Efficacy and toxicity of piroxicam rectal suppositories in palliative management of rectal carcinoma in dogs not receiving curative‐intent surgery: A retrospective case series of eight dogs

Background The aim of this study was to report tolerability, safety and outcome in dogs with malignant epithelial rectal tumours receiving piroxicam suppositories where curative‐intent surgery was not performed. Methods Medical records from one UK referral hospital were retrospectively searched for dogs with malignant epithelial rectal tumours receiving piroxicam suppositories. Dogs receiving curative‐intent surgery or anti‐cancer agents were excluded. The primary outcomes were owner‐reported improvement in clinical signs and veterinarian‐assessed cRECIST (canine Response Evaluation Criteria for Solid Tumours) responses. The secondary outcomes recorded included overall survival time and progression‐free survival. Results Eight dogs were reported. Four patients experienced owner‐reported clinical benefit, characterised by partial ( n = 2) or complete ( n = 2) resolution of clinical signs. Among these, three dogs had stable disease, and one dog achieved a complete response. Drug toxicity included hypersalivation ( n = 1), vomiting ( n = 2), elevations in renal markers ( n = 2) and oliguric acute kidney injury ( n = 1); the latter occurred 1248 days into therapy. Limitations The small number of animals, owner‐reported outcomes, non‐standardised treatments and limited follow‐up may affect the interpretation of the findings. Conclusions Piroxicam suppositories improve clinical signs and may stabilise or reduce tumour volume in some dogs with rectal carcinomas where curative‐intent surgery is not performed. Regular serum biochemistry monitoring is recommended due to the potential for renal toxicity.