FDG PET/CT response evaluation in malignant pleural mesothelioma pa-tients treated with talc pleurodesis and chemotherapy

Purpose: Talc pleurodesis (TP) is employed worldwide for the management of persistent pneumothorax or pleural effusion, particularly of malignant origin. However, there are very little available data on ¹⁸F-fluorodeoxyglucose positron-emission tomography/computed tomography (¹⁸F FDG PET/CT) response evaluation in malignant pleural mesothelioma (MPM) patients treated with TP and chemotherapy. Methods: Patients with histologically confirmed MPM underwent TP and FDG PET/CT staging and restaging after 3-4 courses of chemotherapy. All patients fasted and received a dose of 5.18 MBq ¹⁸F-FDG per kilogram of body weight. Whole-body emission scans were acquired with and without Ordered Subset Expectation Maximization (OSEM) iterative reconstruction algorithm. Results: From January 2004 to March 2010, 8 patients with biopsy confirmed MPM (7 epithelial, 1 biphasic), with a median age of 65 years (range: 54-77), were evaluated. Median follow-up was 31 months (range: 4-44). After TP treatment, there was a mean interval of 14 days (range: 9-22) and 125 days (range: 76-162) between FDG PET/CT staging and restaging. According to modified RECIST and EORTC criteria, there was a concordance between the radiologic and metabolic SUVmean and SUVmax responses in 6 (75%) and 3 (37.5%) patients, respectively. Conclusion: TP produces an increased FDG PET uptake which may interfere with the post-chemotherapy disease evaluation. In our case series, the metabolic response measured by SUVmean seems to be in better agreement with the radiologic response compared to the SUVmax.