title: Performance of standard procedures in detection of EGFR mutations in daily practice in advanced NSCLC patients selected according to the ESMO guideline: a large Caucasian cohort study.
abstract: BACKGROUND
  ESMO consensus recommends EGFR mutation testing in never/former light smokers (<15 pack-years) or patients with non-squamous NSCLC. The aim of this work was to determine the frequency and clinical predictors of EGFR mutations, and the role of specimen sampling tests, in Caucasian standard practice setting.
  
  
  METHODS
  We screened 297 patients according to this consensus. Mutational analysis of EGFR was performed using the Therascreen EGFR RGQ PCR mutation kit. Clinical and pathological correlative data were collected.
  
  
  RESULTS
  An EGFR activating mutation was found in 32 patients (11%), twelve exon 19 deletions, two exon 18 and eighteen exon 21 point mutations. Most were in females, but half were in smokers. Negative TTF-1 staining had a very strong negative predictive value (all except one patient had TTF-1 positive adenocarcinoma). Both biopsies as well as cytology specimens (mainly EBUS-TBNA) did well: 24 mutations in 213 biopsy samples (11.2%) and 8 in 84 cytology samples (9.5%), respectively. The Therascreen acted as a sensitive test in all types of samples: 7 activating mutations were found in samples rated to have <5% of tumour cells, and there were only 4 test failures in the whole series.
  
  
  CONCLUSIONS
  In this Caucasian standard practice NSCLC cohort, tested according to the ESMO consensus, activating EGFR mutation occurred in 11% of the patients. Half of these were in former/current smokers. With our sampling technique and use of the Therascreen kit, EBUS-TBNA cell blocks performed as good as biopsies.
authors.affiliation: Respiratory Oncology Unit, Department Pulmonology, University Hospitals KU Leuven, Leuven, Belgium.
authors.forename: Inge
authors.initials: I
authors.lastname: Hantson
authors.affiliation: Respiratory Oncology Unit, Department Pulmonology, University Hospitals KU Leuven, Leuven, Belgium ; Department of Clinical and Experimental Medicine, Lab for Pulmonology, University of Leuven, Leuven, Belgium.
authors.forename: Christophe
authors.initials: C
authors.lastname: Dooms
authors.affiliation: Pathology, Translation Cell and Tissue Research, University Hospitals KU Leuven, Leuven, Belgium.
authors.forename: Eric
authors.initials: E
authors.lastname: Verbeken
authors.affiliation: Human Genetics, Molecular Diagnostics, University Hospitals KU Leuven, Leuven, Belgium.
authors.forename: Peter
authors.initials: P
authors.lastname: Vandenberghe
authors.affiliation: Human Genetics, Molecular Diagnostics, University Hospitals KU Leuven, Leuven, Belgium.
authors.forename: Liesbet
authors.initials: L
authors.lastname: Vliegen
authors.affiliation: Pathology, Translation Cell and Tissue Research, University Hospitals KU Leuven, Leuven, Belgium.
authors.forename: Tania
authors.initials: T
authors.lastname: Roskams
authors.affiliation: Pathology, Translation Cell and Tissue Research, University Hospitals KU Leuven, Leuven, Belgium.
authors.forename: Sara
authors.initials: S
authors.lastname: Vander Borght
authors.affiliation: Respiratory Oncology Unit, Department Pulmonology, University Hospitals KU Leuven, Leuven, Belgium ; Department of Clinical and Experimental Medicine, Lab for Pulmonology, University of Leuven, Leuven, Belgium.
authors.forename: Kris
authors.initials: K
authors.lastname: Nackaerts
authors.affiliation: Respiratory Oncology Unit, Department Pulmonology, University Hospitals KU Leuven, Leuven, Belgium.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Wauters
authors.affiliation: Respiratory Oncology Unit, Department Pulmonology, University Hospitals KU Leuven, Leuven, Belgium ; Department of Clinical and Experimental Medicine, Lab for Pulmonology, University of Leuven, Leuven, Belgium.
authors.forename: Johan
authors.initials: J
authors.lastname: Vansteenkiste
keywords: Biopsy methods; EGFR mutation; Endobronchial ultrasound; Predictive factors; Real-time quantitative polymerase chain reaction (rt-qPCR)