Endobronchial ultrasound guided transbronchial needle aspiration (EBUS-TBNA) is an accurate modality for evaluation of mediastinal and hilar masses and lymphadenopathy. We sought to identify the various factors affecting the diagnostic yield of EBUS-TBNA.
A review was performed of the first 235 patients who underwent 236 real-time EBUS-TBNA at our institution in 2005; nine procedures included in the analysis were for hilar /mediastinal masses and not lymphadenopathy. Cytological analysis of EBUS-TBNA aspirates were compared to a reference standard of definitive pathological tissue diagnosis or a composite of ≥6 month's clinical follow-up with radiographic imaging by two reviewers.
Sampling accuracy was found to be slightly lower in the paratracheal lymph nodes (84.1%), compared with either the hilar (91.2%) or the subcarinal lymph nodes (93.2%) (p=0.009). The mean lymph node size sampled was 11.41 +/− 0.23 mm. Sampling with EBUS-TBNA was less accurate in lymph nodes ≤5mm (64.7%) compared to lymph nodes >5 mm in diameter (92%) (p=0.0001). Prior cancer therapy was not associated with a statistically significant reduction in the diagnostic yield of EBUS-TBNA in comparison to primary staging in patients with NSCLC. EBUS-TBNA had an overall sensitivity of 86.1% (95% CI: 0.796–0.926), specificity of 100% (95% CI: 0.966–1.00) and the diagnostic yield ranged from 83%–100% for malignancies of varying pathology (p=0.62).
Factors that appear to influence the diagnostic yield of EBUS-TBNA include lymph node size and location (lymph nodes ≤5 mm and those in paratracheal location have a lower diagnostic yield). Histological type of the malignancy and a history of prior treatment (chemotherapy, radiation therapy or both) did not appear to affect the diagnostic yield of EBUS-TBNA.
EBUS-TBNA can be used as an initial diagnostic tool for the evaluation of mediastinal and hilar masses that are greater than 5 mm in size, irrespective of their histological type. Diagnostic yield is lower for sampling lymph nodes in the paratracheal than in the hilar or subcarinal location.
Aditya Gupta, No Financial Disclosure Information; No Product/Research Disclosure Information