Prognostic value of FDG PET imaging in malignant pleural mesothelioma

Despite several attempts at treating malignant pleural mesothelioma with va rious modalities, mortality remains high, with median survival between 12 a nd 18 mo. This disease may have a highly variable clinical course, with occ asional long-term survivors. The purpose of this study was to assess whethe r tumor metabolic activity, as assessed by fluorodeoxyglucose (FDG) PET ima ging, correlates inversely with survival. Methods: Twenty-eight patients wi th suspected mesothelioma underwent FDG PET scanning between September 1995 and May 1997. A diagnosis of mesothelioma was confirmed in 22. Fully corre cted scans with attenuation correction of the entire chest were available i n 17 patients with sufficient follow-up for survival analysis. Standardized uptake values (SUVs) were determined from the most active tumor site in ea ch patient. Results: Seven patients died during follow-up, at a median peri od of 5.3 mo after FDG PET scanning. Follow-up information was available on the remaining 10 patients for a median period of 15.6 mo after the PET stu dy. The mean SUV of the deceased patients was 6.6 +/- 2.9, compared with 3. 2 +/- 1.6 among the combined survivors. The deceased patients had tumor SUV s that were highly correlated with duration of survival after the PET study (r = 0.87, P < 0.05). The cumulative survival estimate by the Kaplan-Meier product limit method was 0.17 at 12 mo for the patients with tumor SUVs gr eater than the median value and 0.86 for those with lower SUVs. The surviva l distribution of the high SUV group showed significantly shorter survivals compared with the low SUV group (P < 0.01). Conclusion: Patients with high ly active mesotheliomas on FDG PET imaging have a poor prognosis. High FDG uptake in these tumors indicates shorter patient survival.