ESTRO 2024 - Abstract Book

S2038

Clinical - Paediatric

ESTRO 2024

Hypofractionated SBRT in locally relapsed ependymoma: a national prospective study (NCT02013297)

Line CLAUDE 1 , Magali MORELLE 2 , Luc OLLIVIER 3 , Valentine MARTIN 4 , Julie LESEUR 5 , Aymeri HUCHET 6 , Alexandre ESCANDE 7 , Sophie CHAPET 8 , Loig DUVERGE 5 , Emmanuel JOUGLAR 3,9 , Stéphane SUPIOT 3 , Stéphanie BOLLE 4 , Anne LAPRIE 10 , Ellen BLANC 11 , Anne DUCASSOU 10 1 Centre Léon Bérard, Radiation Oncology, Lyon, France. 2 Centre Léon Bérard, Clinical research and innovation départment, Lyon, France. 3 Institut de Cancérologie de l’Ouest, Radiation Oncology, Nantes, France. 4 Institut Gustave Roussy, Radiation Oncology, Villejuif, France. 5 Centre Eugène Marquis, Radiation Oncology, Rennes, France. 6 Centre Hospitalier Universitaire, Radiation Oncology, Bordeaux, France. 7 Oscar Lambret comprehensive cancer center, University department of radiation oncology, Lille, France. 8 Centre Hospitalier Universitaire, Radiation Oncology, Tours, France. 9 Institut Curie, Radiation Oncology, Paris, France. 10 Institut Claudius Regaud, IUCT-Oncopôle, Radiation Oncology, Toulouse, France. 11 Centre Léon Bérard, Department of clinical research and innovation,, Lyon, France

Purpose/Objective:

Efficacy and toxicity of hypofractionated Stereotactic Body Radiation Therapy (hSBRT) in pediatric patients with locally relapsed ependymomas need to be assessed. We conducted a prospective multicentric National trial (NCT02013297) on hSBRT in young patients (1.5-20 y.) A specific focus was dedicated to children treated for locally relapsed intracranial ependymoma. Results are presented below.

Material/Methods:

Inclusion criteria included children with exclusive local relapse (tumor relapse volume < 30 cc), within or in border of previous radiation fields (54-59,4 Gy). Complete surgery was performed before hSBRT if possible. All the patients were included after discussion in multidisciplinary staff and after inform consent signature. The time between the first-line radiotherapy and the hSBRT re-irradiation had to be at least 1 year. No concomitant chemotherapy was allowed. If the treatment planning feasibility was confirmed regarding the cumulative dose constraints, a dose randomization for hSBRT was performed between 24 Gy/3 fractions or 25 Gy/5 fractions (isodose 80%). Otherwise patients received 25 Gy/5 fractions outside the randomization. The main objective was to evaluate the 6-months local control (LC) rate (RECIST 1.1). Secondary objectives were to evaluate 1 and 2-year LC rates, progression-free-survival (PFS), overall Survival (OS), acute (< 3 months) and medium-term toxicities (3-24 months) using NCI-CTC-v-4.0. A longer follow-up was performed to present long term results of the strategy.

Results:

Twenty-one patients were prospectively included in 10 institutions (12/2013-12/2019). Fourteen patients (7 patients/arm) were randomized. Due to the impossibility of considering a treatment using 3 fractions (cumulative dose constraints not beeing respected), 7 additional patients were included without randomization and received 5 fractions (total dose 25 Gy on 80% isodose).