title: Rare EGFR exon 18 and exon 20 mutations in non-small-cell lung cancer on 10 117 patients: a multicentre observational study by the French ERMETIC-IFCT network.
abstract: BACKGROUND
  There is scarce data available about epidermal growth factor receptor (EGFR) mutations other than common exon 19 deletions and exon 21 (L858R) mutations.
  
  
  METHODS
  EGFR exon 18 and/or exon 20 mutations were collected from 10 117 non-small-cell lung cancer (NSCLC) samples analysed at 15 French National Cancer Institute (INCa)-platforms of the ERMETIC-IFCT network.
  
  
  RESULTS
  Between 2008 and 2011, 1047 (10%) samples were EGFR-mutated, 102 (10%) with rare mutations: 41 (4%) in exon 18, 49 (5%) in exon 20, and 12 (1%) with other EGFR mutations. Exon 20 mutations were related to never-smoker status, when compared with exon 18 mutations (P < 0.001). Median overall survival (OS) of metastatic disease was 21 months [95% confidence interval (CI) 12-24], worse in smokers than in non-smoker patients with exon 20 mutations (12 versus 21 months; hazard ratio [HR] for death 0.27, 95% CI 0.08-0.87, P = 0.03). Under EGFR-tyrosine kinase inhibitors (TKIs), median OS was 14 months (95% CI 6-21); disease control rate was better for complex mutations (6 of 7, 86%) than for single mutations (16 of 40, 40%) (P = 0.03).
  
  
  CONCLUSIONS
  Rare EGFR-mutated NSCLCs are heterogeneous, with resistance of distal exon 20 insertions and better sensitivity of exon 18 or complex mutations to EGFR-TKIs, probably requiring individual assessment.
authors.affiliation: Department of Biochemistry and Molecular Biology, Strasbourg University Hospital, Strasbourg.
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mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy / Q000235:genetics* / Q000401:mortality; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy / Q000235:genetics* / Q000401:mortality; D018572:Disease-Free Survival; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000235:genetics*; D005091:Exons; D005260:Female; D005787:Gene Frequency; D056726:Genetic Association Studies; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000401:mortality; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D047428:Protein Kinase Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D055815:Young Adult
chemical_list: D000970:Antineoplastic Agents; D047428:Protein Kinase Inhibitors; C512478:EGFR protein, human; D066246:ErbB Receptors
keywords: epidermal growth factor receptor mutations; exon 18 mutations; exon 20 mutations; non-small-cell lung cancer; tyrosine-kinase inhibitors