48.02 Evaluation of the accuracy of endoscopic ultrasound for nodal staging in esophageal cancer

V. Bianco¹, K. S. Mehta¹, M. Sablowsky¹, W. E. Gooding¹, J. D. Luketich¹, A. Pennathur^{1  1}University Of Pittsburgh Medical Center,Department Of Cardiothoracic Surgery,Pittsburgh, PA, USA

Introduction:
The accurate staging of esophageal cancer is important for both prognostic and therapeutic decisions, as well as evaluation of results of treatment.  Of particular importance is the presence of nodal metastases which has a major impact on prognosis and therapeutic approach. Endoscopic ultrasound (EUS) is an important and increasingly used clinical staging modality for the pretreatment evaluation of nodal status in esophageal cancer.   Recently the new AJCC 7^TH edition staging system, which incorporates the number of positive nodes in the nodal (N) staging has been adopted.  While the accuracy of EUS nodal staging has been well studied with the previous AJCC staging version, there are limited studies evaluating the accuracy of EUS in N staging using the recently revised esophageal cancer staging (AJCC 7th edition).  The objective of this study was to analyze the accuracy of EUS, in nodal staging of esophageal cancer using the most recent staging system (AJCC 7th edition).

Methods:
We reviewed the records of 172 patients who had undergone esophagectomy without neoadjuvant treatment and collected data which included both clinical and pathological staging.  The preoperative N stage was acquired from EUS and the pathological stage was assigned based on the esophagectomy specimen.  Staging data was recorded for each patient based on the specific criteria for the 7^th edition.  The accuracy of identifying EUS in nodal disease was evaluated.

Results:
A total of 172 patients (mean age 67, 137 male, 35 female) underwent esophagectomy for esophageal cancer.  The median number of nodes resected was 20 per patient. For the AJCC 7^th edition only 80 of 172 (46%) patients had the N stage correctly classified with EUS (Table).  We identified 92 of 172 (54%) patients who were misclassified (31% under staged, 23% over staged) for AJCC 7. 

Conclusion:
Our results indicate a substantial reduction in the EUS staging accuracy of nodal disease for the AJCC 7^th edition.  These  findings suggest that further advancement is necessary for accurate clinical staging of nodal disease preoperatively.  Potential solutions may include refinement of EUS technology with routine use of EUS-FNA, evaluation of other staging modalities such as laparoscopic staging, and the use of  molecular staging with validated biomarkers.