Epidermal growth factor receptor mutation accelerates radiographic progression in lung adenocarcinoma presented as a solitary ground-glass opacity.

Abstract

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. 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. 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. 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.