Influence of bilateral mediastinal lymph node dissection on survival in non-small cell lung cancer patients-Randomized study

Objectives: This study aimed to analyze the effect of bilateral mediastinal lymphadenectomy (BML) on survival of non-small cell lung cancer (NSCLC) patients. The hypothesis was: BML offers survival benefit as compared with SLND. Methods: A randomized clinical trial including stage I-IIIA NSCLC patients was performed. All patients underwent anatomical lung resection. BML was performed during the same operation via additional cervical incision (BML group). In the control group, standard lymphadenectomy (systematic lymph node dissection, SLND) was performed. Results: In total, 102 patients were randomized. No significant difference was found in the type of lung resection, blood loss, chest tube output, air leak, pain, and complications (p = 0.188-0.959). In the BML group, the operative time was longer (318 vs 223 min, p < 0.001) with higher number of removed N2 nodes (24 vs 14, p < 0.001). The 5-year survival rate was 72 % in the BML group vs 53 % in the SLND group (OR 2.33, 95 % CI 0.95-5.69, p = 0.062). Separate comparisons for different lobar locations of the tumor have shown no significant difference in survival for the right lung tumors and left upper lobe tumors. For the left lower lobe tumors, survival time was longer in the BML group (p = 0.021), and the 5-year survival rate was 90.9 % vs 37.5 %, (OR 16.66, 95 % CI 1.36-204.04, p = 0.0277). Conclusions: In patients with NSCLC located in the left lower lobe, bilateral lymph node dissection may be associated with better survival. The invasiveness of BML is comparable to that of SLND.