title: Inter-reader reproducibility of dynamic contrast-enhanced magnetic resonance imaging in patients with non-small cell lung cancer treated with bevacizumab and erlotinib.
abstract: Objectives When evaluating anti-tumor treatment response by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) it is necessary to assure its validity and reproducibility. This has not been well addressed in lung tumors. Therefore we have evaluated the inter-reader reproducibility of response classification by DCE-MRI in patients with non-small cell lung cancer (NSCLC) treated with bevacizumab and erlotinib enrolled in a multicenter trial.
  
  
  METHODS
  Twenty-one patients were scanned before and 3 weeks after start of treatment with DCE-MRI in a multicenter trial. The scans were evaluated by two independent readers. The primary lung tumor was used for response assessment. Responses were assessed in terms of relative changes in tumor mean trans endothelial transfer rate (K(trans)) and its heterogeneity in terms of the spatial standard deviation. Reproducibility was expressed by the inter-reader variability, intra-class correlation coefficient (ICC) and dichotomous response classification.
  
  
  RESULTS
  The inter-reader variability and ICC for the relative K(trans) were 5.8% and 0.930, respectively. For tumor heterogeneity the inter-reader variability and ICC were 0.017 and 0.656, respectively. For the two readers the response classification for relative K(trans) was concordant in 20 of 21 patients (k=0.90, p<0.0001) and for tumor heterogeneity in 19 of 21 patients (k=0.80, p<0.0001).
  
  
  CONCLUSIONS
  Strong agreement was seen with regard to the inter-reader variability and reproducibility of response classification by the two readers of lung cancer DCE-MRI scans.
authors.affiliation: Department of Pulmonary Diseases, Viecuri Medical Center, Tegelseweg 210, 5912 BL Venlo, The Netherlands; Department of Pulmonary Diseases, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands. Electronic address: vvandenboogaart@maastrichtuniversity.nl.
authors.forename: Vivian E M
authors.initials: VE
authors.lastname: van den Boogaart
authors.affiliation: Department of Radiology, Medical Center Zuiderzee, Ziekenhuisweg 100, 8233AA Lelystad, The Netherlands. Electronic address: Q.deLussanetdelaSabloniere@mcgroep.com.
authors.forename: Quido G
authors.initials: QG
authors.lastname: de Lussanet
authors.affiliation: Department of Radiation-Oncology (Maastro), GROW - School for Oncology and Developmental Biology, Maastricht University Medical Center, P.O. Box 3035, 6202 NA Maastricht, The Netherlands. Electronic address: ruud.houben@maastro.nl.
authors.forename: Ruud M A
authors.initials: RM
authors.lastname: Houben
authors.affiliation: Department of Radiation-Oncology, University Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium. Electronic address: dirk.deruysscher@uzleuven.be.
authors.forename: Dirk
authors.initials: D
authors.lastname: de Ruysscher
authors.affiliation: Department of Pulmonary Diseases, University of Groningen and University Medical Center Groningen, Hanzeplein 1, 9700 RB Groningen, The Netherlands. Electronic address: h.j.m.groen@umcg.nl.
authors.forename: Harry J M
authors.initials: HJ
authors.lastname: Groen
authors.affiliation: Physics and Medical Technology, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands. Electronic address: JT.Marcus@vumc.nl.
authors.forename: J Tim
authors.initials: JT
authors.lastname: Marcus
authors.affiliation: Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands. Electronic address: e.smit@nki.nl.
authors.forename: Egbert F
authors.initials: EF
authors.lastname: Smit
authors.affiliation: Department of Pulmonary Diseases, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands. Electronic address: a.dingemans@mumc.nl.
authors.forename: Anne-Marie C
authors.initials: AM
authors.lastname: Dingemans
authors.affiliation: Department of Radiology, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands. Electronic address: w.backes@mumc.nl.
authors.forename: Walter H
authors.initials: WH
authors.lastname: Backes
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D000068258:Bevacizumab / Q000008:administration & dosage; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis* / Q000188:drug therapy*; D000069347:Erlotinib Hydrochloride / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods / Q000592:standards; D007091:Image Processing, Computer-Assisted; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000188:drug therapy*; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000592:standards; D008297:Male; D015588:Observer Variation; D049268:Positron-Emission Tomography; D013902:Radiography, Thoracic; D015203:Reproducibility of Results
chemical_list: D000068258:Bevacizumab; D000069347:Erlotinib Hydrochloride
keywords: Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI); non-small cell lung cancer; response assessment; targeted therapy; validity and reproducibility