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Fluctuation in Plasma 5-Fluorouracil Concentration During Continuous 5-Fluorouracil Infusion for Colorectal Cancer
Hideo Matsumoto1, Hideo Okumura2, Haruaki Murakami2
1Department of Digestive Surgery, Kawasaki Medical School, Kurashiki City, Okayama, Japan h-matsu@med.kawasaki-m.ac.jp.
Background/Aim:
It is generally believed that the plasma concentration of 5-fluorouracil (5-FU) is constant when 5-FU is continually administered for chemotherapy. The aim of the present study was to verify whether this is true.
Patients And Methods:
Nine patients with colorectal cancer were enrolled in this study. All patients received chemotherapy; four patients received FOLFIRI (leucovorin, 5-fluorouracil, irinotecan) and five received FOLFOX (leucovorin, 5-fluorouracil, oxaliplatin). 5-FU was administered continuously (2400 mg/m(2)) for 46 h. Serum was collected at 12 points after the start of administration. The concentration of 5-FU was evaluated using a new immunoassay method and gas chromatography-mass spectrometric (GC/MS) method.
Results:
The concentrations of 5-FU fluctuated dramatically over time, with greater than 3-fold changes in each individual, and the pattern was not constant.
Conclusion:
Because the serum concentration of 5-FU fluctuates and displays various patterns, the dosage should not be based on body surface area. A new individualized method for determining the 5-FU dosage should be developed.
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