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

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Abstract
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.