Role of Positron Emission Tomography (PET) in a Multimodality Staging Protocol with Endoscopic Ultrasound (EUS) and Computed Tomography (CT) for Esophageal Cancer

Abstract

Background: EUS plus CT is the established diagnostic regimen for staging of primary tumor (T stage), nodal involvement (N stage), and metastases in esophageal cancer (ECA). Little to no data exists on the value and effect of PET scanning when used in conjunction with EUS and CT for staging ECA. Aim: To determine the clinical value and efficacy of a multimodality ECA staging regimen when PET imaging is added to EUS and CT. Methods: Patients with ECA from 3/01-8/03 were retrospectively reviewed. Data regarding TNM staging and presence of celiac axis (CAX) nodes based upon abdominal/chest CT, EUS and PET was collected. Data on age, gender, histology, and therapy provided was examined. Results: 29 patients were identified. 23 (79.3%) adenocarcinoma, 6 (20.7%) squamous cell. 27 (93.1%) male, 2 (6.9%) female. Mean age 63.1 years. CT scan identified the primary tumor in 26/29 (89.7%) of patients, PET 27/29 ( 93.1%), EGD/EUS in 29/29 (100%). CT and PET provided no T staging. T staging by EUS was T1(2/29, 6.9%); T2 (4/29, 13.8%), and T3 (23/29, 79.3%). Locoregional lymphadenopathy was seen on CT in 4/29 (13.8%) patients, 13/29 (44.8%) of patient by PET, and in 22/29 (75.9%) of patients on EUS. Two nodes seen on PET and not EUS were associated with inability to pass the scope past a malignant stricture. CAX nodes were seen on 5/29 (17.2%) of patients on EUS. All CAX nodes were verified on PET but only one on CT. Metastases were seen by CT in 4/29 (13.8%) patients (2 liver, 1 bone, 1 adrenal) compared to 11/29 (37.9%) with PET (6 patients with metastatic nodes, 3 bone, 2 liver). 15 patients underwent surgery, 13 with neoadjuvant therapy; 12 underwent chemo and/or XRT; 2 had esophageal stenting as the primary therapy. EUS directly effected therapy in 14/29 (48.3%) of patients by directing need for neoadjuvant therapy based on T3 or N1 stage. 6 patients (20.7%) were not taken to surgery based on PET scan displaying metastases not identified on other imaging modalities. Conclusions: 1) EUS is superior to PET and CT in identifying locoregional malignant adenopathy in ECA. 2) PET can identify distant metastases in a significant minority of patients not known to have metastatic disease by CT 3) EUS and PET both appear to effect treatment decisions suggesting that EUS and PET have complimentary and necessary roles in the staging of esophageal malignancy.