Efficacy and toxicity of doxorubicin and cyclophosphamide used in the treatment of selected malignant tumors in 23 cats.

Twenty-three cats with malignant, nonhematopoietic tumors were treated with doxorubicin and cyclophosphamide. Fourteen cats had nonresectable tumors of the mammary gland, and nine had tumors of the oral cavity. Of the cats with mammary gland adenocarcinoma, seven cats had a partial response to treatment and seven cats had no response. Of the cats with oral tumors, one cat had a complete response, three cats had a partial response, and five cats had no response. All 23 cats are dead because of tumor progression or recurrence. Toxic effects were seen in 18 of the cats; most were transient and required no alteration in the treatment protocol. A high response rate combined with acceptable toxicity warrants further evaluation of combination doxorubicin and cyclophosphamide chemotherapy in cats with nonhematopoietic neoplasia.