title: The dihydrouracil/uracil ratios in plasma and toxicities of 5-fluorouracil-based adjuvant chemotherapy in colorectal cancer patients.
abstract: BACKGROUND
  This study was designed to measure the dihydrouracil (UH(2))/uracil (U) ratio in plasma as a surrogate marker for dihydropyrimidine dehydrogenase (DPD) activity and to investigate the relationships of the UH(2)/U ratios in plasma with the toxicities of 5-fluorouracil (5-FU)-based adjuvant chemotherapy and 5-FU plasma concentrations in colorectal cancer patients.
  
  
  METHODS
  Thirty colorectal cancer patients received adjuvant chemotherapy of leucovorin plus 5-FU after operations. The concentrations of UH(2), U and 5-FU were assayed by the high-performance liquid chromatography method. The relationships of the UH(2)/U ratios with the 5-FU toxicities and 5-FU plasma concentrations were analyzed.
  
  
  RESULTS
  There was a negative relationship between the UH(2)/U ratios and 5-FU plasma concentrations (p <0.001). 5-FU toxicities had a negative correlation with the UH(2)/U ratios and a positive correlation with 5-FU plasma concentrations (p < 0.05).
  
  
  CONCLUSIONS
  The UH(2)/U ratio in plasma has close correlations with the 5-FU plasma concentration and 5-FU toxicity during chemotherapy, which may highlight the theoretical base of individual therapy for patients with colorectal cancer.
authors.affiliation: Department of Abdominal Surgery, State Key Laboratory of Oncology in Southern China, Cancer Center, Sun Yat-sen University, Guangzhou, China.
authors.forename: Zhi Wei
authors.initials: ZW
authors.lastname: Zhou
authors.forename: Guo Qiang
authors.initials: GQ
authors.lastname: Wang
authors.forename: De Sen
authors.initials: de S
authors.lastname: Wan
authors.forename: Zhen Hai
authors.initials: ZH
authors.lastname: Lu
authors.forename: Ying Bo
authors.initials: YB
authors.lastname: Chen
authors.forename: Su
authors.initials: S
authors.lastname: Li
authors.forename: Gong
authors.initials: G
authors.lastname: Chen
authors.forename: Zhi Zhong
authors.initials: ZZ
authors.lastname: Pan
mesh_terms: D000328:Adult; D000368:Aged; D000964:Antimetabolites, Antineoplastic / Q000009:adverse effects* / Q000493:pharmacokinetics / Q000627:therapeutic use; D017024:Chemotherapy, Adjuvant; D015179:Colorectal Neoplasms / Q000097:blood* / Q000188:drug therapy; D005260:Female; D005472:Fluorouracil / Q000009:adverse effects* / Q000493:pharmacokinetics / Q000627:therapeutic use; D006801:Humans; D002955:Leucovorin / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D014498:Uracil / Q000031:analogs & derivatives* / Q000097:blood*; D014803:Vitamin B Complex / Q000627:therapeutic use
chemical_list: D000964:Antimetabolites, Antineoplastic; C007419:dihydrouracil; D014803:Vitamin B Complex; D014498:Uracil; D002955:Leucovorin; D005472:Fluorouracil