S362
Clinical - CNS
ESTRO 2026
Material/Methods: A single-institution review of medical records, imaging, and RT plans between 2008-2025 was conducted to identify patients with WHO Grade 4 GBM initially treated with surgery and adjuvant CFRT prescribed as 60Gy in 30fx. Patients with imaging or pathology- confirmed rGBM who received a second course of RT were included. OS was defined from the end date of the second RT course; POF were determined as local, regional, or distant recurrence on imaging. Group differences were identified with Kaplan-Meier
https://doi.org/10.1016/j.ijrobp.2025.08.031. Keywords: Recurrent GBM, hypofractionatedRT, conventionalRT
Digital Poster 1724 Stereotactic Radiosurgery for Skull-base Paragangliomas: Clinical & Biochemical Outcomes from a Tertiary UK centre Soirindhri Banerjee 1 , Mary Lei 1 , Kazumi Chia 1 , Omar Al- Salihi 1 , Rupert Obholzer 2 , Delali Adjogatse 1 , Sheila Hassan 1 , Fahmida Khan 1 , Lucy Brazil 1 , Angela Swampillai 1 , Vishal Manik 1 1 Clinical Oncology, Guy's and St. Thomas' NHS Foundation Trust, London, United Kingdom. 2 ENT/Skull Base Surgery, Guy's and St. Thomas' NHS Foundation Trust, London, United Kingdom Purpose/Objective: Skull-base Paragangliomas (SBPGL) although rare, are difficult to treat due to their location. British Skull-Base Society recommends radiotherapy as a safe and effective modality for long-term tumour control of SBPGL1 and Stereotactic Radiosurgery (SRS) has shown promising outcomes2. We report our experience with SRS in SBPGLs treated at our tertiary centre over the last 7 years. Material/Methods: We retrospectively interrogated our institutional database and included consecutive patients with a SBPGL treated with SRS who had completed ≥ 6 months of post treatment follow up between January 2018 to December 2024. We collected patient, tumour & treatment factors, clinical signs & subjective patient symptoms and post treatment adverse events. Data was analysed using SPSS v31 using Pearson correlation, univariate & multivariate analysis. Results: We identified 33 eligible patients with SBPGL treated with SRS with a median follow up of 35 months (6-93). Majority were females (61%, n=20) with median age of 58 years (22 - 83) and median time from diagnosis of 3 years. Tumour location was jugular (39.4%), vagal (27.3% ), jugulo-tympanic (27.3%) and other (6%). Twelve patients (36.4%) had prior surgical intervention. Raised catecholamines were present in 21.2% (n=7) and 42.4% (n=14) had succinate dehydrogenase (SDH) enzyme subunit mutation. Indications for treatment were symptomatic disease 78.8% (n=26) or serial growth 21.2% (n=7) with lower cranial nerve (IX-XII) involvement present in 84.6% (n=22) of symptomatic patients. Median gross tumour volume (GTV) was 7.6 cc (0.5-26.2 cc). Commonest dose fractionation was 25 Gy in 5 fractions (91%, n=30). Post SRS adverse events were noted in 51.5% (n=17) and were predominantly G1 fatigue, headache
analyses. Results: A total of 28 rGBM patients received HFRT
(3.5Gyx10,N=20) or CFRT (1.8Gyx24-25,N=8). The HFRT and CFRT group had a median age of 51 (range,27-70) and 54yrs (range,48-63), respectively, at initial diagnosis. Methylated MGMT promoters were identified in 8 and 5 patients in the HFRT (untested in 6/20) and CFRT groups, respectively. At the start of their second course of RT, the HFRT group had a median KPS of 90 compared to 80 for the CFRT group. Median OS for all 28 patients was 8 months (82days, 762days). The median OS for the HFRT group was 7 months, compared to 16 months for the CFRT group (p=0.22). 10/20 HFRT and 5/8 CFRT patients received TMZ during reirradiation. Common CTCAE toxicities included grade 1 alopecia, fatigue, pain, headache, and dermatitis with significantly more frequent fatigue in the CFRT group, (100% vs 35%,p=0.002). No grade 3 or higher toxicities were reported. All patients had local recurrence. Compared to the HFRT group, the CFRT group had more regional (50% vs 11.8%) and distant recurrences (16.7% vs 5.9%). Conclusion: In this retrospective study of our rGBM cohort, patients who received HFRT had a shorter median OS compared to those who received CFRT. Performance status was similar between the HFRT and CFRT groups, but fewer patients in the HFRT group had known MGMT promoter methylation. POF analysis revealed more regional and distant recurrences detected through imaging after CFRT, possibly due to longer tumor control duration or more frequent imaging. Well-designed randomized, controlled prospective studies are necessary to better determine optimal fractionation strategies for rGBM patients. References: (1) F. Liu, H. Wang, Y. Li, X. Chen, W. Zhu, Y. Li, Y. Qiu, C. Jiang, C. Fan, X. Ye, S. Xiao, S. Hu, K. Chen, X. Wu, W. Wu, L. He, Efficacy of Hypofractionated Stereotactic Radiotherapy with Different Dose Fractionation Regimens Combined with Concurrent Bevacizumab in Recurrent High-Grade Gliomas: A Randomized Controlled Trial. International Journal of Radiation Oncology*Biology*Physics, Volume 123, Issue 4, 2025, Page 1199.
Made with FlippingBook - Share PDF online