A Differentiated Approach to the Choice of Invasive N‑Staging Method for Lung Cancer: Experience of the Sverdlovsk Regional Oncological Dispensary

Introduction . Accurate mediastinal staging in non-small cell lung cancer (NSCLC) determines treatment strategy. The wide adoption of endosonography (EBUS-TBNA/EUS-FNA) has raised questions about the role of video-mediastinoscopy (VMS) and video-assisted mediastinoscopic lymphadenectomy (VAMLA) in the staging algorithm. Purpose of the work is to conduct a comparative analysis of the diagnostic accuracy and safety of video-mediastinoscopy/ VAMLA and endosonography (EBUS/EUS) in N‑staging of lung cancer to optimize the diagnostic algorithm in the Sverdlovsk Regional Oncological Dispensary. Materials and method s. We retrospectively analyzed 58 invasive diagnostic procedures in 54 lung cancer patients with intrathoracic lymphadenopathy (August 2024 — February 2026). The VMS/VAMLA group included 29 procedures (including after non-informative EBUS/EUS), the EBUS/EUS-FNA group 29 primary procedures. Diagnostic accuracy, complications, procedure duration and blood loss were assessed. Results . EBUS/EUS sensitivity was 88.9 % (informativity 62.1 %) (95 % CI 67.2–97.0), specificity 100 %, accuracy 90.0 %; for VMS/VAMLA, all three indicators were 100 %. Informativity was 62.1 % versus 86.2 % (p = 0.04); with immunocytochemistry, potentially 79.3 %. Complications: 0 % and 6.9 % (p = 0.49). Three or more N‑stations were removed in 51.7 % of VMS/VAMLA cases (EBUS/EUS 0 %; p < 0.001). Multizonal (N2b) involvement was found in 31.6 % of confirmed N2 cases. Procedure duration: 42.5 (18.3) min vs 115.7 (38.2) min (p < 0.001). Discussion . The obtained data confirm the high diagnostic value of EBUS-TBNA as a first-line method; however, its informativity (62.1 %) and negative predictive value (50.0 %) limit the use of the method in patients at high risk of N2. VMS/VAMLA provides maximum diagnostic accuracy (100 %) and allows detection of multizonal involvement (N2b) in 31.6 % of patients with confirmed N2, which is critical for choosing the tactics of neoadjuvant therapy. Conclusion . EBUS-TBNA is an effective first-line method. VMS/VAMLA retains clinical value for verification in high-N2‑risk patients (cN1, central tumor) with negative EBUS. VAMLA is the method of choice for determining the extent of N2 (N2a vs N2b) and excluding N3.