Lung Cancer Surgery Part K: Intraoperative Mediastinal Lymph Node Examination Techniques in Non-Small Cell Lung Cancer

Nodal status at the time of staging is a critical determinant of survival in non-small cell lung cancer [NSCLC]. Despite the fact that the use of positron emission tomography [PET] scan and cervical mediastinoscopy–whether in combination or not—in staging has shown an acceptable accuracy rate, the extent of dissection still remains a problem. To date, there has been no consensus among either thoracic surgeons or oncologists regarding the optimal dissection of mediastinal lymph nodes [MLNs] in the early stages of NSCLC. Mediastinal lymph node dissection [MLND] is one of the techniques for MLN assessment and is not dependent on the location of the tumour or the lobe. All mediastinal fatty tissue containing lymphatics and lymph nodes is dissected from surrounding anatomical landmarks by either sharp or blunt dissection. Another technique is mediastinal lymph node sampling [MLNS], in which all mediastinal fatty tissue that potentially contains lymph nodes is not removed. The lymph nodes to be resected are determined preoperatively or intraoperatively. Because of the aggressiveness of MLND and the relative subjectivity of MLNS, some surgeons prefer dissection of the lymphatic pool and do no further dissection if that pool is negative. It is also important to consider N1 disease, and fixed lymph nodes to the bronchus usually necessitate more extensive surgery than lobectomy alone. In brief, questions still remain regarding the extent of lymph node removal. In patients undergoing resection for stage I and stage II NSCLC, it is recommended that intraoperative systematic MLNS or MLND be performed for accurate pathologic staging. Grade of recommendation: 1B.

Keywords: Lymph nodes, mediastinum, intraoperative staging, NSCLC, MLN, MLND, MLNS.