Use of a cyclical hypofractionated radiotherapy regime (‘QUAD shot’) for the treatment of feline sinonasal carcinomas

Abstract

Objectives Radiation therapy is the treatment of choice for cats with sinonasal carcinomas. Different protocols have been described in the literature, though a clear consensus regarding the optimal protocol is lacking. The aim of the study was to describe the tolerability, efficacy and outcome of cats treated with a cyclical hypofractionated protocol. Methods Cats with histologically diagnosed sinonasal carcinomas in a single institution were retrospectively included. All patients were treated with a cyclical hypofractionated protocol (‘QUAD shot’ regime). Cats were treated with 4 Gray (Gy) delivered in four fractions within 48 h, with a minimum of 6 h between two treatments, and repeated every 3–4 weeks for a total dose of 48 Gy in three cycles. Results Seven cats met the inclusion criteria. Nasal discharge and sneezing were the most common presenting complaints. All cats presented with advanced stage of disease with CT examination (three with modified Adams stage 3 and four with stage 4). Clinical improvement was seen in six cats. Five cats had a follow-up CT; one had a complete response, two had partial responses, one had stable disease and one had progressive disease. Two cats were still alive at the time of writing while four were euthanased owing to tumour-related causes. The median overall survival time was 460 days. The 1-year survival time was 80% and the 2-year survival time was 0%. Severe acute or late toxicity was not reported. Conclusions and relevance This is the first report of a cyclical hypofractionated protocol in the veterinary literature that can provide prolonged survival in cats with advanced stage sinonasal carcinoma. Its use should be considered in patients when prolonged hospitalisation can be detrimental to quality of life, while still delivering a therapeutic total dose of radiation therapy.

Description and efficacy of a response‐based “QUAD” cyclical hypofractionated palliative‐intent radiation protocol in dogs with macroscopic solid tumours: 108 cases

“…This is the first reported use of a QUAD cyclical hypofractionated protocol in a cohort of dogs, and largest veterinary study on QUAD radiation. 23 Results suggest that response-based QUAD palliative-intent radiation is a treatment option for dogs with advanced unresectable solid tumours and can provide clinicians with preliminary evidence and expectations for adverse effects, response, and outcome.…”

“…Response rates of 53–77% with palliation of clinical signs in >80% of patients are reported 18–22 . A recent study of “QUAD shot” radiotherapy in 7 cats with sinonasal carcinomas described 86% clinical improvement and no toxicity 23 . QUAD radiation use has yet to be reported in a large canine cohort, but it has the potential benefits of fewer consolidated veterinary visits and intended response‐based repeatability for a high total dose if clinical improvement is seen.…”

“…[18][19][20][21][22] A recent study of "QUAD shot" radiotherapy in 7 cats with sinonasal carcinomas described 86% clinical improvement and no toxicity. 23 QUAD radiation use has yet to be reported in a large canine cohort, but it has the potential benefits of fewer consolidated veterinary visits and intended response-based repeatability for a high total dose if clinical improvement is seen. The primary objective of this retrospective case series is to evaluate clinical benefit, objective response, adverse effects, and outcomes following cyclical QUAD hypofractionated palliative-intent radiation in dogs with macroscopic solid tumours.…”