The effectiveness of mediastinal lymph node evaluation in a patient with ground glass opacity tumor

Background: The prognosis of non-small cell lung cancer (NSCLC) presenting as a ground glass opacity (GGO) nodule is better than other types of lung cancer. The purpose of this study was to evaluate the necessity of mediastinal lymph node evaluation (MLE) in clinical N0 GGO-predominant NSCLC. Methods: We conducted a retrospective chart review of 358 patients treated for clinical N0 NSCLC that was found by curative resection to be 3 cm or smaller in size. We analyzed clinicopathological findings and survival among three groups with either GGO-predominant or solid-predominant tumor: no mediastinal lymph node evaluation (NoMLE) group, mediastinal lymph node sampling (MLS) group, and mediastinal lymph node dissection (MLND) group. Results: Except for sex, there were no differences in clinicopathological characteristics among the three groups with GGO-predominant tumor or solid-predominant tumor. There was no difference in the 5-year recurrence-free survival (RFS) rate among three groups in the GGO-predominant patients (100%, 92.9%, 93.8%, respectively; P=0.889). However, in the solid-predominant tumor group, the 5-year recurrence free survival of the NoMLE group was lower than in the MLND group (48.6% vs. 73.1%, P=0.007). MLE was not a significant risk factor for recurrence in GGO-predominant tumor [hazard ratio (HR) =1.021; P=0.987]. GGO-predominant tumor [odds ratio (OR) =0.063; P=0.008] was identified as the sole parameter that significantly impacted nodal upstaging. Conclusions: MLE is not an essential procedure for clinical N0 NSCLC presenting as a 3 cm or smaller GGO-predominant nodule.