Adjuvant and neoadjuvant therapy of ER+ / HER2– breast cancer

Abstract

Even early-stage breast cancer is a heterogeneous disease, so the optimal treatment depends on the pathological characteristics of the tumor. The vast majority of breast tumors (80%) are classified as estrogen receptor positive (ER+) with varying degrees of ER expression. The benefit of endocrine therapy is small with low ER staining (1–10%), occurring in less than 2% of all cases of ER+ breast cancer. Genetic analyzes are valuable for administration of adjuvant chemotherapy prior to endocrine therapy in ER+ / HER2– pN0–pN1c breast cancer. But such tests are not yet widely available. In practical work, when planning adjuvant and neoadjuvant therapy for patients with ER+ / HER2– breast cancer, pathological assessment of the expression of ER, PR, Ki‑67, as well as the tumor grade (G) remains important. The use of drugs to overcome resistance to endocrine therapy: PI3-kinase inhibitors (taselisib), CDK 4/6 inhibitors (palbociclib, abemaciclib, ribociklib), mTOR inhibitors (everolimus) can enhance the effect of neoadjuvant and adjuvant endocrine therapy.