A retrospective study of 86 dogs with brain tumors was undertaken. Sixty-nine dogs had histologic confirmation of tumor type, whereas the remaining 17 dogs had CT evidence of a brain tumor. All dogs had neurologic abnormalities. Seven dogs received no treatment, 38 dogs received only symptomatic treatment, and 41 dogs received some form of definitive treatment, in addition to medical management. Types of definitive treatment included surgery, cobalt-60 radiation, whole-body hyperthermia, '"I implants, and chemotherapy, alone or in combination. The factor that was most associated with survival duration was mode of therapy. Those dogs who were treated with cobalt-60 radiation, with or without other combinations of therapy, lived significantly longer than dogs who received surgery (f '*'I implants), or dogs who received symptomatic treatment (P = 0.01 and P < 0.001, respectively). After THE INCIDENCE of intracranial neoplasia in dogs is approximately 14.5 per 100,000 at risk.' Recent studies suggest that meningiomas are the most common intracranial neoplasm, followed by astrocytoma~.~-~ Secondary brain tumors can arise by local extension of nasal, skull, or pituitary gland tumors, or by metastasis from distant tumors. Lymphosarcoma can be either a primary or secondary brain tumor, depending on the site of origin.Little data exist concerning survival of dogs with brain tumors. In one study, a median survival time of 56 days (range: 10-307 days) was reported for dogs that received

Medical records for 92 cats with a vaccine associated sarcoma receiving preoperative irradiation, with or without chemotherapy, between December 1985 and September 1998 were reviewed. The purposes were to quantify response to treatment and to attempt identification of factors associated with favorable response. Variables evaluated for a relationship to outcome included signalment, tumor location, presence of gross vs. microscopic tumor, radiation field size, irradiation technique, type of surgical procedure, completeness of excision, and chemotherapy (none, carboplatin alone, and others). Time to first event was calculated for the first day of treatment until local tumor recurrence or metastasis, or the date of euthanasia or death. Median time to first event for all 92 cats was 584 days. Only completeness of surgical excision was related to the time to first event. Median time to first event in cats having complete surgical excision was 986 days compared to 292 days for cats with incomplete excision (P = 0.004). Cats requiring bone removal to effect tumor removal had earlier failure than cats having other types of surgery. There was not a significant relationship between administration of chemotherapy or chemotherapy type and time to first event although outcome in cats receiving carboplatin was better than all other treatment groups. Carboplatin addition to preoperative irradiation appears worthy of further study. Preoperative irradiation is an effective treatment for cats with vaccine associated sarcoma, especially if complete excision can be accomplished following irradiation.

Thirty-three cats with histologically confirmed fibrosarcomas were treated with radiation therapy followed by surgery. The median (95% confidence interval) disease free interval and overall survival were 398 (261,924) and 600 (lower limit 515) days, respectively. There were 19 treatment failures; 11 cats had only local recurrence, 4 cats developed metastatic disease, 3 cats had local recurrence followed by metastasis, and 1 cat developed simultaneous local and distant disease. Twelve cats are alive and disease free. Two cats died without evidence of treatment failure. The presence of tumor cells at the margin of resected tissue after radiation was the only variable which influenced treatment success. The median (95% confidence interval) disease free interval in 5 cats with tumor cells at the margin of the resected specimen was 112 (94,150) days versus 700 (lower limit 328) days for 26 cats with negative tumor margins, p < 0.0001. We did not identify a relationship between tumor volume, number of prior tumor excisions, concomitant use of chemotherapy or various descriptors of the radiation therapy technique and disease free interval.