Circulating Tumor Cells (CTCs) can be defined as cancerous cells, which detach from a tumor and flow through the vascular or lymphatic systems. The blood flow can carry the tumor cells in another region of human body where they can become the starting point for the growth of additional metastases. Because of this behavior, in the CTCs study it is paramount to acquire new data and knowledge to understand the mechanisms that lead to the separation of the cell from the tumor as well as the major characteristics of these cells. The aim of this work is the development of an innovative therapeutic and diagnostic approach able to lead to a new medical device for removing CTCs from the peripheral blood of a patient. The main target of the approach is to detect the CTCs and separate them during a conventional extracorporeal circulation procedure, similar to that used for renal failure. In this work, the CTCs physical properties are investigated in order to explore the possible characteristics that can be exploited in an ad-hoc developed medical device to remove them from the blood flow. The CTCs physical properties are analyzed numerically, and their behavior is studied by means of CFD simulations. The preliminary numerical tests have been carried out on simple geometries in order to assess the influence of magnetic and electric fields on tumor cells’ trajectory. These results are the baseline information to develop more complicated geometries and prototypes for real operations.