ESTRO 2024 - Abstract Book

S812

Clinical - CNS

ESTRO 2024

Twenty-six different dose and fractionation regimes were used globally; the two most common prescriptions were 3000cGy over 10 fractions (45%) and 2000cGy over 5 fractions (43.5%) with a median OS of 2.8 and 3.0 months respectively. In North America, 3.6% of scripts were for 2500cGy over 10 fractions, and 2.8% of Asia’s scripts were for 1000cGy in 5 fractions. Variations in treatment techniques for palliative WBRT exist amongst the contributing centres. Ranging from 2 field parallel pair techniques planned using virtual simulation to VMAT with simultaneous integrated boosts and 3D conformal radiotherapy field in field techniques. Radiographer led planning and approval of plans only occurred in the UK centres with physicians taking responsibility of approving plans elsewhere. Neurocognitive sparing was uncommonly used worldwide, with 74.8% of patients receiving neither memantine nor hippocampal avoidance (HA). Memantine was used in 93 patients (20.1%) and HA was used in 44 (9.5%). Memantine alone was prescribed for 15.6% of patients and HA alone was used for 5.0% of patients. Memantine and HA were used in combination for 4.5% of patients globally. North America accounted for 75% of the worlds HA use despite contributing only 29.9% of the cohort. There was a trend towards a higher OS amongst those who received HA (4.0 months vs 2.6 months, P=0.052). Prior brain SRS was delivered in 32 (6.7%) patients. WBRT accounted for 1-3% of global radiotherapy prescriptions written in 2022. There are some limitations associated with this review. For example, only one African and one Asian country were represented which may greatly generalise these large and diverse continents. Despite regional differences amongst healthcare structures, dose regimens, treatment techniques and neurocognitive sparing techniques this international analysis demonstrates dwindling indications for WBRT. WBRT should be reserved for those with limited estimated survival. Radiation oncologists must carefully consider the risks and benefits and whether any radiotherapy should be chosen over best supportive care as any radiation treatment within the last month of life is unlikely to provide meaningful palliation and may result in side effects which may have a larger impact on quality of life as patients approach the end of life. Conclusion:

Keywords: palliative brain radiotherapy

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Timing of stereotactic radiosurgery within systemic treatment in NSCLC brain metastases

Raphael Bodensohn 1,2,3 , Anna Kolorz 1 , Jonas Reis 4 , Simone Werner 1 , Robert Forbrig 4 , Sylvia Garny 1 , Julian Taugner 2 , Chiara de Colle 2 , Claus Belka 1,5,6 , Farkhad Manapov 1 , Louisa von Baumgarte 7 , Maximilian Niyazi 2,1,8 1 LMU University Hospital, LMU Munich, Department of Radiation Oncology, Munich, Germany. 2 University Hospital Tübingen, Department of Radiation Oncology, Tübingen, Germany. 3 University Hospital Tübingen, Center for Neuro Oncology, Comprehensive Cancer Center Tübingen-Stuttgart, Tübingen, Germany. 4 LMU University Hospital, LMU