Efficacy of frameless stereotactic radiotherapy for the treatment of presumptive canine intracranial gliomas: a retrospective analysis (2014‐2017)

The use of conventional multifractionated radiotherapy for the treatment of glial tumors is well documented in the literature. Recently, stereotactic radiotherapy (SRT) has become more widely available allowing for hypofractionated protocols; however, its usefulness in the treatment of canine intracranial gliomas is largely undetermined. We conducted a retrospective analysis, including 21 dogs diagnosed with presumptive intracranial gliomas treated with one or more courses of 3 fractions of 8-10 Gy CyberKnife SRT. The objective of this study was to evaluate the efficacy, safety and prognostic factors associated with the use of SRT for the treatment of canine intracranial gliomas. Overall MST for all dogs was 636 days (d). Dogs treated with one course of the described SRT protocol had a MST of 258 d while those treated with >1 course had a MST of 865 d (P = 0.0077 log rank, 0.0139 Wilcoxon). Dogs treated with one course of SRT who received adjuvant chemotherapy had a MST of >658 d and lived significantly longer than those who did not receive chemotherapy (MST, 230 d) (P = 0.0414 log rank, 0.0453 Wilcoxon). The most common adverse event included presumptive transient demyelination in 3/21 dogs, which was treated successfully with corticosteroids in all patients. This study provides evidence that SRT is effective in prolonging survival in dogs with intracranial gliomas, and may provide similar results to conventional fractionated protocols, while decreasing the number of hospital visits and anesthetic episodes. Additionally, it appears that patients can be safely treated with multiple rounds of SRT resulting in improved survival times. This article is protected by copyright. All rights reserved.