Mediastinal Staging of Non-Small-Cell Lung Cancer

Christian Lloyd, MD, and Gerard A. Silvestri, MD, FCCP, Division of Pulmonary and Critical Care Medicine at the Medical University of South Carolina, Charleston.

Cancer Control. 2001;8(4) 

In This Article

Transbronchial Needle Aspiration

Transbronchial needle aspiration (TBNA) was developed in the 1980s by Wang and Terry[35] as a method of sampling extra bronchial lesions through a flexible bronchoscope.TBNA requires the same preparation as bronchoscopy(ie, conscious sedation) and has a low risk of morbidity and mortality. TBNA can be performed at the same time as diagnostic bronchoscopy, thus avoiding a separate staging procedure. During the procedure, a needle is passed through the working channel of the bronchoscope and through the wall of the trachea or bronchus into the underlying lymph node. Needles are currently available for both cytology and histology.Accessible mediastinal nodes with a high diagnostic yield include 4R (paratracheal) and station 7 (subcarinal)lymph nodes. Although more difficult, biopsies using TBNA have been performed on 4L and station 5 (aortopulmonary window) nodes.

In a recent prospective study involving community hospitals and academic medical centers, Harrow et al[36] examined the overall sensitivity and specificity of TBNA in staging known bronchogenic carcinoma. Overall,the sensitivity was found to be more than 57% for lymph nodes greater than 10 mm, and the specificity was 99%. TBNA precluded additional surgery in 29% of patients studied. In this study, right-sided tumors and right paratracheal and subcarinal adenopathy were predictive of a positive TBNA biopsy. Overall, the sensitivity of TBNA for staging NSCLC is between 40% and 80%.[35,37,38,39] The presence of a cytopathologist can help to ensure that an adequate lymph node sampling is obtained. At this time, a factor limiting the widespread use of TBNA is training. TBNA is a relatively new procedure and is the most operator-dependent of the bronchoscopic procedures. With more formal training in this procedure, the yield should increase.

Ongoing studies are examining the role of ultrasound-guided fiberoptic bronchoscopy. Ultrasound guidance is performed by first passing an ultrasound probe down the working channel of the bronchoscope to localize the lymph node. The probe is then withdrawn and transbronchial biopsies are performed in the standard fashion. In a prospective, randomized, controlled trial 40 that examined the role of ultrasound-guided TBNA vs standard TBNA, both techniques had a high sensitivity -- 82% and 90%, respectively. Compared with standard TBNA, endobronchial ultrasound decreased the number of aspirates needed to achieve a diagnosis. However, there was no statistical difference in the diagnosis of malignancy. This may be due to the high sensitivity attained in this study using standard TBNA. Development of real-time endobronchial ultrasound techniques is ongoing. This would allow sampling under direct ultrasound visualization. Currently,ultrasound guidance with TBNA is available at only a few major medical centers.


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