Diffuse Lung Metastases in EGFR-Mutant Non-Small Cell Lung Cancer

Abstract

Diffuse lung metastases have been reported in non-small cell lung cancer (NSCLC) harboring epidermal growth factor receptor (<i>EGFR</i>) mutations. The purpose of our study was to compare the incidence of diffuse lung metastases in <i>EGFR</i>-mutant NSCLC and <i>EGFR</i>-wild type NSCLC and to assess other imaging features that may be associated with diffuse lung metastases in <i>EGFR</i>-mutant NSCLC. Two radiologists retrospectively reviewed pre-treatment imaging of metastatic NSCLC cases with known <i>EGFR</i> mutation status. We assessed the imaging features of the primary tumor and patterns of metastases. The cohort consisted of 217 patients (117 <i>EGFR</i>-mutant, 100 <i>EGFR</i> wild-type). Diffuse lung metastasis was significantly more common in <i>EGFR</i>-mutant NSCLC compared with wild-type (18% vs. 3%, <i>p</i> < 0.01). Among the <i>EGFR</i>-mutant group, diffuse lung metastases were inversely correlated with the presence of a nodule greater than 6 mm other than the primary lung lesion (OR: 0.13, 95% CI: 0.04-0.41, <i>p</i> < 0.01). <i>EGFR</i> mutations in NSCLC are associated with increased frequency of diffuse lung metastases. The presence of diffuse lung metastases in <i>EGFR</i>-mutant NSCLC is also associated with a decreased presence of other larger discrete lung metastases. <i>EGFR</i> mutations in NSCLC should be suspected in the setting of a dominant primary lung mass associated with diffuse lung metastases.