Segment-specific lymph node dissection and evaluation during anatomical pulmonary segmentectomy

Lung cancer continues to be the leading cause of cancer related deaths both in men and women. Most patients present with locally advanced disease and are not candidates for resection. A recent surge of lung cancer screening programs for high-risk patients across the western world has led to a rising number of patients with early stage lung cancer. These patients with clinical stage I lung cancer and compromised pulmonary reserves can be candidates for sub-lobar resection with curative intention and similar outcomes as compare to lobectomy. Systemic or lobe-specific mediastinal lymph node dissection is an integral part of lung cancer surgery, especially during lobectomy as nodal upstaging can occur up to 18% of clinical stage I lung cancers and is associated with a worse prognosis. Nodal upstaging can occur in N1 lymph nodes only or as a skip metastasis to the N2 lymph nodes or both. The characteristics and location of the tumor plays an important role in lymph node metastasis. Recently, it has been suggested that a lobe-specific mediastinal lymph node dissection is equivalent to multi-station aggressive nodal dissection for early stage lung cancer detected during screening. Determining mediastinal and intersegmental lymph node metastasis is important during segmentectomy as it is associated with an increase recurrence rate and poor survival. These patients are perhaps better served with lobectomy rather than segmentectomy. The techniques and method of standard mediastinal lymph node dissection are well described in literature but description of a systematical approach for N1 lymph node dissection during a segmentectomy to efficiently identify the nodal upstaging intra-operatively, is lacking. We describe a methodological evaluation of N1 lymph node during segmentectomy in an effort to avoid failure to recognize nodal upstaging.