Use of F-18 fluoro deoxyglucose (FDG) positron emission tomography (PET) in the assessment of malignant mesothelioma

Full text: Australia has the highest mesothelioma incidence rate in the world and the incidence of Mesothelioma is increasing. Therapy for Mesothelioma involves surgery (including phototherapy), radiotherapy and chemotherapy. Computed tomography (CT) is frequently used to stage the extent of Mesothelioma. This study aimed to evaluate the utility of FDG PET in staging Mesothelioma and monitoring response to therapy. Nineteen F-18 FDG PET was performed at the A and RMC Centre for PET in 14 patients (13M: 1F, age range 39-77 years, mean age 58 years) with biopsy proven malignant pleural Mesothelioma. Patients were referred for staging (5 patients) or evaluation of patients post surgery or phototherapy (9 patients). 3 patients had more than 1 PET scan. FDG scans were reviewed with full access to the CT report. Standardised Uptake Values (SUV) were performed in all scans in regions of maximal FDG uptake corresponding to CT abnormality. Normal lung SUVs were also calculated. Follow-up was possible in all patients to the time of death or December 2001 (Follow-up 4 - 45 months, mean 16 months; 3 patients still alive). All FDG PET scans were positive for FDG-avid pleural tissue. No surgery was deferred due to FDG PET findings. In 3 patients mediastinal nodes were identified pre-surgery. Post surgical therapy assessment by FDG PET (9 patients) guided therapy by confirming disease progression or further characterising post-operative changes when CT findings were uncertain. FDG PET was able to more accurately distinguish between collapse/consolidation and recurrent disease than CT scan. Almost all post-surgical scans were performed in patients who received phototherapy. Different Mesothelioma histological subtypes could not be differentiated by SUV criteria. False positive FDG PET studies were seen in 3 patients, all of whom had post-surgical empyemas. In conclusion, FDG PET has a potential role in the management of malignant mesothelioma patients, particularly in the post-therapy assessment. Copyright (2002) The Australian and New Zealand Society of Nuclear Medicine Inc