Abstract
BACKGROUND: We aimed to investigate the impact of epidermal growth factor receptor (EGFR) mutation in the progression of lung adenocarcinoma presented as a solitary ground-glass opacity (GGO) by retrospectively evaluating the correlation between EGFR mutation status and the radiographic features. METHODS: One hundred fifty-six cases of lung adenocarcinoma presented as a solitary GGO were enrolled between 2013 and 2015. Chest CT scans were performed 3 times (1st ≥3 months, 2nd ≤1 week preoperatively and 3rd ≥3 months postoperatively) in each patient. The diameter and volume of every lesion was measured by semiautomated algorithm. EGFR mutation hotspots from exons 18, 19 and 21 were detected by real-time PCR. RESULTS: In the 156 patients who were enrolled in our study, tumors in 75 patients (48.1%) were pathologically diagnosed with EGFR-mutant, with 1, 29 and 45 cases harboring tumors with mutation in exon 18, 19 and 21, respectively. EGFR mutation occurred more frequently in women (P=0.005) and non-smokers (P=0.019). Comparison between the 1st and 2nd preoperative CT scans showed that 28 (37.3%) of 75 patients with EGFR mutations had an over 50% increment of tumor size and 38 (52.0%) displayed a growth of solid component. On the other hand, we found only 9 (11.1%) and 14 (17.3%) in 81 lesions without EGFR mutation had a distinct volume growth and component solidification, respectively, which is significantly less than that in EGFR mutation lesions (P<0.001). Further, in the postoperative CT scan, recurrent GGOs or nodes were identified in 6 (8%) EGFR-mutant patients and 6 (7.4%) in wild-type patients (P=0.89), which indicates no overt statistically difference. At last, we found that EGFR amplification is more frequent as GGO volume percentage decreases and diameter increases. CONCLUSIONS: We found GGOs with EGFR mutation grew faster in volume and solidified more quickly in component than wild-type GGOs. Moreover, in the follow-up after surgery, patients in the EGFR mutation group and EGFR wild-type group showed no significant difference in the imaging evolvement.