were 40,345 patients in the HR+/HER2- cohort, 56,868 in the HER2+ cohort, and 48,484 in the TNBC cohort; 12%, 9.0%, and 8.9% (p < 0.001) had a delay in NACTI, respectively. In multivariable analysis among the HR+/HER2- sub-cohort, characteristics associated with delays in NACTI included Black race (OR 1.71, 95%CI 1.57-1.86) and Hispanic ethnicity (OR 1.76, 95%CI 1.60-1.94) compared to White and non-Hispanic patients. Patients with Medicare, Medicaid, or who were uninsured were more likely to be delayed (OR 1.44 95%CI 1.30-1.58, 2.10, 95%CI 1.92-2.29, 2.28, 95%CI 1.99-2.61) compared to those with commercial insurance. Results were similar in the HER2+and TNBC cohorts, as seen (Table). Conclusions: Among patients with operable BC who received NACT, patients who were Black, Hispanic, had Medicaid or no insurance had as high as a twofold increase in odds of a delay in NACTI. Targeted interventions to address these racial and socioeconomic disparities are necessary to ensure equitable care. Multivariable logistic regression adjusted for demographic, socioeconomic, and tumor characteristics variables (n = 145,697). HR+/HER2-N= 40,345 HER2+N= 56,868 TNBCN= 48,484 OR 95%CI OR 95%CI OR 95%CI Black Race 1.71 1.57-1.86 1.89 1.74-2.04 1.90 1.76-2.06 Hispanic Ethnicity 1.76 1.60-1.94 2.18 2.00-2.36 2.00 1.80-2.21 Medicare 1.44 1.30-1.58 1.46 1.34-1.61 1.45 1.32-1.61 Medicaid 2.10 1.92-2.29 2.13 1.96-2.31 2.14 1.96-2.34 No Insurance 2.28 1.99-2.61 2.36 2.07-2.70 2.25 1.96-2.59