Assessment of EGFR Mutations in Patients Diagnosed of Squamous Non-Small Cell Lung Cancer (NSCLC).

e18106 Background: Mutations in the Epidermal Growth Factor Receptor (EGFR) predict a better outcome to EGFR tyrosine kinase inhibitors than platinum-based chemotherapy in advanced non-small cell lung cancer (NSCLC). Previous studies with Caucasian patients have shown a prevalence of EGFR mutation of 10-15%. The aim of this study is to analyze the prevalence of EGFR mutations in squamous-cell NSCLC patients from an area of influence of 500,000 habitants. Methods: Prospective mutation testing in NSCLC patients included in our institution since October 2010 to January 2012 was performed on DNA obtained from available tumor tissue and cytologic samples, using ARMS-scorpion TheraScreen EGFR 29 Mutation Test Kit (Qiagen). Results: From 218 consecutive NSCLC diagnoses, 18 (8.25%) patients showed EGFR mutations: 6 (33.3%) exon 19 deletion, 9 (50%) exon 21 mutations (7 L858R and 2 L861Q) and 3 (16.6%) cases exon 20 insertion. In the EGFR mutated population, 16 (88.88%) patients were diagnosed as adenocarcinoma and 2 (11.11%) as squamous cell carcinoma. The characteristics of these squamous cell cancer patients were: 2 male; 1 non-smoker, 1 former-smoker; 1 stage IV and 1 stage IB at diagnosis; one case exon 20 insertion and one exon 21 mutation (L858R). Conclusions: The EGFR mutation rate in squamous-cell NSCLC patients in our referral area is superior (11.17%) than previously reported, reinforcing the importance of including EGFR mutation testing in squamous-cell NSCLC population for selecting optimal therapy for these patients.