Utilizing [¹⁸F]-FDG PET/CT Imaging for Enhanced Staging and Treatment Decisions in Pediatric Rhabdomyosarcoma

Accurate staging is vital for optimizing outcomes in pediatric rhabdomyosarcoma (RMS). While [¹⁸F]-FDG PET/CT is increasingly utilized, its specific impact on clinical management and its prognostic value compared to conventional imaging (CI) require further evaluation.

In this retrospective single-center study, we reviewed 56 pediatric patients with RMS who underwent [¹⁸F]-FDG PET/CT at our center. Imaging findings were compared with CI (CT/MRI) and correlated with clinical management and survival outcomes.

In the total cohort (n = 56), PET/CT demonstrated high concordance with CI for nodal assessment, with an apparent sensitivity of 89.5% and specificity of 94.6%. PET/CT identified skeletal metastases in 5 patients (8.9%) and correctly characterized suspicious pulmonary nodules in one case, though it failed to detect a 0.6 cm lung nodule visualized on chest CT. Notably, PET/CT findings directly altered clinical management in 16.1% of patients (n = 9), primarily through radiotherapy adjustments, including field expansions (n = 4), field reductions (n = 3), and the initiation of previously unplanned radiotherapy (n = 2). At a median follow-up of 33.3 months, an exploratory analysis showed that patients with an SUVmax ≥3.6 had a lower 3-year EFS (57.6% vs. 71.6%; p = 0.51) and OS (60.4% vs. 71.6%; p = 0.63); neither comparison reached statistical significance.

[¹⁸F]-FDG PET/CT is a powerful adjunct in pediatric RMS staging, particularly for nodal and skeletal evaluation. Its ability to refine radiotherapy planning in nearly one-sixth of cases underscores its clinical utility. SUVmax is not a validated prognostic or predictive biomarker in pediatric RMS; prospective, adequately powered multicenter studies, ideally incorporating volumetric PET parameters, are needed before any role in risk-stratified therapy can be defined.