Safety and feasibility of short course pre-operative radiation therapy followed by surgical excision for canine solid tumours.

ABSTRACT

Surgical resection of solid tumours, especially in early stages of disease, remains a cornerstone of cancer treatment in dogs and cats. There are numerous publications that show a strong association between local tumour control and outcome. To achieve local control in some cases radiation therapy and surgery are combined, with radiation therapy being delivered in the neoadjuvant or adjuvant setting. The objective of the study was to report acute toxicity and surgical site complication data in dogs that received a short-course pre-operative (SCPO) radiation therapy protocol, followed by surgical excision for various solid tumours. Medical records were reviewed, and data was analysed retrospectively. Dogs were included if a dermal or subcutaneous solid tumour was treated with SCPO radiation therapy and then was resected on the last day of radiation or 2-3 weeks later. A total of 34 dogs with 35 primary tumours were included. Acute radiation toxicity was diagnosed in 14 sites (40%). VRTOG scores were grade 1 in 50%, grade 2 in 43%, and grade 3 in 7%. Surgical site complications were identified in 17% of dogs with an overall surgical site infection rate of 11%. According to the Clavien-Dindo classification, two dogs required medical intervention (grade 2), 1 dog required surgical intervention under general anaesthesia (grade 3b), and 1 dog died as a result of complications (grade 5). Logistic regression analysis found that anatomic site was significantly associated with complications, where tumours located on the extremity was protective (P = .02; OR 0.06).