The effect of circulating tumor cells on prognosis in patients with advanced breast cancer

Introduction. Detection of circulating tumor cells (CTCs) correlates with a poor prognosis in metastatic breast cancer (MBC), however, there is clearly insufficient data to prove the level and phenotypic characteristics that are predictors of an unfavorable prognosis. In addition, the high cost and complexity of analyzing test systems registered in the world makes it impossible to conduct routine research and encourages the search for other methods for detecting CTCs, analyzing their characteristics and predictive values. The purpose of this study was to study the effect of CTC on the course of MBC, taking into account their level and qualitative composition using the flow cytometry method in accordance with the original methodology of the A.F. Tsyba MRRC. Materials and methods. The study included 21 patients with MBC. The average age of the patients was 52.7 years. The median follow–up was 21.4 months. The absolute majority of patients had involvement of regional lymph nodes in the tumor process (80.9%), metastatic bone damage was most often noted in 17 (80.9%) patients and brain damage in 9 (42.8%) patients. The most common biological subtype of the tumor was the triple negative subtype (28.7%). Before starting therapy, all patients underwent a CTC assessment using the multiparameter flow cytometry method according to the original method of the Tsyba MRSC. Not only the number of CTCs, but also their immunophenotypic features were evaluated based on the analysis of the expression of CAM5.2, BerEP4, HLA antigens-DR and CD95. All patients were treated according to the biological subtype of the tumor in accordance with the clinical recommendations of the Ministry of Health of the Russian Federation. Results. CTCs in peripheral blood were detected in 20 patients (95.3%), their number ranged from 1 to 107 cells. We found that the threshold value that significantly affects the prognosis for MBC is 8 CTCs for assessing overall survival (OS) and 5 CTCs for assessing progression-free survival (PFS) in 7.5 ml of blood. Thus, 2-year OS in the group of patients with 8 or more CTC (n=12) was 50%, in the group with less than 8 CTC (n=9) – 77.8% (p=0.1); The 2-year PFS was 5.6% in the group of patients with 5 or more CTC, and 100% in the group with less than 5 CTC (p=0.008). The features of the qualitative composition of the CTC associated with the forecast are established. The group with the CTC immunophenotype CAM5.2+BerEP4+ was prognostically unfavorable compared with the CAM5 group.2+BEREP4 is a 2-year-old OS with the CAM5 phenotype.2+BEREP4+ was 46.2%, with the CAM5 phenotype.2+BEREP4-– 85.7% (p=0.096); 2-year AFD with CAM5 phenotype.2+BEREP4+ was 0%, with the CAM5 phenotype.2+BEREP4-– 42.9% (p=0.002). Conclusions. CTCs in MBC are detected in 95.3% of cases and represent an immunophenotypically heterogeneous subset of tumor cells in the expression of pan-epithelial markers. The number of CCPs and their qualitative composition are significantly related to the prognosis of MBC. © 2025, LLC MMA MediaMedika. All rights reserved.