18F-FDG PET/CT as an Indicator of Progression-Free and Overall Survival in Osteosarcoma

The aim of our study was to retrospectively evaluate whether maximum standardized uptake value (SUVmax), total lesion gylcolysis (TLG), or change therein using 18F-FDG PET/CT performed before and after initial chemotherapy were indicators of patient outcome. Methods: Thirty-one consecutive patients who underwent 18F-FDG PET/CT before and after chemotherapy, followed by tumor resection, were retrospectively reviewed. Univariate Cox regression was used to analyze for relationships between covariates of interest (SUVmax before and after chemotherapy, change in SUVmax, TLG before and after chemotherapy, change in TLG, and tumor necrosis) and progression-free and overall survival. Logistic regression was used to evaluate tumor necrosis. Results: High SUVmax before and after chemotherapy (P = 0.008 and P = 0.009, respectively) was associated with worse progression-free survival. The cut point for SUVmax before chemotherapy was greater than 15 g/mL* (P = 0.015), and after chemotherapy it was greater than 5 g/mL* (P = 0.006), as measured at our institution and using lean body mass. Increase in TLG after chemotherapy was associated with worse progression-free survival (P = 0.016). High SUVmax after chemotherapy was associated with poor overall survival (P = 0.035). The cut point was above the median of 3.3 g/mL* (P = 0.043). High TLG before chemotherapy was associated with poor overall survival (P = 0.021). Good overall and progression-free survival was associated with a tumor necrosis greater than 90% (P = 0.018 and 0.08, respectively). A tumor necrosis greater than 90% was most strongly associated with a decrease in SUVmax (P = 0.015). Conclusion: 18F-FDG PET/CT can be used as a prognostic indicator for progression-free survival, overall survival, and tumor necrosis in osteosarcoma.