Optimizing Mediastinal Lymph Node Dissection by Integrating Tumour Location, Consolidation Tumour Ratio, and Size for Lung Cancer

OBJECTIVES: Several mediastinal lymph node dissection strategies have been proposed for non-small-cell lung cancer based on prognostic analysis. However, as the lymph metastatic pattern of non-small-cell lung cancer has not been fully revealed, there are still needs for optimization of lymph node management. METHODS: Data on 7067 invasive non-small-cell lung cancer patients who underwent pulmonary resection with systematic lymph node dissection were retrospectively analysed. The tumour size, location, and consolidation tumour ratio (CTR) were identified with computed tomography scans. Other clinical features including visceral pleural invasion were also gathered. RESULTS: None of the tumours with CTR ≤ 0.5 had lymph node involvement. For tumours with CTR between 0.5 and 1.0, if the tumour size ≤ 2 cm, we found no inferior mediastinal lymph metastases in all the upper lobe tumours, and no superior mediastinal lymph metastases in the lower lobe tumours as well. If the size is ≤ 1 cm, inferior mediastinal lymph metastasis was not found in upper lobe tumours, and superior mediastinal lymph metastasis was not found in lower lobe tumours. CONCLUSIONS: In clinical practice, we can reliably predict a minimal risk of lymph node metastases by assessing various clinical features. Based on these findings, we laid the foundation for proposing an innovative strategy for mediastinal lymph node dissection in addition to our previous work.