EGFR and neoplasm: Although tumor burden is a promising candidate, its prognostic role in guiding epidermal growth factor receptor (EGFR)-targeted kinase inhibitor (TKI) therapies remains understudied in real-world settings.<h4>Methods</h4>We identified patients with de novo stage IV <i>EGFR</i>-mutant NSCLC treated with first-line EGFR-TKI at Stanford Health Care (2000-2021).