Esophageal Ultrasound (eus) for Mediastinal Tumor Invasion (T4) in Nsclc

Introduction: Lung tumor invasion in the mediastinum/vascular (T4) is often difficult to assess due to the limited accuracy of CT. In addition to nodal staging, EUS can assess mediastinal invasion of lung tumors that are situated adjacent to the esophagus. The value of EUS for T4 assessment is unknown. Objective: To assess the value of EUS for mediastinal invasion (T4) in NSCLC and relate this to CT and surgical-pathological staging. Methods: Patients who underwent EUS(-B) for the diagnosis and staging of lung cancer in whom the primary tumor was detected by EUS and additionally underwent a thoracotomy were retrospectively selected from two university hospitals (1999 -2016). T status was reviewed based on EUS, CT and thoracotomy findings. Surgical pathological staging was the reference standard. Results: In 425 patients, the lung tumor was detected by EUS. 74 patients underwent subsequent thoracotomy. Final staging showed that 20 (27%) patients were staged T4 based on vascular (n=9, 45%), mediastinal (n=8, 40%) invasion or both (n=2 ,10%); 1 patient (5%) had vertebral involvement. 11 patients were judged to have stage T4 by EUS, of which 8 were confirmed at surgery. The 3 false positive cases concerned suspected vascular invasion [pulmonary vein (n=1), pulmonary artery (n=2)]. The sensitivity, specificity, PPV were for EUS (n=74): 40%, 94%, 72%, for computed tomography (n=67): 76%, 64%, 42% and for EUS+CT combined (both positive or negative for T4, n=38) 71%, 100%, 100%. Conclusion: EUS(-B) has a high specificity and PPV for mediastinal T4 assessment of para esophageally located lung tumors and provides important added value to chest CT scan.