Maximum Standardized Uptake Value On F-18-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Improves Outcome Prediction In Retroperitoneal Liposarcoma

While F-18-fluorodeoxyglucose positron emission tomography/computed tomography (F-18-FDG PET/CT) has been investigated in extremity sarcomas, there is no evidence on its usefulness in retroperitoneal sarcoma. This study was designed to evaluate the usefulness of F-18-FDG PET/CT in predicting aggressiveness of retroperitoneal liposarcoma. Patients experienced surgery for retroperitoneal liposarcoma from November 2007 to February 2018 and underwent preoperative F-18-FDG PET/CT were included. Preoperative maximum standardized uptake value (SUVmax) was calculated. To evaluate the predictability of SUVmax for Federation Nationale des Centres de Lutte Contre le Cancer (FNCLCC) grade 3, receiver operating characteristics (ROC) curve analysis was performed. To analyze whether SUVmax can be a risk factor for prognosis, multivariable Cox regression was performed including potential risk factors regarding operation and histopathology. A total of 133 patients were included. ROC curve showed area under the curve of 0.877 (P < 0.001), with a cut-off point of 4.5 SUVmax showing 85.7% sensitivity and 78.3% specificity. Cox analyses showed that SUVmax > 4.5 was a significant factor for recurrence-free survival (HR = 2.148, CI 1.301-3.546, P = 0.003) and overall survival (HR = 5.052, CI 1.854-13.766, P = 0.002). SUVmax is highly predictive of FNCLCC grade 3 and SUVmax > 4.5 can be used as a prognostic factor before obtaining the histopathology.