Endoscopic ultrasound-guided biopsy in the chest

To the Editors:

We read with interest the editorial comment on endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) biopsy in the chest by Vilmann and Larsen 1.

With conviction, they claim the importance of EUS-FNA in the work-up of enlarged mediastinal lymph nodes, especially in lung cancer patients. They even state that: “we really do not need additional proof before EUS-FNA is considered the gold standard for invasive staging of nonsmall cell lung cancer and for diagnosis of posterior mediastinal lesions”.

However, as they also state in their discussion, no studies have actually compared mediastinoscopy (the current gold standard) and EUS-FNA in a controlled and blinded study design. Moreover, other concerns about EUS-FNA can be raised, which are not mentioned in their comments, such as the following.

First, according to Vilmann and Larsen 1, the sensitivity of EUS-FNA biopsies of mediastinal lymph nodes is very high. This may be true for the nodes within reach of the transoesophageal needle. Due to the anatomical position of the oesophagus, only nodes in the distal and posterior mediastinum can be reached. The right-sided mediastinal nodes 2R and 4R cannot be reached by EUS-FNA in a significant number of cases, as is confirmed in the article by Rintoul et al. 2, published in the same issue of the European Respiratory Journal. Here the diagnosis of the 2R and 4R nodes was obtained using a transbronchial approach 2.

Before EUS-FNA is claimed to be the gold standard for invasive staging of nonsmall cell lung cancer, a prospective study should demonstrate the number of cases of enlarged lymph nodes which are out of reach for EUS-FNA, but can be reached by mediastinoscopy, the current gold standard. Such a study would demonstrate a more accurate sensitivity of EUS-FNA in an unselected group of lung cancer patients with enlarged lymph nodes.

Secondly, Vilmann and Larsen 1 begin their editorial with the statement that “tissue diagnosis of pathological lesions located in the mediastinum has been difficult to obtain by non-surgical methods”. However, they forget to mention transbronchial needle aspiration (TBNA), a technique known since 1949 3, which has been used with the flexible bronchoscope since 1979 4. This nonultrasound-guided procedure has a diagnostic sensitivity of >70% in many studies 5–7. Moreover, these results are not reserved for expert centres alone. After 24 months of training, the diagnostic sensitivity of pulmonologists without experience in TBNA rose from 24 to 78% 5.

TBNA has some important advantages. 1) It can be performed during the bronchoscopic procedure that is already necessary in the work-up of patients suspected for lung cancer. The extra time is limited to a few minutes and the additional costs of a TBNA needle are ∼90\#8364;. 2) The use of ultrasound is a necessity in the oesophagoscope as there are no anatomical landmarks in the oesophagus. During bronchoscopy, one can rely on several endobronchial landmarks to localise lymph nodes. In the only randomised trial in the literature concerning the use of ultrasound-guided versus “blind” TBNA, there was no significant difference in the diagnostic yield of subcarinal lymph nodes 8. 3) It is a cost-effective procedure which may diagnose N3 disease in an important number of cases, and consequently avoid mediastinoscopy (1,550\#8364; in our hospital) 6. 4) From the patient's point of view, if TBNA performed during the necessary bronchoscopy is diagnostic, no additional endoscopic procedures are needed. After all, who would volunteer for oesophagoscopy?

In an editorial comment on the endoscopic approach of mediastinal lymph nodes, the vast literature on the excellent results of TBNA should not be neglected.

Before endoscopic ultrasound-guided fine-needle aspiration is proclaimed as the new gold standard, and pulmonologists are advised to learn oesophagoscopy, we should first learn to perform a routine transbronchial needle aspiration during the bronchoscopy. This approach is cost-effective and limits the number of endoscopic procedures, which may even be unnecessary. Your patient will be grateful to you!