Presence of Even a Small Ground-Glass Component in Lung Adenocarcinoma Predicts Better Survival

The impact of having a small ground-glass opacity component in an otherwise mostly solid lung adenocarcinoma at prognosis was evaluated using Kaplan-Meier and Cox analyses of 123 patients who underwent lobar or sublobar resection of clinical N0 lung adenocarcinomas without induction therapy. Patients with tumors that had a minor ground-glass component that comprised less than 25% of the overall tumor size had less pathologic upstaging and far better 5-year overall survival compared to patients who had a 100% solid cancer. Background: While lepidic-predominant lung adenocarcinomas are known to have better outcomes than similarly sized solid tumors, the impact of smaller noninvasive foci within predominantly solid tumors is less clearly characterized. We tested the hypothesis that lung adenocarcinomas with even a small ground-glass opacity (GGO) component have a better prognosis than otherwise similar pure solid (PS) adenocarcinomas. Patients and Methods: The maximum total and solid-component diameters were determined by preoperative computed tomography in patients who underwent lobar or sublobar resection of clinical N0 adenocarcinomas without induction therapy between May 2003 and August 2013. Survival between patients with PS tumors (0% GGO) or tumors with a minor ground-glass (MGG) component (1%-25% GGO) was compared by Kaplan-Meier and Cox analyses. Results: A total of 123 patients met the inclusion criteria, comprising 54 PS (44%) and 69 MGG (56%) whose mean ground-glass component was 18 +/- 7%. The solid component tumor diameter was not significantly different between the groups (2.3 +/- 1.2 cm vs. 2.5 +/- 1.3 cm, P = .2). Upstaging to pN1-2 was more common for the PS group (13% [7/54] vs. 3% [2/69], P = .04), but the distribution of pathologic stage was not significantly different between the groups (PS 76% stage I [41/54] vs. MGG 80% stage I [55/69], P = .1). Having a MGG component was associated with markedly better survival in both univariate analysis (MGG 5-year overall survival 86.7% vs. PS 64.5%, P = .001) and multivariable survival analysis (hazard ratio, 0.30, P = .01). Conclusion: Patients with resected cN0 lung adenocarcinoma who have even a small GGO component have markedly better survival than patients with PS tumors, which may have implications for both treatment and surveillance strategies.