Ultrasound-Guided Transbronchial Needle Aspiration*

Ultrasound-Guided Transbronchial Needle Aspiration*

bronchoscopy Ultrasound-Guided Transbronchial Needle Aspiration* An Experience in 242 Patients Felix J. Herth, MD, FCCP; Heinrich D. Becker, MD, FCCP;...

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bronchoscopy Ultrasound-Guided Transbronchial Needle Aspiration* An Experience in 242 Patients Felix J. Herth, MD, FCCP; Heinrich D. Becker, MD, FCCP; and Armin Ernst, MD, FCCP

Study objectives: Conventional transbronchial needle aspiration (TBNA) is a valuable procedure but remains underutilized. Recently, imaging guidance such as CT fluoroscopy has created considerable interest. As CT fluoroscopy is cumbersome and exposes patients and staff to radiation, we have examined the feasibility of endobronchial ultrasound (EBUS) in providing imaging support for TBNA. Design: Prospective consecutive patient enrollment. Setting: University-related tertiary referral centers for pulmonary diseases. Results: From January 1999 to January 2000, 242 consecutive patients were entered into this prospective study (82 women and 160 men; mean age, 60.0 years). Indications for TBNA were diagnosis of enlarged lymph nodes and cancer staging. The average lymph node size was 1.7 cm (SD, 0.47; range, 0.8 to 4.3 cm). Target lymph nodes were visualized with EBUS, followed by TBNA in standard fashion. All targets could be visualized with EBUS. In 207 patients, the lymph nodes were successfully sampled (86%). This was independent of lymph node size and location. A firm diagnosis or cancer stage could be obtained in 172 patients (72%). There were no complications associated with the use of EBUS. Conclusion: EBUS is simply performed and if used for TBNA guidance affords an excellent yield independent of lymph node location. Randomized trials comparing standard TBNA and imagingguided TBNA by CT fluoroscopy and EBUS are indicated. (CHEST 2003; 123:604 – 607) Key words: bronchoscopy; diagnosis; endobronchial ultrasound; transbronchial needle aspiration Abbreviations: EBUS ⫽ endobronchial ultrasound; TBNA ⫽ transbronchial needle aspiration

needle aspiration (TBNA) is a T ransbronchial well-established bronchoscopic technique. It allows for tissue sampling from submucosal layers, parabronchial and paratracheal lymph nodes and masses, as well as from parenchymal abnormalities.1–3 The yield for TBNA varies widely in the *From the Department of Interdisciplinary Endoscopy (Drs. Herth and Becker), Thoraxklinik, Heidelberg, Germany; and Division of Pulmonary and Critical Care (Dr. Ernst), Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA. Manuscript received January 4, 2002; revision accepted June 28, 2002. Correspondence to: Armin Ernst, MD, FCCP, Director, Interventional Pulmonology, Pulmonary and Critical Care Division, Beth Israel Deaconess Medical Center, Harvard Medical School, One Deaconess Rd, Boston, MA 02115; e-mail: aernst@caregroup. harvard. edu 604

literature (20 to 89%) and seems to be related to the size and location of the lesion as well as operator experience.3– 8 Additionally, even though TBNA is proven effective for mediastinal lung cancer staging and in some situations may be the only technique yielding positive results,2 it remains underutilized and is not uniformly taught in training programs.9,10 As conventional TBNA does not allow for imaging of the needle placement, it is a fairly “blind” technique. Also, failure to place the needle directly into the lesion is the leading cause of a lower yield on biopsy.11 Recently, there has been increasing interest in real-time guidance for TBNA addressing this problem. Several studies have evaluated the use of CT and more recently CT fluoroscopy and found significant improvement in the yield of TBNA.4,12,13 Bronchoscopy

CT guidance requires planning, the use of the CT suite can be costly, and staff and patient are exposed to radiation. Despite these drawbacks, and because real-time imaging during the procedure is helpful, we evaluated the feasibility of endobronchial ultrasound (EBUS) for TBNA guidance during bronchoscopy. Materials and Methods

mens (MW 522; Bard; Billerica, MA) and 19-gauge needles for histology cores (MW 319; Bard). The “jabbing” method2 was used for all punctures. Cytology specimens were air-dried on-site, and histology specimens were fixed in formalin before being sent to the pathology department. Statistical Analysis Means, SEs, and percentages are presented as appropriate. Spearman rank correlations for nonparametric samples were used to correlate the choice of needle to the different variables.

Patients Between January 1999 and January 2000, all patients referred for diagnostic TBNA of mediastinal lymph nodes were included into this prospective study. Bronchoscopy was performed in standard fashion either under general anesthesia for combined rigid and flexible examinations or conscious sedation for flexible endoscopy. TBNA and EBUS were performed as detailed below. Indications for TBNA, lesion size on chest CT, number of passes, diagnosis, and complications were recorded. EBUS and TBNA were performed by pulmonologists routinely performing both procedures. EBUS EBUS was performed as previously described in detail.14,15 Through a bronchoscope with 2.8-mm working channel (Olympus p 20 and Olympus p 40 D; Olympus; Tokyo, Japan), a flexible ultrasound probe with a 20-MHz transducer was introduced (UM-2R/3R with driving unit MH-240 and processor EU-M 20 and 30; Olympus). The balloon on the tip was inflated to achieve coupling with the airways, resulting in a 360° image of the airway wall and adjacent tissue. This is in contrast to EBUS systems without a balloon-tipped catheter, which only afford a limited sectorial view. Orientation as well as interpretation with those is significantly more difficult. The exact location of the target lymph nodes and their relation to the tracheobronchial tree were noted (Fig 1). The probe was then removed from the working channel and TBNA was performed. TBNA TBNA was performed in previously described standard fashion.2,16 Needles used were 22-gauge needles for cytology speci-

Results Two hundred forty-two patients underwent TBNA; 82 patients were women and 160 were men (mean age, 60.0 years; SD, 11.8; range, 33 to 76 years). Target lymph nodes are listed in Table 1. The mean lymph node size was 1.7 cm (SD, 0.47; range, 0.8 to 4.3 cm). The main indications for TBNA were for diagnosis of enlarged lymph nodes with unknown origin and cancer staging, especially exclusion of N3 nodes. In 207 patients (86%), the lymph nodes were accessed successfully by TBNA (specific diagnosis or lymphocytes on the specimen). Biopsy success was not dependant on node location or size (Table 1). In 172 patients, we were able to establish a diagnosis or a definitive staging (Table 2). These corresponded to a diagnostic yield of 71%. All patients without a specific diagnosis underwent a surgical biopsy procedure. No patients with lymphocytes only on TBNA had a more specific diagnosis after surgery. Among the patients with lymphocyte-negative TBNA (n ⫽ 35, 14%), 27 patients proved to have a malignancy, 1 patient had sarcoidosis, and 7 patients had nonspecific findings. The mean time required for EBUS plus TBNA was 5.7 min. There were no complications associated with the use of EBUS and TBNA.

Figure 1. Left: Endobronchial view of an EBUS probe with inflated balloon in the bronchus intermedius (BI). Right: Corresponding EBUS image with a lymph node (LN) and its typical hypoechogenic appearance. www.chestjournal.org

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Table 1—Nodal Stations Accessed by EBUS-Guided TBNA, With Distribution and Size of the Nodes* Localization

No.

Percent of All Nodes

Size, cm†

Positive Results, No.‡

Positive Result, %‡

2r 2l 3 4r 4l 7 10l 10r APW

17 21 22 43 40 48 14 10 27 242

7 9 9 18 17 20 6 4 11 100

1.8 ⫾ 0.2 1.5 ⫾ 0.2 1.9 ⫾ 0.4 1.3 ⫾ 0.4 1.8 ⫾ 0.3 2.1 ⫾ 0.6 1.9 ⫾ 0.3 1.7 ⫾ 0.5 1.5 ⫾ 0.4 1.72 ⫾ 0.5

14 18 19 36 35 42 12 8 23 207

82 86 86 86 88 87 85 80 85 86

*Stations named according to Mountain et al.18 †Mean ⫾ SD. ‡Definitive diagnosis or lymphocyte-positive specimen.

Discussion TBNA is a well-established bronchoscopic technique but remains underutilized and the yield varies widely. This fact may be due to the long learning curve and its associated frustrations. Additionally, conventional TBNA is a fairly blind technique preventing target visualization. This makes accessing smaller lymph nodes and nodes in some locations more difficult. Imaging of the target during the procedure has received increased attention recently, and studies have found the use of CT fluoroscopy during TBNA to be helpful. In a study by Rong and Cui,4 the yield improved from 20% for conventional TBNA to 60% when adding CT guidance. Unfortunately, the use of CT guidance requires planning, expense, and a move to the CT suite in many hospitals. EBUS seems well suited for the task to provide TBNA guidance. It can be performed during routine bronchoscopy and does not require any particular planning or moving. Current technology allows for visualization of airway wall structures and ultrasound penetration of up to 5 cm, easily identifying lymph nodes and vessels,14 while only adding a few minutes to the procedure in experienced hands. Also, con-

Table 2—Diagnosis Obtained in 172 Patients Through EBUS-Guided TBNA Diagnosis

No. (%)

Squamous cell carcinoma Adenocarcinoma Small cell carcinoma Large cell carcinoma Metastasis Lymphoma Sarcoidosis Tuberculosis

53 (31) 48 (28) 42 (24) 6 (3.5) 2 (1) 1 (0.5) 15 (9) 5 (3)

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trary to CT fluoroscopy, there is no radiation exposure for patients and staff. Our study establishes the technique of performing EBUS-guided TBNA and confirmed our assumption that the use of EBUS for TBNA results in a high success rate for accessing lymph nodes (86%) and a high diagnostic yield (71%). It allowed for reliable biopsy of even small nodes and nodes in difficult locations. As a matter of fact, when using EBUS, lymph node location and size did not influence the success of actually “hitting” the intended node. This is in contrast to conventional TBNA, where there is a significant difference in diagnostic success depending on node location. This gives additional creed to the assumption that imaging guidance is beneficial for TBNA. Interestingly, all nondiagnostic negative TBNA results with presence of lymphocytes on the smear were confirmed to be negative for specific diseases on surgical biopsy. A significant number of lymphocyte negative specimens proved to be from a malignancy by surgical biopsy. This reaffirms the statement that negative biopsy results need to be followed with surgery, as needles may miss malignant cell “nests.” As expected, no significant morbidity and no mortality were associated with the use of EBUS in TBNA. One prior study examined the use of EBUS for TBNA guidance and failed to demonstrate any benefit.17 In this particular study, a system without balloon-tipped probes was used to image the parabronchial structures. This approach, which does afford only a limited and inconsistent view, and the baseline high sensitivity of conventional TBNA in the study precluded to show any advantage in the use of EBUS-guided TBNA. Current technology constitutes a significant advance in development. It is important to realize that the described apBronchoscopy

proach does not constitute “real-time” imaging guidance, as the probe has to be removed before TBNA. Nevertheless, the nodes are visualized during the endoscopy, and appropriate anatomic landmarks are chosen during the EBUS exam under vision. Even though our results are excellent, it is conceivable that the introduction of dedicated EBUS scopes (similar to endoscopic ultrasound endoscopes in gastroenterology) for TBNA may increase the yield even further. Also, the impact of the needle type (histology vs cytology needles) was not assessed in this study, and this may have a small influence on the results. The results in this trial are in line with trials employing other means of imaging guidance, such as CT fluoroscopy. The data consistently indicate that imaging guidance seems to be beneficial for performing TBNA. A randomized trial addressing yields and expense may be indicated, as both EBUS and CT fluoroscopy have now been established as viable means of providing imaging support. References 1 Gasparini S, Zuccatosta L, DeNictolis M. Transbronchial needle aspiration of mediastinal lesions. Monaldi Arch Chest Dis 2000; 55:29 –32 2 Metha AC, Kavuru MS, Meeker DP, et al. Transbronchial needle aspiration for histology specimens. Chest 1989; 96: 1268 –1272 3 Wang KP, Brower R, Haponik EF, et al. Flexible transbronchial needle aspiration for staging of bronchogenic carcinoma. Chest 1983; 84:571–576 4 Rong F, Cui B. CT scan directed transbronchial needle aspiration biopsy for mediastinal nodes. Chest 1998; 114: 36 –39 5 Harrow EM, Abi-Saleh W, Blum J, et al. The utility of transbronchial needle aspiration in the staging of broncho-

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