Air bronchogram on chest CT in radiological pure-solid appearance lung cancer: Correlation analysis with genetic pathological features and survival outcomes

Purpose To investigate the correlation of air bronchogram sign with clinicopathological characteristics and prognosis in patients with clinical stage (c-stage) I non-small cell lung cancer (NSCLC) with radiological pure-solid appearance. Method We retrospectively evaluated 276 patients with pure-solid c-stage I NSCLC and assessed the correlation between the air bronchogram and clinicopathological characteristics. A Cox proportional hazards model was performed to identify the effect of air bronchogram and clinicopathological variables on oncological outcomes. Recurrence-free survival (RFS) and overall survival (OS) were calculated by Kaplan-Meier curves and were compared using log-rank tests. Results Presence of air bronchogram was associated with a well differentiated degree (P =.026), higher incidence of EGFR mutation (P <.001) and lower recurrence(P =.021). Kaplan-Meier survival curves showed that air bronchogram group was associated with favorable RFS(67.0% vs. 50.2%; P =.015). A multivariable analysis revealed that air bronchogram and EGFR mutation were independent significant prognostic factors associated with RFS (hazard ratio [HR] = 0.495, 95% confidence interval [CI]: 0.322–0.761, P =.001; HR = 1.625, 95% CI: 1.074–2.457, P =.021; respectively), but not with OS. Additionally, we found that pathological lymph node metastasis was identified as an independent prognostic factor associated with poor RFS and OS(HR = 2.808, 95% CI: 1.913–4.123, P <.001 for RFS; HR = 1.983, 95% CI: 1.185–3.318, P =.009 for OS). Conclusions Presence of air bronchogram was associated with well differentiated degree, higher incidence of EGFR mutation and had additional positive prognostic value for RFS in c-stage I NSCLC with a radiological pure-solid appearance.