Systematic nodal dissection in the intrathoracic staging of patients with non-small cell lung cancer

Although systematic nodal dissection is accepted as an important component of the intrathoracic staging of disease in patients undergoing thoracotomy for lung cancer, many surgeons still do not routinely perform it. We reviewed our practice to assess the information provided by its routine application even when lymph node metastases are considered unlikely.

The records of 240 patients undergoing thoracotomy for clinically staged cT1-3 N0-1 non-small cell lung cancer were reviewed. In 5 cases (2%) mediastinal dissection was not performed because of specific contraindications and in 8 cases (3%) exploratory thoracotomy was performed. The pathologic findings in the 227 patients who underwent pulmonary resection with systematic nodal dissection were analyzed.

The median number of nodal stations, including N1 and N2, examined and submitted separately for histologic assessment was 7 per patient (range 3-13). N2 disease was disclosed in 46 patients overall (20%), including 41 of the 227 patients undergoing pulmonary resection (18%) and 5 of those undergoing exploratory thoracotomy (62.5%). No subgroup had a 0% incidence of N2 metastases. Multivariate analysis showed that younger age, increasing tumor size, left lower lobe origin, and bronchial origin were significant independent variables for prediction of lymph node metastases at the N1 level, the N2 level, or both.

Because no clinical or pathologic subset of patients with a negligible incidence of N2 disease could be discriminated, systematic nodal dissection must be routinely employed for accurate intrathoracic staging of non-small cell lung cancer.