Stereotactic radiotherapy (10 Gy X 3) for canine nonlymphomatous intranasal tumors is associated with prolonged survival and minimal risk of severe radiotoxicity

Abstract

OBJECTIVE To describe oncologic outcomes following administration of a uniform stereotactic radiotherapy protocol (SRT; 10 Gy X 3) for canine intranasal tumors and to identify whether any clinical or dosimetric factors were predictive of event-free or overall survival time (EFST or OST). ANIMALS 129 dogs. PROCEDURES In this single-institution retrospective study, the medical records database was searched for canine nonlymphomatous intranasal tumors treated with 10 Gy X 3 SRT between August 2013 and November 2020. Findings regarding adverse effects and outcomes were analyzed overall, for dogs grouped on the basis of life stage (mature adult, senior, or end of life), and for treatment-related or tumor-related variables to identify potential predictors of outcome. RESULTS After SRT, most dogs clinically improved with minimal acute radiotoxicity. The median EFST was 237 days; median OST was 542 days. Receipt of other tumor-directed therapies before or after SRT was associated with improved EFST in senior dogs (hazard ratio [HR], 0.416) and improved OST in mature adult (HR, 0.241) and senior dogs (HR, 0.348). In senior dogs, administration of higher near-minimum radiation doses was associated with improved EFST (HR, 0.686) and OST (HR, 0.743). In senior dogs, chondrosarcoma was associated with shorter OST (HR, 7.232), and in dogs at end of life, having a squamous cell or transitional carcinoma was associated with worse EFST (HR, 6.462). CLINICAL RELEVANCE This SRT protocol results in improved quality of life and prolonged OST for dogs of all life stages. Radiation protocol optimization or use of multimodal therapy may further improve outcomes.

A retrospective study of sinonasal tumors in 182 dogs treated with stereotactic radiotherapy (3 × 10 Gy) (2010‐2015)

“…3,13,14,18,19 Fractionated IMRT and VMAT decrease acute Later, a report of 29 dogs with stage 4 tumors treated with fractionated MV radiotherapyshowed improved OST of 318 days, 30 which concurs with the Gieger 2017 publication with 29 dogs. 13 However, a more recent paper by the same group with 129 dogs 24 showed dogs with modified Adams stages 1-4a had superior DSST than dogs with stage 4b. One possible reason for this difference between the Nolan study and the current study was our higher proportion of stage The dogs treated in the early in the initiation of the protocol did not have a CTV expansion.…”

“…The median ST of dogs with nonlymphomatous sinonasal tumors ranges from 240 to 399 days in 2 previous reports but 14,19 there is a high incidence of radiation adverse events. SRT improved quality of life and prolonged OST in 129 dogs of all life stages 24 . The objective of this retrospective study was to provide additional data to inform optimization of future SRT protocols by evaluating treatment efficacy and documenting acute and late radiation adverse events.…”

“…SRT improved quality of life and prolonged OST in 129 dogs of all life stages. 24 The objective of this retrospective study was to provide additional data to inform optimization of future SRT protocols by evaluating treatment efficacy and documenting acute and late radiation adverse events.…”