High-dose infusional 5-FU in the treatment of advanced colorectal cancer: a summary of the European experience.

5-fluorouracil (5-FU) is the best available drug for the treatment of advanced colorectal cancer. A review of published data strongly suggest that with continuous infusion an enhanced treatment outcome as opposed to treatment with standard bolus injections can be obtained. This could be due to the schedule, the high dose-intensity or both. It is likely that there exists a relationship between the dose intensity of 5-FU and the response in colorectal cancer. With weekly 24 to 48 hours continuous infusion of 5-FU a very high dose intensity can be achieved. High-dose infusional 5-FU is noncross-resistent with (modulated) bolus 5-FU and the European experience with this treatment modality will be reviewed. The comparison of the activity of modulated "standard" bolus 5-FU versus high-dose infusional 5-FU, given by weekly intermittent or by protracted continuous infusion (PCI), is the subject of ongoing trials. Additional studies will answer the question whether modulation of high-dose 5-FU will result in a superior treatment outcome compared with high-dose 5-FU alone.