RESUMEN
Non-small cell lung adenocarcinoma is the most common type of lung cancer but is often difficult to treat. New treatment options have emerged with the class of tyrosine kinase inhibitors, but it has been found that certain genetic mutations in the epidermal growth factor receptor (EGFR) receptor are not as sensitive to this treatment as others. We present a case of a 78-year-old man who was diagnosed with stage IV non-small cell lung adenocarcinoma with an EGFR exon 20 mutations treated with pemetrexed, nivolumab, and then docetaxel. He has lived over four years after his initial diagnosis. This case illustrates the importance of genetic testing of patients to evaluate for specific gene mutations. It highlights the fact that these patients with exon 20 mutations are not sensitive to tyrosine kinase inhibitor treatment and often respond better to chemotherapeutic agents.