Abstract
BACKGROUND: Subsolid lung nodules represent a distinct group of lung cancers with less-aggressive biological behavior and favorable survival. We aimed to examine the prognostic impact of the ground-glass opacity (GGO) in clinical stage IA (cIA) lung adenocarcinoma with high metabolic activity. METHODS: A retrospective study was conducted among patients with resected hypermetabolic and/or pure-solid cIA lung adenocarcinoma from a single institution database. The primary outcome was recurrence-free survival (RFS). The secondary outcomes included overall survival, pathological nodal upstaging, and recurrence rate. RESULTS: A total of 621 patients were reviewed and classified into three groups: patients with low metabolic, solid nodules (SNs) into group A (N = 128), patients with hypermetabolic ground-glass nodules (GGNs) into group B (N = 105), and patients with hypermetabolic SNs into group C (N = 388). The five-year RFS of group B was significantly better than that of group C in the cT1a + T1b (93.3% vs. 72.5%, p = 0.002) subgroup but not in the cT1c (73.4% vs. 69.0%, p = 0.23) subgroup. Multivariable analysis showed that GGO component was an independent prognostic factor of RFS (hazard ratio [HR] = 0.41, 95% confidence interval [CI]: 0.19-0.89, p = 0.02) and protective factor of nodal upstaging (odds ratio [OR] = 0.44, 95% CI: 0.21-0.94, p = 0.03) among the hypermetabolic subgroup. All except one postoperative recurrence occurred in GGNs with solid component size > 2 cm. CONCLUSIONS: The presence of GGO component was an independent prognostic factor even in hypermetabolic cIA lung adenocarcinoma. However, the oncologic outcomes of hypermetabolic GGNs were not equally favorable in different T categories.