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 with anthracyclines and taxanes achieved an 18% reduction of recurrence risk in early breast cancer (BC). The optimal chemotherapy schedule and interval between cycles remain under investigation.

METHODS

Overall, 990 patients were randomised to receive either three 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 three cycles of intensified CMF (Control Arm A, E-T-CMF) that was previously used in BC or three cycles of epirubicin followed by three cycles of CMF followed by nine consecutive weekly cycles of docetaxel (wD) 35 mg/m² (Arm B, E-CMF-wD) or nine consecutive weekly cycles of paclitaxel (wT) 80 mg/m² (Arm C, E-CMF-wT). Trastuzumab was administered for HER2-positive disease.

RESULTS

At a median follow-up of 13.3 years, 330 disease-free survival (DFS) events (33.3%) were reported. DFS and overall survival (OS) did not differ between patients in the combined B and C arms versus arm A either in the entire cohort (HR = 0.90, P = 0.38 and HR = 0.85, P = 0.20) or among 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 survival were found amongst the studied regimens after a long-term observational period.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ACTRN12610000151033.

Dose-dense adjuvant chemotherapy in HER2-positive early breast cancer patients before and after the introduction of trastuzumab: Exploratory analysis of the GIM2 trial

Dose-dense adjuvant chemotherapy is standard of care in high-risk early breast cancer patients. However, its role in HER2-positive patients is still uncertain. In this exploratory analysis of the GIM2 trial, we investigated the efficacy of dose-dense chemotherapy in HER2-positive breast cancer patients with or without exposure to trastuzumab. In the GIM2 trial, node-positive early breast cancer patients were randomized to receive four cycles of (fluorouracil)epirubicin/cyclophosphamide followed by four cycles of paclitaxel administered every 2 (dose-dense) or 3 (standard-interval) weeks. After approval of adjuvant trastuzumab, protocol was amended in April 2006 to allow use of trastuzumab for 1 year after chemotherapy completion in HER2-positive patients. The efficacy of dose-dense chemotherapy in terms of disease-free survival (DFS) and overall survival (OS) was assessed according to HER2 status and trastuzumab use. Out of 2,003 breast cancer patients, HER2 status was negative/unknown in 1,551 patients; among the 452 patients with HER2-positive breast cancer, chemotherapy alone or followed by trastuzumab was given to 320 and 132 patients, respectively. Median follow-up was 8.1 years. No significant interaction between HER2 status, trastuzumab use and chemotherapy treatment was observed for both DFS (p = 0.698) and OS (p = 0.708). Nevertheless, there was no apparent benefit in the HER2-positive group treated with trastuzumab (DFS: HR, 0.99; 95% CI 0.52-1.89; OS: HR, 0.95; 95% CI 0.37-2.41). Although dose-dense chemotherapy was associated with a significant survival improvement in high-risk breast cancer patients, its benefit appeared to be smaller (if any) in patients with HER2-positive disease who received adjuvant trastuzumab.