Optimizing mediastinal lymph node dissection by integrating tumor location, consolidation tumor 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 analyzed. The tumour size, location, and consolidation tumour ratio were identified with computed tomography scans. Other clinical features including visceral pleural invasion were also gathered. RESULTS None of the tumors with consolidation tumour ratio ≤ 0.5 had lymph node involvement. For tumors with consolidation tumour ratio between 0.5 and 1.0, if the tumour size ≤ 2 cm, we found no inferior mediastinal lymph metastases in all the upper lobe tumors, and no superior mediastinal lymph metastases in the lower lobe tumors as well. If the size is ≤ 1 cm, inferior mediastinal lymph metastasis was not found in upper lobe tumors, and superior mediastinal lymph metastasis was not found in lower lobe tumors. 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.