Rechallenge of Prior Regimen in Third or Later-line Chemotherapy in Metastatic Colorectal Cancer

This is a single-arm, open-label, single-center prospective phase II study to evaluate the efficacy and safety of rechallenge chemotherapy in the third or later-line treatment in patients with advanced colorectal cancer. The primary end point is progression free survival (PFS). A total of 42 patients who failed with oxaliplatin, irinotecan and fluorouracil in previous treatment and could not receive the target therapy presently are planned for recruitment. For patients with metastatic colorectal cancer who met admission criteria, oxaliplatin- or irinotecan-based chemo regimen could be used and evaluation was repeated every 6 weeks. The treatment continues until the disease progression or the untolerable adverse reaction.