© 2006 American Thoracic Society doi: 10.1164/rccm.200607-925ED
Bronchoscopy for Small Pulmonary Nodules and Mediastinal Staging of Lung CancerJust Do It!University Hospital Basel, Basel, Switzerland Bronchoscopy has evolved from being a traumatic experience (rigid bronchoscopy without sedation) to a well-tolerated procedure with a low incidence of complications (1, 2). The last few years have seen continuous improvement and innovation in bronchoscopy technology. Transbronchial needle aspiration (TBNA) was added in the early 1980s to bronchial washings/lavage, endobronchial biopsy, and transbronchial biopsy and has become an integral part of routine diagnostic bronchoscopy (3). It took time to establish TBNA in the community of pulmonologists. More than 10 years after its introduction, only 11.8% of United States' pulmonologists were using this technique (4, 5). Performing TBNA successfully for peripheral lesions and mediastinal staging requires some experience, but is not limited to super-specialized bronchoscopists, as shown by studies that demonstrated good diagnostic yields achieved by trained fellows (6). Rapid onsite cytology has further improved the diagnostic yield of TBNA, and this technique is now being used internationally (7, 8). Endobronchial ultrasound (EBUS) has developed from a simple observational tool to a helpful method to guide TBNA or transbronchial biopsy (9, 10). Despite such improvements in techniques, bronchoscopy has not been wholeheartedly recommended in the diagnosis of small pulmonary nodules or has been underutilized in the mediastinal staging of lung cancer (4, 11). In the current issue of the Journal (pp. 982–989), Gildea and coworkers present data of a new adjunct to bronchoscopy, electromagnetic navigation (EMN) bronchoscopy, a methodology that permits directing biopsy instruments directly to the mediastinal lymph nodes or peripheral nodules (12). With the broad use of computed tomography (CT) scans, lesions less than 1 cm in diameter are increasingly being encountered as incidental findings and a risk stratification approach might be suitable for their evaluation. The diagnostic yield of bronchoscopy in the assessment of small pulmonary nodules averages about 50%, but increases up to 75% when peripheral lesions more than 3 cm are also included. Combining TBNA with positron emission tomography (PET) scan has a very good negative predictive value, therefore avoiding thoracotomy in a considerable number of patients (13). Furthermore, almost 10% of patients with a small pulmonary nodule up to 3 cm in diameter might have an endobronchial lesion and these are best diagnosed using bronchoscopy (13). Endobronchial ultrasound using a radial probe and sheath to guide biopsy instruments provides a yield of 77% (10). Interestingly, the authors also reported a diagnostic yield of 76% in lesions 1 cm or less (10). The mean size of the peripheral lesions in the study reported by Gildea and colleagues was 22.8 mm and the diagnostic yield 74% (12). EMN does not seem to add too much time to bronchoscopy. Adverse events with the procedure itself, such as pneumothorax, can be expected to be considerably lower than CT-guided transthoracic biopsy. In addition to offering a high diagnostic yield, EMN also allows the evaluation of endobronchial lesions and the sampling of mediastinal lymph nodes, which is almost impossible with CT guidance. The next step necessary to prove a real benefit of this new procedure should be a randomized study comparing the EMN approach with bronchoscopy using a similar steerable probe but with conventional fluoroscopy. In our view, it is clear that bronchoscopic methods have a definitive role in the diagnosis of small pulmonary nodules and the study of Gildea and colleagues further supports and enhances this approach. TBNA is a safe and effective procedure to diagnose mediastinal lymphadenopathy. Combining TBNA results with PET improves the negative predictive value of each procedure alone (14). For subcarinal lymph nodes, the diagnostic yield of conventional TBNA is similar to that of radial probe EBUS-guided TBNA (15). However, for other lymph node stations, there are advantages of EBUS guidance (15). A disadvantage of the classical radial EBUS is that the probe has to be withdrawn to introduce the TBNA needle and hence real-time ultrasound guidance is not possible unless a double-channel bronchoscope is used. The recently introduced convex probe EBUS permits TBNA under real-time ultrasound guidance and has a high diagnostic yield for mediastinal and hilar lymphadenopathy (9). Gildea and colleagues report a yield of 100% in the diagnosis of mediastinal lymphadenopathy using EMN in a small number of patients. How does it compare with real-time EBUS? A recent study revealed a 94% sensitivity of real-time EBUS for mediastinal staging in 500 patients (16). The advantage of EMN over real-time EBUS TBNA is debatable. To prove the advantage, a very large number of patients would need to be randomized as both methods have an excellent diagnostic yield. Also, cost-effectiveness would need to be evaluated. The future will show which method will win the competitive race, including cost-effectiveness and preferences of bronchoscopists. One point is clear: bronchoscopy methods have a definitive role in the diagnosis of mediastinal or hilar lymphadenopathy and the time for mediastinoscopy is running out. What do these innovations mean to practicing pulmonologists? Should they give up performing routine bronchoscopy (transbronchial biopsy, brushings, or TBNA) while evaluating patients with peripheral lesions or mediastinal lymphadenopathy and refer all patients to specialist centers? Our answer is "yes and no." First, in our opinion, every pulmonologist seeing patients with lung cancer should be able to perform conventional TBNA. If not, the patient should be referred to a setting where this technique is available. Second, decision making should be guided by the clinical scenario, availability of instrumentation, skills, and cost-effectiveness. If results of TBNA are inconclusive, these patients may be referred for EBUS or EMN. In the case of peripheral lesions, if only conventional methods are available, brushings, biopsy, bronchoalveolar lavage, and TBNA should be performed. If these are inconclusive, then EBUS, EMN, or CT-guided transthoracic needle aspiration should be considered. Alternatively, negative cytology may also be interpreted in light of a PET result (13, 14). Selected patients might still need mediastinoscopy or video-assisted thoracic surgical biopsy/resection. The bottom line is that bronchoscopy must be performed to diagnose mediastinal lymphadenopathy or small peripheral lesions. Just do it! FOOTNOTES Conflict of Interest Statement: Neither of the authors has a financial relationship with a commercial entity that has an interest in the subject of this manuscript. REFERENCES
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