Ulnar osteosarcoma in dogs: 30 cases (1992-2008).

OBJECTIVE: To examine the biological behavior of ulnar osteosarcoma and evaluate predictors of survival time in dogs. DESIGN: Retrospective case series. ANIMALS: 30 dogs with primary ulnar osteosarcoma. PROCEDURES: Medical records were reviewed. Variables recorded and examined to identify predictors of survival time were signalment, tumor location in the ulna, tumor length, serum alkaline phosphatase activity, surgery type, completeness of excision, tumor stage, tumor grade, histologic subtype, development of metastases, and use of chemotherapy. RESULTS: 30 cases were identified from 9 institutions. Eleven dogs were treated with partial ulnar ostectomy and 14 with amputation; in 5 dogs, a resection was not performed. Twenty-two dogs received chemotherapy. Median disease-free interval and survival time were 437 and 463 days, respectively. Negative prognostic factors for survival time determined via univariate analyses were histologic subtype and development of lung metastases. Telangiectatic or telangiectatic-mixed subtype (n = 5) was the only negative prognostic factor identified via multivariate analysis (median survival time, 208 days). Dogs with telangiectatic subtype were 6.99 times as likely to die of the disease. CONCLUSIONS AND CLINICAL RELEVANCE: The prognosis for ulnar osteosarcoma in this population was no worse and may have been better than the prognosis for dogs with osteosarcoma involving other appendicular sites. Partial ulnar ostectomy was associated with a low complication rate and good to excellent function and did not compromise survival time. Telangiectatic or telangiectatic-mixed histologic subtype was a negative prognostic factor for survival time. The efficacy of chemotherapy requires further evaluation.

Study of feline oral squamous cell carcinoma: potential target for cyclooxygenase inhibitor treatment.

Oral squamous cell carcinoma (OSCC) is associated with high morbidity and mortality. A potential target for OSCC treatment is cyclooxygenase-2 (cox-2). Pet cats with naturally occurring OSCC may offer the opportunity to study anticancer activity of cox inhibitors. Cox-2 expression in feline OSCC was determined by immunohistochemistry. High intensity cox-2 immunoreactivity was detected in 6 of 34 (18%) feline OSCC samples. Weak immunoreactivity was noted in 22 OSCCs and in epithelial cells from oral mucosa of clinically normal cats. Pharmacokinetics of a cox inhibitor (piroxicam, 0.3 mg/kg) were studied in carcinoma-bearing cats to confirm a dose for follow-up trials. The average peak serum piroxicam concentration (948 ng/ml, which inhibited cox-2 activity) and serum half-life (15.9 h) were similar to that in normal cats. These results provide information (cox-2 expression as an inclusion criteria, 0.3 mg/kg daily piroxicam) for the design of follow-up trials of cox inhibitor treatment in pet cats with OSCC.