Circulating tumor cells in patients with locally advanced breast cancer in evaluation of antitumor treatment efficacy.

Abstract

e12064 Background: Circulating tumor cells (CTC) are of great importance in modern cancer research. Biological characteristics of CTC allow using them as tumor markers of high prognostic value. Their quantitative evaluation during treatment can be used to monitor the response to treatment in patients receiving systemic chemotherapy (CT). The purpose of the study was to assess the role of CTC in the prognosis of treatment efficacy in patients with locally advanced Her-2 negative breast cancer. Methods: The study included 42 patients aged 30-65 years with stage IIIA, IIIB, IIIC locally advanced Her-2 negative breast cancer, ECOG-WHO Performance Status from 0 to 2, Karnofsky Performance Status from 100% to 80%. CTC were determined using the CellSearch Veridex System (Johnson & Johnson, USA), taking into account morphological characteristics and expression of epithelial cell adhesion markers EpCAM, CD45 and cytokeratins 8, 18 and 19. Results: CTC were found in 86% (36 of 42 patients) before treatment. CTC were not registered in 6 (14%) patients. 1 CTC was detected in 14% (6 patients); 2-3 CTC – 33% (14 patients); more than 3 CTC – 38% (16 patients). 12% (5) patients showed more than 10 CTC, with the maximum of 64 CTC in 1 patient. After 2 cycles of polychemotherapy, CTC were detected in 50% (21 patients). Other 21 patients did not show presence of CTC. Among CTC-positive patients, 1 CTC was detected in 4 patients (19%); from 2 to 3 CTC – in 9 patients (43%); more than 3 CTC – 8 patients (38%). 2 patients (10%) still showed more than 10 CTC – 28 and 33 CTC in the peripheral blood. After 2 cycles of polychemotherapy, the number of patients with more than 1 CTC decreased from 86% to 50%. Polychemotherapy regimen was changed for patients with increasing amounts of CTC. Conclusions: Determination of the CTC number allows evaluation of the treatment efficacy and is a specific marker for the change of applied polychemotherapy for such cancer type.