A retrospective Italian Society of Veterinary Oncology (SIONCOV) study of 56 cats with appendicular osteosarcoma.

Osteosarcoma is the most common malignant primary bone cancer, but it is infrequently reported in cats. Feline appendicular osteosarcoma typically exhibits good prognosis when treated with surgery alone. A retrospective multi-institutional study was conducted to identify possible prognostic factors. Cats diagnosed with appendicular osteosarcoma were included if initial staging and follow-up information were available. Data including signalment, tumour characteristics, treatment modalities, and survival outcomes were collected and analysed. Fifty-six cats were included; the femur was the most frequently affected bone. Eight cats had distant metastasis at admission and an additional 9 developed metastatic disease during follow-up, resulting in an overall metastatic rate of 30%. Forty-nine (87.5%) cats underwent surgery, and 4 also received adjuvant chemotherapy. Among operated cats, median time to local progression (TTLP), time to distant progression and tumour-specific survival (TSS) were not reached. One- and 2-year survival rates were 66% and 55%, respectively. Seven (12.5%) cats received no treatment; 1- and 2-year survival rates were 25% and 0%, respectively. Operated cats had significantly longer TTLP (P < .001) and TSS (P = .001) compared with non-operated cats. Among operated cats, young age negatively impacted local tumour progression, while the presence of distant metastasis at diagnosis was associated with a higher risk of tumour-related death. This study reaffirms the good prognosis for cats with appendicular osteosarcoma undergoing surgery, but sheds light on some additional factors to consider. Accurate initial staging is recommended, as the metastatic rate may exceed many previous estimations. Surgery substantially extends survival time, whereas the role of chemotherapy remains uncertain.

Survey of UK-based veterinary surgeons' opinions on the use of surgery and chemotherapy in the treatment of canine high-grade mast cell tumour, splenic haemangiosarcoma and appendicular osteosarcoma.

The objective of this study was to determine the frequency of recommendation of adjuvant chemotherapy by UK-based general veterinary practitioners (GVPs) for canine patients with high-grade mast cell tumours (HGMCTs), splenic haemangiosarcomas (SHSs) and appendicular osteosarcomas (AOSs); to determine which chemotherapeutic protocols are used by GVPs; and to evaluate reasons why chemotherapy may or may not be recommended postoperatively. An internet survey was created in 2013 using an online programme and was distributed to GVPs. Questions relating to the use of adjuvant chemotherapy for three tumours were selected. In total, 300 responses were generated. Surgery was seen as primary therapy by most GVPs for HGMCT (91 per cent) and SHS (88 per cent), but less frequently for AOS (59 per cent). Also, 90, 40 and 57 per cent of respondents recommended adjuvant chemotherapy for HGMCT, SHS and AOS, respectively. Of these, an appropriate chemotherapy protocol was not known by 25, 51 and 36 per cent of GVPs for HGMCT, SHS and AOS, respectively. From the GVPs not recommending chemotherapy, 29, 64 and 66 per cent did not believe chemotherapy to be efficacious for these tumours. The frequency of recommendation regarding postoperative chemotherapy is variable by tumour type. Reasons given why postoperative chemotherapy is not recommended also vary by tumour type.

ASSOCIATION BETWEEN COMPUTED TOMOGRAPHIC CHARACTERISTICS AND FRACTURES FOLLOWING STEREOTACTIC RADIOSURGERY IN DOGS WITH APPENDICULAR OSTEOSARCOMA.

The objective of this observational, descriptive, retrospective study was to report CT characteristics associated with fractures following stereotactic radiosurgery in canine patients with appendicular osteosarcoma. Medical records (1999 and 2012) of dogs that had a diagnosis of appendicular osteosarcoma and undergone stereotactic radiosurgery were reviewed. Dogs were included in the study if they had undergone stereotactic radiosurgery for an aggressive bone lesion with follow-up information regarding fracture status, toxicity, and date and cause of death. Computed tomography details, staging, chemotherapy, toxicity, fracture status and survival data were recorded. Overall median survival time (MST) and fracture rates of treated dogs were calculated. CT characteristics were evaluated for association with time to fracture. Forty-six dogs met inclusion criteria. The median overall survival time was 9.7 months (95% CI: 6.9-14.3 months). The fracture-free rates at 3, 6, and 9 months were 73%, 44%, and 38% (95% CI: 60-86%, 29-60%, and 22-54%), respectively. The region of bone affected was significantly associated with time to fracture. The median time to fracture was 4.2 months in dogs with subchondral bone involvement and 16.3 months in dogs without subchondral bone involvement (P-value = 0.027, log-rank test). Acute and late skin effects were present in 58% and 16% of patients, respectively. Findings demonstrated a need for improved patient selection for this procedure, which can be aided by CT-based prognostic factors to predict the likelihood of fracture.

Toxicity and efficacy of a novel doxorubicin and carboplatin chemotherapy protocol for the treatment of canine appendicular osteosarcoma following limb amputation.

OBJECTIVE: To evaluate the safety and efficacy of a novel doxorubicin and carboplatin chemotherapy protocol for the treatment of dogs with appendicular osteosarcoma following limb amputation. DESIGN: Retrospective study. PROCEDURE: Dogs diagnosed with appendicular osteosarcoma, with no evidence of metastatic disease, treated with amputation and adjuvant chemotherapy consisting of two doses of doxorubicin given 14 days apart, followed by four doses of carboplatin at 3-weekly intervals between September 2003 and December 2009 were identified from the medical records of Perth Veterinary Oncology. Haematological and gastrointestinal toxicities were assessed based on information in the medical records and recorded complete blood count results. The efficacy of the protocol was assessed by determining the median disease-free interval (DFI) and overall survival time (OST) using the Kaplan-Meier product-limit method. RESULTS: In total, 33 dogs met the inclusion criteria. The median DFI was 231.5 days and the median OST was 247 days. With regard to haematological toxicity, 56% of dogs had a grade 1-2 neutropenia recorded as their highest marrow toxicity and 9% of dogs experienced a grade 3-4 neutropenia, all subsequent to doxorubicin administration. The highest gastrointestinal toxicity was grade 1-2 in 15 dogs (47%) and 5 dogs (16%) experienced grade 3-4 gastrointestinal toxicity. CONCLUSION: This chemotherapy protocol did not result in a longer time to disease recurrence or OST in this population of dogs. Dual-agent protocols have failed to improve survival times and therefore we conclude that a single-agent protocol using carboplatin may be equally effective with less toxicity.