Journal Article

Impact of Smoking and Brain Metastasis on Outcomes of Advanced EGFR Mutation Lung Adenocarcinoma Patients Treated with First Line Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors

Loo, Chian Min, Gan, Eugene MingJin, Takano, Angela, Tan, Wu Meng, Lim, Wan Teck, Ng, David Zhihao, Kim, Su Woon, Jain, Amit, Devanand, Anantham, Kanesvaran, Ravindran, Chowbay, Balram, Koh, Tina, Lim, Cindy, Ang, Mei Kim, Fong, Kam Weng, Oon, Lynette, Ng, Quan Sing, Chan, Kian Sing, Hsu, Anne Ann Ling, Yap, Swee Peng, Tan, Daniel Shao Weng, Koong, Heng Nung, Tan, Eng Huat, Lim, Kiat Hon, Toh, Chee Keong, Lim, Chong Hee

2015

Overview

This purpose of this study was to examine clinical-pathologic factors--particularly smoking and brain metastases--in EGFR mutation positive (M(+)) lung adenocarcinoma (ADC) to determine their impact on survival in patients treated with first line EGFR TKI. A retrospective review of EGFR mutation reflex testing experience for all ADC diagnosed at a tertiary Asian cancer centre from January 2009 to April 2013. Amongst this cohort, patients with advanced EGFR M(+) ADC treated with first line EGFR TKI were identified to determine factors that influence progression free and overall survival. 444/742 (59.8%) ADC reflex tested for EGFR mutations were EGFR M(+.) Amongst never-smokers (n=468), EGFR M(+) were found in 74.5% of females and 76.3% of males, and amongst ever smokers (n=283), in 53.3% of females and 35.6% of males. Exon 20 mutations were found more commonly amongst heavy smokers (> 50 pack years and > 20 pack years, Pearson's chi square p=0.044, and p=0.038 respectively). 211 patients treated with palliative first line TKI had a median PFS and OS of 9.2 and 19.6 months respectively. 26% of patients had brain metastasis at diagnosis. This was significantly detrimental to overall survival (HR 1.85, CI 1.09-3.16, p=0.024) on multivariate analysis. There was no evidence that smoking status had a significant impact on survival. The high prevalence of EGFR M(+) in our patient population warrants reflex testing regardless of gender and smoking status. Smoking status and dosage did not impact progression free or overall survival in patients treated with first line EGFR TKI. The presence of brain metastasis at diagnosis negatively impacts overall survival.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Adenocarcinoma / Adenocarcinoma - drug therapy / Adenocarcinoma - enzymology / Adenocarcinoma - genetics / Adenocarcinoma of Lung / Adult / Aged / Aged, 80 and over / Brain / Brain cancer / Brain Neoplasms - enzymology / Brain Neoplasms - genetics / Brain Neoplasms - secondary / Brain research / Cancer therapies / Chemotherapy / Chi-square test / Clinical trials / Cohort Studies / Critical care / Demography / Diagnosis / Disease Progression / Disease-Free Survival / DNA Mutational Analysis / Epidermal growth factor / Epidermal growth factor receptors / ErbB Receptors - antagonists & inhibitors / ErbB Receptors - genetics / Female / Females / Hospitals / Humans / Kaplan-Meier Estimate / Laboratories / Lung cancer / Lung Neoplasms - drug therapy / Lung Neoplasms - enzymology / Lung Neoplasms - genetics / Male / Males / Medical diagnosis / Medical prognosis / Medicine / Metastases / Metastasis / Middle Aged / Multivariate Analysis / Mutation / Mutation - genetics / Neoplasm Staging / Oncology / Pathology / Patients / Protein Kinase Inhibitors - pharmacology / Protein Kinase Inhibitors - therapeutic use / Protein-tyrosine kinase receptors / Reflex - drug effects / Smoking / Smoking - adverse effects / Survival / Survival analysis / Treatment Outcome / Tyrosine