[Current situation and issues regarding preoperative chemotherapy for HER2-positive breast cancer].

Objective: The clinical significance of preoperative chemotherapy, including trastuzumab for HER2-positive breast cancer, was examined based on hormone receptors(HR)to clarify future issues.
Subjects: 104 HER2-positive breast cancer patients who completed preoperative chemotherapy and underwent surgery from May 2005 to August 2010. All patients received sequential treatment with taxane±trastuzumab for FEC(5-FU+epirubicin+cyclophosphamide)therapy, and from 2008 they received trastuzumab postoperatively for one year.
Results: Concerning the histological effects, the rate of comprehensive pCR(CpCR)in the 104 patients(31 HR-negative administered trastuzumab, 15 HR-negative not administered trastuzumab, 28 HR-positive administered trastuzumab, 30 HR-positive not administered trastuzumab)was 65%, 47%, 21% and 23% for each group, respectively CpCR was a significant factor(p<0. 05)in prolonged distant disease-free survival(DDFS)in the HR-negative group. Distant metastasis occurred in 14 patients, namely, brain metastasis in 7 patients(4 HR-negative administered trastuzumab, 1 HR-negative not administered trastuzumab, 2 HR-positive administered trastuzumab). The therapeutic efficacy was pINV in 5 of these 7 patients(3HR-negative administered trastuzumab, 1 HR-negative not administered trastuzumab, 1 HR-positive administered trastuzumab), and 4 of those 5 patients received trastuzumab postoperatively.
Discussion: The responsiveness to preoperative chemotherapy including trastuzumab for HER2-positive breast cancer differs between HR-positive and HR-negative. pINV patients seem to be at a high risk for brain metastasis regardless of HR, and it may be difficult to suppress its occurrence only with trastuzumab adjuvant therapy.