The prognostic value of baseline EARL standardized FDG PET indices in pediatric and adolescent high-grade osteosarcoma.

OBJECTIVE

To investigate the prognostic value of baseline European Association of Nuclear Medicine Research Ltd. (EARL) standardized [F]fluorodeoxyglucose positron emission tomography-computed tomography ([F]FDG PET-CT) quantitative values for survival and to evaluate cutoff values identified in other studies.

MATERIALS AND METHODS

Pediatric and adolescent patients with high-grade osteosarcoma were included. Baseline [F]FDG PET-CT, with EARL-accredited reconstructions, was the standard diagnostic staging procedure. Cox proportional hazard analysis for event-free survival (EFS) and overall survival (OS) was performed with clinical prognostic factors. Kaplan-Meier analysis and log-rank tests were applied to investigate the prognostic performance of the [F]FDG PET indices.

RESULTS

In total, 66 patients were included in this study. In the univariable Cox regression analysis, peak lean-body mass corrected SUV (SUL) (hazard ratio (HR): 1.04), total lesion glycolysis (TLG) (HR: 1.0), and metabolic tumor volume (MTV) (HR: 1.0) were not associated with EFS or OS. Log-rank analysis showed a significant difference in EFS for all SUL and SUL cutoffs. For MTV the maximum Youden, and for TLG the maximum Youden and maximally selected rank cutoff resulted in a significant EFS difference. No cutoff for any measure showed a significant difference in OS between the groups. ROC curves for event status had an AUC of 0.67, 0.66, 0.64, and 0.64 for SUL, SUL, MTV and TLG, respectively.

CONCLUSION

In this study, the baseline EARL-standardized [F]FDG PET indices of children and adolescents with osteosarcoma were not prognostic of EFS or OS. The proposed prognostic cutoffs from earlier studies suffer from important technical and statistical issues.

KEY POINTS

Question Prognostic value of baseline [F]FDG PET-CT imaging markers have been reported for histologic response and survival in high-grade osteosarcoma but have not been validated for clinical practice. Findings Baseline SUV, TLG, and MTV measured on EARL-accredited reconstructions were not prognostic factors for survival in pediatric and adolescent patients with high-grade osteosarcoma. Clinical relevance A wide range of values for SUV and SUV cutoffs with similar prognostic value were identified, questioning the value of a single proposed cutoff. Lack of validation, with important technical and statistical issues of proposed prognostic cutoffs, limits clinical implementation.