S957
Clinical - Non-malignant & functional radiotherapy
ESTRO 2026
Material/Methods: Our review included 639 TN patients who underwent GKRS and had follow-up data. Radiation planning documents were reviewed to determine the shot placement relative to the brainstem, separated into distal and proximal halves of the nerve. The primary outcome was pain response as a binary endpoint with responders defined as having decreased pain, reduction in pain medication, or both. Other variables collected included age, sex, comorbid multiple sclerosis, atypical pain, total number of medications, previous intervention (rhizotomy, microvascular decompression [MVD], alcohol injection), vascular compression, laterality, and dose rate >=2.30 Gy/min. Univariable logistic regression models identified variables associated with pain response; variables with significant associations were evaluated as independent predictors in a multivariable model. Results: Patients were treated with a maximum radiation dose of 80 Gy and the median follow-up time was 6 months (range, 0-109 months). Univariable analysis showed that the relative distance of radiation to the brainstem was not associated with pain relief (OR = 0.96, 95% CI = 0.56-1.61, p = 0.89). Older age was associated with increased odds of pain relief (OR = 1.03, 95% CI = 1.01- 1.05, p = 0.003), while prior MVD (OR = 0.33, 95% CI = 0.18-0.63, p <0.001) and prior injection (OR = 0.30, 95% CI = 0.15-0.64, p = 0.001) were associated with decreased odds of pain relief. Multivariable analysis showed that the independent predictors of pain relief were age (Adj. OR = 1.03; 95 % CI 1.01–1.05; p = 0.005), prior MVD (Adj. OR = 0.41; 95 % CI 0.22–0.80; p = 0.007), and prior injection (Adj. OR = 0.33; 95 % CI 0.16–0.70; p = 0.003). Conclusion: In TN patients treated with GKRS, older age was associated with increased odds of pain relief, while a history of MVD or alcohol injections was associated with decreased odds. There was no difference in pain relief based on shot placement along the nerve. Keywords: trigeminal neuralgia, gamma knife radiosurgery Stereotactic Arrhythmia Radiotherapy for Refractory Ventricular Tachycardia: Interim Results from the Ongoing STARNL-2 Trial (NCT05439031) Wiert F Hoeksema 1 , Edith MT Dieleman 2 , Jorrit Visser 2 , Luuk HGA Hopman 1 , Nick HJ Lobe 3 , Rianne HA De Bruin-Bon 4 , Niek Van Wieringen 2 , Martijn H Van der Ree 1 , Pranav Bhagirath 1 , Hein J Verberne 3 , Joost JC Verhoeff 2 , Michiel JB Kemme 1 , Brian V Balgobind 2 , Pieter G Postema 1 Proffered Paper 4972
proportions were 48.9% versus 17.8%, and for D_0.5cc ≥ 20 Gy, they were 31.1% versus 15.6%. Conclusion: In this STAR cohort, despite the mitral valve receiving a substantially higher dose than the aortic valve, no significant association between mitral valve side effects and doses was seen. Given the absence of valve - specific constraints in current guidance, it may help minimize potential radiation-related side effects. We advocate routine reporting of dose-volume parameters for valves and prospective correlation with cardiac adverse events in longer follow-up. References: 1. Ha š ková J, Wichterle D, Kautzner J, et al. Efficacy and Safety of Stereotactic Radiotherapy in Patients With Recurrent Ventricular Tachycardias (Czech Experience). JACC: Clinical Electrophysiology. 2024. DOI: 10.1016/j.jacep.2023.12.002.2. Viani GA, Gouveia AG, Pavoni JF, Louie AV, Detsky J, Spratt DE, Moraes FY. A meta-analysis of the efficacy and safety of stereotactic arrhythmia radioablation (STAR) in patients with refractory ventricular tachycardia. Clinical Oncology. 2023;35(9):611–620. doi:10.1016/j.clon.2023.04.004.This work was supported by the STOPSTORM consortium under the European Union’s Horizon 2020 research and innovation programme (grant agreement No. 945119). Keywords: ventricular tachycardia, STAR, mitral regurgitation Digital Poster Highlight 4936 Predictive factors affecting the efficacy of gamma knife radiosurgery in trigeminal neuralgia Stephanie Fu 1 , Adrienn Bourkas 1 , Suneil K Kalia 2 , Dana Keilty 3 , Anna Santiago 4 , Derek S Tsang 3 , Mojgan Hodaie 2 , Michael Yan 3 1 Queen's School of Medicine, Queen's University, Kingston, Canada. 2 Division of Neurosurgery, University Health Network, Toronto, Canada. 3 Radiation Medicine Program, University Health Network, Toronto, Canada. 4 Department of Biostatistics, University Health Network, Toronto, Canada Purpose/Objective: Gamma Knife radiosurgery (GKRS) is a minimally invasive procedure used to treat trigeminal neuralgia (TN) by using ionizing radiation to create a lesion on the trigeminal nerve, reducing pain signal transmission. There is variability in GK shot placement along the nerve based on individual patient anatomy and institutional practice. We conducted a retrospective review of our institutional experience to determine factors associated with GKRS efficacy in TN, including the GK shot position.
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