ESTRO 2022 - Abstract Book

S209

Abstract book

ESTRO 2022

patients experienced any grade acute facial nerve toxicity, 5 (17%) received 1# with 2 (11%) receiving 3# (p=0.52). 6 of the 7 patients experienced G1 facial twitching alone, 1 patient’s facial nerve function deteriorated to House Brackmann G3 toxicity at 5 months and unfortunately long-term follow up of that patient was not achieved as they died of other causes at 15 months post treatment, they had received 1# treatment. 13 patients experienced any grade acute trigeminal nerve toxicity, 9 (31%) receiving 1# treatment with 4 (21%) receiving 3# (p=0.45). 5 patients had persistent symptoms beyond a year and received medical therapy for management, 3 in the 3# group and 2 in the 1# group. No patients developed hydrocephalus following SRT. Conclusion Despite statistically significantly bigger tumour volumes receiving 3# there were lower rates of acute trigeminal and facial nerve toxicity seen in this series although this did not reach statistical significance. A randomised trial comparing treatment with 12Gy in 1# vs 18Gy in 3# in VS over 4cc not suitable for surgery or where surgery is declined is warranted. M. Amorim 1 , C. Silva 1 , M.A. Costa 2 , G. Fonseca 2 , C. Calçada 2 , J. Conde 2 , O. Carvalhosa 1 , S. Ramos 1 , J. Vale 2 , A. Cavaco 2 , P. Vieira 2 , P. Genésio 2 , P. Costa 2,1 1 Hospital de Braga, Radiation Oncology, Braga, Portugal; 2 Instituto CUF - Júlio Teixeira S.A. , Radiation Oncology, Porto, Portugal Purpose or Objective Trigeminal Neuralgia (TN) is a debilitating condition characterized by agonizing, paroxysmal, and lancinating pain. TN is also called “suicide disease”, terminology denoting the pain extent of these patients. Cyberknife® radiosurgery (CKRS) consists of a radiotherapy non-invasive image-guided procedure. Our propose is to evaluate the effectiveness and safety of CKRS for medically and surgically intractable TN. Materials and Methods We retrospectively evaluated 15 patients (3 male and 12 female) with recurrent TN submitted to CKRS between March 2016 and June 2021, at our institution (9 with left, 5 with right and 1 with bilateral TN). Patients received CKRS with a mean dose of 70 Gy applied to an average 77% isodose line on the affected trigeminal nerve. The final plan was developed according to the individual anatomy and dose distribution over the trigeminal nerve and maximum dose on the brainstem. Trigeminal pain and hypoesthesia were classified according to the Barrow Neurological Institute (BNI). Results Median age was 68 (44-81) years old. Before radiosurgery, all patients reported uncontrolled/recurrent pain with medication, being carbamazepine and pregabalin the most common drugs used. The median follow-up was 36,5 months (4- 67). Median target volume was 0,08 cm ³ (0,05-0,21) and median normalized conformity index was 1,83 (1,34-2,71). One patient had TN secondary to multiple sclerosis. One patient had been previously submitted to surgery and one had undergone CKRS one year before. All the patients reported pain relief within the first 3 months after CKRS treatment. The majority (62%) were free of antalgic medication (BNI I/II) for a median period of 34 months (1-64 months). In the last follow- up, 38% of the patients reported controlled pain with medication (BNI III) and we haven’t observed cases of inadequately controlled or severe pain (BNI IV-V). Most of the patients (72%) didn’t report facial numbness after CKRS. We observed facial hypoesthesia in 28% of the patients, half of them presented with bothersome facial numbness (BNI IV). Conclusion Frameless image-guided robotic radiosurgery in experienced hands is a safe and effective procedure for the treatment of TN, providing excellent pain control rates in absence of major neurological complications. Even patients with severely debilitating symptoms may experience significant and sustained pain relief after CKRS. Thus, it should be considered as a viable alternative to more invasive treatments for this painful condition, with a real impact on the quality of life of these patients. PD-0248 Treatment outcomes following Cyberknife radiosurgery for refractory Trigeminal Neuralgia.

PD-0249 Dynamics in the Sizes of Brain Metastases to Predict Survival Outcome of Stereotactic Radiotherapy

S.F. Lee 1,2 , P.L. Yip 2 , C.W.H. Choi 3 , V. Lee 2 , A. Wong 2

1 University of Hong Kong, Department of Clinical Oncology, Hong Kong, Hong Kong (SAR) China; 2 Tuen Mun Hospital, Department of Clinical Oncology, Hong Kong, Hong Kong (SAR) China; 3 University of Hong Kong, School of Public Health, Hong Kong, Hong Kong (SAR) China Purpose or Objective To analyze a newly proposed prognostic model for patients with brain metastases treated with stereotactic radiosurgery (SRS) and compare to two alternate prognostic models (Score Index for Radiosurgery in Brain Metastases [SIR] and Basic Score for Brain Metastases [BS-BM]) in predicting overall survival (OS). Materials and Methods We analyzed the patients receiving Linac-based stereotactic radiosurgery between 2010 and 2020. Patient and oncologic factors including the changes in sizes of brain metastasis between the diagnostic and stereotactic magnetic resonance imaging (MRI) for SRS were collected. The associations between prognostic factors and OS were assessed using Cox