Neoadjuvant combination of trastuzumab and chemotherapy resulted in a high pCR rate in HER2-overexpressing primary breast cancer. Patients with a pCR after neoadjuvant anti-HER2 therapy in combination with chemotherapy followed by maintenance trastuzumab have an improved long-term outcome. Patients without a pCR had an increased risk for relapse and death.

2 Abstract PurposePathological complete response (pCR) to neoadjuvant treatment correlates with outcome in breast cancer. We determined whether characteristics of neoadjuvant therapy are associated with pCR. MethodsWe used multi-level models, which accounted for heterogeneity in pCR across trials and trial arms, to analyze individual patient data from 3332 women included in 7 German neoadjuvant trials with uniform protocols.

This combined treatment modality is active in LAEC, with a PCR in 33% of the patients undergoing surgery. The results appear improved compared with those reported with surgery alone, by approximately doubling the 3-year survival rate. The high efficacy of preoperative chemoradiation warrants evaluation of the role of surgery in LAEC.

Dose-dense and -intensified neoadjuvant chemotherapy with E(dd)→T(dd)→CMF was potentially superior to EC→T in terms of pCR. Primary use of DA did not affect pCR.