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.

Evaluation of lung cancer biomarkers profile for the decision of targeted therapy in EBUS-TBNA cytological samples

“…Beyond this, these small cytological specimens could lead false to negativity with its minimum burden of mutations . 10–12 Also, many of these studies about EBUS-TBNA for biomarker testing included only adenocarcinomas or concentrated on a single molecular test such as EGFR or ALK, and there are not enough studies on other tests yet. 9,13,14…”

“…Beyond this, these small cytological specimens could lead false to negativity with its minimum burden of mutations. [10][11][12] Also, many of these studies about EBUS-TBNA for biomarker testing included only adenocarcinomas or concentrated on a single molecular test such as EGFR or ALK, and there are not enough studies on other tests yet. 9,13,14 The main objective of our study was to assess the adequacy of EBUS-TBNA for testing lung cancer biomarkers include EGFR, ALK, ROS-1, BRAF and PD-L1 expression in patients diagnosed with NSCLC during the 9-year experience of our centre.…”