Prognosis after surgical excision of fibrosarcomas in cats.

Forty-four cats from which fibrosarcomas had been excised were studied for a minimum of 3 years, of until death. Two factors, tumor site and mitotic index, were found to be of prognostic significance, but tumor size, duration of growth, and histologic appearance were not. Following removal of fibrosarcomas from the pinna or flank in 6 cats, none died as a result of the tumor but 24 of 35 (70%) cats with fibrosarcoma in the skin of the head, back, or limbs were euthanatized because of local recurrence, usually within 9 months of surgery. The median survival time of cats with a tumor of mitotic index 6 or more in the head, back, or limbs was 16 weeks, compared with 128 weeks when the mitotic index was less than 6. Eleven percent of cats developed pulmonary metastases.