Intentional marginal excision of canine limb soft tissue sarcomas followed by radiotherapy

Objectives: To evaluate the outcome in a group of dogs treated with postoperative radiotherapy following intentional marginal excision of soft tissue sarcomas from their limbs and to assess parameters for prognostic significance. Method: Patients that had had intentional marginal excision of limb soft tissue sarcomas followed by radiotherapy were selected. A coarse fractionated protocol of four once weekly 8 to 9 Gy by 4 MV x-rays was used. The time to local recurrence was determined. Tumour grade, size, site, number of surgeries, surgeon and time from last surgery to radiotherapy were evaluated as potential prognostic indicators. Results: Fifty-six cases were included. Minor surgical complications occurred in four patients (7%). Tumour recurred locally in 10 dogs (18%). Fourteen dogs died from tumour-related causes (25%). From Cox proportional hazard analysis time from surgery to radiotherapy was the only predictor of tumour recurrence (P=0·039); hazard ratio 8·63. Delaying radiotherapy beyond 4 weeks was associated with improved outcomes. Three dogs developed serious but non-life-threatening local complications; wound dehiscence, self-trauma and osteonecrosis of underlying bone. Clinical Significance: Intentional marginal excision followed by hypofractionated radiotherapy is a viable option for canine limb soft tissue sarcomas, providing good long-term clinical outcomes and low morbidity.