Current evidence of irinotecan combination chemotherapy with TS-1 in patients with advanced colorectal cancer

A combination of irinotecan (CPT-11) with continuous intravenous infusions of (infusional) 5-fluorouracil (5-FU) and Leucovorin (LV) is one of the standard treatments for advanced colorectal cancer patients. However, recent concerns about safety and convenience have prompted the development of new oral fluoropyrimidine derivatives and improved regimens. TS-1, the oral fluoropyrimidine widely used in the treatment for gastric cancer, was approved for advanced colorectal cancer. Recently, several phase I/II studies assessed the efficacy and safety of combined treatment with TS-1 plus CPT-11 in patients with advanced colorectal cancer. These results showed that TS-1 plus CPT-11 was very effective. Toxicity was generally mild and manageable on an outpatient basis. Current evidence showed that a combination of CPT-11 plus TS-1 was more convenient and easier to administer than a combination of CPT-11 plus infusional 5-FU and LV. It is essential to prove that the combination of TS-1 plus CPT-11 can replace the combination of infusional 5-FU and LV plus CPT-11 without negatively affecting efficacy and toxicity.