In conclusion, we report results from a large population-based study evaluating real-world outcomes for 131 NSCLC patients with exon 20 insertion mutations in EGFR and HER2. This study reflects the clinical practice and treatment patterns of physicians and clinical outcomes of patients in an era when exon 20 insertion-targeted therapy was either unavailable or had just become available for select patients. This evidence concerns the gene ERBB2 and non-small cell lung carcinoma.