© 2007 American Thoracic Society doi: 10.1164/rccm.200704-518ED
Boys (and Girls) and Their ToysA Look at New Technologies in the Bronchoscopy SuiteMedical University of South Carolina, Charleston, South Carolina In one survey of pulmonary trainees and practicing pulmonologists, nearly 80% of respondents reported that interest in procedures and interventions led them to pursue a career in pulmonary and critical care medicine (1). If that is the case, it is an interesting time to be a pulmonologist. An ability to miniaturize equipment, technologic breakthroughs in optics, the ability to draw technology from other fields, coupled with thoughtful physician inventors, and an industry that recognizes an enormous business opportunity have created an influx of new technologies for the bronchoscopy suite. But the confluence of these factors has created the setting for the "perfect storm" in the field of interventional pulmonology. Over the past several years, we have been inundated with tantalizing new technologies. Devices that are in various stages of development, testing, FDA approval, and clinical practice include endobronchial valves, plugs and glue for the treatment of emphysema, bronchial thermoplasty for the treatment of asthma, and systems such as optical coherence tomography, endobronchial ultrasound with fine needle aspiration of mediastinal lymph nodes (EBUS-TBNA), and electromagnetic navigation bronchoscopy (ENB) (2–9). In this issue of the Journal (pp. 36–41), Eberhardt and colleagues share the results of a prospective, multicenter, randomized trial of two of these newer technologies, EBUS and ENB, either alone or in combination for the diagnosis of peripheral nodules (10). The design of the study deserves comment and compliment. Rarely do we see a prospective, multicenter trial in the field of interventional pulmonology. Rarer still are subjects randomized to different treatment strategies. The end result is that clinicians are left with the impossible task of choosing between technologies that have not been compared directly and are forced to base their decisions on poorly done, often retrospective, case series that leave questions regarding the validity and generalizability of the findings. This study randomized 120 patients with peripheral nodules to either EBUS-guided biopsy alone, ENB-guided biopsy alone, or the combination of the two. They found that using the technologies in combination resulted in the highest diagnostic yield (88%) as opposed to either alone. What about these two technologies? EBUS has exploded onto the scene over the past several years. We should have seen its expansion coming. Blind transbronchial needle aspirate (TBNA) was the first bronchoscopic method used for the diagnosis of mediastinal lymphadenopathy, although the results have been somewhat disappointing. One meta-analysis reported a pooled sensitivity of approximately 40% (11). Reports of the use of endoscopic ultrasound with fine needle aspiration (EUS-FNA) for the diagnosis and staging of lung cancer have been in the literature for more than 10 years with sensitivity and specificity approaching that of mediastinoscopy (12–14). EBUS- TBNA has been available for nearly 2 years and its use is likely to change our approach to lung cancer diagnosis and staging. The technology, modified from the gastrointestinal ultrasound endoscope, allows for real-time needle biopsy under direct visualization of most lymph node stations in the mediastinum and hilum. The results have been stunning, with sensitivity approaching 95%, even in patients with lung masses and a radiographically normal mediastinum (15). In addition, both diagnosis and staging can often be accomplished simultaneously. Used less frequently, a radial EBUS probe can be inserted through a bronchoscope and then directed out toward the lesion to achieve ultrasonic visualization of the nodule. Then, with or without fluoroscopy, the patient can have a biopsy or brush performed. A yield of 50 to 80% can be expected (69% in this study). ENB can be thought of as the GPS of your bronchoscope rather than your car. This remarkable technology will likely have applications that are much broader than just bronchoscopy. The system utilizes the patient's computed tomography scan, computer software, an electromagnetic navigation board, and a locatable sensor probe. It allows for real-time navigation of an extended working channel through the tracheobronchial tree to targets in the periphery of the lung. Biopsy forceps or brush is then introduced through the extended working channel to the lesion. Early reports have been promising, with yields in the 70% range (59% in this study) (8, 9, 16). In the future, the yield may increase with the development of a "smart needle," which has a microsensor within the needle hub allowing for real-time specimen retrieval when the navigation system places the probe within striking distance of the lesion (Atul Mehta, personal communication). With all of these technologies, we often lose sight of the context for their use. In the clinical scenario described in the article, we are evaluating patients with solitary pulmonary nodules. In those who are surgical candidates and in whom the pretest probability of cancer is high, a biopsy is often not necessary. This is so because a positive biopsy for cancer will lead to surgery and a negative biopsy carries too high of a false-negative rate, leading to surgery. When the result of a diagnostic test does not alter how we proceed, the test should not be done. There are three main reasons to pursue a tissue diagnosis in patients with a solitary pulmonary nodule. The first is patient preference (i.e., the patient wishes to confirm a diagnosis of cancer before proceeding to resection). The second is that the physician has a specific benign diagnosis in mind. The third is when the patient is medically inoperable but tissue confirmation of cancer is required before proceeding with treatment (e.g., radiotherapy with curative intent). It is this last indication that fits very well with this new technology. These patients, often with severe comorbidities, including emphysema, are at high risk of pneumothorax from transthoracic needle aspirate and the risk profile can be lowered by using an EBUS/ENB-guided biopsy. A recent study by Makris and colleagues performed ENB in just such a high-risk population and obtained a diagnosis in 63% of patients with minimal side effects (16). Why may this be the perfect storm? Despite the excitement generated by this new technology, there are troubling questions. The authors rightly point out that each piece of equipment alone is expensive, with disposables that will significantly drive up the cost per case. Reimbursement has not been well established. There are training issues, because fellows may not receive training in some basic and most advanced bronchoscopic techniques (17). Can we expect the high diagnostic yields reported here when the procedures are performed outside the expert centers? Should patients be referred to high-volume centers? How will hospitals, bronchoscopy labs, and physicians decide which technology to purchase? Will industry drive the agenda? Who will fund the needed research to evaluate new technology? Still, there is something beautiful about watching a powerful storm blow through. The better technology will weather the storm and be incorporated into clinical practice and the lesser will be washed away. FOOTNOTES Conflict of Interest Statement: G.A.S. received a grant from Olympus from September 12, 2005, to September 2, 2006, of $11,600 to evaluate narrow band imaging to detect early malignancy of the airways. REFERENCES
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