Association of Neoadjuvant Chemotherapy Dose Intensity with Pathological Complete Response and Event-Free Survival in HER2-Negative Early Breast Cancer
Menée en Italie à partir de données portant sur 365 patientes atteintes d'un cancer du sein HER2- de stade précoce, cette étude de cohorte rétrospective analyse l'association entre l'intensité de la dose de chimiothérapie néoadjuvante et le taux de réponse complète ainsi que la survie sans événement
Background: In early-stage breast cancer (eBC), the efficacy of neoadjuvant chemotherapy (NACT) may be compromised by dose delays or reductions. A reduced relative dose intensity (RDI, i.e. the ratio of the delivered to planned chemotherapy dose), can lead to diminished clinical outcomes, but real-world data are limited in this setting.
Methods: We retrospectively analyzed data from HER2-negative eBC patients who received NACT at two Italian centers. RDI was assessed categorically with a 85% threshold and continuously. We assessed the association between RDI and pathological complete response (pCR) and event-free survival (EFS) using regression analysis.
Results: 365 patients were included, comprising 218 triple-negative (TN) and 147 hormone receptor-positive (HR+) cases. In the TN cohort, 63.3% of patients received a high RDI. High RDI was significantly associated with increased pCR rates in univariate and multivariate analyses (categorical RDI: OR 3.15, p < 0.001; continuous RDI: OR 1.05, p < 0.001). High RDI was associated with improved EFS in univariate analysis (categorical RDI: HR 0.48, p = 0.010; continuous RDI: HR 0.98, p = 0.011); however, this association was not retained in multivariate model adjusted for pCR, age, stage, and dose-dense chemotherapy. In the HR+ cohort, where 88.4% of patients received a high RDI, no association was observed between RDI and pCR. Nevertheless, high RDI was significantly associated with improved EFS in univariate and multivariate models (categorical RDI: HR 0.29, p = 0.006; continuous RDI: HR 0.96, p = 0.004) adjusted for age, stage, and treatment schedule.
Conclusion: High RDI is associated with improved clinical outcomes in patients with HER2-negative eBC undergoing NACT. Maintaining an optimal RDI is crucial to maximize treatment efficacy in the curative setting.
European Journal of Cancer , résumé, 2025