Comparison between whole-body positron emission tomography and bone scintigraphy in evaluating bony metastases of esophageal carcinomas

Background: Positron emission tomography (PET) with 18-F-fluorodeaxyglucose (FDG) has already proved useful in assessing the extension of esophageal carcinomas, detecting tumor recurrence and monitoring responses to therapy. This study aimed to elucidate the potential role of FDG-PET compared with technetium-99m methylene diphosphonate (Tc-99m MDP) bone scintigraphy in the evaluation of bony metastasis in esophageal carcinoma patients. Patients and Methods: Forty-four patients with thoracic esophageal carcinomas, who underwent FDG-PET together with bone scintigraphy within I month between January 2000 and September 2003, were included in this study. Results: Of the 44 patients, 13 had 31 bone metastases and, of these, 6 were diagnosed pretreatment and 7 had recurrence after esophagectomy surgery. Of the 31 metastases, 9 were in the vertebral column, 11 in the thoracic cage (including the ribs, clavicle. sternum and scapula), 9 in the pelvic bones and 2 in the long bones of the extremities. In evaluating the detection of bony metastasis, FDG-PET showed 92% sensitivity, 94% specificity and 93% accuracy, compared with 77%, 84% and 82%, respectively, for bone scintigraphy. Although the sensitivity, specificity and accuracy of PET were slightly higher than those of bone scintigraphy, these differences were not statistically significant according to the McNemar's test. Three patients with false-negative findings on their bone scans had positive findings with PET; all of these lesions were osteolytic metastases. Conclusion: FDG-PET scans were superior to bone scintigraphy in detecting bony metastases of esophageal carcinomas. Therefore, FDG-PET can be used for the detection and follow-up of bone tumors when Tc-99m MDP bone scintigraphy gives negative findings.