ESTRO 2024 - Abstract Book

S803

Clinical - CNS

ESTRO 2024

OS at 6, 12 and 24 months were 79.1%, 61.9% and 46% respectively. On UVA, parameters significantly associated with longer OS included longer time from SBRT to local failure (p <0.0001), primary site (p <0.0001), oligometastasis (≤ 5 metastases) (p < 0.0001), lower Spinal Instability Neoplastic Score (SINS) (p <0.0001), better ECOG (p <0.0001), age < 86 (p=0.038) and absence of epidural extension (p=0.0006). Patients 86 years or older had a median OS of 14.3 months (95% CI 6.3-27.8, 12 month OS of 51%) compared with a median OS for those under 86 of 20.4 months (95% CI 15.0-29.4, 12 month OS of 63%). The cumulative incidence of LF at 6, 12 and 24 months were 5%, 9.3% and 14.3% respectively. On UVA, parameters significantly associated with higher risk of LF were higher SINS (p=0.004), paraspinal extension (p=0.004), and previous SBRT to the same spinal level (p=0.007). Age at treatment did not influence the LF rate (p=0.33).

Conclusion:

We report the largest series of elderly patients treated with spine SBRT. The 2-year risk of VCF among all patients aged 70 or above was 12.6%, similar to previously reported rates in patient of all ages. However, those older than 86 years had a significantly higher risk of VCF (2-year estimate of 30.3%) with an earlier median time to onset of 3.4 months post SBRT. The median OS of 20.3 months for the entire cohort, including a median OS of 14.3 months for those age over 86, suggests durable local and pain control remain important considerations for these patients. This data may help to inform patient selection and counselling of treatment risks and benefits in the elderly.

Keywords: geriatric oncology, stereotactic radiotherapy

938

Poster Discussion

Radiation-induced cerebral contrast enhancements strongly share ischemic stroke risk factors

Tanja Eichkorn 1 , Jonathan W. Lischalk 2 , Robert Schwarz 1 , Lena J. Bauer 1 , Maximilian Y. Deng 1 , Sebastian Regnery 1 , Christine Jungk 3 , Juliane Hörner-Rieber 1 , Klaus Herfarth 1 , Laila König 1 , Jürgen Debus 1 1 Heidelberg University Hospital, Department of Radiation Oncology, Heidelberg, Germany. 2 Perlmutter Cancer Center, Department of Radiation Oncology, New York, USA. 3 Heidelberg University Hospital, Department of Neurosurgery, Heidelberg, Germany

Purpose/Objective:

Radiation-induced cerebral contrast enhancements (RICE) are feared given their frequency ranging from 5% to as high as 31% and potentially life-threatening consequences. Several publications in the literature have shown an association between RICE and particle therapy. There is in-vitro evidence of a (locally) higher radiobiological effectiveness (RBE) of protons than the world-wide accepted constant factor of 1.1, which can lead to uncertainties in dose calculation and may lead to excess radial biological dose deposition. One manifestation of this hitherto unrealized elevation in RBE is the risk of radiation-induced contrast enhancements (RICE). The pathophysiology of RICE appears to be the result of transient blood-brain barrier disruptions. Risk factors are poorly understood. A