The pattern of lymph node involvement influences outcome after extrapleural pneumonectomy for malignant mesothelioma

Abstract

We sought to examine the distribution and prognostic implications of nodal metastasis in patients undergoing extrapleural pneumonectomy for malignant mesothelioma in a specialist center. We have examined the lymphadenectomy specimens from 92 consecutive cases of malignant mesothelioma undergoing extrapleural pneumonectomy from September 1999 through February 2005 inclusive. Nodal stations (Naruke) were assigned to all nodes, and patients were staged according to the current International Union Against Cancer system. The status and number of nodes in each station were recorded, and results were correlated with the results of preoperative mediastinoscopic findings (n = 30) and survival. The nodal distribution was 48 N0, 9 N1, and 35 N2. Single and multistation nodal involvement was present in 20 and 24 cases, respectively. Among the patients undergoing mediastinoscopy, N2 disease after extrapleural pneumonectomy occurred in 10 (33%). Skip N2 metastasis was present in 10 (42%) cases. Positive N2 nodes inaccessible by mediastinoscopy were present in 17 (49%) cases. N2 metastasis was associated with reduced survival (P = .02), but there was no difference between N1 and N2 cases (P = .4). The number of positive nodes correlated with survival (P = .001), although the number of involved stations and their anatomic location did not. There was no difference in survival between skip N2 cases and either other N2 or N1 cases. The classical anatomic location is not as important as the scatter of nodal involvement. Every effort should be made to obtain biopsy specimens from as many stations as possible before undertaking extrapleural pneumonectomy for malignant mesothelioma.