Efficacy and Tolerance of Maintenance Therapy in Patients With Incurable Advanced Colorectal Cancer

1. To evaluate efficacy, safety, and feasibility of maintenance therapy with Cetuximab combined with irinotecan or fluorouracil after Cetuximab plus irinotecan and fluorouracil(FOLFIRI) in patients with incurable colorectal cancer. 2. The relevant phase III studies reported that the progression free-survival of cetuximab combined with FOLFIRI in advanced colorectal cancer was 4.3 months up to 6.8 months. This study assumed that the progression free-survival was 5.1 months which was not inferior to the continuous chemotherapy