Preoperative Hormone Therapy in the Treatment of Breast Cancer: What Do We Know So Far?

Breast cancer is the most common malignant disease in the world. One of the methods of treating breast cancer is neoadjuvant chemotherapy. Neoadjuvant chemotherapy (NCT) is now the standard of care for locally advanced breast cancer. Patients with HER2-positive and triple-negative breast cancer subtypes benefi t the most from NCT, with a 50–60 % chance of achieving pCR, while patients with hormone-sensitive, HER2-negative breast cancer subtypes have an average chance of achieving pCR of 10–20 %. For patients with locally advanced, hormone-sensitive Her2neu-negative breast cancer, neoadjuvant hormone therapy contributes to a tumor downstaging and an increasing rate of organ-preserving surgery. However, neoadjuvant hormone therapy is still not used routinely. There are a limited number of clinical guidelines that describe the choice of the optimal drugs, the optimal duration of hormone therapy and the criteria for selecting patients for preoperative hormone therapy. This is the first literature review in Russia that includes a systematization of the evidence regarding the effectiveness of neoadjuvant hormone therapy, a comparison of hormone therapy with neoadjuvant chemotherapy, comparison of hormonal drug groups, optimal duration of hormone therapy, attempts to combine hormone therapy with drugs of the group of selective CDK4/6 cyclin-dependent kinase inhibitors and phosphatidylinositol 3-kinase inhibitors for women with locally advanced hormone-sensitive Her2neu-negative breast cancer. The possibilities of using modern commercial multigene panels to assess the feasibility of identifying the cohort of patients for whom neoadjuvant hormone therapy would be most effective are also considered.