e18038 Background: Gefitinib has received European approval for the treatment of adult patients (pts) with locally advanced or metastatic NSCLC with activating mutations of the epidermal growth factor receptor (EGFR) tyrosine kinase. In Europe EGFR mutation testing is not well established, preventing access to new targeted therapies for NSCLC pts. Methods: An IASLC-ETOP European multidisciplinary workshop developed recommendations to facilitate implementation of standardized EGFR mutation testing in clinical practice. Results: The treating physician makes the decision to request EGFR mutation testing; the results of which should be available within 7 working days. All pts with NSCLC may eventually be tested, but exceptions may be made when likelihood of mutation is low. There was no consensus agreement on pre-screening algorithms. At diagnosis, the most accessible tissue is usually sampled, but re-biopsy at recurrence or disease progression should be considered. More data on potential heterogeneity between different biopsy sites are also needed. Sampling techniques include needle core biopsy, transbronchial biopsy, endobronchial biopsy, computed tomography-guided needle biopsy, mediastinoscopy, video-assisted thoracic surgery and thoracotomy. Further studies are needed to evaluate the use of cytology samples. Tumor specimen handling needs to be standardized. Fixation with 10% neutral-buffered formalin is optimum. Tumor cell enrichment of samples may be needed, depending upon the sensitivity of the test used. The tumor to normal cell ratio is important, although the minimum tumor cell number is ill-defined: ideally 200-400 cells are used. Various methods can be used to detect EGFR mutations: direct sequencing, ARMS, length analysis, dHPLC etc. Some tests only seek the most common activating mutations, others detect all mutations. Ideally pathologists should report tumor histology and mutation status concurrently, including sample size/quality, tumor nuclei percentage, methodology used, exons tested and mutation present/absent. Reference laboratories may be helpful. Conclusions: These recommendations will help to optimize routine EGFR mutation testing in Europe. Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration AstraZeneca, Boehringer Ingelheim, Lilly, Merck Serono, Roche, Roche/Genentech/OSI AstraZeneca, Boehringer Ingelheim, Lilly, Menarini, Merck, Merck Serono, Roche Roche