Colorectal cancer (CRC) is diagnosed in more than 400.000 people in Europe per year, and almost a half develop distant metastases. New drugs, such as bevacizumab, cetuximab, panitumumab, aflibercept, ramucirumab regorafenib and TAS-102 have been shown to lead to a significant improvement in median survival in patients with unresectable metastatic CRC. However, these new, molecular target drugs, which are directed towards specific targets defined as "actionable", cause heterogeneous tumour response, depending on patient's clinical characteristics and/or disease biology. Of note, they also have…