The Role of Combined Positron Emission Tomography/Computed Tomography (PET/CT) and Endoscopic Ultrasound (EUS) in the Staging of Esophageal Cancer

Abstract

Background: Accurate staging of esophageal cancer (ECA) is critical in determining appropriate therapy. EUS, CT, and PET scanning are used in various combinations for this purpose. PET scanning combined with a simultaneous non-contrast CT scan can facilitate more accurate localization/detection of lesions (PET/CT scan). No data exists regarding the utility of PET/CT compared to EUS in the staging of ECA. Aim: To compare PET/CT and EUS in the staging of ECA. Methods: Patients with ECA diagnosed from 5/04-8/06 undergoing both PET/CT and EUS were reviewed. Data regarding TNM staging and presence of celiac axis (CAX) lymph nodes based on these exams and surgical pathology were collected. Data on age, gender, histology, and treatment rendered was examined. Results: 42 patients identified. Mean age 64 years. 33 (78.6%) male, 9 (22.4%) female. 30 (71.4%) adenocarcinoma, 12 (28.6%) squamous cell. PET/CT identified the primary tumor in 37/42 (88.1%) of cases, compared to 42/42 (100%) with EUS. PET/CT provided no T-staging. T-staging by EUS was T1 (5/42, 12%), T2 (4/42, 9.5%), and T3 (33/42, 78.6%). Malignant appearing locoregional adenopathy was seen by PET/CT in 15/42 (35.7%) of cases, compared to 25/42 (59.5%) by EUS (p = 0.0039). No locoregional nodes seen by PET/CT were missed by EUS. PET/CT identified CAX adenopathy in 6/42 (14.3%) of cases, compared to 5/42 (11.9%) with EUS. The one CAX node missed by EUS was due to inability to pass the scope past the tumor. 8/42 (19%) of cases had distant metastases identified by PET/CT (4 distant nodes, 3 liver, 1 lung). 27 patients underwent surgery, 13 with neo-adjuvant therapy; 11 received chemo ± XRT as primary therapy; 4 received palliation. EUS directly affected therapy in 13/42 (31%) of cases by directing the need for neo-adjuvant therapy based on T3 or N1 stage. 8/42 (19%) were not taken to surgery based on PET/CT findings of distant metastatic disease. 13 patients undergoing surgery as primary therapy without chemo/XRT were examined with regard to accuracy of T and N staging using surgical pathology as the gold standard. T-staging by EUS was accurate in 11/13 (84.6%) of cases (two T2 lesions by EUS proved to be T3 at surgery). There was a trend toward more accurate N-staging by EUS (10/13, 76.9% of cases) compared to PET/CT (8/13, 61.5%), though this was not statistically significant (p = 0.15). Conclusions: 1) EUS is superior to PET/CT for T-staging and in identifying locoregional malignant adenopathy in ECA while PET/CT provides M staging. 2) EUS and PET/CT appear to independently affect treatment decisions, indicating complimentary roles in the staging of esophageal cancer.