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Thirty-five dogs with appendicular osteosarcoma were treated with 5 doses of doxorubicin (30 mg/m2 of body surface, i.v., every 2 weeks). Surgical excision of the primary tumor was performed 13 days after the second (n = 18) or third (n = 17) treatment, and the subsequent doxorubicin treatment was given the day following surgery. Resected tumors were evaluated histologically to determine response to preoperative chemotherapy (ie, percentage of the tumor that was necrotic). Survival data for the 35 dogs were compared with survival data for a historical control group, consisting of 162 dogs with appendicular osteosarcoma treated by amputation alone. Administration of doxorubicin at 2 week intervals was well tolerated. Three dogs were alive and did not have evidence of disease at the time of reporting. Of the remaining 32 dogs, 3 died or were euthanatized because of cardiomyopathy presumably caused by doxorubicin; 1 died suddenly 116 weeks after initiation of treatment; and the remaining 28 were euthanatized because of problems documented to be related to distant metastases. Thirteen dogs (40.6%) were euthanatized because of pulmonary metastases, 10 dogs (31.3%) were euthanatized because of bone metastases, and 5 dogs (15.6%) were euthanatized because of metastases in other sites. The proportion of dogs euthanatized because of bone metastases was significantly (P0.001) higher for the study group than for the control group. Median survival time for the 35 dogs that received doxorubicin was estimated to be 52.3 weeks, and 1- and 2-year survival rates were estimated to be 50.5 and 9.7%, respectively. Survival time was significantly (P0.0001) longer for these dogs than for control dogs.(ABSTRACT TRUNCATED AT 250 WORDS)

Twenty-two dogs with appendicular osteosarcoma were treated by amputation (n = 17) or limb-sparing surgery (n = 5). All dogs were given cisplatin (60 mg/m2 of body surface, IV) at 3-week intervals, beginning 1 week after surgery. Number of cisplatin treatments ranged from 1 to 6. Survival data for the 22 dogs were compared with survival data from a historical control group consisting of 162 dogs with appendicular osteosarcoma treated by amputation alone. Median survival time for the 22 dogs given cisplatin was estimated to be 46.4 weeks, and 1- and 2-year survival rates were estimated to be 45.5 and 20.9%, respectively. Survival time was significantly (P less than 0.0001) longer for treated dogs than for control dogs. Statistically significant relation was not found between survival time and number of cisplatin treatments. Three dogs were alive with no evidence of disease at the time of reporting. Of the remaining 19 dogs, 14 (73.4%) were euthanatized for problems documented to be related to metastases. Nine (47.4%) dogs were euthanatized because of bone metastases, and 5 (26.3%) were euthanatized because of pulmonary metastases. The proportion of dogs euthanatized because of bone metastases was significantly (P less than 0.0001) higher for treated than for control dogs. Median survival times for dogs developing bone and lung metastases were estimated to be 51.2 weeks and 21.2 weeks, respectively; however, this difference was not statistically significant. One local tumor recurrence was observed among dogs that had limb-sparing surgery. Significant difference in survival time was not observed between dogs that had limb-sparing surgery and dogs that underwent amputation.

The case records of and histopathologic findings in 57 dogs with nonangiogenic and nonlymphomatous splenic sarcomas were reviewed. Splenic neoplasms in these dogs included leiomyosarcoma, fibrosarcoma, undifferentiated sarcoma, liposarcoma, osteosarcoma, chondrosarcoma, myxosarcoma, rhabdomyosarcoma, and fibrous histiocytoma. The clinical signs associated with splenic sarcoma included anorexia or decreased appetite, abdominal distention, polydipsia, lethargy, vomiting, weight loss, and weakness. An abdominal mass was detected in 86% of the dogs by use of abdominal palpation (63%), and/or abdominal radiography (74%). The diagnosis was based on histopathologic findings in the spleen. Abdominal exploratory surgery was performed on 43 of the 57 dogs. Twenty-seven dogs were treated by splenectomy, and 16 were euthanatized at the time of surgery because of widespread metastatic lesions. Of the 14 dogs on which surgery was not performed, 11 were euthanatized on the basis of results of preoperative diagnostic tests, and the remaining 3 dogs had splenic neoplasms that were incidental findings at necropsy. Of the 27 surgically treated dogs, 5 died in the immediate postoperative period, 12 died or were euthanatized within 1 year after splenectomy, and only 5 dogs survived greater than or equal to 1 year. Three dogs were lost to follow-up evaluation, and 2 were still alive 6 and 7 months after surgery. The median survival time of the 22 dogs for which survival was known was 2.5 months. The median survival time for 11 dogs with no obvious metastasis at the time of splenectomy was 9 months.(ABSTRACT TRUNCATED AT 250 WORDS)