Tolerance of cutaneous or mucosal flaps placed into a radiation therapy field in dogs

OBJECTIVE: To determine the clinical outcome and factors affecting cutaneous or mucosal flaps in dogs treated with radiation therapy (RT). STUDY DESIGN: Longitudinal clinical study. ANIMALS: Twenty-six client-owned dogs. METHODS: Dogs entered in the study had a flapping procedure and RT as part of their treatment. The sequence of flapping and RT included: (1) planned preoperative RT, (2) postoperative RT, and (3) flapping as a salvage procedure for management of complications or local tumor recurrence after RT. Flap complications were defined as necrosis, local infection, dehiscence, and ulceration. The risk and severity of flap complication were analyzed independently. RESULTS: Twenty (77%) dogs had a complication; 6 dogs required an additional flapping procedure; and 4 dogs had an unresolved complication. Flapping procedures performed to correct a complication, or failure of RT, had a significantly greater risk for complication; however, postoperative RT decreased the severity of complication. A dose per fraction of 4 Gy compared with 3 Gy was prognostic for increased severity of complications, whereas the head and neck location was prognostic for decreased severity of complication. CONCLUSIONS: Although morbidity was substantial, cutaneous or mucosal flaps were used successfully in an RT field in 85% of the dogs. Flaps that were part of the planned therapy as opposed to those used to correct a complication or failure of RT had a better clinical outcome. CLINICAL RELEVANCE: Cutaneous or mucosal flaps can be part of the treatment of dogs with tumor when adjuvant or neoadjuvant RT is to be used.