Preoperative 18F-fluorodeoxyglucose PET/computed tomography maximum standardized uptake value is independently associated with overall survival in surgically resected undifferentiated pleomorphic sarcoma

BACKGROUND: Undifferentiated pleomorphic sarcoma (UPS) is the most common adult soft tissue sarcoma subtype, with heterogeneous survival despite optimal surgery. We evaluated whether the preoperative maximum standardized uptake value (SUVmax) on 18F-fluorodeoxyglucose PET/computed tomography (18F-FDG PET/CT) is independently associated with overall survival (OS) in surgically resected UPS. METHODS: This retrospective cohort study included 79 patients with localized UPS who underwent curative resection between 2015 and 2023. Preoperative SUVmax, tumor grade (French Federation of Cancer Centers Sarcoma Group), tumor size, and Ki-67 index were assessed. Cox proportional hazards regression was used to identify independent prognostic factors for OS. RESULTS: The median age was 59 (range: 18-92) years; 53.2% of patients were male, and 59.5% of tumors were high grade. The median tumor size, Ki-67 index, and SUVmax were 60 mm, 60%, and 10, respectively. At a median follow-up of 58.9 months, median OS was not reached. In univariable analysis, tumor size (P = 0.007), Ki-67 (P = 0.001), SUVmax [hazard ratio: 1.08 per unit, 95% confidence interval (CI): 1.04-1.10, P = 0.001], and high grade (P = 0.003) were associated with worse OS. In multivariable analysis, only SUVmax remained independently associated with OS (adjusted hazard ratio: 1.06 per unit, 95% CI: 1.02-1.10, P = 0.002), whereas grade, size, and Ki-67 did not retain significance. CONCLUSION: Preoperative 18F-FDG PET/CT SUVmax is independently associated with OS in surgically resected UPS and provides prognostic information beyond conventional clinicopathological parameters.