5-FU infusion in advanced colorectal cancer: a comparison of three dose schedules.

Ninety-four patients with advanced colorectal adenocarcinoma were treated by continuous iv 5-FU infusion on three different dose schedules. Thirty-three patients received a 72-hour infusion of 5-FU (30 mg/kg/24 hours) every 3 weeks (Group A); 31 received a 72-hour infusion of 5-FU (30 mg/kg/24 hours) every 2 weeks (Group B); and 30 received a 48-hour infusion of 5-FU (30 mg/kg/24 hours) every week (Group C). Although this was a sequential nonrandomized study of the dose schedules, the groups were comparable with respect to various prognostic factors. Response rates were as follows: Group A--three patients had minor response (9%) and 30 had no response (91%); Group B--five patients achieved partial response (16%), nine had minor response (29%), and 17 had no response (55%), and Group C--one patient achieved complete response (3%), eight achieved partial response (27%), five had minor response (17%), and 16 had no response (53%). The median survival time for Group A was 9 months, for Group B was 9.5 months, and for Group C was 14 months. Intensifying the dose schedule of 5-FU by increasing the frequency of administration has significantly improved response rates. A prolongation of the median survival time of patients treated with a 48-hour infusion at 1-week intervals was noted, although this was not statistically significant.