title: Serum creatinine and creatinine clearance for predicting plasma methotrexate concentrations after high-dose methotrexate chemotherapy for the treatment for childhood lymphoblastic malignancies.
abstract: OBJECTIVE
  Monitoring of plasma methotrexate (MTX) concentrations allows for therapeutic adjustments in treating childhood acute lymphoblastic leukemia (ALL) or non-Hodgkin lymphoma (NHL) with high-dose MTX (HDMTX). We tested the hypothesis that assessment of creatinine clearance (CrCl) and/or serum Cr may be a suitable means of monitoring plasma MTX concentrations.
  
  
  METHODS
  All children in the study had ALL or NHL, were in complete remission, and received HDMTX (3 or 5 g/m(2))+leucovorin. Plasma MTX concentrations were measured at 24, 48, and 96 h. CrCl was determined at 24 and 48 h. Correlations between 24- and 48-h plasma MTX concentrations and CrCl and serum Cr concentrations were determined. CrCl and serum Cr concentrations were compared over time between children who had delayed and non-delayed MTX elimination.
  
  
  RESULTS
  A total of 105 children were included. There were significant negative correlations between CrCl at 24 and 48 h and plasma MTX concentrations at 24 (both p < 0.001) and 48 h (both p < 0.001). There were significant positive correlations between serum Cr concentrations at both 24 and 48 h and plasma MTX concentrations at 24 (both p < 0.001) and 48 h (both p < 0.001). There were 88 (30.2 %) instances of elimination delay. Children with elimination delay had significantly lower CrCl and higher Cr concentrations at 24 and 48 h compared with children without elimination delay (all p < 0.05).
  
  
  CONCLUSIONS
  Our findings suggest that, with further refinement, assessment of renal function may be a useful means of monitoring plasma MTX concentrations during HDMTX for ALL and NHL.
authors.affiliation: Division of Hematology-Oncology, Children's Hospital of Zhejiang University, School of Medicine, #57 Zhuganxiang Road, Yan-an Street, Hangzhou, 310003, People's Republic of China.
authors.forename: Wei-qun
authors.initials: WQ
authors.lastname: Xu
authors.forename: Ling-yan
authors.initials: LY
authors.lastname: Zhang
authors.forename: Xue-ying
authors.initials: XY
authors.lastname: Chen
authors.forename: Bin-hua
authors.initials: BH
authors.lastname: Pan
authors.forename: Jun-qing
authors.initials: JQ
authors.lastname: Mao
authors.forename: Hua
authors.initials: H
authors.lastname: Song
authors.forename: Jing-yuang
authors.initials: JY
authors.lastname: Li
authors.forename: Yong-min
authors.initials: YM
authors.lastname: Tang
mesh_terms: D000293:Adolescent; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D003404:Creatinine / Q000097:blood*; D005260:Female; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000188:drug therapy*; D008297:Male; D008657:Metabolic Clearance Rate; D008727:Methotrexate / Q000097:blood / Q000627:therapeutic use*; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000097:blood / Q000188:drug therapy*
chemical_list: D000964:Antimetabolites, Antineoplastic; D003404:Creatinine; D008727:Methotrexate