Predictive Value of Endobronchial Ultrasound Strain Elastography in Mediastinal Lymph Node Staging: The E-Predict Multicenter Study Results

Abstract

Background: Systematic assessment of lymph node status by endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is indicated in (suspected) lung cancer. Sampling is herein guided by nodal size and FDG-PET characteristics. Ultrasound strain elastography (SE) might further improve risk stratification. By imaging tissue deformation over time, SE computes relative tissue strain. In several tissues, a lower strain (deformation) has been associated with a higher likelihood of malignancy. Objectives: To assess if EBUS-SE can independently help predict malignancy, and when combined with size and FDG uptake information. Methods: This multicenter (n = 5 centers) prospective trial included patients with suspected or proven lung cancer using a standardized measurement protocol. Cytopathology combined with surgery or follow-up imaging (> 6 months) were used as reference standard. Results: Between June 2016 and July 2018, 327 patients and 525 lymph nodes were included (mean size 12.3 mm, malignancy prevalence 0.48). EBUS-SE had an overall AUC of 0.77. A mean strain < 115 (range 0-255) showed 90% sensitivity, 43% specificity, 60% positive predictive value, and 82% negative predictive value. Combining EBUS-SE (< 115) with size (< 8 mm) and FDG-PET information into a risk stratification algorithm increased the accuracy. Combining size and SE showed that the 48% a priori chance of malignancy changed to 11 and 70% in double negative or positive nodes, respectively. In the subset where FDG-PET was available (n = 370), triple negative and positive nodes went from a 42% a priori chance of malignancy to 9 and 73%, respectively. Conclusions: EBUS-SE can help predict lymph node malignancy and may be useful for risk stratification when combined with size and PET information.

Occult lymph node metastases in clinical N0/N1 NSCLC; A single center in-depth analysis

“…All patients with a suspected or proven NSCLC in the Radboudumc routinely receive diagnostic and staging work-up according to ACCP and ESTS guidelines and multi-disciplinary team (MDT) decision-making, with the exception being that our pulmonary nodule diagnostic program routinely includes an EBUS evaluation in combination with a navigation bronchoscopy, irrespective of PET/CT findings and despite the limited tumor size in this subgroup [32]. In our routine EBUS staging procedures, all lymph nodes >5 mm short axis are aspirated [33,34]. Our MDT consists out of oncological pulmonologists, thoracic radiologists, pathologists, radiation oncologists and cardiothoracic surgeons, organized in a multidisciplinary team dedicated to lung cancer care [35].…”

Influential Factors for Assessing Endobronchial Ultrasound Elastography

“…Only 2 of the patients were diagnosed with pneumoconiosis before EBUS-E. Although our EBUS-E evaluation criteria were different from those of Verhoeven et al [1], considering the principle of EBUS-E, a patient’s background can greatly influence the strain values on EBUS-E. The LNs in patients with a history of occupational exposure and without a diagnosis of pneumoconiosis may be hardened, and are likely to give false-positive results on EBUS-E.…”

“…We read the article by Verhoeven et al [1] with great interest and appreciate the authors’ efforts in investigating the diagnostic accuracy rate (DAR) of endobronchial ultrasound elastography (EBUS-E) with strain values (≥115) that can be evaluated in real-time. They showed that DAR increased when size (≥8 mm) and 18 F-fluorodeoxyglucose positron emission tomography (FDG-PET) findings were considered.…”

“…Accordingly, a detailed interview about the occupational and exposure histories before EBUS-E evaluation is necessary. According to Figure 3 in the manuscript by Verhoeven et al [1], the positive predictive value was 73% when using strain values, size, and the FDG-PET mentioned above. However, 27% of cases were false-positive; we would therefore like to know if these false-positive cases included patients with a history of tuberculosis and/or occupational dust exposure.…”

Reply to Letter to the Editor: “Influential Factors for Assessing Endobronchial Ultrasound Elastography” by Uchimura et al. Respiration. DOI: 10.1159/000510643

“…Thank you for your interest in our work on EBUS strain elastography [1] and for sharing your experience. In our reply, we will discuss the points raised and address several points for clinical application of EBUS strain elastography and for further research with this technology.…”