By following a robust process, including using multiple information sources, conducting the research in several rounds, adapting patient interviews and study samples, and clinical experts' input, we identified a core set of 12 symptomatic AEs that are directly relevant to NSCLC with EGFR Exon 20ins and its treatments, notwithstanding their relevance to other forms of NSCLC. The gene discussed is EGFR; the disease is non-small cell lung carcinoma.