Additional benefit of F-18 FDG PET/CT in the staging and follow-up of pediatric rhabdomyosarcoma

Abstract

PURPOSE: The therapeutic management of rhabdomyosarcoma (RMS) is strongly dependent on initial staging. This study aimed to evaluate F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) as an adjunct to conventional imaging (CI) in the staging and follow-up of pediatric RMS. MATERIALS AND METHODS: A total of 13 consecutive children and adolescents (12 males, 1 female; mean age, 9.6 years) with histologically proven RMS (10 alveolar, 3 embryonal), in whom FDG PET/CT was performed at staging and follow-up, were retrospectively included. In total, 35 FDG PET/CT were compared with CI (MRI, CT, and bone scintigraphy) performed with a less than a 15-day interval. Histologic data, follow-up (mean, 27 months), and the final judgment of a multidisciplinary tumor board were considered as the standard of reference for result interpretation. RESULTS: At staging, FDG PET/CT revealed 1 RMS of the prostate missed by CI, and found 19 true-positive lymph node territories in 4 patients and 11 bone metastases in 3 patients, versus 12 and 3, respectively, with CI. Conversely, FDG PET/CT was less sensitive for detecting infracentimetric lung nodules in 1 patient. On the whole analysis, FDG PET/CT modified lymph node staging in 4 of 13 patients, bone involvement in 2 patients, and led to treatment alteration in 2 children. CONCLUSIONS: FDG PET/CT can be useful in staging and restaging pediatric RMS, especially for assessing lymph nodes and bone involvement, and for detecting unknown primary sites of RMS, with potential therapeutic strategy alteration. Copyright © 2011 by Lippincott Williams &Wilkins.