Irinotecan and 5-FU/ leucovorin in metastatic colorectal cancer: balancing efficacy, toxicity, and logistics.

Variations of fluorouracil (5-FU) therapy have formed the backbone of chemotherapy for advanced colorectal cancer for many years. With the advent of newer agents that often work best with or even require chemotherapy to optimize their activity, the issue of the optimal schedule and regimen of administration of 5-FU has taken on a renewed importance. The combination of irinotecan with 5-FU/leucovorin has consistently improved survival and response rates in comparison to 5-FU/leucovorin alone. However, the combination also increases the toxicity of the treatment, thus resulting in continuing attempts to improve on the toxicity profile of the combination, while retaining or improving upon the therapeutic outcomes. This article reviews the various combinations of irinotecan with 5-FU/leucovorin.