Keywords:
EBUS-TBNA, Education, Training, Transbronchial needle aspiration

Dear Editor,

The recently published study on the learning curve for endobronchial ultrasound-transbronchial needle aspiration (EBUS-TBNA) is a welcome addition to the state of understanding of this important topic [1]. It is of course attractive to be able to adopt a stance whereby 25 procedures are thought to be sufficient to achieve acceptable standards in EBUS-TBNA so that more trainees can be ‘trained' and service requirements can be met in a shorter space of time. However, the key issue is what should be the metrics for training studies in EBUS-TBNA. Sample adequacy and diagnostic accuracy are intimately linked and are both important. But what are the thresholds for minimum acceptability in diagnostic accuracy, and is the learning curve really only 20-25 procedures?

We and others [2,3,4,5]have previously looked at this. Interestingly, in two independent studies [2,3], diagnostic accuracy peaked with a 95% accuracy at 100 procedures, peaking at a 100% accuracy in the longer study at 160 procedures [2]. At our own institution, two other EBUS bronchoscopists have attained an accuracy of >95% (98.4 and 97.6%), but again in excess of 100 procedures (122 and 163) and both reaching a 90% accuracy after 50 procedures, adding support to the previous findings (unpublished data). This has led to much discussion about supporting a minimum of 50 procedures [6], mirroring the American College of Chest Physicians recommendations [7], although in the other study, accuracy was only 83% at 60 procedures, climbing to 90% at 80 procedures [3]. A recent UK study using cusum analysis further demonstrated the heterogeneity of learning amongst experienced bronchoscopists, including two of five studied operators who were still in the learning phase at 100 procedures [4]. A more recent North American study using more detailed metrics found ongoing improvements at 200 procedures amongst trainees as well as a failure rate of 33% to attain expert standards at all even at that time [5].

In conclusion, learning appears to be heterogeneous, but there must be a common minimum acceptable standard in diagnostic accuracy to aspire to, accepting the fact that other confounding factors exist such as lymph node size, rapid on-site cytology, sedation type, bronchoscopic and pathologic expertise and disease prevalence. If we accept that the minimum standard should at least be a 90% accuracy, the minimum number of procedures seems to be 50-80. If the bar is raised to a 95% accuracy, then >100 procedures would appear to be necessary, with support for this from four studies [2,3,4,5]. A consistency of acceptable standards between organisations would help maintain standards, planning of curricula and future studies in this area.

1.
Bellinger CR, Chatterjee AB, Adair N, Houle T, Khan I, Haponik E: Training in and experience with endobronchial ultrasound. Respiration 2014;88:478-483.
2.
Medford AR: Learning curve for endobronchial ultrasound-guided transbronchial needle aspiration. Chest 2012;141:1643-1644.
3.
Fernández-Villar A, Leiro-Fernández V, Botana-Rial M, Represas-Represas C, Núñez-Delgado M: The endobronchial ultrasound-guided transbronchial needle biopsy learning curve for mediastinal and hilar lymph node diagnosis. Chest 2012;141:278-279.
4.
Kemp SV, El Batrawy SH, Harrison RN, Skwarski K, Munavvar M, Rosell A, Cusworth K, Shah PL: Learning curves for endobronchial ultrasound using cusum analysis. Thorax 2010;65:534-538.
5.
Stather DR, Chee A, MacEachern P, Dumoulin E, Hergott CA, Gelberg J, Folch E, Majid A, Gonzalez AV, Tremblay A: Endobronchial ultrasound learning curve in interventional pulmonary fellows. Respirology 2015;20:333-339.
6.
Folch E, Majid A: Point: are >50 supervised procedures required to develop competency in performing endobronchial ultrasound-guided transbronchial needle aspiration for mediastinal staging? Yes. Chest 2013;143:888-895.
7.
Ernst A, Silvestri GA, Johnstone D: Interventional pulmonary procedures: guidelines from the American College of Chest Physicians. Chest 2003;123:1693-1717.
© 2015 S. Karger AG, Basel
2015
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.