Abstract:
RATIONALE: EBUS-TBNA has become an effective way of tissue assessment for evaluating mediastinal lymph nodes. Identifying molecular mutations is a key to personalized management in malignant disease. The success of molecular analysis depends on adequate tissue specimens consisting of an absolute number of tumor cell counts and the neoplastic cell percentage (NCP) estimation. This study aimed to evaluate the efficacy of EBUS-MFB added on EBUS-TBNA to improve the tissue adequacy and the overall diagnostic yield. In this prospective study, patients with enlarged intrathoracic lymph nodes underwent EBUS-TBNA followed by EBUS-MFB. The tissue adequacy for molecular analysis required that the tissue samples met both a tumor cell count of more than 100 cells and an NCP estimation of more than 25%. RESULTS: Fifty-two patients (57 nodes) with enlarged intrathoracic lymphadenopathy were enrolled. Twenty-one of fifty-seven nodes were diagnosed with malignant disease by both EBUS-TBNA and EBUS-MFB. The tissue adequacy of EBUS-TBNA was 19/21 (90.5%) comparable to EBUS-MFB added on EBUS-TBNA, which was 20/21 (95.2%) with no statistical significance (p=0.317). EBUS-TBNA resulted in higher tumor cell counts; more than 1,000 cells were shown in 17/21 (80.9%) compared to EBUS-MFB 10/21 (47.6%) (p=0.039). The EBUS-MFB added on EBUS-TBNA significantly improved the overall diagnostic yield compared to EBUS-TBNA alone (98.2% vs 87.7%; p=0.031). The discordant cases between EBUS-TBNA and EBUS-MFB were 19 of the 29 nodes (65.5%). Within these, 6/29 (20.7%) nodes were misdiagnosed with EBUS-TBNA, but EBUS-MFB demonstrated a valid diagnosis including three anthracotic lymph node, two granulomatous nodes, and one silicotic node. No serious adverse events were observed, only 2 patients out of 52 (3.84%) had minor bleeding. CONCLUSION: The tissue adequacy for molecular analysis by EBUS-TBNA and EBUS-MFB added on EBUS-TBNA were not different. However, EBUS-TBNA showed better tumor cell counts of specimens. Also, the EBUS-MFB added on EBUS-TBNA is a feasible and safe procedure which may provide more diagnostic yield, particularly in nonmalignant disease.
