P1.37: First Line Treatment Outcome for EGFR Mutated Metastatic Non-Small Cell Lung Cancer-A Single Institution 5 Years Experience

Abstract

Non-Small Cell Lung Cancer (NSCLC) Classification is rapidly evolving depending upon histology and driver mutations. 10-15% of patients with advanced NSCLC have a tumour with an EGFR mutation. 20-30% of adenocarcinomas have epidermal growth factor receptor (EGFR) mutations. These mutations promote cell growth and cell survival. EGFR domain can have mutation from exon 18 to exon 21 but most common (90%) EGFR mutations are exon 19 deletions or exon 21 point mutation, especially L858R. EGFR mutated lung adenocarcinomas are uniquely susceptible to selective Tyrosine Kinase Inhibitors (TKIs). Such patients may experience dramatic tumour shrinkage and show durable response to TKIs. Recent trials have shown improvement in Overall Survival (OS) Progression Free Survival (PFS) with TKIs as compared to chemotherapy as first line treatment. We looked at safety, efficacy, OS and PFS in EGFR mutated metastatic adenocarcinoma patients treated with TKIs over 5 years at University Hospital of North Midlands UK. Hospital electronic notes were retrospectively studied for patients undergoing TKIs treatment either with Geftinib, Afatinib or Erlotinib for mNSCLC over 5 years from January 2011 to December 2015. Subset analysis of treatment outcome with efficacy and safety was also performed comparing 3 TKI drugs. 2498 total lung cancer patients were diagnosed over 5 years. Among them 636 were adenocarcinoma, of whom 51 were metastatic. Among metastatic adenocarcinoma, 23 (45%) were positive for EGFR mutation. 13 females and 10 males with median age of 66 years. 15 (65%) had exon 19 deletion and 7(30%) had exon 21 point mutation. All received treatment either with Geftinib, Afatinib or Erlotinib as first line. All had ECOG performance status 0 to 2. Median OS was 12 months, median PFS was 10 months. Majority of side effects were Grade 1/2. Common side effects observed were skin rash, pruritus, dry eyes, fatigue and diarrhoea. One patient on Geftinib developed Grade 3 pneumonitis. Dose modification and treatment interruption was done in 5 (21%) patients. No toxicity related death was seen. Currently 13 (56%) patients are still on treatment. Subset analysis has shown better OS and PFS favouring Erlotinib over Geftinib and Afatinib. Our results were comparable with LUX-Lung 3 trial demonstrating significant PFS, OS and tumour response when treated with first line TKI as standard therapy either with Geftinib, Afatinib or Erlotinib. Toxicity was manageable. Current study demonstrates that median OS may extend beyond 12 months as more than half of the patients are still on treatment.