Abstract 742P
Background
To improve clinical outcomes in osteosarcoma, the intervention for the patients with worse prognosis was needed. The objective of this study is to find a new biomarker using semiquantitative fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) to identify the patients with a worse prognosis of pediatric and young adult osteosarcomas.
Methods
Overall, 54 patients with conventional osteosarcoma aged 39 years or younger were included. All patients underwent 18F-FDG PET/CT at both pre (PET1) and after neoadjuvant chemotherapy (PET2). Semiquantitative 18F-FDG PET/CT maximum standardized uptake value (SUVmax) and its changes (⊿PET=PET2/PET1) were also examined. Patients were classified into four groups by histological tumor necrosis rate (TNR) according to the Huvos grades: G0 (50%<), G1 (50-90%<), G2 (90%-99%), and G3 (100%). G0 and G1 patients were enrolled in the standard responder (SR) group (n=35), and G2 and G3 patients were in the good responder (GR) group (n=19). The rate of change in SUVmax and overall survival (OS), and progression free survival (PFS) among each group were examined. In the SR group, the median value of ⊿SUVmax was calculated and correlated with prognostic stratification.
Results
PFS in the GR group was better compared to the SR group (p=0.03). However, in the SR group, there were no differences in OS and PFS between G0 and G1. Patients in the SR group were stratified into two groups by median value of ⊿SUVmax (0.62). Patients with ⊿SUVmax <0.62 had significantly better OS (P<0.01) and PFS (P=0.02) compared to the patients with ⊿SUVmax≥0.62. In the multivariate analyses, ⊿SUVmax was one of the prognostic factors correlated with OS in SR group.
Conclusions
This study reveals that ⊿SUVmax may confirm the preoperative stratification of the prognosis in the SR group patients and can be a predictive biomarker for them. Moreover, to identify the patients with worse prognosis in the SR group preoperatively has a significant impact to improve the clinical outcomes in osteosarcoma.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.