Neoadjuvant Aromatase Inhibitor(AI) With Ovarian Suppression Versus Chemotherapy in Premenopausal Breast Cancer Patients

Neoadjuvant therapy is nowadays the standard treatment for both early stage and locally advanced breast cancer, and exhibited similar benefit compared with adjuvant therapy in terms of disease free and overall survival. Patients achieved pathological complete response(pCR) after neoadjuvant chemotherapy have superior outcome compared with those with residual tumors in breast and/or axilla. pCR is now the most wildly accepted surrogate marker for long-term survival of patients, especially in those with triple negative or human epidermal growth factor receptor-2(HER2)-positive breast cancer. However, in luminal HER2-negative breast cancer, neoadjuvant chemotherapy is not as effective as in other subtypes of breast cancer, pCR is less noted and seems barely correlated to long-term survival benefit. In postmenopausal patients with hormone receptor-positive breast cancer, neoadjuvant endocrine therapy of aromatase inhibitor achieved similar clinical response rate compared with neoadjuvant chemotherapy, and in premenopausal hormone receptor-positive, HER2-negative breast cancer patients, neoadjuvant aromatase inhibitor plus ovarian function suppression(OFS) has showed more pronounced efficacy than tamoxifen plus OFS. In adjuvant setting, aromatase inhibitor combined with OFS in premenopausal patients with hormone receptor-positive breast cancer has demonstrated superior benefit in terms of disease free survival, and has been established as one of the routine options of adjuvant endocrine therapy. Notwithstanding the remarkable performance of combination of aromatase inhibitor and OFS in adjuvant therapy, the role of this treatment strategy in neoadjuvant setting has yet not been proved when compared with neoadjuvant chemotherapy. The aim of this study is to prospectively compare the efficacy and safety of neoadjuvant aromatase inhibitor plus OFS with chemotherapy in premenopausal patients with hormone receptor-positive HER2-negative breast cancer.