2. CTCs as a screening tool

Several studies observed the presence of CTCs in patients with no clinically detected metastatic lesion [2, 3]. Illie et al. revealed association of CTC presence with early carcinogenesis and risk of cancer [4]. However, the use of CTC presence as a screening tool to diagnose early breast cancer (EBC) is challenged by the low sensitivity of current CTC detection methods. Current CTC detection platforms such as the FDA-approved CellSearch™ system can only detect CTCs in about 70% of patients with metastatic breast cancer [5]. One of the solutions to improve sensitivity may be the previous performance of leukapheresis. Compared to 20–30% of CTC detection by the CellSearch™ system in early breast cancer, the combination of leukapheresis and the CellSearch™ system has revealed to be able to identify CTCs in 90% of patients with early breast cancer [6]. Respectively, rise of sensitivity due to enrichment techniques may pave the way to use CTCs for early breast cancer screening or diagnosis. An ongoing trial is currently enrolling patients who do not have a prior history of invasive breast carcinoma or clinically apparent metastatic disease to investigate the potential role of CTCs as a screening tool (NCT01322750).
