Non-anthracycline-containing docetaxel and cyclophosphamide regimen is associated with sustained worse outcome compared with docetaxel, anthracycline and cyclophosphamide in neoadjuvant treatment of triple negative and HER2-positive breast cancer patients: updated follow-up data from NATT study.

OBJECTIVE: A previous study demonstrated that non-anthracycline-containing docetaxel plus cyclophosphamide (TC) regimen was inferior to docetaxel, anthracycline and cyclophosphamide (TAC) in neoadjuvant treatment of triple-negative breast cancer (TNBC) and human epidermal growth factor receptor-2-(HER2)-positive breast cancer in a short-term follow-up. Herein, long-term follow-up survival outcomes have been investigated.

METHODS: TNBC or HER2-positive patients were randomized to receive 6 cycles of TC or TAC neoadjuvant treatment. The primary endpoint was pathological complete remission (pCR). Secondary endpoints included clinical response rate, event-free survival (EFS), and overall survival (OS).

RESULTS: A cohort of 96 patients consisted of 45 in TC and 51 in TAC arm. With a median follow-up period of 53 (range, 8-76) months, the patients achieving pCR post neoadjuvant chemotherapy exhibited superior EFS and OS than patients without pCR (P<0.05). TAC treatment resulted in consistently better EFS than TC treatment: the estimated 5-year EFS was 66.1% vs. 29.8% (P=0.002). Moreover, the estimated 5-year OS was also in favor of TAC: 88.4% vs. 51.6% (P<0.001). Multivariable analysis demonstrated that the treatment regimen was an independent prognostic factor, and patients treated with TAC had a superior EFS [hazard ratio (HR), 0.48; 95% confidence interval (95% CI), 0.26-0.90; P=0.021] and OS (HR, 0.20; 95% CI, 0.08-0.60; P=0.003).

CONCLUSIONS: The updated long-term follow-up data demonstrated a sustained benefit in EFS and OS from anthracycline-containing TAC treatment, indicating that anthracycline is an essential and effective drug in this clinical trial.