ESTRO 2024 - Abstract Book

S1985

Clinical - Mixed sites, palliation

ESTRO 2024

mixed histology (p<0.001) (cf. McGee et al and Ito et al.). Logistic regression models for LC of mixed and radiation resistant histology at 1 year post-SBRT as well as mixed histology at 2 years post-SBRT are shown in Figure 1.

Conclusion:

In this work, regression models for LC of spinal metastases have been generated based on pooled data from 33 studies and 5093 lesions. The 1-year LC data appear consistent with the analysis performed in the HyTec initiative (Soltys et al.). In order to achieve 90% LC at 1 year, a single fraction of 18 Gy is adequate for a mixed histology cohort, which is equivalent to 24 Gy in 2 fractions (alpha/beta=10). For radiation resistant histology a single fraction of 21.5 Gy should achieve about 90% at 1 year, which is approximately equivalent to 28 Gy in 2 fractions. The potential benefit of increased LC with higher radiation dose should be accompanied by strategies to mitigate the increased risk of complications. Lack of detailed dosimetry information such as GTV/PTV dose coverage, tumor histology, as well as varying methods of calculating LC were limitations to this work. Therefore, improved statistical models for LC might be achieved through more detailed classification of histopathology, more consistent definitions