The Neoadjuvant Combined Hormone Therapy in Premenopausal Women With Locally Advanced ER+/HER2- Breast Cancer

Breast cancer take a leading position in the structure of morbidity and mortality from malignant tumors among women. Today the interest of many scientists and pharmaceutical companies is focused on the study of metastatic breast cancer forms. While we obtain little experimental data and practical research about the treatment of locally advanced forms. In this regard, the study of new neoadjuvant drug therapy regimen for estrogen-receptor positive breast cancer in premenopausal woman is very relevant. The proposed research will be the absolutely innovative investigation worldwide. The study will consist of two modes of treatment, combined hormone therapy with CDK4/6-ingibitors and chemotherapy (the control), each replicated four times in a randomized, complete block design. This research aims to improve the results of treatment, namely to increase the percentage of successfully treated patients and reduce toxicity from treatment. Primary study endpoints will include the frequency of objective response and complete pathomorphological response (according to the Miller-Payne classification). Secondary endpoints will include a decrease of the Ki67 level in postoperative material compared to primary biopsy, the frequency of organ-preserving operation after neoadjuvant treatment and quality of life. Study hypothesis: neoadjuvant combined hormone therapy with CDK4/6-ingibitors in premenopausal women with luminal breast cancer leads to at least the same results as neoadjuvant chemotherapy, but with less toxicity.