Endobronchial ultrasound for lung cancer staging: how many stations should be sampled?

No guidelines exist regarding the number of mediastinal lymph node stations that should be sampled to ensure adequate preoperative staging of lung cancer patients. In recent reports of esophageal endoscopic ultrasound and endobronchial ultrasound (EBUS), fewer than two stations/patient were sampled. An experience with systematic sampling using EBUS to determine how many stations should be sampled to adequately detect mediastinal disease was evaluated.

Records were reviewed for all patients with lung cancer who had EBUS between March 9, 2006, and January 6, 2009. For each station sampled the sequence and result (positive, negative, and nondiagnostic) were recorded. For those with a positive biopsy, the sequence number of the first positive station was determined. The affect of systematic sampling on detection of N3 disease was also evaluated.

Ninety-three patients with non-small cell lung cancer had EBUS; 271 mediastinal stations were sampled (range, 0 to 6; mean, 2.9 per patient), with N3 and N2 stations sampled in 51 and 90 patients, respectively. Mediastinal disease was found in 25 patients; 15 patients had multistation N2 disease and 6 patients had N3 disease. In 15 patients (60%), mediastinal disease was detected in the first station sampled; three samples were required to detect 90% of disease, and the remaining 3 patients had their disease detected with the fourth sample.

Introduction of EBUS as a tool for non-small cell lung cancer staging has led to a shift from systematic nodal sampling to targeted nodal sampling. These results indicate that systematic nodal sampling is feasible with EBUS, and that routinely sampling more than two mediastinal stations may improve staging.