ESTRO 2024 - Abstract Book

S935

Clinical - CNS

ESTRO 2024

univariate and multivariate analysis [p=0,0010]. Molecular profile, interval time until BM diagnosis, systemic therapy after SRS were observed as conditioning outcome.

Conclusion:

To our knowledge this is the largest series of BM-BC treated with SRS. Satisfactory local control has been obtained conditioning survival. A careful assessment of prognostic factors and multidisciplinary evaluation are mandatory for the optimal therapeutic approach.

Keywords: Brain Metastases SRS

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Digital Poster

Local reirradiation of pediatric CNS tumors with proximity to brainstem using proton beam therapy

Carola Lütgendorf-Caucig, Birgit Flechl, Piero Fossati, Mansure Shafasand, Petra Mozes, Markus Stock, Eugen Hug

MedAustron, Radiation therapy, Wiener Neustadt, Austria

Purpose/Objective:

Reirradiation (reRT) for locoregional recurrences of CNS tumors in pediatric patients with proximity to the brainstem poses unique challenges and risks due to dose limiting normal tissues. Proton beam therapy (PBT) is well suited for this purpose due to its physical advantages of normal tissue sparing.

Material/Methods:

Eleven patients treated between 10/2018 and 11/2021 had been diagnosed with infield or marginal recurrence following a full course of radiotherapy with proximity to brain stem (see table). A full, second course of PBT with curative intent was applied definitively or after resection.

Results:

Median time between first radiation and ReRT was 1.8 years (1.1-13.4 years). Median PBT dose was 54.0GyRBE (44.0-54.0 GyRBE), median dose per fraction 1.8 GyRBE (1.8-2.2 GyRBE). The planning rational of permitting in summation up to 85 GyRBE to the brainstem surface, resulted in a median maximum cumulative dose (D1%) to brainstem of 78.4 GyRBE (71.1-95.5 GyRBE).