EBUS-TBNA Provides Highest RNA Yield for Multiple Biomarker Testing from Routinely Obtained Small Biopsies in Non-Small Cell Lung Cancer Patients - A Comparative Study of Three Different Minimal Invasive Sampling Methods

Abstract

BackgroundMultiple biomarker testing is necessary to facilitate individualized treatment of lung cancer patients. More than 80% of lung cancers are diagnosed based on very small tumor samples. Often there is not enough tissue for molecular analysis. We compared three minimal invasive sampling methods with respect to RNA quantity for molecular testing.Methods106 small biopsies were prospectively collected by three different methods forceps biopsy, endobronchial ultrasound (EBUS) guided transbronchial needle aspiration (TBNA), and CT-guided core biopsy. Samples were split into two halves. One part was formalin fixed and paraffin embedded for standard pathological evaluation. The other part was put in RNAlater for immediate RNA/DNA extraction. If the pathologist confirmed the diagnosis of non-small cell lung cancer(NSCLC), the following molecular markers were tested: EGFR mutation, ERCC1, RRM1 and BRCA1.ResultsOverall, RNA-extraction was possible in 101 out of 106 patients (95.3%). We found 49% adenocarcinomas, 38% squamouscarcinomas, and 14% non-otherwise-specified(NOS). The highest RNA yield came from endobronchial ultrasound guided needle aspiration, which was significantly higher than bronchoscopy (37.74±41.09 vs. 13.74±15.53 ng respectively, P = 0.005) and numerically higher than CT-core biopsy (37.74±41.09 vs. 28.72±44.27 ng respectively, P = 0.244). EGFR mutation testing was feasible in 100% of evaluable patients and its incidence was 40.8%, 7.9% and 14.3% in adenocarcinomas, squamouscarcinomas and NSCLC NOS subgroup respectively. There was no difference in the feasibility of molecular testing between the three sampling methods with feasibility rates for ERCC1, RRM1 and BRCA1 of 91%, 87% and 81% respectively.ConclusionAll three methods can provide sufficient tumor material for multiple biomarkers testing from routinely obtained small biopsies in lung cancer patients. In our study EBUS guided needle aspiration provided the highest amount of tumor RNA compared to bronchoscopy or CT guided core biopsy. Thus EBUS should be considered as an acceptable option for tissue acquisition for molecular testing.

Endobronchial Ultrasound–Guided Transbronchial Needle Aspiration for the Diagnosis and Subtyping of Lymphoma

“…A median of five needle passes were performed per lymph node (range, [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. There was no difference in the number of passes between patients with and without lymphoma (p=0.27).…”

“…8,9 The diagnostic utility of EBUS-TBNA in lung cancer diagnosis and staging, including biomarker analysis, has been well established. 10,11 Emerging data suggest that EBUS-TBNA, along with appropriate immunohistochemical, flow cytometric, cytogenetic, and molecular studies, can definitively diagnose lymphoma. 12,13 Nonetheless, because disease management often hinges on the pathologic subtype and grade, there is concern that the smaller samples obtained via EBUS-TBNA compared with those obtained by surgical or core needle biopsy may be insufficient to guide treatment decisions.…”

Adequacy of endobronchial ultrasound-guided transbronchial needle aspiration samples processed as histopathological samples for genetic mutation analysis in lung adenocarcinoma

“…Several studies have investigated whether samples obtained during EBUS-TBNA are sufficient for molecular analysis and have demonstrated high, although variable, adequacy rates (77.7-98.7%) (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25). These studies were heterogeneous in terms of cytohistopathological techniques and sample size.…”

Liquid-Based Cytology Preparation Can Improve Cytological Assessment of Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration

“…In addition, the introduction of EBUS-TBNA has resulted in a cost benefit in terms of minimally invasive lung cancer staging [5,6]. Cytology samples obtained from EBUS-TBNA in routine practice are suitable for the subtyping of non-small cell lung cancer and epidermal growth factor receptor mutation analysis [7,8]. Hence, EBUS-TBNA has effectively been replacing mediastinoscopy for the staging of lung cancer [9] and in establishing a definitive diagnosis of mediastinal and hilar lymphadenopathy owing to its high diagnostic rate, minimal invasiveness and cost benefit.…”