Prognostic effect of ground-glass opacity in subcentimeter invasive lung adenocarcinoma

BACKGROUND: Although subcentimeter nodules represent precursor or minimally invasive lung cancer in most cases, there are still a few that are subcentimeter invasive adenocarcinoma (IAC). The aim of this study was to investigate the prognostic effect of ground-glass opacity (GGO) and the optimal surgical procedure in this special group. METHODS: Patients with subcentimeter IAC were enrolled and were categorized into pure GGO, part-solid, and solid nodules based on the radiological appearance. Cox proportional hazards model and the Kaplan-Meier method were used for survival analyses. RESULTS: A total of 247 patients were enrolled. Among them, 66 (26.7%) were in the pure-GGO group, 107 (43.3%) were in the part-solid group, and 74 (30.0%) were in the solid group. Survival analysis demonstrated a significantly worse survival in the solid group. Cox multivariate analyses confirmed that the absence of GGO component was an independent risk factor for worse recurrence-free survival (RFS) and overall survival (OS). As for surgical procedures, lobectomy did not provide a significant better RFS or OS than sublobar resection in the whole cohort or in a subgroup of patients with solid nodules. CONCLUSIONS: The radiological appearance stratified the prognosis of IAC with size of smaller than or equal to 1 cm. Sublobar resection may be feasible for subcentimeter IAC, even for those appearing as solid nodules; however, caution should be taken when applying wedge resection.