Results of irradiation of infiltrative lipoma in 13 dogs

Thirteen dogs with infiltrative lipomas were treated with cobalt 60 radiati on. Four of the thirteen dogs also received either whole body (n = 2) or co mbination local/whole body (n = 2) hyperthermia in conjunction with radiati on therapy. Cytoreductive surgery was performed prior to radiation in 10 do gs, although only 3 dogs had microscopic disease at the time of radiation t herapy, Dogs received a fetal dose of 45.6 Gy-63 Gy in 2.5-4 Gy/fraction on either a Monday/Wednesday/Friday schedule or on a daily Monday through Fri day schedule. Twelve of the 13 dogs had computed tomography (CT) images acq uired prior to irradiation, Survival time was determined from the time of c ompletion of radiation therapy. Survival ranged from 6 months to 94 months, with a median (95% confidence interval) of 40 (18.5-77) months and a mean of 46.4 months. Only one dog was euthanized due to persistent signs related to the infiltrative lipoma at 6 months after the end of radiation therapy. There was no apparent difference in response based on whether or not the d ogs received hyperthermia in conjunction with irradiation, although the num bers were too small to make any significant conclusions. It appears that do gs with infiltrative lipomas can benefit from external beam irradiation alo ne or in combination with surgery to effect long-term local tumor control.