Fluctuation in Plasma 5-Fluorouracil Concentration During Continuous 5-Fluorouracil Infusion for Colorectal Cancer.
OBJECTIVE
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.


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.


CONCLUSIONS
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.
Department of Digestive Surgery, Kawasaki Medical School, Kurashiki City, Okayama, Japan h-matsu@med.kawasaki-m.ac.jp.
Hideo
H
Matsumoto
Department of Digestive Surgery, Kawasaki Medical School, Kurashiki City, Okayama, Japan.
Hideo
H
Okumura
Department of Digestive Surgery, Kawasaki Medical School, Kurashiki City, Okayama, Japan.
Haruaki
H
Murakami
Department of Digestive Surgery, Kawasaki Medical School, Kurashiki City, Okayama, Japan.
Hisako
H
Kubota
Department of Digestive Surgery, Kawasaki Medical School, Kurashiki City, Okayama, Japan.
Masaharu
M
Higashida
Department of Digestive Surgery, Kawasaki Medical School, Kurashiki City, Okayama, Japan.
Atsushi
A
Tsuruta
Department of Laboratory Medicine, Kawasaki Medical School, Kurashiki City, Okayama, Japan.
Kaoru
K
Tohyama
Department of Digestive Surgery, Kawasaki Medical School, Kurashiki City, Okayama, Japan.
Toshihiro
T
Hirai
D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D002166:Camptothecin / Q000008:administration & dosage / Q000031:analogs & derivatives; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage / Q000097:blood; D005500:Follow-Up Studies; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007118:Immunoassay; D007262:Infusions, Intravenous; D000077146:Irinotecan; D002955:Leucovorin / Q000008:administration & dosage; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000401:mortality / Q000556:secondary; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D009367:Neoplasm Staging; D009944:Organoplatinum Compounds / Q000008:administration & dosage; D000077150:Oxaliplatin; D011379:Prognosis; D011446:Prospective Studies; D015996:Survival Rate
D009944:Organoplatinum Compounds; D000077150:Oxaliplatin; D000077146:Irinotecan; D002955:Leucovorin; D005472:Fluorouracil; D002166:Camptothecin
5-FU-based chemotherapy; Concentration of 5-FU; FOLFIRI; FOLFOX; My5-FU™ immunoassay