Outpatient weekly high-dose continuous-infusion 5-fluorouracil plus oral leucovorin in advanced colorectal cancer. A phase II trial

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Abstract
Background: In a previous phase I–II trial we showed that maximum tolerable dose (MTD) of 5-fluorouracil (5-FU) a weekly 48-hour continuous infusion (CI) was 3.5 g/m2. In a subsequent confirmative phase II trial with 85 evaluable patients, a 38.5% response rate was obtained, and a median survival of 12 months. These data were comparable to those achieved by biochemical modulation of 5-FU with leucovorin. On this basis we attempted to modulate high-dose 5-FU (3 g/m2) with oral leucovorin (LV) but the regimen too toxic and the dose had to be reduced. A new phase II trial with 2 g/m2/week plus oral leucovorin was planned. From July 1992 to June 1994, 110 previously untreated patients with advanced, measurable colorectal cancer were included in a multicenter study. The patients received, on an outpatient basis, 5-FU 2 g/m2 by continuous infusion for 48 hours once a week until progression or the appearance of toxic effects. Oral leucovorin (60 mg every six hours) was also given during the 5-FU infusion. Patients received a median dose intensity of 5-FU of 1.6 g/m2/week (range 0.9–2). Three complete responses and 36 partial responses were observed. The overall response rate was 37.5% (95% CI, 28% to 46.8%), the median time to progression 7.4 months and median survival 14.5 months. W.H.O. grade 3 diarrhea occurred in 27 patients (24.5%); grade 3 mucositis was observed in 9 (8.1%) patients and grade 4 in one. Grade 3 nausea and vomiting was reported in 13 (11.7%) patients, while grade 3 hand-foot syndrome was detected in only 5 (4.5%). Grade 4 leukopenia occurred in one patient and grade 3–4 thrombocytopenia in two. Oral leucovorin modulation of weekly 48-hour continuous infusion of 5-FU at 2 g/m2 is an active regimen, with diarrhea and mucositis as the main limiting toxic effects. Its antitumor activity does not seem superior to that obtained with a weekly 48-hour continuous infusion of 5-FU alone at a dose of 3.5 g/m2.