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

Abstract

The use of conventional multi-fractionated radiotherapy for the treatment of glial tumours is well documented in the literature. Recently, stereotactic radiotherapy (SRT) has become more widely available allowing for hypo-fractionated 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 three fractions of 8 to 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 days while those treated with >1 course had a MST of 865 days (P = .0077 log rank, 0.0139 Wilcoxon). Dogs treated with one course of SRT who received adjuvant chemotherapy had a MST of >658 days and lived significantly longer than those who did not receive chemotherapy (MST, 230 days) (P = .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 anaesthetic episodes. Additionally, it appears that patients can be safely treated with multiple rounds of SRT resulting in improved survival times.

CyberKnife stereotactic radiotherapy for treatment of primary intracranial tumors in dogs

“…In our study, the PFI for dogs with intracranial tumors treated with CyberKnife radiation therapy was 347 days, and the MST was 738 days. This is a similar to possibly improved MST as compared to other published MSTs for dogs with intracranial tumors treated with SRT 4,7,8,13 . Discernible differences in outcome between different types of SRT have not been identified.…”

“…This is a similar to possibly improved MST as compared to other published MSTs for dogs with intracranial tumors treated with SRT. 4,7,8,13 Discernible differences in outcome between different types of SRT have not been identified. Further studies, ideally headto-head, are needed to allow for comparison.…”

“…CyberKnife is 1 type of SRT system, employing real‐time image guidance and a synchronized tumor tracking system to deliver radiation dynamically with submillimeter accuracy 11,12 . By sparing healthy tissues, fewer early and late adverse radiation effects are anticipated 11,13 …”

“…11,12 By sparing healthy tissues, fewer early and late adverse radiation effects are anticipated. 11,13 The purpose of our study is to determine the prognosis and any prognostic factors for dogs with primary intracranial tumors treated with CyberKnife radiation therapy. We hypothesize that dogs treated with CyberKnife have an MST equal to or greater than published MST for dogs treated with other forms of radiation therapy due to the increased accuracy feasible with this system.…”

Comparison of response assessment in veterinary neuro‐oncology and two volumetric neuroimaging methods to assess therapeutic brain tumour responses in veterinary patients

“…A total of 22 patients met the inclusion criteria for this study consisting of 18 dogs (five males and 13 females) and four cats (three males and one female) (Table 3). The median age was 8 years (range, [3][4][5][6][7][8][9][10][11][12][13][14] for dogs and 10 years (range, 8-14) for cats.…”