Randomised comparison of weekly bolus 5-fluorouracil with or without leucovorin in metastatic colorectal carcinoma.

148 patients with advanced untreated colorectal cancer were randomised to receive a weekly bolus of 5-fluorouracil (5-FU) 600 mg/m2 alone, with or without leucovorin (LV) 500 mg/m2. 5-FU plus LV produced a higher response rate than 5-FU alone: 23% (5 complete response, 11 partial response) vs. 8% (2 complete response, 4 partial response) (P = 0.03) out of 70 and 72 evaluable patients, respectively. Median survival was 11 months in both groups and median time to progression was not significantly different (P = 0.08). The combined regimen was more toxic than 5-FU alone, as evidenced by (a) a higher percentage of grade 3-4 diarrhoea, 19.5% vs. 8.5% (P = 0.045) and conjunctivitis, 26.5% vs. 5.6% (P = 0.0025); (b) the recording of one toxic death in the combined arm; and (c) the reduction of the median dose intensity of 5-FU actually delivered during the first 2 months of treatment. We conclude that 5-FU plus LV at a price of a higher toxicity is more active than 5-FU alone without improving survival and progression-free survival.