Adjuvant (Ad) and neoadjuvant (NAd) strategies in higher risk hormone receptor–positive (HR+)/HER2-negative (HER2−) early breast cancer (EBC): Moroccan real-world outcomes.

Abstract

e12735 Background: In low- and middle-income countries, many higher-risk HR+/HER2- EBC patients (pts) often undergo primary surgery followed by adjuvant anthracyclines (ATC) and taxanes (TX)-based chemotherapy (CT) and endocrine therapy (ET), while a smaller proportion receive NAdj CT-based ATC and TX followed by postoperative ET, frequently with deviations from established guidelines. The benefits derived from these two approaches and the incremented benefit attributable to specific CT combinations remain unclear. Methods: In this unicentric, retrospective cohort, we included stage I-III higher-risk HR+/HER2- EBC patients, aged > = 18 years, treated between January 1 st , 2020, and June 30 th , 2024, who received either Ad or NAd ATC +/- TX, followed by radiotherapy when indicated, and ET-based tamoxifen for premenopausal or fulvestrant/aromatase inhibitor for postmenopausal pts for up to 5-7 years or until local/regional/distant relapse or progression precluding surgery. Overall survival (OS) was the primary endpoint. Disease-free survival (DFS), event-free survival (EFS), and safety were the secondary endpoints. Results: At the data cutoff, 424 pts received Ad, and 236 pts received NAd, CT-based doxorubicin-cyclophosphamide (AC) monotherapy, AC with docetaxel (AC-D), AC with paclitaxel (AC-P), epirubicin-cyclophosphamide monotherapy (EC), EC with docetaxel (EC-D), EC with paclitaxel (EC-P), or TX (P or D) followed by ET. The median follow-up was 42 months (m) (IQR: 35, 48). There was no statistical difference in OS between the Ad and NAd groups (adjusted hazard ratio [aHR], 0.87; 95% CI, 0.58 to 1.3; p = 0.5). In the Ad group, the median DFS was 44m (95% CI, 26-Not Estimable [NE]) with EC-D, 36m (95% CI, 33-NE) with EC-P, 32m (95% CI, 24-NE) with AC-D, 28m (95% CI, 19-NE) with AC-P, 29m (95% CI, 16-NE) with ATC, and 20m (95% CI, 13-NE) with TX (aHR, 0.61; 95% CI, 0.38, 1.07; p = 0.06). In the NAd group, the median EFS was NE with EC-D, 22m (95% CI, 17-NE) with EC-P, 35m (95% CI, 27-NE) with AC-D, 29m (95% CI, 21-NE) with AC-P, 37m (95% CI, 30-NE) with ATC, and 28m (95% CI, 18-NE) with TX (aHR, 1.36; 95% CI, 0.82, 2.53; p = 0.56). Safety findings were consistent with expected profiles, predominantly grade 1-2 hematologic events; EC-D showed a lower incidence, and no treatment discontinuations occurred. Conclusions: The findings suggest that both strategies were similarly effective for treating higher-risk HR+/HER2- EBC, with a potential advantage favouring EC-D in both approaches; however, as these results remain early and exploratory, longer follow-up and larger, more inclusive cohorts are needed to confirm this observation, all with fewer adverse events, supporting its use in low-resource settings without compromising patient-reported quality of life.