Assessing the influence of circulating tumor cells on the prognosis of breast cancer

Aim. To monitor antitumor therapy using the level of circulating tumor cells (CTC) in the peripheral blood of breast cancer (BC) patients using aptamers.Materials and methods. The study included 34 patients with BC. The primary determination of CTC content was performed before surgical treatment in 2017. 32 and 48 months after surgical treatment, the number of CTC and their derivatives was re-determined to assess the dynamics of the disease. Detection of CTC was carried out in 3.5 ml of blood from BC patients using the aptamer MDA231, which is affinity for BC cells and labeled with the fluorescent dye Cy5. Counting of CTC in smears of blood samples was performed using fluorescence and scanning laser microscopy.Results. The observation period for patients ranged from 1 to 143 months. 7 (20.6 %) of 34 patients experienced disease progression. The median time to disease relapse was 69 months. A statistically significant inverse moderate correlation (p 0.05) was revealed between age and the number of CTC (–0.39). A statistically significant direct average correlation (p 0.05) between proliferative activity index Ki-67 and the number of CTC (0.42) was also found. Statistically significant differences were found between patients divided into two groups depending on the presence or absence of CTC in the time until the onset of disease relapse (p = 0.015). The median survival and interquartile range in patients with CTC was 68 (23–70) months, and in patients without CTC 76 (58–108) months.Conclusion. The risk of developing BC relapse with positive detection of CTC is 28.6 %. The value of the absolute risk indicator in BC patients without CTC in the peripheral blood is 5.9 %. The value of the relative risk indicator is 4.857.