The accurate diagnosis of enlarged mediastinal lymph nodes is necessary for determining the most appropriate therapy in the treatment of both malignant and benign diseases. TBNA has been widely utilized as a nonoperative diagnostic tool. TBNA’s diagnostic accuracy ranges from 63-85%. The wide variation, mainly due to negative TBNA results(-TBNA), often requires mediastinoscopy(gold standard) for definitive diagnosis. Confident therapeutic decisions require knowledge of institutional diagnostic accuracy of TBNA before recommendations regarding mediastinoscopy can be made. Therefore, we reviewed our TBNA results and identified clinical predictors which yield positive TBNA(+TBNA).
We retrospectively reviewed data between 1997 and 2004. TBNA results were obtained and compared to pathologic diagnosis obtained from mediastinoscopy. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy were calculated. +TBNA was assumed to be a true positive, and did not undergo mediastinoscopy. Spearman correlation analysis, contingency testing, and multilogistic regression analysis was performed utilizing clinical variables that might predict a +TBNA. A p-value less than 0.05 was considered significant.
92 TBNAs on 90 (49 male) patients were performed. Median age was 63 (range 27 -88). There were 71 malignant (60 NSCLC and 11 small cell) and 21 benign (16 sarcoidosis) diagnoses. Sensitivity was 76.6%, specificity 100%, positive predictive value 100%, negative predictive value 65%, and diagnostic accuracy 83%. Spearman coorelation indentified five risk factors that were important in predicting a +TBNA. Contingency tests revealed the greater the number of risk factors present, the higher the probablility of a +TBNA(Figure 1, p<.001). After multilogistic regression analysis, only lymph node size (>2.5cm) independently predicted a +TBNA(p<0.05).
TBNA at our institution has a diagnostic accuracy of 83%. Accumulation of defined risk factors predicts +TBNA. Only lymph node size independently predicted an accurate diagnosis. Given low sensitivity and negative predicted value of TBNA, patients with a negative result should undergo mediastinoscopy.
Patients with mediastinal adenopathy and a negative TBNA require mediastinoscopy for accurate diagnosis.
D. Gallo, None.