Added predictive value of 18F-FDG PET/CT for pediatric rhabdomyosarcoma.

ABSTRACT

OBJECTIVE: To determine the prognostic value of quantitative fluorine-18-fluorodeoxyglucose (F-FDG) standardized uptake value (SUV) in patients with pediatric rhabdomyosarcoma (RMS). PATIENTS AND METHODS: Consecutive 98 (50 males and 48 females) (age range 4 months to 17.5 years, mean age 5.8 ± 4.5) patients with pathologically proven RMS who underwent PET/computed tomography for initial staging were retrospectively assessed for whether primary SUVmax and the primary/liver SUVmax ratio could predict event-free survival (EFS) and overall survival (OS) for 36 months using receiver operating characteristic curve analysis. Univariate and multivariate analyses were used to determine the reliability of these metabolic parameters and various clinical factors. RESULTS: Higher SUVmax was significantly related to the presence of regional or distant metastasis with worse prognosis. With receiver operating characteristic curve marked cut-off values of 3.6 and 2.1 for primary SUVmax and the primary/liver SUVmax ratio, respectively, both EFS and OS proved to be higher in patients with SUVmax ranked below the determinate values. Patients with a primary/liver SUVmax ratio below the cut-off value of 2.1 had OS (60.8%) and EFS (48.1%) compared with 44.5 and 14.8% for patients with lesions exceeding the cut-off point of uptake; however, this failed to achieve statistical significance. In the evaluation of primary SUVmax, similar results were obtained with P values of 0.76 and 0.62, respectively. High SUVmax was more prevalent among patients with less favorable clinical and pathological features including unfavorable primary site, alveolar pathology, and high-risk group. CONCLUSION: F-FDG PET/computed tomography may be considered an additional prognostic predictor of outcome in RMS patients, where higher F-FDG uptake seems to be linked to lower survival and correlated to different unfavorable parameters.