Prognostic role of station 3A mediastinal nodes for non-small-cell lung cancers

Abstract

Station 3A nodes have been commonly neglected in surgical practice. This retrospective study collected information on the incidence and risk factors of Station 3A node to ascertain the prognostic role of 3A nodal involvement. A total of 180 consecutive pN2 (stage IIIa) non-small-cell lung cancer (NSCLC) cases who underwent systemic lymphadenectomy and contained Station 3A nodes were enrolled. Survival rates were calculated according to the final pathology of Station 3A lymph node: Station 3A node (+) and Station 3A node (-). Statistical analysis was conducted using Kaplan-Meier and Cox regression models. Station 3A nodal metastasis was validated in 32 cases, and the incidence of Station 3A node involvement was 17.8%. Station 3A nodes involvement was strongly associated with the metastatic status of Station 4R nodes and histological nature of pulmonary cancer. The overall 3-year survival was 53% and median survival time was 40.6 months. The 3-year survival difference was significant between Station 3A node (-) and Station 3A node (+) (63 vs 22%, χ(2) = 16.426, P < 0.001). Moreover, the overall 3-year survival was closely related with the number of involved nodal zones (χ(2) = 31.156, P < 0.001). Multivariate analysis showed two statistically significant risk factors for survival including metastasis of Station 3A node and the number of positive nodal zones (hazard ratios [HR]: 2.702; 95% confidence intervals [CI]: 1.008-7.242; P = 0.027; and HR: 7.404; 95% CI: 3.263-16.936, P < 0.001, respectively). The involvement of Station 3A lymph nodes predicts poor prognosis of right-sided stage pIIIa-N2 NSCLC patients. Therefore, systemic lymphadenectomy for right-sided cancers should include Station 3A nodes when ascertaining a complete resection.