Mutational Profiling by Next-Generation Sequencing in Patients with Metastatic Non-Small Cell Lung Carcinoma: Our Experience

Introduction According to GLOBOCAN 2020, overall lung cancer is the second most common cancer in both sexes (11.4%) accounting for highest cancer-related mortality (18%).1 Adenocarcinoma subtype of non-small cell lung cancer (NSCLC) is the most common subtype and is divided into further molecular subtypes based on oncogenic driver mutations. Overall survival in these patients is poor with the use of conventional platinum-based double chemotherapy and various recent studies on targeted therapy studies have showed improved survival. Therefore, broad panel-based testing like next-generation sequencing (NGS) is strongly recommended to identify these targetable driver mutations. Aims and Objectives The aim of this study was to evaluate the mutational profile in patients with metastatic NSCLC (mNSCLC) by NGS method. Materials and Methods A hospital-based prospective observational study done on 88 patients under the Department of Medical Oncology, State Cancer Institute during a period of 1 year. All patients above 18 years of age diagnosed as mNSCLC having Eastern Cooperative Oncology Group performance status 0 to 2 and evaluated for mutational profiling by NGS method were included. Five gene panel tests including endothelial growth factor receptor (EGFR), echinoderm microtubule-associated protein-like 4 and anaplastic lymphoma kinase (EML4-ALK), BRAF, mesenchymal epithelial transition (MET), and ROS proto-oncogene 1 (ROS1) were used. Results and Observations Majority of mNSCLC cases were in the age group of 41 to 50 years (n = 30, 34.1%) with average age at presentation being 53.74 years. Male: female ratio was 1.14:1 and most patients were nonsmokers. Adenocarcinoma subtype of mNSCLC cases had the highest mutational burden (n = 55, 62.5%). EGFR (n = 32, 56.14%) was the most common mutation followed by EML4-ALK (n = 19, 33.33%). Most common EGFR mutation was in Exon 19. Other rare mutations were ROS1 (n = 4), BRAF V600E (n = 1), and MET (n = 1). Skeleton was the most common site of metastasis across all driver mutations. Conclusion EGFR and EML4-ALK were the commonest targetable mutations detected in the study. As there is very limited data from North Eastern region of India regarding mutational status in mNSCLC, this study opens up possibilities for further studies targeting multiple mutations to give us more comprehensive understanding of the mutational landscape of mNSCLC in this era of precision medicine.