In 161 patients with known extrathoracic malignancy and enlarged hilar/mediastinal lymph nodes, endobronchial ultrasound FNA was very helpful at identifying metastasis to the chest.
EBUS found lymph node mets in 44% of the patients and a new lung cancer in 12%. Sarcoidosis was discovered in 9%. Neal et al followed-up these 161 patients for 6 months to allow an alternative diagnosis (i.e., undiscovered metastasis) to manifest if the EBUS initially was negative.
Ultimately, 110 patients were found to have thoracic metastasis, and EBUS-FNA was 87% sensitive at detecting it. However, negative predictive value was only 73%, so more invasive testing would often be necessary after negative EBUS cytology.
Neal N et al. Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration for the Diagnosis of Intrathoracic Lymphadenopathy in Patients with Extrathoracic Malignancy: A Multicenter Study. J Thorac Oncol 2011; 6:1505-1509.
This study should be sharply delineated from this one, which asked essentially the same question in people with asymptomatic, incidentally discovered chest lymphadenopathy (without known extrathoracic malignancy). It showed equally striking results -- that EBUS did not identify any previously undetected cancer.