Endoscopic ultrasound as a first test for diagnosis and staging of lung cancer - A prospective study

Rationale: Multiple tests are required for the management of lung cancer. Objectives: Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) was evaluated as a single test for the diagnosis and staging (thoracic and extrathoracic) of lung cancer. Methods: Consecutive subjects with computed tomography (CT) findings of a lung mass were enrolled for EUS and results were compared with those from CT and positron emission tomography scans. Results: Of 113 subjects with lung cancer, EUS was performed as a first test (after CT scan) for diagnosis in 93 (82%) of them. EUS-FNA established tissue diagnosis in 70% of cases. EUS-FNA, CT, and positron emission tomography detected metastases to the mediastinal lymph nodes with accuracies of 93, 81, and 83%, respectively. EUS-FNA was significantly better than CT at detecting distant metastases (accuracies of 97 and 89%, respectively; p = 0.02). Metastases to lymph nodes at the celiac axis (CLNs) were observed in 11% of cases. The diagnostic yields of EUS-FNA and CT for detection of metastases to the CLNs were 100 and 50%, respectively (p < 0.05). EUS was able to detect small metastases (less than 1 cm) often missed by CT. Metastasis to the CLNs was a predictor of poor survival of subjects with non-small cell lung cancer, irrespective of the size of the CLNs. Of 44 cases with resectable tumor on CT scan, EUS-FNA avoided thoracotomy in 14% of cases. Conclusions: EUS-FNA as a first test (after CT) has high diagnostic yield and accuracy for detecting lung cancer metastases to the mediastinum and distant sites. Metastasis to the CLNs is associated with poor prognosis. EUS-FNA is able to detect occult metastasis to the CLNs and thus avoids thoracotomy.