Biochemical modulation of fluorouracil: evidence of significant improvement of survival and quality of life in patients with advanced colorectal carcinoma.

The purpose of this study was to evaluate the effectiveness of several new approaches designed to enhance the activity of fluorouracil (5-FU) in the management of advanced colorectal cancer. A total of 429 patients were randomized to one of the following regimens: single-agent 5-FU, given by standard 5-day, intensive-course intravenous bolus technique; 5-FU plus high-dose folinic acid (leucovorin) or 5-FU plus low-dose leucovorin; 5-FU plus high-dose methotrexate (MTX) with oral leucovorin rescue; 5-FU plus low-dose MTX; and 5-FU plus cisplatin (CDDP). The median survival for patients receiving 5-FU alone was 7.7 months. The high- and low-dose leucovorin plus 5-FU regimens had median survivals of 12.2 and 12.0 months, respectively, and offered a significant survival advantage over 5-FU alone with one-sided P values of .037 and .050, respectively (P = .051 for each treatment after correction for prognostic variables). The only other regimen possibly associated with improved survival was high-dose MTX plus 5-FU, with a median survival of 10.5 months (P = .21, P = .076 corrected). In addition, both high- and low-dose leucovorin plus 5-FU regimens were associated with significantly improved tumor response rates (P = .04 and .001) and significantly improved interval-to-tumor-progression rates (P = .015 and .007) when compared with 5-FU alone. Only the low-dose leucovorin plus 5-FU regimen was associated with significant (P less than .05) superiority in each of the following parameters of quality of life: performance status, weight gain, and symptomatic relief. The overall most therapeutically favorable regimen in this trial was 5-FU given with low-dose leucovorin; fortuitously, this regimen is associated with very low drug cost. Whereas this is the first study to demonstrate both improved palliation and survival for any regimen compared with 5-FU given by rapid intravenous (IV) injection for 5 consecutive days at a dose of 500 mg/m2/d in patients with advanced colorectal cancer, the magnitude of the gain is still relatively small. Our low-dose leucovorin plus 5-FU regimen is currently being studied in a national trial with the hope that this increased advanced disease activity may produce more substantive gains in the surgical adjuvant setting.