Endobronchial Ultrasonography in the Diagnosis of Sarcoidosis
Sarcoidosis is a benign, inflammatory condition which will typically involve the lungs and
mediastinal lymph nodes. The diagnosis of sarcoidosis is usually confirmed with tissue
biopsy, especially if patients in whom treatment with corticosteroids is required.
Asymptomatic patients not requiring treatment may not require biopsy, although this is
commonly performed because of patient's preference in confirming the diagnosis and concerns
about other diagnostic possibilities such as lymphoma.
Given the predilection of this disease to the chest, the lung and mediastinal lymph nodes
are the most common sites for biopsy. Bronchoscopic samples are often obtained initially
given their good sensitivity for this disease and low complication rates. If the diagnosis
of sarcoidosis is not confirmed by bronchoscopy, more invasive surgical procedures such as
mediastinoscopy or open lung biopsy may be required. As such, any improvement in the
minimally invasive methods for diagnosis of this condition would be of benefit these
patients and may also lead to cost efficiencies for the health care system.
Transbronchial needle aspiration (TBNA) with a 19 gauge "histology" needle has been the
standard bronchoscopic approach to the biopsy of mediastinal lymph nodes in patients with
suspected sarcoidosis. Using anatomical landmarks and computed tomography (CT) images, the
TBNA needle is advanced "blindly" through the airway wall, and into the mediastinal lymph
node. Because of the lack of real-time visual guidance, it is possible to miss the targeted
lymph node as well as enter vascular structures with the needle system and cause bleeding.
A new method of performing TBNA has now been developed which uses real-time endobronchial
ultrasonography to advance a 22 gauge needle into mediastinal lymph nodes under direct
visualization (EBUS-TBNA). While this technique has been proven to be effective in the
diagnosis and staging of lung malignancy, its sensitivity for the diagnosis of sarcoidosis
is unclear given that larger biopsy samples are often required to make this diagnosis.
This study will aim to randomize patients with a clinical suspicion of sarcoidosis and
mediastinal adenopathy undergoing bronchoscopy to TBNA vs. EBUS-TBNA in order to compare the
sensitivity of these tests for sarcoidosis.
Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Single Blind, Primary Purpose: Diagnostic
Alain Tremblay, MDCM
University of Calgary
Canada: Health Canada