RADIOTHERAPY OF INCOMPLETELY RESECTED, MODERATELY DIFFERENTIATED MAST-CELL TUMORS IN THE DOG - 37 CASES (1989-1993)

Thirty-seven dogs with moderately differentiated cutaneous mast cell t umors had incomplete surgical excisions as determined by histopatholog y, but no gross evidence of tumor. All dogs were irradiated to a total dose of between 46.2 and 48.0 Gy using either an orthovoltage source (n=20) or a linear accelerator (megavoltage) (n=17). Radiation was del ivered to an area bordered by margins of 3 cm or greater around the su rgical scar, The mast cell tumors had not recurred in 97% of dogs by o ne year after radiation therapy and had not recurred in 93% of dogs by three years after radiation. Both orthovoltage and megavoltage radiat ion provide excellent local control of moderately differentiated mast cell tumors in dogs.