Figure 3. Therapeutic options in targeting CTCs and DTCs.

After initial diagnosis, patients eligible for operation undergo surgical resection of the primary tumors in combination with chemo- and radiation therapy. Resection margins should be controlled through novel, sensitive techniques including probe-based confocal laser endomicroscopy (pCLE) to assure complete withdrawal of tumors. Routinely, the expression of therapeutic target antigens such as e.g. EGFR, EpCAM and PD-L1 should be assessed in order to improve adjuvant therapy through adequate stratification. Simultaneously, blood draws will serve to assess CTC numbers and to perform molecular characterization of the expression of therapeutic antigens. CTC enumeration will be implemented into decisions concerning adjuvant chemo- and radiation therapies. Molecular profiling of CTCs will allow for the determination of the application of novel therapeutic antibodies and small molecule inhibitors.