Background: Endoscopic ultrasound (EUS)-guided fine needle aspiration is a safe, cost-effective procedure that can confirm the presence of mediastinal lymph node metastases and mediastinal tumor invasion. We studied the accuracy of EUS in a large population of lung cancer patients with and without enlarged mediastinal lymph nodes on computed tomographic (CT) scan.
Methods: From 1996 to 2000 all patients referred to our institution with lung tumors and no proven distant metastases were considered for EUS and surgical staging. Patients had endoscopic ultrasound with fine needle aspiration of abnormal appearing mediastinal lymph nodes and evaluation for mediastinal invasion of tumor (stage III or IV disease). Patients without confirmed stage III or IV disease had surgical staging.
Results: Two hundred seventy-seven patients met the inclusion criteria, including 121 who had EUS. Endoscopic ultrasound and fine needle aspiration detected stage III or IV disease in 85 of 121 (70%). Among patients with enlarged lymph nodes on CT, 75 of 97 (77%) had stage III or IV disease detected by EUS. Among a small cohort of patients without enlarged mediastinal lymph nodes on CT, 10 of 24 (42%) had stage III or IV disease detected by EUS. For mediastinal lymph nodes only, the sensitivity of endoscopic ultrasound and CT was 87%. The specificity of EUS (100%) was superior to that of CT (32%) (p < 0.001).
Conclusions: Endoscopic ultrasound with fine needle aspiration identified and histologically confirmed mediastinal disease in more than two thirds of patients with carcinoma of the lung who have abnormal mediastinal CT scans. Although mediastinal disease was more likely in patients with an abnormal mediastinal CT, EUS also detected mediastinal disease in more than one third of patients with a normal mediastinal CT and deserves further study. Endoscopic ultrasound should be considered a first line method of presurgical evaluation of patients with tumors of the lung.