Comparison of Treatment Outcome in EGFR Positive and Negative Patients with Non Small Cell Lung Cancer: A Longitudinal Study

Abstract

Introduction: Lung cancer is one of the most common malignancies to occur worldwide. Two main subtypes of lung cancer include small cell lung cancer and Non Small Cell Lung Cancer (NSCLC). Patients with advanced stage NSCLC who achieve good response with Tyrosine Kinase Inhibitors (TKI) have been found to have Epidermal Growth Factor Receptor (EGFR) mutation. The first biomarker identified for targeted treatment in lung cancer was EGFR and patients of NSCLC with EGFR mutation have superior survival outcome when treated with targeted therapy as compared to conventional chemotherapy. Aim: To compare the outcome of targeted therapy to mutation to EGFR and conventional therapy in non mutant lung cancer patient of NSCLC. Materials and Methods: The present longitudinal study was conducted in the Department of TB and Respiratory Diseases, Jawaharlal Nehru Medical College and Hospital, Aligarh, Uttar Pradesh, India from July 2017 to November 2019 on a sample size of 80. Patients diagnosed with NSCLC and EGFR mutation status were included in the study. They were started on TKI if tumour was EGFR positive and on conventional chemotherapy (cisplatin plus paclitaxel) if no mutation was detected on histopathology. Among the study group, 35 patients were EGFR positive and started on geftinib (group I), 45 were EGFR negative and received platinum-based chemotherapy (group II). Outcomes were measured in terms of progression-free survival, Overall Survival (OS), and toxicities. Statistical analysis of data was done using Statistical Package for the Social Sciences (SPSS) version 20.0. Results: Among the study group, 35 patients were EGFR positive and started on geftinib (Group I), 45 were EGFR negative and received platinum-based chemotherapy (group II). The mean age of EGFR positive patients was 58.91 years and for EGFR negative patients was 60.11 years. In group I, there was no complete response while 28.5% had partial response, 45.5% had stable disease and 25.7% had progressive disease. In group II, 15.5% patients had complete response, 33.3% had partial response,17.7% had stable disease and 33.3% had progressive disease. Mean progression-free survival in group I (5.65 months) was significantly higher than group II (4.26 months). The mean OS in group I (7.85 months) was slightly higher than group II (6.72 months). Both haematological and non haemaotlogical toxicities were significantly higher in group II. Conclusion: Patients with EGFR positive expression subjected to Gefitinib had significant mean progression-free survival with an acceptable range of non haematological toxicities and no haematological toxicities, as compared to the EGFR negative patients on conventional chemotherapy.