FDG-PET in Esophageal Cancer. Incremental Value over Computed Tomography

OBJECTIVES: To evaluate the clinical utility of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) in patients with cancer (CA) of the esophagus, and its incremental value over computed tomography (CT) scan.METHODS: Positron emission tomography (PET) scan and CT scan reports of all patients with biopsy-proven CA esophagus from December 1995 to August 1998 were reviewed. PET images were acquired on a high-resolution dedicated PET scanner 45 minutes to 1 hour after intravenous injection of 370 MBq of fluorine-18-fluorodeoxyglucose (F-18-FDG). Emission images of the neck, chest, and abdomen were obtained, followed by transmission scans at selected sites.RESULTS: One hundred fifty-one scans were performed on 109 patients. The clinical indications were staging (67), follow-up evaluation after chemoradiation (66), and evaluation of possible recurrence after surgery (18). A final diagnosis was reached in 99 patients at 276 sites by histology (91.3%) or clinical follow-up of over 6 months (8.7%). FDG-PET scan showed a sensitivity of 80%, specificity of 95%, and accuracy of 86% compared with 68%, 81%, and 73% for CT. Of the 32 false negatives, 23 were perigastric or paraesophageal lymph nodes close to the primary, and 5 were peritoneal or pleural spread. PET detected 99% of the primary lesion (66 out of 67) with a mean standardized uptake value (SUV) of 11 (3.6 to 46). There was no apparent difference in 18F-fluorodeoxyglucose (FDG) uptake between squamous cell CA (N = 15, mean SUV 10.5), adenoCA (N = 48, mean SUV 11.2), and other cell types (N = 3, mean SUV 10.3). The one case where PET missed the primary lesion turned out to have a lesion measuring 0.4 cm in its maximum diameter. In 20 patients out of the 99 with confirmed diagnosis (20%), PET detected 24 confirmed lesions not seen on CT, and in 14 patients (14%) management was changed as a result of the PET finding.CONCLUSION: FDG-PET scan is more accurate than CT (86% vs. 73%; P = 0.0002) in the evaluation of patients with CA esophagus. It provides additional information over CT, impacting on management in 14% of patients.