Resected lung adenocarcinoma with lymph node metastasis: is ground glass opacity component a prognostic factor?

ABSTRACT

Background: Ground glass opacity (GGO)-featured lung adenocarcinoma generally has excellent prognosis, and here is rarely the occurrence of lymph node metastasis. We conducted a retrospective cohort study to explore the prognostic impact of GGO component in node-positive lung adenocarcinomas. Methods: A total of 669 patients with pathologic N1/N2 lung adenocarcinoma receiving R0 resection and systemic lymph node dissection from 2008 to 2015 were reviewed, including 635 solid and 34 part-solid lesions. Propensity score matching (PSM) was performed to compare survival outcomes of solid and part-solid lesions, in order to determine the prognostic value of GGO component. Cox proportional hazard model was performed to identify significant prognostic factors for resected node positive lung adenocarcinoma. Results: About 5.1% (34 of 669) of resected node-positive lung adenocarcinoma presented as part-solid nodules on computed tomography (CT) images in this cohort. The median nodule size on CT of the 34 part-solid lesions was 31 mm (range, 15-68 mm), median solid component size on CT was 24 mm (range, 12-62 mm), and median consolidation/tumor ratio was 0.8 (range, 0.64-0.95). After 14 PSM, 136 patients and 34 patients were matched from the solid and part-solid groups. No significant difference in either recurrence-free survival (RFS) (P=0.71) or overall survival (OS) (P=0.82) was found between the solid and part-solid groups. Multivariable Cox regression showed that pN stage was the strongest prognostic factor for RFS and OS. GGO component was not an independent prognostic factor toward for RFS [P=0.75; hazard ratio (HR) =0.93; 95% confidence interval (CI) 0.59-1.46] or OS (P=0.53; HR =1.19; 95% CI 0.69-2.05). Conclusions: A minority of resected node-positive lung adenocarcinoma presents as GGO component on CT. The presence of GGO component does not predict better prognosis in node-positive lung adenocarcinoma.