Neoadjuvant human epidermal growth factor receptor-2 targeted therapy in patients with locally advanced breast cancer.

Purpose: We analyzed the responses of patients with locally advanced breast cancer to neoadjuvant chemotherapy (NAC) and NAC combined with neoadjuvant human epidermal growth factor receptor-2 (HER2) targeted therapy (NCHTT).

Methods: We retrospectively reviewed 59 patients with HER2 amplified locally advanced breast cancer among patients who were treated surgically after neoadjuvant therapy at Samsung Medical Center between 2005 and 2009. Thirty-one patients received conventional NAC and 28 patients received NCHTT. Pathologic responses were assessed according to response evaluation criteria in solid tumors (RECIST) guidelines.

Results: Pathologic complete response (pCR) was achieved in 13 out of 28 patients treated with NCHTT and in 6 out of 31 patients treated with NAC alone (46.4% vs. 19.4%, respectively, P = 0.049). Breast conserving surgery (BCS) was more frequently performed in the NCHTT group than in the NAC only group (71.4% vs. 19.4%, P < 0.001). The 3-year recurrence-free survival (RFS) rate was 100% in the NCHTT group and 76.4% in the NAC group (P = 0.014). Together, NCHTT, type of operation (BCS vs. mastectomy) and pathologic nodal status were significant prognostic factors for RFS in univariate analysis.

Conclusion: We found that NCHTT produced higher pCR rates than NAC alone in locally advanced breast cancer.