Prognostic value of FDG-PET metabolic parameters and their correlation with histological grade in patients with andiosarcoma

Objectives: Angiosarcoma is a rare, aggressive malignant tumor of vascular origin with high mortality. As there are no single studies investigating prognostic value of fluorine-18 fluorodeoxyglucose (FDG)-positron emission tomography (PET), we assessed whether FDG-PET metabolic parameters correlate with histologic grade and prognosis.

Methods: Patients with histologically proven angiosracoma, who had performed FDG-PET (/CT) at initial diagnosis, were retrospectively analyzed in this study. Tumors were histologically divided into high (well-differentiated) or low (poorly differentiated) grade. The maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV) obtained with a threshold of SUVmax greater than 2.5, and total lesion glycolysis (TLG) were obtained for the primary tumor (p-MTV, p-TLG) and also the total metabolically active lesions (t-MTV, t-TLG). Prognostic value of PET parameters and clinicopathologic factors including age, tumor size, histologic grade, multiple/single lesion were evaluated using Kaplan-Meier survival analysis and also Cox regression analysis. Continuous variables were dichotomized by the median in the Kaplan-Meier analysis.

Results: Fifteen patients were finally analyzed in this study; ten patients were high-grade and five patients were low-grade angiosarcoma. SUVmax was significantly higher in high-grade angiosarcoma than in low-grade angiosarcoma (p=0.0003), whereas no other PET parameters were associated with histologic grade. Kaplan-Meier analysis for overall survival (OS) showed no significant correlation with any variables. Univariate Cox regression analysis revealed that p-MTV, p-TLG, t-MTV and t-TLG were significant predictors for OS (p=0.0008, 0.001, 0.022 and 0.012, respectively) as well as multiple/single lesions (p=0.003). Neither SUVmax nor histologic grade was associated with OS.

Conclusion: The FDG-PET parameters of MTV and TLG can be good predictors for OS in patients with angiosarcoma. The histologic grade was significantly correlated only with SUVmax, while neither of them showed significant correlation with OS. Research Support: none