Local Control by Mediastinal Lymph-Node Dissection in Stage I Non-Small-Cell Lung Cancer

Area of Science:

• Thoracic Surgery
• Oncology
• Pulmonary Medicine

Background:

• Mediastinal lymph-node dissection (MLND) is a standard procedure for resectable non-small-cell lung cancer (NSCLC).
• The prognostic significance of MLND in early-stage NSCLC, particularly solid-dominant tumors, remains debated.
• Accurate staging is crucial for guiding adjuvant therapy decisions.

Purpose of the Study:

• To evaluate the impact of MLND on prognosis and local control in patients with radiologically solid-dominant clinical stage I NSCLC.
• To compare outcomes between patients who underwent MLND versus those who did not.
• To assess the role of MLND in identifying occult mediastinal metastases and guiding treatment.

Main Methods:

• Retrospective review of 2212 patients with clinical stage I NSCLC who underwent lobectomy (2010-2022).
• Comparison of prognosis and local control between MLND (n=1912) and non-MLND (n=300) groups.
• Propensity score matching was used to adjust for baseline differences between the groups.

Main Results:

• After matching, 5-year overall survival showed no significant difference (85.3% vs 79.3%, P=.089).
• MLND detected occult pN2 metastasis in 7.3% of patients and significantly reduced mediastinal lymph-node recurrence (P=.017).
• Patients with pN2 disease in the MLND group who recurred had more extensive nodal involvement and a lower rate of skip-N2 metastasis.

Conclusions:

• MLND enhances local control by decreasing mediastinal recurrence rates in clinical stage I NSCLC.
• MLND is essential for accurate pathological staging, informing adjuvant therapy selection.
• The direct survival benefit of MLND requires further evaluation in prospective randomized controlled trials.