Optimization of mediastinal staging in potential candidates for stereotactic radiosurgery of the chest

Patients with medically inoperable nonsmall-cell lung cancer generally have limited staging of the mediastinum using computed tomography and combined positron emission tomography and computed tomography, before stereotactic radiosurgery. Historical data have demonstrated the superiority of tissue sampling techniques such as endobronchial ultrasonography and mediastinoscopy compared with imaging studies in accurately determining the nodal stage. We believe, that at a minimum, mediastinal interrogation with endobronchial ultrasonography should be performed before patients undergo stereotactic radiosurgery.

A retrospective review of 59 consecutive patients undergoing bronchoscopic fiducial marker placement as potential candidates for stereotactic radiosurgery was done. All these patients had undergone endobronchial ultrasonography to assess the mediastinum. Transbronchial needle aspirates were taken using standard criteria defined by a lymph node size greater than 5 mm in diameter and/or in the appropriate lymph node drainage pathway. The biopsies were reviewed by the institution's pathologists.

Mediastinal lymph node specimens were not taken in 9 patients because they did not meet our criteria. Of the 50 patients who underwent mediastinal lymph node sampling, 10 had evidence of nodal involvement. On review, 2 of these 10 patients had evidence of mediastinal adenopathy on computed tomography. After excluding those 2 patients, the mediastinal lymph nodes were positive for metastatic disease in 8 (16%) of 50 patients without previous radiographic evidence of disease. These patients were previously thought to be suitable candidates for stereotactic radiosurgery. Also 5 of 10 patients with endobronchial ultrasound-positive lymph nodes had had positron emission tomography-negative findings in the mediastinum. Finally, 10% of the patients suspected to have stage II or III were downstaged with endobronchial ultrasonography and considered for stereotactic radiosurgery.

Endobronchial ultrasonography-transbronchial needle aspirates is more accurate than computed tomography and positron emission tomography in staging the mediastinum, can be performed with minimal morbidity, and should be considered for all patients considered candidates for stereotactic radiosurgery.