Inflammatory mammary carcinoma in 12 dogs: clinical features, cyclooxygenase-2 expression, and response to piroxicam treatment.

Canine inflammatory mammary carcinoma (IMC) is a rare, locally aggressive, highly metastatic tumor that is poorly responsive to treatment. The purposes of this study were to retrospectively evaluate the history, signalment, and clinical signs of dogs with IMC; compare the outcome of affected dogs treated with traditional chemotherapy with those treated with piroxicam; evaluate Cox-2 expression of IMC cells; and correlate Cox-2 expression with outcome based on treatment. Strong cyclooxygenase-2 expression was present in all tumors. Improvement in clinical condition and disease stability was achieved in all dogs treated with piroxicam, with mean and median progression-free survival of 171 and 183 days, respectively. Median survival time of 3 dogs treated with doxorubicin-based protocols was 7 days, which was significantly less than that of dogs treated with piroxicam (median, 185 days). In conclusion, piroxicam should be considered as a single agent for the treatment of dogs with inflammatory mammary carcinoma.