title: RAS testing practices and RAS mutation prevalence among patients with metastatic colorectal cancer: results from a Europe-wide survey of pathology centres.
abstract: Treatment options for patients with metastatic colorectal cancer (mCRC) include anti-epithelial growth factor therapies, which, in Europe, are indicated in patients with RAS wild-type tumours only and require prior mutation testing of "hot-spot" codons in exons 2, 3 and 4 of KRAS and NRAS. The aim of this study was to evaluate the implementation of RAS testing methods and estimate the RAS mutation prevalence in mCRC patients.
  
  
  
  Overall, 194 pathology laboratories were invited to complete an online survey. Participating laboratories were asked to provide information on their testing practices and aggregated RAS mutation data from 20 to 30 recently tested patients with mCRC.
  
  
  
  A total of 96 (49.5 %) laboratories across 24 European countries completed the survey. All participants tested KRAS exon 2, codons 12 and 13. Seventy (72.9 %) laboratories reported complete testing of all RAS hot-spot codons, and three (3.1 %) reported only testing KRAS exon 2. Sixty-nine (71.9 %) laboratories reported testing >80 patients yearly for RAS mutation status. Testing was typically performed within the reporting institution (93.8 %, n = 90), at the request of a treating oncologist (89.5 %, n = 85); testing methodology varied by laboratory and by individual codon tested. For laboratory RAS testing, turnaround times were ≤10 working days for the majority of institutions (90.6 %, n = 87). The overall crude RAS mutation prevalence was 48.5 % (95 % confidence interval: 46.4-50.6) for laboratories testing all RAS hot-spot codons. Prevalence estimates varied significantly by primary tumour location, approximate number of patients tested yearly and indication given for RAS testing.
  
  
  
  Our findings indicate a rapid uptake of RAS testing in the majority of European pathology laboratories.
authors: Department of Pathology, Radboud University Medical Centre, Geert Grooteplein-Zuid 10, 6525 GA, Nijmegen, The Netherlands.
authors: Annemarie
authors: A
authors: Boleij
authors: Department of Public Health and Primary Care, University of Leuven, Herestraat 49, Box 602, 3000, Leuven, Belgium.
authors: Véronique
authors: V
authors: Tack
authors: Centre for Observational Research, Amgen Ltd, 1 Uxbridge Business Park, Uxbridge, UB8 1DH, UK.
authors: Aliki
authors: A
authors: Taylor
authors: Centre for Observational Research, Amgen Ltd, 1 Uxbridge Business Park, Uxbridge, UB8 1DH, UK.
authors: George
authors: G
authors: Kafatos
authors: Adelphi Research (Global), Adelphi Mill, Bollington, Manchester, SK10 5JB, UK.
authors: Sophie
authors: S
authors: Jenkins-Anderson
authors: Department of Public Health and Primary Care, University of Leuven, Herestraat 49, Box 602, 3000, Leuven, Belgium.
authors: Lien
authors: L
authors: Tembuyser
authors: Department of Public Health and Primary Care, University of Leuven, Herestraat 49, Box 602, 3000, Leuven, Belgium. Els.dequeker@kuleuven.be.
authors: Els
authors: E
authors: Dequeker
authors: Department of Pathology, Radboud University Medical Centre, Geert Grooteplein-Zuid 10, 6525 GA, Nijmegen, The Netherlands.
authors: J Han
authors: JH
authors: van Krieken
mesh_terms: D003062:Codon; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology; D004252:DNA Mutational Analysis; D005060:Europe; D005091:Exons; D005260:Female; D011905:Genes, ras; D005820:Genetic Testing; D019538:Health Care Surveys; D006801:Humans; D008297:Male; D009154:Mutation
chemical_list: D003062:Codon
keywords: KRAS; Laboratory practices; Metastatic colorectal cancer; NRAS; Prevalence; RAS testing