Lobe-specific extent of systematic lymph node dissection for non–small cell lung carcinomas according to a retrospective study of metastasis and prognosis

Abstract

Background: Complete lymphadenectomy of the mediastinum is advised for patients with lung cancer to provide prognostic information and possible survival benefit. The proper extent of dissection should be further defined. Method: The lymphatic metastatic patterns according to the primary site and prognoses were retrospectively analyzed in 166 patients with non–small cell carcinoma who underwent at least lobectomy with hilar and mediastinal lymphadenectomy. All patients had histologically proven mediastinal metastasis (pN2). Results: Among 54 right upper lobe tumors the most common site of metastasis was the lower pretracheal station (74%), whereas metastases to the subcarinal station were seen only in 13%. Among 8 patients with right middle lobe tumors and 41 patients with right lower lobe tumors, both superior mediastinal and subcarinal stations were involved. The 34 left upper segment tumors metastasized to the aorticopulmonary window most commonly (71%) and to the subcarina only in 12% of cases. Inversely, the 10 left lingular tumors metastasized to the subcarina most commonly (50%) and to the aorticopulmonary window only in 20% of cases. Among 44 left lower lobe tumors the subcarinal station was most common for metastasis (58%), with infrequent metastases to the aorticopulmonary window. The 5-year survival for all 166 patients was 35%. Patients with single-station and single-node metastases had a significantly better prognosis than those with more extensive metastases. Right lower lobe tumors with superior mediastinal metastasis carried a particularly poor 5-year survival of only 4.1%. Comment: Subcarinal lymphadenectomy is not always necessary for tumors of the right upper lobe and left upper segment. For tumors of other lobes both superior mediastinal dissection and subcarinal dissection are advised. However, superior mediastinal metastasis should be recognized as an indicator of poor prognosis in tumors of both lower lobes. (J Thorac Cardiovasc Surg 1999;117:1102-11)