Prevalence and Clinicopathologic Risk Factors for Epidermal Growth Factor Receptor, Anaplastic Lymphoma Kinase, and ROS-1 Fusion in Metastatic Non-small Cell Lung Carcinoma

The purpose of he study was to evaluate the prevalence of epidermal growth factor receptor (EGFR) mutations, anaplastic lymphoma kinase (ALK), and ROS-1 fusions in the patients with metastatic non squamous nonsmall cell lung carcinoma (NSCLC) and their relation with different demographic and clinical variables. A cross-sectional study was carried out on 87 adult patients >18 years of age with a confirmed diagnosis of Stage IV metastatic NSCLC. All the patients were studied for EGFR mutations, ALK, and ROS-1 fusions. The outcome measures were the presence of EGFR, ALK, and ROS-1 fusions among the patients with NSCLC and the risk association with age, gender, smoking, and tumor differentiation. Out of 87 patients, 26 (29.89%) patients tested positive for EGFR mutations, 4 (4.6%) for ALK, and a single case for ROS-1 fusion. The mean age of the patients who were EGFR positive was significantly younger than the mean age of those without EGFR mutation (56.77 ± 12.01 vs. 66.69 ± 11.34, P = 0.0004). As for the gender, females had significantly more EGFR mutations (53.85% vs. 46.15%, P = 0.013) with an odds ratio (OR) of 3.281 (1.257–8.562). Ex-smokers or nonsmokers showed an increased risk of EGFR mutation with an OR of 87.212 and 38.405 (P < 0.0001). There was no association of histology or grading with EGFR mutation. ALK and ROS-1 showed no significant association with clinical variables (P > 0.05). EGFR mutation is the most common occurrence in NSCLC, with other minor mutations being ALK fusion and ROS-1 rearrangements. Females, young age, and non-smoking behavior carry a significantly higher risk of EGFR mutation, which usually confers a good prognosis. (author)