Positron emission tomography defines metastatic disease but not locoregional disease in patients with malignant pleural mesothelioma

Background: Computed tomography and magnetic resonance imaging often fail to predict resectability in patients with malignant pleural mesothelioma. Small studies suggest that fluorodeoxyglucose-positron emission tomography may improve staging. We analyzed our experience to determine more definitively the potential utility of fluorodeoxyglucose-positron emission tomography. Methods: Patients with malignant pleural mesothelioma who underwent fluorodeoxyglucose-positron emission tomography scanning were identified from an institutional database. All patients fasted and received a minimum of 10 mCi of F-18-fluorodeoxyglucose. Whole-body emission studies were acquired, followed by whole-body transmission studies, allowing iterative reconstruction. Blinded review of positron emission tomography scans was performed for clinical staging, which was then correlated with surgical and pathologic findings. Sensitivity and specificity were determined for tumor and nodal status. Results: From 1998 to 2002, 63 patients underwent positron emission tomography scans, 60 preoperatively and 3 to assess disease recurrence after surgery. Increased fluorodeoxyglucose uptake was seen in all but 1 tumor, which was very early stage (IA). Positron emission tomography findings yielded sensitivities of only 19% and 11% for tumor and nodal status, respectively. However, a high standard uptake value in the primary tumor correlated with the presence of N2 disease. Positron emission tomography correctly identified supraclavicular N3 or M1 disease in 6 patients. Conclusions: Positron emission tomography does not identify the local extent of tumor or mediastinal nodal metastases reliably but detects extrathoracic metastases, thereby obviating inappropriate thoracotomy. Further studies of the association between tumor standard uptake value and the presence of N2 disease are warranted.