Prevalence of EGFR mutations in the Peruvian population: Study in a large cohort of patients with NSCLC.

Abstract

e13076 Background: The evaluation of EGFR mutational status of the EGFR in non-small cell lung cancer (NSCLC) is crucial to select the adequate targeted therapy and to know the outcome of patients. Previous studies in relative small sample sizes have described a higher prevalence of EGFR mutations in Peruvian population than other Latin American countries. Our aim in this study was to determine the prevalence of activating and resistance mutations of EGFR in a large cohort of Peruvian patients. Methods: We profiled metastatic tumor samples from 847 NSCLC patients for known EGFR mutations associated to sensitivity or resistance EGFR inhibitors, including exon 18 (G719X), exon 19 (deletions), exon 20 (T790M, S768I and insertions) and exon 21 (L858R). All samples were centrally tested in reference laboratory (Roe laboratory, Lima-Peru). Results: A total of 847 samples were profiled for EGFR mutational status. EGFR mutations were present in 32.9% of cases (n = 279). In regard to distribution of mutations in cases EGFR mutated, G719X (in exon 18) was present in 2.5% (n = 7); deletions in exon 19 had a frequency of 58.4% (n = 163). Mutations in exon 20 were present in 9.7% (n = 27). In patients with exon 20 mutated, 14 cases had insertions, 9 cases had the mutation T790M and 4 cases had the mutation S768I. Mutation L858R (exon 21) was present in 34.1% (n = 95) of cases. Coexistence of two mutations were present in exon 18/exon 20 (n = 1), exon 19/exon 20 (n = 7) and exon 20/ exon 21 (n = 5). In tumors with EGFR mutated. The sensible profile for EGFR tyrosine kinase inhibitors (TKI´s) was present in 96.8% of cases (n = 138). Conclusions: We have a high prevalence of EGFR mutations compared than Caucasian or other Hispanic cohorts. It has relevance in the Peruvian public health because more efforts should be done to screen NSCLC patients for EGFR mutations.