Treatment of Dogs with Lymphoma Using a 12-Week, Maintenance-Free Combination Chemotherapy Protocol

Abstract

Abstract Background: Treatment of lymphoma in dogs by long-term chemotherapy has favorable results. However, the efficacy of short-term, maintenance-free treatment protocols on remission and survival times in dogs has not been determined. Hypothesis: That treatment using a 12-week chemotherapy protocol would be associated with satisfactory treatment outcome in dogs with lymphoma. Animals: 77 dogs with histologically or cytologically confirmed diagnosis of lymphoma. Methods: Prospective clinical trial in which dogs were treated with a 12-week chemotherapy protocol consisting of L-asparaginase, vincristine, cyclophosphamide, doxorubicin, and prednisolone. Results: Complete remission rate was 76.3%. Multivariate logistic regression analysis revealed that clinical substage (P= .006) and immunophenotype (P= .003) had a significant influence on the likelihood of a dog achieving complete remission. Median duration of first complete remission was 243 days (range 19–1, 191 days). The 6-month, 1-year, and 2-year remission rates were 68%, 28%, and 16%, respectively. In the multivariate analysis of patient variables, immunophenotype (P= .022) revealed a significant influence on first remission duration. Toxicosis was mild with the exception of 1 treatment-associated death. Conclusions and Clinical Importance: In this group of dogs the 12-week maintenance-free chemotherapy protocol was well tolerated and had satisfactory results.