Imaging Characteristics of Driver Mutations in <i>EGFR</i>, <i>KRAS</i>, and <i>ALK</i> among Treatment-Naïve Patients with Advanced Lung Adenocarcinoma

<div><p>This study aimed to identify the computed tomography characteristics of treatment-naïve patients with lung adenocarcinoma and known driver mutations in <i>EGFR</i>, <i>KRAS</i>, or <i>ALK</i>. Patients with advanced lung adenocarcinoma (stage IIIB–IV) and known mutations in <i>EGFR</i>, <i>KRAS</i>, or <i>ALK</i> were assessed. The radiological findings for the main tumor and intra-thoracic status were retrospectively analyzed in each group, and the groups’ characteristics were compared. We identified 265 treatment-naïve patients with non-small-cell carcinoma, who had <i>EGFR</i> mutations (n = 159), <i>KRAS</i> mutations (n = 55), or <i>ALK</i> rearrangements (n = 51). Among the three groups, we evaluated only patients with stage IIIB–IV lung adenocarcinoma who had <i>EGFR</i> mutations (n = 126), <i>KRAS</i> mutations (n = 35), or <i>ALK</i> rearrangements (n = 47). We found that ground-glass opacity at the main tumor was significantly more common among <i>EGFR</i>-positive patients, compared to <i>ALK</i>-positive patients (<i>p</i> = 0.009). Lymphadenopathy was significantly more common among <i>ALK</i>-positive patients, compared to <i>EGFR</i>-positive patients (<i>p</i> = 0.003). Extranodal invasion was significantly more common among <i>ALK</i>-positive patients, compared to <i>EGFR</i>-positive patients and <i>KRAS</i>-positive patients (<i>p</i> = 0.001 and <i>p</i> = 0.049, respectively). Lymphangitis was significantly more common among <i>ALK</i>-positive patients, compared to <i>EGFR</i>-positive patients (<i>p</i> = 0.049). Pleural effusion was significantly less common among <i>KRAS</i>-positive patients, compared to <i>EGFR</i>-positive patients and <i>ALK</i>-positive patients (<i>p</i> = 0.046 and <i>p</i> = 0.026, respectively). Lung metastases were significantly more common among <i>EGFR</i>-positive patients, compared to <i>KRAS</i>-positive patients and <i>ALK</i>-positive patients (<i>p</i> = 0.007 and <i>p</i> = 0.04, respectively). In conclusion, <i>EGFR</i> mutations were associated with ground-glass opacity, <i>KRAS</i>-positive tumors were generally solid and less likely to metastasize to the lung and pleura, and <i>ALK</i>-positive tumors tended to present with lymphadenopathy, extranodal invasion, and lymphangitis. These mutation-specific imaging characteristics may be related to the biological differences between these cancers.</p></div>