Impact of EUS-guided FNA of enlarged mediastinal lymph nodes on subsequent thoracic surgery rates

BACKGROUND: A histopathologic diagnosis of metastasis in enlarged mediastinal lymph nodes usually results in non-surgical management. Cytologic specimens obtained by EUS-guided FNA can be used to detect malignancy in posterior mediastinal lymph nodes. The purpose of this study was to determine the rate of thoracic surgery after EUS-guided FNA of enlarged mediastinal lymph nodes. METHODS: A prospective observational study of patients with enlarged posterior mediastinal lymphadenopathy who were referred for EUS-guided FNA. All patients were candidates for mediastinoscopy. Patients were followed for 12 months to determine the subsequent rate of mediastinoscopy or thoracotomy and the diagnostic accuracy of EUS-guided FNA. RESULTS: Evaluation of cytologic specimens obtained by EUS-guided FNA revealed malignancy in 23 of 59 (39%) patients. The overall rate of surgery was 22% (13/59): 95% CI[0.12, 0.35]. The surgery rate for patients with a positive cytologic result was 4% (1/23) compared with 33% (12/36) for those with a negative result (p=0.009). Of patients with CT findings of a peripheral lung mass plus mediastinal lymphadenopathy, 22 of 26 (42%) underwent surgery after EUS-guided FNA, compared with two of 33 (6%) of those with mediastinal lymphadenopathy alone (p=0.0009). For cytologic evaluation of specimens obtained by EUS-guided FNA, the overall sensitivity, specificity, and accuracy for the diagnosis of malignant lymphadenopathy were 96%, 100%, and 98%, respectively. CONCLUSIONS: Few patients who undergo EUS-guided FNA of enlarged posterior mediastinal lymph nodes require subsequent thoracic surgery.