Sobic Saranovic, Dragana P. (57202567582)Dragana P. (57202567582)Sobic SaranovicNikitovic, Marina (6602665617)Marina (6602665617)NikitovicSaponjski, Jelena (57207943674)Jelena (57207943674)SaponjskiGrozdic Milojevic, Isidora (37107616900)Isidora (37107616900)Grozdic MilojevicParipovic, Lejla (55342754900)Lejla (55342754900)ParipovicSaranovic, Djordjije (57190117313)Djordjije (57190117313)SaranovicBeatovic, Slobodanka (6507312377)Slobodanka (6507312377)BeatovicArtiko, Vera M. (55887737000)Vera M. (55887737000)Artiko2025-06-122025-06-122020https://doi.org/10.1016/j.ejrad.2020.109076https://www.scopus.com/inward/record.uri?eid=2-s2.0-85084817378&doi=10.1016%2fj.ejrad.2020.109076&partnerID=40&md5=cdfa6d1fb5f6613bf513db1c0b5322c6https://remedy.med.bg.ac.rs/handle/123456789/4784Purpose: To determine if post-treatment F-18 FDG PET/CT results (overall positive findings, specific localizations) are independent predictors of disease progression in young patients with Ewing sarcoma and Primitive neuroectodermal tumor. Method: A consecutive sample of 48 patients (age 14 ± 5 years, 32 male) was referred to F-18 FDG PET/CT for the suspected progression of Ewing sarcoma (39 patients) and Primitive neuroectodermal tumor (PNET) (9 patients) and followed-up clinically for 4.3 ± 2.3 years after F-18 FDG PET/CT (range 1–8 years). The diagnostic value of F-18 FDG PET/CT was determined in comparison to the biopsy. Kaplan-Meier analysis was used to compare progression-free survival between the groups with positive and negative F-18 FDG PET/CT findings. Variables included in the Cox regression for predicting the progression-free survival were sex, age, F-18 FDG PET/CT findings, MDCT findings, and MR ratio. Results: F-18 FDG PET/CT findings were positive in 32 (67 %) patients (sensitivity 93.7 %, specificity 87.5 %, accuracy 91.7 %) with an average SUVmax of 5.8 ± 3.2 (95 % CI 4.8–7.1). The progression-free survival was significantly lower (p = 0.001) in patients with positive F-18 FDG PET/CT findings (median 28 months) and when recurrence was located in bones, soft tissues, and muscles (p = 0.02, median 21 months). The significant predictors of the disease progression were the overall positive F-18 FDG PET/CT findings (HR 8.36, p = 0.004) and, specifically, the local recurrence in the bone with infiltration of soft tissue/muscles (HR 4.08, p = 0.003). Conclusion: Post-treatment F-18 FDG PET/CT findings are useful for predicting the progression of Ewing sarcoma and PNET and should be included in the clinical monitoring of these patients. © 2020 Elsevier B.V.Ewing sarcoma and PNETF-18 FDG PET/CTFollow-upMetastatic diseaseProgression-free survivalRecurrence