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

Abstract

Abstract Purpose Ground glass opacity (GGO)-featured lung adenocarcinoma generally has excellent prognosis, and rarely has lymph node metastasis. We aim 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) resected node-positive lung adenocarcinoma presented as part-solid nodules on CT images in this cohort. The median nodule size on CT of 34 part-solid lesions was 31mm (range: 15-68mm), median solid component size on CT was 24mm (range: 12-62mm), and median consolidation/tumor ratio was 0.8 (range: 0.64–0.95). After 1:4 PSM, 136 patients and 34 patients were matched from solid and part-solid groups. No significant difference in either RFS (P = 0.71) or OS (P = 0.82) were found between solid and part-solid groups. Multivariable Cox regression pN stage as the strongest prognostic factors for RFS and OS. GGO component was not an independent prognostic factor toward either RFS [P = 0.753, HR(95%CI) = 0.93(0.59–1.46)] or OS [P = 0.528, HR(95%CI) = 1.19(0.69–2.05)]. Conclusion A minority of resected node-positive lung adenocarcinoma present as GGO component on CT. The presence of GGO component does not predict better prognosis in node-positive lung adenocarcinoma.