title: Applicability of the Japanese equation for estimating glomerular filtration rate in patients with advanced-stage thoracic cancer.
abstract: BACKGROUND
  The 24-h creatinine clearance (24-h Ccr) and the Cockcroft-Gault equation (CG) are commonly used as markers of renal function in clinical practice. However, the utility of the Japanese equation for estimating glomerular filtration rate (eGFR) in cancer patients has not yet been evaluated. The aim of this cross-sectional study was to investigate the extent and correlating factors for differences between eGFR and both 24-h Ccr and CG in advanced-stage thoracic cancer patients.
  
  
  METHODS
  eGFR, 24-h Ccr, and CG were calculated in 90 patients with thoracic malignancies. We evaluated how these three parameters are affected by clinical factors, including age, body surface area, serum creatinine concentration, and body mass index.
  
  
  RESULTS
  eGFR and CG were significantly correlated with 24-h Ccr (r=0.64, p<0.001 and; r=0.67, p<0.001, respectively). However, the median value derived from eGFR was higher than the median 24-h Ccr and the CG value (74.0, 65.2, and 63.9mL/min, respectively). Age had a significant positive correlation with the differences between eGFR and both 24-h Ccr and CG value (r=0.30, p=0.005 and; r=0.47, p<0.001, respectively). The differences between eGFR and the other two parameters were significantly higher in older patients (age≥70 years) than in younger patients (age<70 years) (p=0.023, p<0.001, respectively).
  
  
  CONCLUSIONS
  eGFR is likely to overestimate the renal function of elderly cancer patients. A modified equation for evaluating the renal function of Japanese older patients might be needed.
authors.affiliation: Third Department of Internal Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan. Electronic address: imagesandwords1981@gmail.com.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kikuchi
authors.affiliation: Third Department of Internal Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan. Electronic address: h-akamat@wakayama-med.ac.jp.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Akamatsu
authors.affiliation: Clinical Trial Management Department, Shizuoka Cancer Center, 1007, Shimo-Nagakubo, Sunto-Nagaizumi, Shizuoka 411-8777, Japan. Electronic address: ke.mori@scchr.jp.
authors.forename: Keita
authors.initials: K
authors.lastname: Mori
authors.affiliation: Third Department of Internal Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan. Electronic address: ayakat@wakayama-med.ac.jp.
authors.forename: Ayaka
authors.initials: A
authors.lastname: Tanaka
authors.affiliation: Third Department of Internal Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan. Electronic address: kanaik@wakayama-med.ac.jp.
authors.forename: Kuninobu
authors.initials: K
authors.lastname: Kanai
authors.affiliation: Third Department of Internal Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan. Electronic address: atsushih@wakayama-med.ac.jp.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hayata
authors.affiliation: Third Department of Internal Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan. Electronic address: ntokudom@wakayama-med.ac.jp.
authors.forename: Nahomi
authors.initials: N
authors.lastname: Tokudome
authors.affiliation: Third Department of Internal Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan. Electronic address: akamatsu@wakayama-med.ac.jp.
authors.forename: Keiichiro
authors.initials: K
authors.lastname: Akamatsu
authors.affiliation: Third Department of Internal Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan. Electronic address: ykoh@wakayama-med.ac.jp.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Koh
authors.affiliation: Third Department of Internal Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan. Electronic address: masa-n@wakayama-med.ac.jp.
authors.forename: Masanori
authors.initials: M
authors.lastname: Nakanishi
authors.affiliation: Third Department of Internal Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan. Electronic address: hu11@wakayama-med.ac.jp.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Ueda
authors.affiliation: Third Department of Internal Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan. Electronic address: nbyamamo@wakayama-med.ac.jp.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Yamamoto
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D015992:Body Mass Index; D001830:Body Surface Area; D003404:Creatinine / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007668:Kidney / Q000503:physiopathology*; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D009367:Neoplasm Staging; D012189:Retrospective Studies; D013899:Thoracic Neoplasms / Q000503:physiopathology*
chemical_list: D003404:Creatinine
keywords: Cockcroft–Gault equation; Creatinine clearance; Estimated glomerular filtration rate; Lung cancer; Malignant mesothelioma