Evaluation of the results of a L-asparaginase-based continuous chemotherapy protocol versus a short doxorubicin-based induction chemotherapy protocol in dogs with malignant lymphoma.

The results of an L-asparaginase-based continuous chemotherapy protocol (n = 52) versus a short doxorubicin-based induction chemotherapy protocol (n = 65) were evaluated in 117 dogs with malignant lymphoma. There were no differences between the two groups in patient characteristics or incidence of protocol-related toxicity. Complete remission was induced in 71.2% of the dogs treated with the L-asparaginase protocol and in 67.7% of the dogs treated with the doxorubicin-plus protocol. The calculated Kaplan-Meier one- and two-year survival fractions in the L-asparaginase group were 48% and 26%, and in the doxorubicin-plus group 35%, and 22%, respectively. Differences in remission and survival between the two treatment groups were not significant. A multivariate Cox proportional hazards survival analysis revealed that elevated pretreatment plasma creatinine concentration and prior treatment with prednisolone were associated with shorter survival times. An elevated pretreatment plasma creatinine concentration and total leucocyte count were associated with a decrease in the disease-free period. Differences in efficacy and toxicity between the two protocols were not significant. There is no apparent advantage in using the continuous L-asparaginase protocol, and the shorter doxorubicin-plus protocol is less expensive and less time consuming.