Prospective randomised trial comparing fluorouracil versus doxifluridine for the treatment of advanced colorectal cancer

Doxifluridine (dFUR) is a fluoropyrimidine derivative that has shown activity on a variety of solid tumours. The purpose of this study was to compare its therapeutic effect with a standard fluorouracil (FU) regimen in patients with locally advanced or metastatic colorectal cancer. 222 previously untreated patients were randomised to receive dFUR (4000 mg/m2) or FU (500 mg/m2) daily for 5 days every 28 days. The primary tumour originated in the colon in two-thirds of the cases in both groups; approximately 90% of patients had metastatic extension, and liver involvement was present in 69% of the patients in the dFUR and FU groups. A good performance status (ECOG 0–1) was recorded in 90% of cases in both arms. A median of five cycles was administered to the patients (range 1–12). Only one partial response among 110 patients in the FU arm and one complete response and five partial responses out of 112 evaluable patients in the dFUR group were observed. Time to progression was significantly longer in the dFUR group (P = 0.02); overall survival, while longer in the dFUR arm (48 weeks vs. 39 weeks), was not significantly so (P = 0.08). Toxicity was acceptable in both arms, although grade 3–4 neurological side-effects and leukopenia were more common after dFUR infusion. Despite the low response rate, our results indicate that dFUR may be a superior alternative to FU. The possibility of enhancing significantly the activity of dFUR with biochemical modulators should be further investigated.