Prognostic impact of multiple N2 stations in patients with non small cell lung cancer

OBJECTIVE: Lung cancer is currently the leading cause of cancer-related death in men and the second most common cause in women worldwide. In the 9th edition of the TNM classification, N2 lymph node involvement has been divided into two subgroups: N2a and N2b. In this study, we aimed to examine the differences within the N2 group and to identify factors that may affect prognosis. METHODS: Between 2002 and 2023, patients who underwent preoperative mediastinal staging (EBUS/Mediastinoscopy) and were found to have N2 involvement following lung resection for non-small cell lung cancer across 7 different clinics were included in the study. A total of 149 patients met the inclusion criteria. Of these, 98 had single-station N2 involvement, while 51 had multiple-station N2 involvement. The groups were evaluated in terms of parametric and non-parametric variables using Student's t-test and Chi-square analysis. Survival analysis was performed using the Kaplan-Meier method and Cox regression analysis. A p-value of < 0.05 was considered statistically significant. RESULTS: When comparing the groups based on demographic data, the mean age was 61.3 ± 8.2 years in patients with single-station N2 involvement and 59.6 ± 8.3 years in those with multiple-station N2 involvement (p = 0.979). No statistically significant difference was observed between the groups in terms of sex (p = 0.456). There was no significant difference in overall survival between the two groups (p = 0.675). However, adenocarcinoma diagnosis, TNM stage, and receipt of neoadjuvant therapy were identified as statistically significant factors associated with survival (p = 0.024, p = 0.006, and p < 0.001, respectively). In the Cox regression analysis, both pathological diagnosis and neoadjuvant therapy emerged as independent prognostic factors for survival (p = 0.046 and p < 0.001, respectively). DISCUSSION: Identifying prognostic factors in NSCLC patients with N2 involvement is crucial for determining appropriate treatment and follow-up strategies. In our study, patients with single and multiple N2 involvement exhibited similar demographic characteristics. When the two groups were evaluated in terms of survival, patients diagnosed with adenocarcinoma, those at Stage 3 A, and those who had not received neoadjuvant therapy were found to have significantly better survival outcomes. Our findings also indicated that patients with adenocarcinoma and unexpected N2 involvement had better survival. Independent negative prognostic factors included a non-adenocarcinoma diagnosis and prior neoadjuvant therapy. In cases of NSCLC with multiple N2 involvement, those diagnosed with non-adenocarcinoma type or who had received neoadjuvant therapy should be considered at higher risk for poor prognosis.