CLINICAL-SIGNIFICANCE OF INTRANODAL AND EXTRANODAL GROWTH IN LYMPH-NODE METASTASES OF NONSMALL CELL LUNG-CANCER

In non-small cell lung cancer with mediastinal lymph node metastasis, intranodal growth is regarded as prognostically more favourable than e xtranodal growth. We evaluated the clinical implications. Mediastinal lymph node metastases removed at mediastinoscopy and/or surgery were c lassified as intranodal, extranodal or indefinite. ''Minimal N2 diseas e'' denoted a solitary, intranodal metastasis, ''extranodal'' at least one extranodal lymph node metastasis, and ''indefinite'' more than on e intranodal or at least one indefinite metastasis. Although in patien ts with resected N2 disease, c. 21% of the nodal metastases were ''ind efinite'', survival was significantly better in minimal N2 disease tha n in the combined groups with extranodal and indefinite lymph node met astases. Of the metastatic nodes removed at mediastinoscopy, 75% were unsuitable for definite classification as only intranodal or extranoda l. Only 1 of 49 patients had purely intranodal N2 disease. Thus, it wa s seldom feasible to classify mediastinoscopic lymph node involvement as intranodal or extranodal, and this classification is unhelpful as r egards decisions on thoracotomy. However, when,nodal involvement in re sected N2 disease was limited to a single node with intranodal growth, the prognosis was better than in patients with extranodal disease or more than one intranodal metastasis or indefinite nodes.