Primary systemic therapy in HER2-positive operable breast cancer using trastuzumab and chemotherapy: efficacy data, cardiotoxicity and long-term follow-up in 142 patients diagnosed from 2005 to 2016 at a single institution

OBJECTIVE: The aim of this study was to evaluate the efficacy, cardiotoxicity profile and long-term benefits of neoadjuvant therapy in human epidermal growth factor receptor 2-positive operable breast cancer patients. PATIENTS AND METHODS: A total of 142 patients diagnosed from 2005 to 2016 were included in the study. The treatment consisted of a sequential regimen of taxanes and anthracyclines plus trastuzumab. The clinical and pathological responses were evaluated and correlated with clinical and biological factors. The cardiotoxicity profile and long-term benefits were analyzed. RESULTS: The median age was 49 years, and 4%, 69% and 27% of patients had stage I, II and III breast cancer, respectively, while 10% had inflammatory breast cancer at diagnosis. Hormone receptor (HR) status was negative in 43%, and 62% had grade III breast cancer. The clinical complete response rate was 49% and 63% as assessed using ultrasound and magnetic resonance imaging, respectively, and this allowed a high rate of conservative surgery (66%). The pathological complete response (pCR) rate was 52%, and it was higher in HR-negative (64%) patients than in HR-positive (41%) patients and in grade III breast cancer (53%) patients than in grade I–II breast cancer (45%) patients. Patients who achieved pCR had longer disease-free survival and a trend toward improved overall survival. A total of 2% of patients showed a 10% decrease in left ventricular ejection fraction to <50% during treatment. All patients except one recovered after discontinuation of trastuzumab. CONCLUSION: A sequential regimen of taxanes and anthracyclines plus trastuzumab was effective, with high pCR rates and long-term benefit, and had a very good cardiotoxicity profile.