Circulating tumor cell parameters during systemic therapy in primary breast cancer

Circulating tumor cells (CTCs) are frequently studied in terms of their prognostic significance during perioperative systemic therapy (periST) for breast cancer (BC). it is not yet clear whether there are unique changes in the CTC parameters that could be used as a predictor of the effectiveness of neoadjuvant (neoST) or adjuvant (aST) systemic therapy. The aim of the study was a comparative analysis of parameters of once-isolated CTCs in BC patients with high risk of progression, who received neoST or aST. Material and Methods . The study included BC 39 patients who received neo-ST (group 1: 16 patients) or aST (group 2: 23 patients). Blood sampling for CTC isolation using microfiltration was performed after 2–5 cycles of periST. Results . No significant differences in the number of CTC-positive patients (87.5 % in group1 and 82.6 % in group 2) and the frequency of isolation of 5 or more CTCs (37.5 % in group 1 and 52.2 % in group 2, p=0.563), as well as CTC clusters (56.2 % and 43.5 % of patients in groups 1 and 2 groups, respectively, p=0.646) between the neoST and aST groups were found. There were no significant differences in the quantitative parameters (Me) of CTCs between the groups (1 group – 3 [1.8; 7.8] CTCs, 2 group – 5 [2; 6.5] CTCs, p=0.785). Regardless of the group, most patients had CTC clusters consisting of 2 to 3 cells (88.9 % and 100 % of patients in groups 1 and 2, respectively). During peri ST, a high count of CTCs was associated with the detection of CTC clusters and the presence of lymphatic metastases. Conclusion . No significant differences in CTC count and characteristics between the neoST and aST groups were found. it indicates that breast tumor resection has a minor effect on CTC parameters. . The findings highlight that CTCs hold similar prognostic value regardless of whether they are measured before or after surgery, aiding in the prediction of periST.