Changes in the presence of circulating tumor cells in the peripheral blood of breast cancer patients during the course of treatment
Abstract
Presence of tumor cells circulating in peripheral blood is associated with systemic disease and shortened survival of breast cancer (BC) patients. The aim of this study was to identify circulating tumor cells (CTC) in peripheral blood as potential biomarker for therapy response monitoring and metastatic relace risk prediction in BC management.
A total of 138 patients with diagnosed BC at stage I to III, and 42 metastatic patients were enrolled into prospective study between years 2008 - 2010. Peripheral blood (5ml) for CTC detection was collected from primary BC patients before chemotherapy (CHT), after 2 cycles of CHT and after CHT.
Metastatic BC patiens have been examined for CTCs before starting new line of the treatment. 439 blood samples have been analyzed in total. CTCs from whole blood was followed characterization using AdnaTest BreastCancer Select and Detect kit.
After modification of immunomagnetic isolating procedure, we were able to analyze captured CTC-cells morphologically and get approximate counts of viable CTC in 1 ml of blood. This type of analysis enabled us further to cultivate CTC for purpose of single cell PCR-analysis.
In group of metastatic patients CTCs have been identified in 43% of patients in first sampling. After treatment (CHT, RT) positivity rate decreased to the 12%.
In group of neoadjuvant patients 35% samples have been positive before therapy, after 2 CHT-cycles only 5% remained positive. Comparing dynamics of CTC count within adjuvant treatment, CTC-positivity rate decreased after completing CHT from 26% down to 13%, emphasizing that there is a group of patients with CTC abundance after treatment, which should be handled differently with special focus on metastasis prevention.
Our results indicate, that CTC-test could be used for monitoring therapeutical intervention success in adjuvancy and neoadjuvancy.