P3.02b-070 NSCLC with Detectable EGFR Mutation: Institutional Experience: Topic: EGFR Clinical

Abstract

EGFR is one of the most commonly mutated proto-oncogenes in lung cancer. The frequency of such mutations varies from approximately 10% of lung adenocarcinomas in North American and European populations to as high as 50% in Asia. The leucine to arginine substitution at position 858 (L858R) in exon 21 and short in-frame deletions in exon 19 are the most common sensitizing mutations, comprising approximately 90% of cases. Approximately 50% of EGFR TKI resistance is due to a second site mutation, the T790M mutation occurring within exon 20. We describe our experience in patients with lung cancer with detectable EGFR mutation. Describe the epidemiological characteristics and the incidence of mutations in patients diagnosed with advanced NSCLC in our institution. Analyze toxicities and adherence to treatment. Evaluate treatments performed and the problem of the analysis of the biopsy. We analyzed patients from June 2012 to date. We found 61/326 (18.7%) patients with detectable EGFR mutation, 47 women (77%) and 39% smokers, 47 patients had advanced or unresectable disease. The most common sites of metastases were bone and lymph nodes. 27 of the 61 patients had mutation of exon 19, 27 patients with mutation of exon 21, others in 18 and 20. Five of them with detectable T790M mutation confirmed by repeat biopsy after progressing to ITK. The most common side effects were diarrhea and rash, 12 patients had toxicities which had to reduce dose or discontinue treatment. The most common side effects were diarrhea and rash, 12 patients had toxicities which had to reduce dose or discontinue treatment. We had a low incidence of invalid or not evaluable biopsies. although not all patients with detectable mutation were treated with ITK, who received such treatment had good adhesion and a low percentage of patients had to discontinue treatment.