ESTRO 2024 - Abstract Book

S870

Clinical - CNS

ESTRO 2024

Total 139 patients with biopsy proven high grade glioma were retrospectively evaluated between January 2019- December 2022. There were 95 patients in the post-RT adjuvant TMZ group (PORT followed by TMZ) (n==95) and 39patients in the pre-RT adjuvant TMZ group (TMZ followed by PORT) (n=39). Both groups received PORT of 60 Gy with concurrent TMZ at 75mg/m², and adjuvant TMZ of at least 6 cycles every 28 days, starting at 150mg/m² for the first cycle and increasing to 200mg/m² in subsequent cycles. Following a median follow-up of 21.4 months, neither median OS nor median PFS were reached in either group or the entire cohort. The median PFS of the post-RT TMZ group was 32.9 months (95% CI 23.2-42.6 months). No significant difference in OS (p=0.727) or PFS (p=0.679) was noted between the two groups. No significant differences in haematological toxicity grades were observed between the two groups.

Conclusion:

Adjuvant TMZ prior to PORT did not alter clinical outcomes in terms of toxicity or survival outcome. This alternative sequence may be considered for mitigating the delays and effectively bridging of time gap. However further randomised clinical trials are needed to further optimise the timing and sequencing of adjuvant Temozolomide.

Keywords: glioblastoma, adjuvant temozolomide, adjuvant RT

1913

Digital Poster

Influence of [68Ga]-DOTATATE-PET/CT on Target Volume Definition in Low-Grade Skull Base Meningiomas

Frederik Fuchs 1 , Jan Hofmaier 2 , Sebastian Norbert Marschner 1,3 , Maya Rottler 1 , Raphael Bodensohn 1,4 , Claus Belka 1,5,3 , Maximilian Niyazi 1,4 , Franziska Walter 1 1 LMU University Hospital, Department of Radiation Oncology, Munich, Germany. 2 Faculty of Physics, Ludwig Maximilians-Universität München, Department of Medical Physics, Munich, Germany. 3 German Cancer Consortium (DKTK), partner site Munich, a partnership between DKFZ and LMU University Hospital Munich, Radiation Oncology, Munich, Germany. 4 University Hospital Tübingen, Department of Radiation Oncology, Tübingen, Germany. 5 Bavarian Cancer Research Center (BZKF), Radiation Oncology, Munich, Germany

Purpose/Objective:

The use of [68Ga]-DOTATATE-PET/CT for imaging of high- and low-grade meningiomas is well-established. The standard imaging modality for radiation therapy planning of meningiomas is MRI. Particularly in the context of meningeal extensions (the so-called 'Dural Tails') and bone infiltration, functional imaging can meaningfully complement the morphological information provided by MRI. With this study we are investigating the added value of [68Ga]-DOTATATE-PET/CT for radiation therapy planning in low-grade skull base meningiomas.

Material/Methods: