Circulating tumor cells as early predictors of metastatic spread in breast cancer patients with limited metastatic dissemination (Breast Cancer Research)

IntroductionTraditional factors currently used for prognostic stratification do not always predict adequately treatment response and disease evolution in advanced breast cancer patients. Therefore, the use of blood-based markers, such as circulating tumor cells (CTCs), represents a promising complementary strategy for disease monitoring. In this retrospective study, we explored the role of CTC counts as predictors of disease evolution in breast cancer patients with limited metastatic dissemination. Methods: 492 advanced breast cancer patients who had a CTC count assessed by CellSearch prior to starting a new line of systemic therapy were eligible for this analysis. Using the threshold of 5 cells/7.5?mL of blood, pretreatment CTC counts were correlated in the overall population with metastatic site distribution, evaluated at baseline and at the time of treatment failure, using the Fisher?s Exact test. Time to visceral progression, as well as, time to the development of new metastatic lesions and sites were estimated in patients with non-visceral metastases and with single-site metastatic disease, respectively, by the Kaplan-Meier method. Survival times were compared among groups according to pretreatment CTC count by log-Rank test. Results: In the overall population, pretreatment CTCs???5 were associated with increased baseline number of metastatic sites, compared with CTCs?