An analysis of the therapeutic efficacy of protracted infusion of low-dose 5-fluorouracil and cisplatin in advanced gastric cancer.

To analyze the clinical efficacy of a protracted infusion of low-dose 5-fluorouracil (5-FU) and cisplatin (CDDP), a phase II study was performed in 36 patients with advanced gastric cancer. The treatment schedule of the low-dose administration of 5-FU and CDDP (FP) was a continuous infusion of 5-FU (250 mg/m2) for 28 consecutive days and a drip infusion of CDDP (3.5 mg/m2) for 5 consecutive days, followed by a 2-day interval each week in one cycle. The overall response rate was 47.2%. Of importance, the improvement in quality of life assessed by performance status (PS) and oral intake was 13.9% and 33.3%, respectively. The toxicity in low-dose FP treatment was less than grade 2, including gastrointestinal toxicities and bone marrow suppression, and this was tolerable during the treatment. The median survival time (MST) and 1-year survival rate were 8 months and 36.2%, respectively. In a pharmacokinetic analysis following the protracted infusion of low-dose FP, the plasma concentrations of 5-FU and CDDP were increased to about 120-130 ng/ml and 0.3-0.5 microg/ml on day 21 after the treatment, respectively. The plasma concentrations of 5-FU and CDDP were not significantly different between responders and non-responders. The tumor response to low-dose FP treatment was associated with the induction of apoptotic cell death and with the overexpression of apoptosis-related genes, such as Bax and Bcl-Xs, in cancer cells. These results indicate that the protracted infusion of low-dose FP could be a useful regimen for patients with advanced gastric cancer, in terms of the high response rate and low toxicity, possibly leading to the prolongation of survival and improvement in the quality of life.