Conventional vs. endobronchial ultrasound-guided transbronchial needle aspiration. A randomized trial

Abstract

Chest 2004;125:322–5. Herth F, Becker HD, Ernst A. Study Summary: In this prospective, randomized study, Herth and coworkers compared the diagnostic yield of standard transbronchial needle aspiration (TBNA) with that of endobronchial ultrasound-guided TBNA (EBUS). Two hundred patients with enlarged mediastinal lymph nodes were included in the study. The study patients were divided into 2 groups: those with subcarinal lymph node enlargement (group A, N = 100) and those with lymph node enlargement at other stations (group B, N = 100). Patients in each group were randomized into standard TBNA group and EBUS-guided TBNA group. EBUS was performed using a balloon-tipped 20-MHz transducer. After locating the lymph node, the EBUS probe was removed. The information obtained was used to guide subsequent TBNA procedure (Chest 2003;123:604–7). TBNA cytology specimens were obtained using a MW 522 needle. On-site cytology was not used, and the interpreting pathologists were not aware of the method used to retrieve the TBNA specimen. The mean lymph node size was 1.76 cm (range, 0.8–4.3 cm) in group A and 1.53 cm (range, 0.7–2.3 cm) in group B. In group A, the diagnostic yield for the specific diagnosis was 72% with conventional TBNA and 80% with EBUS-guided TBNA. This difference did not reach statistical significance. In group B, the diagnostic yield for the specific diagnosis was 54% with conventional TBNA and 74% with EBUS-guided TBNA (P < 0.001). The mean time for EBUS-guided TBNA was 6.3 minutes and for conventional TBNA it was 3.8 minutes (P < 0.05). There were no procedure-related complications. The authors concluded that US-guided TBNA improves diagnostic yield from lymph node stations other than subcarinal lymph nodes. Comments: There is a growing interest in increasing diagnostic yield of TBNA. A successful TBNA is cost-effective and avoids need for more invasive procedure such as mediastinoscopy (Chest 1996;110[suppl]:24S). In some cases, TBNA is the only source of diagnostic material during flexible bronchoscopy (Am J Respir Crit Care Med 2000;161:601–7). Rapid on-site cytology (ROSE) and computed tomography– (CT) fluoroscopy-guided TBNA have been reported to improve TBNA yield in prior studies (Chest 1990;98:59–61, Chest 2000;118:1630–8, Chest 2001;119:329–32). However, there are logistic problems with both ROSE and CT fluoroscopy. On the contrary, US guidance is simple, safe, and adds little to the overall procedure time. In addition, there are no radiation issues with EBUS. Ultrasound guidance during TBNA did not increase diagnostic yield from subcarinal lymph nodes. This is not unexpected given the easy access to this area during standard TBNA. A careful review of their data (presented in Table 2 of the original paper) also indicates that EBUS guidance during TBNA does not appear to improve yield from right or left paratracheal lymph nodes. Reanalysis of the data show that the yield of conventional TBNA from station 4r and 4l (11 of 16; 69%) is similar to yield from EBUS-guided TBNA (13 of 18; 72%). However, the diagnostic yields with EBUS-guided TBNA for other stations were higher than that with the conventional procedure. The study was not designed to look into the possible additional role of ROSE in increasing diagnostic yield when used with EBUS-guided TBNA. Cost-effectiveness and reimbursement are other important considerations. Incorporation of EBUS with TBNA will increase the overall cost of the procedure. Future studies should address this issue. Nevertheless, overall results of this study are convincing and indicate that EBUS guidance can improve diagnostic yield of TBNA in selected patients. The authors rightly point out that there is a learning curve for EBUS. Bronchoscopists should consider learning this technique and adding EBUS facilities in their bronchoscopy suites. EBUS guidance during TBNA could improve operators’ confidence and could prove to be a good learning tool for the trainees.