Background: The presence and the number of lymph node metastasis have been identified as significant prognostic factor in patients with esophageal adenocarcinoma. Therefore, assessment of lymph node status is important to separate patients with advanced lymph node disease who may benefit from neoadjuvant therapy from those with limited lymph node disease who can be cured by surgical resection alone. Endoscopic ultrasound (EUS) is a reliable staging tool to determine tumor depth and identify abnormal lymph nodes. The aim of this study was to assess the accuracy of EUS in determining the number of lymph nodes involved.
Methods: We reviewed the records of all patients who underwent esophagectomy with a systematic thoracic and abdominal lymphadenectomy at our institution between 1991 and 2007 as primary therapy for esophageal adenocarcinoma. EUS was performed by the operating surgeon and limited disease was defined by involvement of ≤ 4 lymph nodes and advanced disease by involvement of 5 or more lymph nodes. The results of EUS were compared with pathological findings of the esophagectomy specimen.
Results: A total of 139 patients were included. In 103 patients (74%), EUS correctly identified limited versus advanced lymph node involvement. The positive predictive value for identifying limited node disease was 79%. EUS was more accurate in assessing lymph node involvement in patients with T1 and T2 tumors than in T3/T4 disease (98%, 79%, and 56%, p<0.0001). In patient with T1/T2 tumors, EUS had a positive predictive value of 100%. There were 23 patients (17%) with advanced lymph node disease and the predictive value for EUS was only 48%. Patients with advanced node disease on EUS had a significantly worse disease free survival compared to patients with limited node disease (p=0.0035).
Conclusions: Endoscopic ultrasound can accurately identify patients with limited node disease with a positive predictive value of nearly 80%. This allows identification of patients unlikely to benefit from neoadjuvant therapy. Advanced node disease on EUS is associated with less survival.