What is the role of mediastinal lymphadenectomy in the staging of NSCLC?

Updated: Dec 10, 2019
  • Author: R James Koness, MD, FACS; Chief Editor: Erik D Schraga, MD  more...
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Answer

After Cahan's first description of radical mediastinal lymphadenectomy in 1951, [1]  complete mediastinal lymph node dissection for non-small cell lung cancer (NSCLC) remained a controversial procedure. The procedure was found to provide optimal staging for resectable NSCLC, but its therapeutic value continued to be debated. One study reported that only 57.3% of patients had any mediastinal nodes removed at the time of pulmonary resection. [2]

Accurate pretreatment staging of mediastinal lymph nodes in lung cancer is essential to determining prognosis and treatment because patients with involved mediastinal lymph nodes may not benefit from upfront surgical resection. Computed tomography (CT) and positron emission tomography (PET) lack both sensitivity and specificity for accurate lymph node staging. Transbronchial and esophageal needle aspiration provide specificity, but technical constraints hamper sensitivity.

Surgical mediastinoscopy is the pretherapeutic staging maneuver with the highest sensitivity and specificity, but it is dependent on the number of lymph nodes sampled and has technical limitations, especially for left-upper-lobe tumors. Additionally, the lymphatic system of the lungs has substantial anatomic variability, and skip metastasis can be found in 25% of cases. [3]  Thus, a significant number of patients who undergo surgical resection of their lung cancer may harbor positive mediastinal lymph nodes.

A mediastinal lymphadenectomy may be performed to achieve complete staging (possibly to make postoperative treatment decisions), better locoregional control, and improved overall survival. Arguments against the procedure include increased operating time, possible increased morbidity, and lack of conclusive evidence to support an increased survival rate from the procedure.

The results of the American College of Surgeons Oncology Group (ACOSOG) Z0030 study suggested that complete mediastinal lymphadenectomy does not improve survival for early-stage NSCLC. However, in this trial, complete dissection was compared with rigorous systematic sampling. Thus, surgeons adhering to the highest standards of complete lung cancer staging should continue to perform thorough mediastinal lymph node sampling.


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