%0 Generic %A Tensaouti, Fatima %A Ducassou, Anne %A Chaltiel, Léonor %A Bolle, Stéphanie %A Habrand, Jean Louis %A Alapetite, Claire %A Coche-Dequeant, Bernard %A Bernier, Valérie %A Claude, Line %A Carrie, Christian %A Padovani, Laetitia %A Muracciole, Xavier %A Supiot, Stéphane %A Huchet, Aymeri %A Leseur, Julie %A Kerr, Christine %A Hangard, Grégorie %A Lisbona, Albert %A Goudjil, Farid %A Ferrand, Régis %A Laprie, Anne %D 2019 %T Table_3_Feasibility of Dose Escalation in Patients With Intracranial Pediatric Ependymoma.DOCX %U https://frontiersin.figshare.com/articles/dataset/Table_3_Feasibility_of_Dose_Escalation_in_Patients_With_Intracranial_Pediatric_Ependymoma_DOCX/8306933 %R 10.3389/fonc.2019.00531.s004 %2 https://frontiersin.figshare.com/ndownloader/files/15564605 %K photon therapy %K proton therapy %K boost %K treatment planning %K ependymoma %K intracranial %X

Background and purpose: Pediatric ependymoma carries a dismal prognosis, mainly owing to local relapse within RT fields. The current prospective European approach is to increase the radiation dose with a sequential hypofractionated stereotactic boost. In this study, we assessed the possibility of using a simultaneous integrated boost (SIB), comparing VMAT vs. IMPT dose delivery.

Material and methods: The cohort included 101 patients. The dose to planning target volume (PTV59.4) was 59.4/1.8 Gy, and the dose to SIB volume (PTV67.6) was 67.6/2.05 Gy. Gross tumor volume (GTV) was defined as the tumor bed plus residual tumor, clinical target volume (CTV59.4) was GTV + 5 mm, and PTV59.4 was CTV59.4 + 3 mm. PTV67.6 was GTV+ 3 mm. After treatment plan optimization, quality indices and doses to target volume and organs at risk (OARs) were extracted and compared with the standard radiation doses that were actually delivered (median = 59.4 Gy [50.4 59.4]).

Results: In most cases, the proton treatment resulted in higher quality indices (p < 0.001). Compared with the doses that were initially delivered, mean, and maximum doses to some OARs were no higher with SIB VMAT, and significantly lower with protons (p < 0.001). In the case of posterior fossa tumor, there was a lower dose to the brainstem with protons, in terms of V59 Gy, mean, and near-maximum (D2%) doses.

Conclusion: Dose escalation with intensity-modulated proton or photon SIB is feasible in some patients. This approach could be considered for children with unresectable residue or post-operative FLAIR abnormalities, particularly if they have supratentorial tumors. It should not be considered for infratentorial tumors encasing the brainstem or extending to the medulla.

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