Conventional Transbronchial Needle Aspiration (cTBNA) and EBUS-Guided Transbronchial Needle Aspiration (EBUS-TBNA): A Retrospective Study on the Comparison of the Two Methods for Diagnostic Adequacy in Molecular Analysis

Abstract

Introduction: In recent years, there has been a growing development of molecularly targeted therapies for various types of solid tumors—in particular, in non-small-cell lung cancer (NSCLC). This has required the need for greater quantities of tissue that is able to support ancillary studies, alongside cyto-histological diagnoses for the assessment of molecular targets. Conventional TBNA (cTBNA) and EBUS-guided TBNA (EBUS-TBNA) have shown a high diagnostic yield for malignant mediastinal and/or hilar lymph node enlargement and peribronchial masses; however, few studies have compared these two procedures. We retrospectively compared TBNA patients (EBUS-TBNA and cTBNA) in order to determine the diagnostic yield and material adequacy for subsequent ancillary analyses. Materials and Methods: We retrospectively evaluated 318 patients with clinical suspicion of lung cancer or with disease recurrence. All of the patients underwent TBNA (either EBUS-TBNA or cTBNA) on enlarged mediastinal and/or hilar lymph nodes and peribronchial masses between January 2017 and June 2021 at the University Hospital of Pisa, Italy. After a definitive diagnosis, molecular analyses and an evaluation of PD-L1 expression were performed in the cases of adenocarcinoma, squamous cell carcinoma, and NSCLC, not otherwise specified (NOS). Results: EBUS-TBNA was performed in 199 patients and cTBNA was performed in 119 patients with 374 and 142 lymph nodes, respectively. The overall diagnostic yield for positive diagnoses was 59% (diagnostic rate of 61% in EBUS-TBNA, and 55% in cTBNA). Adenocarcinoma (ADC) was the most frequent diagnosis in both methods. EBUS-TBNA diagnostic adequacy was 72% for molecular analysis, while it was 55.5% for cTBNA, showing a statistical trend (p = 0.08) towards the significance of EBUS. The average percentage of neoplastic cells was also statistically different between the two methods (p = 0.05), reaching 51.19 ± 22.14 in EBUS-TBNA and 45.25 ± 22.84 in cTBNA. With regard to the PD-L1 protein expression, the percentage of positivity was similar in both procedures (86% in EBUS-TBNA, 85% in cTBNA). Conclusions: Conventional TBNA (cTBNA) and EBUS-guided TBNA (EBUS-TBNA) are minimally invasive diagnostic methods that are associated with a high diagnostic yield. However, EBUS-TBNA has an improved diagnostic adequacy for molecular analysis compared to cTBNA, and is associated with a higher average percentage of neoplastic cells.