Long-term follow-up of HER2-overexpressing stage II or III breast cancer treated by anthracycline-free neoadjuvant chemotherapy.

ABSTRACT

BACKGROUND: Very effective trastuzumab-based primary systemic therapy (PST) can be proposed for conservative surgery purpose to human epidermal growth factor receptor 2 (HER2)-positive breast cancer (HER2+BC). Long-term follow-up (LTFU) warrants further data. PATIENTS AND METHODS: LTFU of patients, with stage II/III HER2+BC, treated by trastuzumab associated with docetaxel (Taxotere(®)) and/or carboplatin used as anthracycline-free PST was studied. RESULTS: Among 135 patients, with a median follow-up of 48.3 months [95% confidence interval (CI) 45.3-52.4 months], the relapse-free survival (RFS) rate was 73.2% (95% CI 63.76% to 80.55%) while the overall survival (OS) rate was 91.87% (95% CI 84.23% to 95.90%). Adjuvant trastuzumab favorably influenced RFS in univariate analysis while the pathological nodal invasion unfavorably influenced RFS [Cox multivariate analysis (hazard ratio = 2.80, 95% CI 1.36-5.76, P = 0.0052)] and OS. Cardiac toxicity was minor (2.2% transient, reversible asymptomatic decrease in left ventricular ejection fraction). CONCLUSION: This is the first report of LTFU showing that anthracycline-free trastuzumab-based PST combined either with docetaxel and/or carboplatin can achieve, without cardiac toxicity, very competitive results in terms of pathological complete response, RFS and OS, in HER2+BC. The choice of this schedule could be proposed to patients with vascular contraindication for anthracyclines or because patient's or physician's preference for a taxane-only schedule.