Prognostic Significance of Extranodal Cancer Invasion of Mediastinal Lymph Nodes in Lung Cancer

The presence of perinodal cancer invasion in specimens obtainedfrom the mediastinum during curative surgery on 49 patientswith metastasis-bearing mediastinal nodes was determined andevaluated with special reference to its prognostic significance. When an en-bloc dissection technique for the mediastinal lymphnodes and fatty tissue surrounding the nodes during surgerywas used, lymphatic vessel invasion in fatty tissue other thana breach in the capsule of a lymph node by cancer could be seen.A breach in the node capsule and lymphatic vessel invasion aredesignated as "extranodal invasion" in this paper. A breach in the capsule was seen in 16 cases, lymphatic vesselinvasion in 12 and both a breach in the capsule and lymphaticvessel invasion in 4. In 17 cases there was only intranodalcancer metastasis. The 5-yr survival rate was 37.5% and 17.7%for patients with and without extranodal invasion, respectively.However, extranodal invasion did not seem to be a distinctiveprognostic factor.