Abstract P1-12-01: Dose-dense sequential adjuvant chemotherapy in the trastuzumab era: Final long-term results of the hellenic cooperative oncology group phase III HE10/05 trial

Background: Dose-dense sequential chemotherapy based on anthracyclines and taxanes has achieved an 18% reduction of recurrence risk in the adjuvant setting of early breast cancer (BC). However, the optimal chemotherapy schedule and the preferable interval between cycles are still under investigation. Methods: A total of 990 eligible BC patients were randomized to receive either 3 cycles of epirubicin (E,110 mg/m2) every 2 weeks followed by 3 cycles of paclitaxel (T, 200 mg/m2) every 2 weeks followed by 3 cycles of intensified CMF (Control Arm A, E-T-CMF; 333 patients) or three cycles of epirubicin followed by 3 cycles of CMF followed by 9 consecutive weekly cycles of docetaxel (wD) 35 mg/m2 (Experimental Arm B, E-CMF-wD; 331) or 9 consecutive weekly cycles of paclitaxel (wT) 80 mg/m2 (Experimental Arm C, E-CMF-wT; 326). Trastuzumab was administered for HER2-positive disease. The primary endpoint was disease-free survival (DFS). Results: At a median follow-up of 13.3 years, 330 DFS events (33.3%) had been reported. DFS and overall survival (OS) did not differ between patients in the combined B and C arms versus control arm A either in the entire cohort (HR=0.90, p=0.38 and HR=0.85, p=0.20) or among HER2-positive, trastuzumab-treated patients (HR=0.69, p=0.13 and HR=0.67, p=0.13). Thirty-four patients (3.4%) developed secondary neoplasms. Conclusions: Overall, no significant differences in DFS or OS were found amongst the studied regimens after a long-term observational period. Trial registration: Australian New Zealand Clinical Trials Registry ACTRN12610000151033 Citation Format: Flora Zagouri, Georgia-Angeliki Koliou, Foteinos Dimitrakopoulos, Christos Papadimitriou, Ioannis Binas, Angelos Koutras, Pavlos Papakostas, Christos Markopoulos, Vasileios Venizelos, Grigorios Xepapadakis, Charisios Karanikiotis, Amanda Psyrri, Dimitrios Bafaloukos, Paris Kosmidis, Gerasimos Aravantinos, Eleni Res, Davide Mauri, Anna Koumarianou, Kalliopi Petraki, Anna Tsipoura, Dimitrios Pectasides, Helen Gogas, George Fountzilas. Dose-dense sequential adjuvant chemotherapy in the trastuzumab era: Final long-term results of the hellenic cooperative oncology group phase III HE10/05 trial [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-12-01.