Evaluation of the role of FDG-PET imaging in malignant pleural mesothelioma (MPM)

Abstract

17113 Background: MPM is a rapidly progressive malignancy with a median survival of 6 to 9 months. Studies in non-small cell lung cancer, gastrointestinal stromal tumours, and breast cancer suggest that Positron Emission Tomography (PET) scanning may predict the clinical outcome of chemotherapy at an early stage of treatment. The role of PET in predicting and monitoring response to treatment in MPM is unclear. In this study we assessed if baseline and early interval PET scanning could be of benefit in MPM, correlating the results with standard Computerised Tomography (CT) assessment using the modified Response Evaluation Criteria In Solid Tumours (RECIST) of Byrne and Nowak. Methods: 10 patients with histologically proven MPM proceeded to baseline PET and CT scanning prior to chemotherapy. In 8 patients a second PET scan was performed within three weeks of commencing treatment. The following PET derived parameters were calculated: Standard Uptake Value (SUV)maximum, SUVaverage, PETvolume, and Total Lesion Glycolysis (TLG). Baseline SUVmaximum and early PET response was compared with CT response and survival. Results: Baseline SUVmaximum predicted subsequent CT response in the 10 patients studied. Four out of 5 patients with baseline SUVmaximum of <15 showed a subsequent partial response on CT, whilst the 5th patient had resolution of a pleural effusion. All 5 patients with baseline SUVmaximum of >15 had stable or progressive disease on CT. In contrast change in early SUVmaximum from baseline to 3 weeks did not predict subsequent CT response (Kappa value 0.07) in the 8 patients evaluated. Change in PET volume and TLG correlated with subsequent CT response (Kappa value= 0.80 for both). Only 1 patient with a partial response on % PETvolume and %TLG has died 14 months after commencing treatment. The other 3 patients are alive at 17+, 19+ and 20+ months. The 4 patients with stable or progressive disease using these parameters were deceased at 5, 6, 10, and 12 months respectively. Conclusion: PET may be useful in predicting and evaluating response to treatment in MPM. Furthermore, the results suggest that PET response may be a useful prognostic tool in this disease. It is important to use the appropriate PET derived parameters. Further study with a larger patient population is warranted. No significant financial relationships to disclose.