An Assessment of the Adequacy of Endobronchial Ultrasound to Assess Mediastinal Lymph Nodes Accompanying Extrathoracic Malignancies

Objective: Correct sampling with a targeted diagnosis of pathological mediastinal lymph nodes (LNs) accompanying extra-thoracic malignancies (ETMs) is necessary to grade tumors and evaluate the treatment response. However, debate continues about the adequacy of endobronchial ultrasound (EBUS) assessment. This study was designed to determine the efficiency and reliability of EBUS in the diagnosis of mediastinal LNs in patients with ETMs.
Materials and Methods: A retrospective analysis was conducted of patients with suspicious mediastinal LNs accompanying ETM observed at diagnosis or in follow-up who underwent EBUS. The data assessed were age, gender, ETM, LN diameter observed in both computed tomography (CT) and EBUS, LN metabolic activity recorded with positron emission tomography (PET)-CT, the histopathological diagnosis of LNs sampled using EBUS, and the actual LN diagnosis based on mediastino-scopic LN sampling or radiological stability.
Results: Samples were taken from a total of 78 LN stations from 50 patients with a mean age of 61.28±10.92 years. Of 22 LNs with actual malignancy, 16 were identified with EBUS. The mean LN diameter determined with CT and EBUS, and the mean PET-CT maximum standard uptake (SUVmax) value was 17.36±7.90 mm, 22.90±9.87 mm, and 8.17±5.44, respec-tively. The malignant LN diameter measured using both CT and EBUS was significantly higher than that of benign LNs (re-spectively p=0.001, p=0.026). There was no significant difference between the SUVmax values of malignant and benign LNs.
Conclusion: As some of the LNs found to be reactive with EBUS were malignant, we recommend confirming the diagnosis with mediastinoscopy sampling or radiological follow-up.