title: Cystatin C - a fast and reliable biomarker for glomerular filtration rate in head and neck cancer patients.
abstract: OBJECTIVE
  Determination of renal function is a prerequisite for planning therapy in cancer patients. Limitations of creatinine as marker for the glomerular filtration rate (GFR) led to the proposal of cystatin C as a more accurate biomarker especially in mild renal insufficiency or in patients with low muscle mass. We compared the accuracy of cystatin C- and creatinine-based equations to estimate GFR in head and neck cancer (HNC) patients receiving platinum-based radiochemotherapy.
  
  
  METHODS
  The study population consisted of 52 HNC patients (GFR range, 37-105 mL/min/1.73 m(2) complemented by 17 patients with known renal insufficiency (GFR range, 10-60 mL/min/1.73 m(2)). Intraclass correlation coefficients were calculated between the reference method (51)Cr-EDTA clearance and estimated GFR by creatinine clearance and equations based on creatinine (Cockroft-Gault, modification of diet in renal disease (MDRD), Wright) or cystatin C (Larsson, Dade-Behring, Hoek). In addition, sensitivity and specificity to discriminate GFR > 60 mL/min/1.73 m(2) were evaluated by receiver operating characteristic curve (ROC).
  
  
  RESULTS
  The highest correlation coefficients were found for the cystatin C-based estimates in comparison with creatinine-based estimates or creatinine clearance, even though Bland-Altman plots revealed GFR overestimation for all equations tested. The cystatin C-based Hoek formula exhibited the highest overall precision and accuracy. GFR of < 60 mL/min/1.73 m(2) was assumed as a cut-off for chemotherapy. ROC analyses revealed the highest AUC to predict a GFR > 60 mL/min/1.73 m(2) for the creatinine-based Wright formula, closely followed by the MDRD formula and cystatin C-based equations of Larsson, Dade-Behring, and Hoek.
  
  
  CONCLUSIONS
  Cystatin C-based GFR estimates showed the overall strongest correlation to the reference method. Thus, we recommend cystatin C for GFR estimation in HNC patients as an alternative method to the estimated creatinine clearance in clinical practice.
authors.affiliation: Department of Radiation Therapy and Radiation Oncology, University of Düsseldorf, Germany. boelke@med.uni-duesseldorf.de
authors.forename: Edwin
authors.initials: E
authors.lastname: Bölke
authors.forename: Gisela
authors.initials: G
authors.lastname: Schieren
authors.forename: Stephan
authors.initials: S
authors.lastname: Gripp
authors.forename: Gerald
authors.initials: G
authors.lastname: Steinbach
authors.forename: Matthias
authors.initials: M
authors.lastname: Peiper
authors.forename: Klaus
authors.initials: K
authors.lastname: Orth
authors.forename: Christiane
authors.initials: C
authors.lastname: Matuschek
authors.forename: Maximilian
authors.initials: M
authors.lastname: Pelzer
authors.forename: Guido
authors.initials: G
authors.lastname: Lammering
authors.forename: Ruud
authors.initials: R
authors.lastname: Houben
authors.forename: Christina
authors.initials: C
authors.lastname: Antke
authors.forename: Lars Christian
authors.initials: LC
authors.lastname: Rump
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Mota
authors.forename: Peter Arne
authors.initials: PA
authors.lastname: Gerber
authors.forename: Patrick
authors.initials: P
authors.lastname: Schuler
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Hoffmann
authors.forename: Ethelyn
authors.initials: E
authors.lastname: Rusnak
authors.forename: Derik
authors.initials: D
authors.lastname: Hermsen
authors.forename: Wilfried
authors.initials: W
authors.lastname: Budach
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy / Q000473:pathology / Q000503:physiopathology* / Q000532:radiotherapy*; D000328:Adult; D000368:Aged; D018277:Carcinoma, Mucoepidermoid / Q000188:drug therapy / Q000503:physiopathology* / Q000532:radiotherapy*; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000473:pathology / Q000503:physiopathology* / Q000532:radiotherapy*; D017024:Chemotherapy, Adjuvant; D003131:Combined Modality Therapy; D003404:Creatinine / Q000097:blood; D055316:Cystatin C / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D010039:Otorhinolaryngologic Neoplasms / Q000188:drug therapy / Q000473:pathology / Q000503:physiopathology* / Q000532:radiotherapy*; D011237:Predictive Value of Tests; D012016:Reference Values; D051437:Renal Insufficiency / Q000503:physiopathology
chemical_list: D055316:Cystatin C; D003404:Creatinine