Purpose: In an era where neoadjuvant dual blockade is emerging as the standard of care for early and locally advanced HER2-positive breast cancer, we aimed to identify predictors of response to single-blockade chemotherapy.
Methods: This retrospective analysis reviewed all the incident stage I-III HER2-positive breast cancer patients who received neoadjuvant docetaxel, carboplatin, and trastuzumab (TCH) in three institutions. pCR was defined as the absence of invasive tumor in breast and axillary nodes (ypT0/isypN0).
Results: From 2008 to 2015, 84 patients receiving neoadjuvant TCH were identified within our institutions. The mean age at diagnosis was 51.8 years. 59.5% of the patients were hormone receptor (HR) positive, lymph node involvement occurred in 67.9%, and clinical distribution was 2.4, 65.5, and 32.1% for stage I, II, and III, respectively. pCR rate was 47.6%; there was a significantly lower response in HR-positive patients compared to HR-negative ones (34 vs 67.6%, p = 0.005). pCR rate was associated with tumor size, whereas differences did not reach significance either for stage or for nodal status. Multivariate analysis found that only HR status was associated with response (p = 0.003). At a median follow-up of 31.7 months, disease-free survival, distant disease-free survival, and overall survival were 78.6, 85.7, and 94%, respectively. Breast-conserving surgery was performed in 44% of the patients. Overall, TCH was well tolerated, with low rates of grade 3-4 adverse events, and neither late toxicities nor cardiac dysfunctions were reported.
Conclusions: Neoadjuvant TCH, an anthracycline-free single-blockade regimen, achieved a pCR of 47.6%. Further molecular analyses are required in order to identify stronger predictive markers of pCR and thus for an accurate selection of patients who do not benefit from dual blockade.
Keywords: Anthracycline-free; Breast cancer; HER2-positive; Neoadjuvant; Single blockade; TCH.