e12580 Background: Axillary lymph node dissection is a redundant method of surgical treatment and axillary staging for a large number of patients receiving neoadjuvant therapy with positive lymph nodes before NCT. Methods: The study included 212 patients with breast cancer (cT1-3N1M0) who received treatment at the breast tumors department of the N.N. Petrov NMRC of Oncology from 2019 to 2021 All patients included in the study had the cN1 initial status of the axillary lymph nodes. All patients underwent neoadjuvant systemic therapy and subsequent sentinel lymph node biopsy (SLNB). In patients with pathomorphologically proven metastatic lymph nodes (cN1) even at the initial diagnosis, lymph node marking was performed before the start of NCT and targeted axillary lymph node dissection after the completion of neoadjuvant systemic therapy. In the same patients, after SLNB and targeted axillary lymph node dissection, a complete (standard) axillary lymph node dissection was performed to determine the false-negative rate and the oncological safety of the procedure. Results: The identification rate of only one sentinel lymph node was 21% (40 out of 193 patients), two sentinel lymph nodes - 30% (58 out of 193 patients), more than 3 - 49% (95 out of 193 patients). When only 1 sentinel lymph node was found, the false-negative rate of SLNB was 20.0% (4 of 20) (95% CI, 5.7 to 43.7). When two sentinel lymph nodes were found, the false-negative rate of SLNB was 20.0% (6 of 30) (95% CI, 7.7 to 38.6). When three sentinel lymph nodes were found, the false negative rate of SLNB was 4.7% (2 of 43) (95% CI, 0 to 15.8). Among 45 patients who had a microseed with the iodine-125 radioisotope installed before the start of treatment, the frequency of identifying a marked node was 100%. In 19 patients, tumor cells were found in the lymph nodes. The false-negative rate of targeted axillary dissection in combination with SLNB was 5.3% (1 of 19) (95% CI, 0 to 26.0). Conclusions: Targeted axillary dissection and sentinel lymph nodes biopsy, provided that 3 SLNs are removed, are reliable methods for identifying patients in whom systemic therapy is guaranteed to achieve complete response of regional lymph nodes (ypN0), thereby relieving patients of the need to perform a crippling complete axillary lymph node dissection. Clinical trial information: 3/198.

BACKGROUND: BRCA-associated triple-negative breast cancer does not only have a better overall survival rate, but also a longer recurrence-free period in compatison to patients with sporadic breast cancer. BRCA-associated triple-negative breast cancer shows high sensitivity to chemotherapeutic agents, but the benefit of systemic neoadjuvant therapy for patients with tumor size T1 in triple-negative breast cancer is unclear. AIM: The aim of the study is to determine the recurrence rate in the patients with BRCA-associated triple-negative breast cancer and to determine the recurrence rate for the group of patients with tumor size T1, depending on the initial treatment. MATERIALS AND METHODS: The study includes the data of 129 patients diagnosed with BRCA-associated triple-negative breast cancer treated in the period from 2010 to 2022 at the Department of Breast Tumors of the N.N. Petrov National Medical Research Center of Oncology. All the patients have been divided into two groups depending on the initial treatment. Group I included 93 (72.1%) patients whose treatment was started with systemic neoadjuvant therapy, group II, whose initial treatment involved surgery, included 36 (27.9%) patients. RESULTS: In group I, the number of recurrences was 22 (23.6%), and in group II 6 (16.6%). Depending on the pathomorphological response to systemic neoadjuvant therapy, the patients of group I have been separated: in the group of patients with a complete pathomorphological response, the number of relapses was 6 (13.3%), and in the group of patients with a partial pathomorphological response 16 (33.3%). A comparative analysis of 2 groups with tumor size T1 has shown that in group I the number of patients with tumor size T1 was 11 (11.8%) cases, and in group II 16 (44.4%). Subgroup comparative analysis in group I, taking into account tumor size T1, has shown that recurrence has not been observed when a complete pathomorphological response was achieved in 8 (17.7%) patients, and in the group with partial pathomorphological response in 3 (6.25%) patients with tumor size T1. A relapse has been observed in 1 (2%) case. With clinical tumor size T1 (n = 16), there was no recurrence in group II. CONCLUSIONS: Patients diagnosed with BRCA-associated triple-negative breast cancer remain at a high risk of recurrence at a later stage of the disease, but this does not apply to patients with a tumor size T1 since the difference in relapse-free survival [AP1] between patients, whose treatment was started with neoadjuvant systemic therapy and patients, whose initial treatment involved surgery % with a clinical tumor size T1, is not confirmed.

Background. BRCA-associated triple negative breast cancer (TNBC) is considered one of the most aggressive subtypes of breast cancer with high sensitivity to chemotherapy, which leads to increased interest in finding new treatment options for patients with this subtype of breast cancer.   Aim. To determine the role of adding a platinum drug to standard systemic neoadjuvant therapy (NAC) for patients with primary BRCA-associated TNBC with clinical stage T1–3N0–3M0, and to evaluate the effect of platinum-based drugs on recurrence-free survival in patients of this category.   Materials and methods. The study included 75 patients diagnosed with primary BRCA-associated TNBC. They were divided into 2 groups depending on the NAC provided, and then they were subdivided depending on the completion of the course of ongoing NAC, the final pathomorphological result and the presence of recurrence.   Results. Group I included 48 (64 %) patients who received the AC–T regimen; in group II (n = 27 (36 %)) patients received NAC according to the AC–TCarb regimen. Patients of group II showed a higher frequency of achieving pathological complete response (pCR) compared with patients of group I (73.7 % versus 41.2 %, respectively, p = 0.0433). Taking into account the NAC regimens being carried out, patients of group I had a slightly higher risk of recurrence compared to patients of group II (p = 0.099).   Conclusion. In patients with primary BRCA-associated TNBC, the addition of platinum compounds to the systemic NAC resulted in achieving of pCR in 73.7 % cases compared with 41.2 % pCR after the standard anthracycline-taxane NAC, which entails a reduced risk recurrence in this category of patients. Performing a full course of planned NAC has a positive trend in achieving pCR in patients of this category.

BACKGROUND: Surgical treatment of breast cancer plays a major role in the combined and complex treatment of patients. The purity of the examined edges of the resected breast tissue is the main indicator of the reliability of the breast-conserving surgery and one of the main factors in the development of local recurrence. Neoadjuvant (preoperative) systemic therapy allows evaluating the effectiveness of therapy in vivo and reducing the size of the initial formation, both in locally advanced and resectable forms of breast cancer. The main advantage of this treatment is the ability for surgeons to perform breast-conserving surgery to improve patients quality of life and aesthetic outcomes without compromising disease-free and overall survival. AIM: To study the clinical and pathological characteristics and analyze of the breast-conserving surgery in patients with breast cancer after neoadjuvant chemotherapy. MATERIALS AND METHODS: 156 performed breast-conserving surgery after neoadjuvant chemotherapy were analyzed. Breast-conserving resection implied radical removal of the residual tumor node within healthy breast tissues with the achievement of negative resection margins. If pathologists detected stained invasive cells/cancer in situ in a formalin-fixed preparation, a second surgical intervention was performed. RESULTS: Of the 156 studied anatomical preparations after breast-conserving surgery, a positive margin was found in 4 (2.56%) cases. In 4 patients, positive margin was represented by ductal carcinoma in situ. According to the results of trephine biopsy, no intraductal component was found before neoadjuvant chemotherapy. The greatest length of the ductal carcinoma in situ section is 2.2 mm. In 3 cases, the distance to the stained resection margin of the micropreparation was 1 mm. As a result of repeated pathomorphological examination of pre-cut margins after surgical intervention, cancer in situ was not found. CONCLUSIONS: The ongoing neoadjuvant systemic therapy for breast cancer with a partial or complete response of the tumor increases the percentage of breast-conserving surgery performed in patients who initially belong to the group of radical mastectomy, but who want to save breast tissue.