SURGERY FEATURES IN THE TREATMENT OF PATIENTS WITH HER2-neu POSITIVE BREAST CANCER

Galaychuk I.Y.

• I. Horbachevsky Ternopil National Medical University

Aim: based on author’s clinical observation and data from the scientific literature, to analyze direct results of systemic neoadjuvant chemo-targeted therapy (NACTT) (general tumor response) in patients with HER2-neu positive breast cancer (BC) and to demonstrate feasibility of conservative surgery for BC in this group of patients. Object and methods: medical records of patients with BC stages T1N0M0 (3), T2N0M0 (2), T2N1M (4), T2N2M0 (1) were analyzed. Five patients were diagnosed with luminal B (ER/PR⁺, Her2-neu⁺⁺⁺) molecular subtype of breast cancer, in 5 others — HER2-neu positive subtype with negative hormone receptors (ER/PR^-, Her2-neu⁺⁺⁺). Seven patients received NACTT. Five patients underwent radical sectoral resections with axillary lymphadenectomy of I–II levels. The others underwent Madden mastectomy. The observation period is 1–7 years. Results: in most of the patients, systemic NACTT has been shown to result in complete therapeutic pathomorphosis (pCR) of both breast tumors and regional lymph nodes (ypT0 ypN0 (0/0), LVI0, Pn0, R0). Preoperative ultrasound, mammography, or CT scans can diagnose complete «visual» regression of breast tumors, which coincides with the morphological data of tumor devitalization. Under these conditions, organ-saving surgery should be preferred to mastectomy. Conclusions: in patients with HER2-neu positive BC under the condition of «visual» regression of tumor after NACTT, surgery intervention is advisable to be limited to sectoral resection of the breast with sentinel lymph node biopsy, or level I–II lymph node dissection, or so-called targeted axillary dissection (TAD). In case of the patient’s refusal of surgery, it is necessary to carry out active follow-up (ultrasound, mammography, MRI, CT) and to continue the planned systemic or endocrine therapy.