Disparities in delays and outcomes in patients with HER2-positive breast cancer

Neoadjuvant chemotherapy (NACT) is often the preferred systemic treatment modality for advanced breast tumors. Delays in NACT initiation are associated with worse outcomes although it is unclear which patients are at the highest risk for delays and whether these delays impact pathologic complete response (pCR). We sought to determine the incidence, predictors, and cancer-related outcomes associated with delays in NACT initiation among patients with HER2-positive (HER2 +) breast cancer in the modern era.

We retrospectively analyzed a cohort of patients with stage II-III HER2 + breast cancer who were treated with NACT and surgery using the National Cancer Database. Multivariable logistic regression, adjusted for demographic, socioeconomic and tumor characteristics, was used to identify characteristics associated with and the likelihood of achieving a pCR with delays in NACT initiation.

56,868 patients were included in the analysis. Delays in NACT initiation of > 60 days from diagnosis was observed in 9% of patients. In a multivariable analysis, patients who were Black (OR 1.88 95%CI 1.74-2.04), Hispanic (OR 2.19, 95%CI 2.00-2.39), had Medicaid (2.14, 95%CI 1.97-2.32), or no insurance (2.39, 95%CI 2.09-2.72) were more likely to be delayed. Delay was associated with a lower likelihood of achieving pCR (OR 0.86 95% CI 0.81-0.92) and an increased risk of death (HR 1.15 95%CI 1.03-1.29).

There are racial, ethnic, and socioeconomic disparities in NACT initiation delays and an association with worse cancer-related outcomes. Future studies and interventions are needed to mitigate these delays.