Endobronchial Ultrasound-Guided Fine Needle Biopsy in the Diagnosis of Mediastinal Lymphadenopathy

BACKGROUND: The comparative sampling efficacy of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) needles in mediastinal lymphadenopathy remains unclear. Would the fine needle biopsy (FNB), with its Franseen design, provide better results than the fine needle aspiration (FNA) during EBUS-TBNA? METHODS: We performed a single-center, investigator-initiated, single-blinded, randomized, parallel-group, superiority trial between August 2022 and July 2023. Consecutive patients were randomly assigned (1:1) to undergo EBUS-TBNA with either 19-gauge (G) FNA or 22-G FNB. The primary endpoint was the diagnostic yield, while the secondary endpoints were specimen adequacy and complication rates. RESULTS: The study included 150 patients with a mean age of 44.5±15.1 years (50.7% female patients). The diagnostic yield of FNB was not significantly different from FNA (94.7% vs. 89.3%; difference, 5.4%; 95% CI: -4.0% to 15.0%; P=0.23). Despite this, FNB had a higher rate of adequate tissue (98.6% vs. 86.7%; difference, 11.9%; 95% CI: 4.0%-22.0%; P<0.001) and larger core tissue (11.52 vs. 9.29 mm; mean difference, 2.23 mm; 95% CI: 1.4-3.1mm; P<0.001) than FNA. FNB showed a significantly higher diagnostic yield for histologic samples (90.7% vs. 76.0%; difference, 14.7%; 95% CI: 3.0-27.0; P=0.016) in post hoc analysis; however, this should be considered a hypothesis-generating finding. All procedures were well tolerated except for minor bleeding. CONCLUSION: Despite similar diagnostic yields, FNB was more effective than FNA in providing larger, adequate core tissue samples. This improvement in specimen quality may suggest a potential clinical benefit for comprehensive diagnosis and advanced pathologic work-up.