EGFR mutations are significantly associated with visceral pleural invasion development in non-small-cell lung cancer patients

OBJECTIVES: A retrospective study was performed to investigate the association between EGFR mutations and visceral pleural invasion (VPI), and evaluate the prognostic value of EGFR in resected non-small-cell lung cancer (NSCLC) patients with VPI. MATERIALS AND METHODS: Clinicopathological characteristics and follow-up information were collected from 508 consecutive patients with surgically resected stage I–III NSCLC, and EGFR mutations were detected based on real-time PCR technology. Significant results (P<0.05) from univariate logistic regression analysis were involved as covariates to adjust confounding factors in the analysis of independent factors. RESULTS: VPI and EGFR mutations were detected in 229 (45.1%) and 243 (47.8%) cases in NSCLC, respectively. There was a significant association between EGFR mutations and VPI development. Both 19-del (adjusted OR =2.13, 95%CI =1.13–3.99, P=0.019) and L858R (adjusted OR =2.89, 95%CI =1.59–5.29, P=0.001) could significantly increase the risk of VPI development compared with EGFR wild-type. Higher frequency of L858R (adjusted OR =2.63, 95%CI =1.42–4.88, P=0.002) was detected in VPI patients compared with non-VPI patients. 19-del (adjusted HR =0.31, 95%CI =0.12–0.80, P=0.015) was an independent prognostic factor for a better disease-free survival (DFS) in non-VPI patients. No significant association was shown between EGFR mutations and DFS in VPI patients. CONCLUSION: EGFR mutations were significantly associated with VPI development in NSCLC, but no significant association was observed between EGFR mutations and DFS in the patients with VPI. 19-del was a favorable prognostic factor for DFS in non-VPI patients.