Postoperative radiotherapy for canine soft tissue sarcoma

Thirty-five dogs with 37 soft tissue sarcoma tumors that were incompletely excised and treated with radiotherapy in the postoperative, adjuvant setting were reviewed. Variables evaluated included age, sex, tumor site, tumor histology, total tumor radiation dose, radiotherapy field size. time to recurrence, and survival. The majority of tumors were fibrosarcomas and hemangiopericytomas, but small numbers of other tumor types were also represented. Total tumor radiation dose ranged from 42 to 57 Gy given in 3- to 4.2-Gy daily fractions on a Monday through Friday schedule. Overall median survival was 1,851 days. Median time to local recurrence was greater than 798 days. Soft-tissue sarcoma tumors at oral sites had a statistically significant lower median survival (540 days) as compared to other tumor sites (2,270 days). Radiotherapy may be a useful adjuvant therapy for incompletely excised soft-tissue sarcomas with a reasonable expectation for long-term patient survival.