Circulating Tumor Cells: Applications for Early Breast Cancer.

Breast cancer is the most common malignancy among women. Most of breast cancer patients are diagnosed in early stages and will be treated with curative intent. Despite this, some patients will relapse. The identification of patients at high risk remains an important challenge. CTCs can be useful to identify this patients, to assess tumor dynamics and to monitoring therapy. There is definitive evidence on the prognostic role of CTCs in early breast cancer (eBC) but its clinical utility in daily practice is still lacking. We have to take into consideration that the studies published to date mainly evaluated the presence of CTC based on the expression of epithelial surface markers. Future studies need to overcome this limitation and important advances in technical methods can assess CTCs and capture the heterogeneity of the tumor landscape. It is also tempting to speculate that CTCs may also provide complementary information on the interplay of tumor cells with the immune system. The combination of different methods to detect tumoral disease by liquid biopsy may provide new ways to personalize in an unprecedented manner the management of patients with eBC.