[Transbronchial needle aspiration of diseased mediastinal lymph nodes: predictors of positive findings].

OBJECTIVE To assess the factors that may determine the effectiveness of transbronchial needle aspiration through a flexible bronchoscope in the diagnosis of diseased mediastinal lymph nodes in patients with lung or extrapulmonary tumors. METHODS Prospective study carried out at 2 hospitals between 1998 and 2004 that included all transbronchial needle aspirations performed on patients who had diseased mediastinal lymph nodes larger than 10 mm and nonlymphoid neoplasms. Univariate and multivariate analysis of the diagnostic results of transbronchial needle aspiration were performed according to the type and location of the primary neoplasm and the lymph node station biopsied, the diameter of the affected node, endoscopic findings, and the results of other bronchoscopic techniques. RESULTS The study evaluated the transbronchial needle aspiration of 230 lymph node stations in 207 patients. Histologic examination revealed 151 cases (72.9%) of non-small cell lung cancer, 42 cases (20.3%) of small cell lung cancer, and 14 cases (6.8%) of extrapulmonary cancer. The best predictors of obtaining a diagnostic sample were a diameter of the diseased node greater than 20 mm in diameter (odds ratio [OR], 2.4; 95% confidence interval [CI], 1.2-4.7; P=.01) and a histologic diagnosis of small cell lung cancer (OR, 2.7; 95% CI, 0.9-8.2; P=.07). CONCLUSIONS The size of the diseased node and the tumor type are the best predictors of obtaining a diagnostic sample with transbronchial needle aspiration of diseased mediastinal lymph nodes in patients with lung or extrapulmonary tumors.