The blood test allows us to detect cells, which have left the tumor and entered the bloodstream.
Some of these so-called circulating (epithelial) tumor cells (CETCs / CTCs) may be responsible for metastases (metastatic spread) occurring, and thus responsible for further progression of the disease.
Using the diagnostics to detect and analyze cell count, the extent to which treatment is proving successful can be monitored. For this assessment, the number of circulating cells is determined before therapy start, and this is compared with the number of cells over the course of therapy. The resulting progression of results gives an indication of whether cells are being destroyed by the cancer therapy, i.e. whether the patient is responding to the treatment. Should this not be the case, there is the possibility of testing other substances directly on the circulating tumor cells.