 The purpose of this study is to exploratorily examine efficacy and safety in the patients with chemotherapy-naïve unresectable, advancedrecurrent colorectal carcinoma of KRAS wild-type who have been treated with 6 cycles 2 weekscycle of first-line mFOLFOX6 panitumumab combination therapy and then assigned to two groups i.e., a group receiving 5-FULV panitumumab combination therapy and a group receiving mFOLFOX6 panitumumab combination therapy. 