ESTRO 2025 - Abstract Book

S1565

Clinical – Mixed sites & palliation

ESTRO 2025

Conclusion: Metastasis-directed SBRT for oligometastatic NSCLC, BC, CRC and PC patients was associated with favorable toxicity profile. No increased risk of severe AEs observed in patients treated with concomitant systemic therapy.

Keywords: oligometastases, SBRT, stereotactic radiotherapy

3732

Digital Poster Use of Stereotactic Body Radiotherapy (SBRT) for Spine Metastases with Robotic Radiosurgery Unit Cyberknife in Patients with Oligometastatic Disease Adrián Durango Méndez 1 , David Sevillano Martínez 2 , Maria E Centelles Hidalgo 1 , Juan D Garcia Fuentes 2 , Ignacio M Gomez Paloma 1 , Margarita Martin Martin 1 , Mercedes Martin Sanchez 1 , Isabel Alvira Ortiz 1 , Maria D Espinosa Cuesta 1 , Carolina De La Pinta Alonso 1 , Eva Fernandez Lizarbe 1 , Feliciano Garcia Vicente 2 , Sonsoles Sancho Garcia 1 1 Radiotherapy Oncology, H. U. Ramón y Cajal, Madrid, Spain. 2 Physics, H. U. Ramón y Cajal, Madrid, Spain Purpose/Objective: To evaluate the efficacy and safety of stereotactic body radiotherapy (SBRT) using the Cyberknife system for spine metastases, focusing on patient outcomes, progression-free urvival (PFS), and treatment-related toxicities. Material/Methods: From May 2004 to August 2024, 61 patients with 73 spine metastases were treated using Robotic Radiosurgery Unit Cyberknife in our centre. The mean age at diagnosis was 61 years. Baseline performance status showed 94% of patients with an ECOG score of 1 – 2 and 74.6% with a Karnofsky index of 90 or higher. Patient eligibility for spine SBRT was determined based on the SINS scale and Bilsky classification. Treatment doses varied from single-fraction regimens in which most frequent dose was 18Gy, to multi-session regimens of 21-35Gy in 3-5 fractions. The mean planning target volume (PTV) was 53.47 cc, with a mean maximum dose in PTV of 22,8Gy for single fraction; 29.5Gy for 3 fractions schemes and 32.13Gy for 5 fractions schemes. Results: The median follow-up was 21 months (1-60). Local control at 24 months for patients receiving single-fraction SBRT was 92.1% compared to 88% for those treated with fractionated schemes. The median progression-free survival has not been reached. At two years local relapse free survival was 90%. Median overall survival was 40 months. The two-year overall survival was 65.4%. There was no significant difference in overall survival between the different fractionation regimens. Regarding tolerance, 89.6% of patients experienced no acute toxicities from SBRT. Seven patients reported acute toxicity, none exceeding grade II. The most common acute side effects included asthenia followed by esophagitis and enteritis. 6 cases of vertebral compression fracture (VCF) have been reported out of 73 lesions treated (8.22%). All cases of VCFs occurred in patients treated with a single fraction. There are no significant differences in the maximum dose in PTV or in the degree of previous SINS related to the VCFs cases.