L-Asparaginase, Doxorubicin, Vincristine, and Prednisolone (LHOP) Chemotherapy as a First-Line Treatment for Dogs with Multicentric Lymphoma.

Cyclophosphamide exhibits the weakest therapeutic effect compared with vincristine and doxorubicin in the CHOP (C, cyclophosphamide; H, doxorubicin; O, vincristine; and P, prednisolone) chemotherapeutic protocol for the treatment of canine lymphoma. Twenty dogs with multicentric lymphoma were treated using the LHOP protocol, which used l-asparaginase in place of cyclophosphamide, and the outcomes were historically compared with those of dogs that received CHOP chemotherapy in the same institution. No significant differences were found in age (p = 0.107), body weight (p = 0.051), sex (p = 0.453), clinical stage V (p = 1), substage b (p = 0.573), T-cell phenotype (p = 0.340), overall response (p = 1), and hypercalcaemia status (p = 1) between the LHOP and CHOP groups. The adverse effects of l-asparaginase were well tolerated and self-limiting. The median PFS (progression-free survival) and median ST (survival time) in the LHOP group were 344 days (range: 28-940 days) and 344 days (range: 70-940 days), respectively. The median PFS and median ST in the CHOP group were 234 days (range: 49-1822 days) and 314 days (range: 50-1822 days), respectively. The dogs that received LHOP chemotherapy had a significantly longer PFS than the dogs that received CHOP chemotherapy (p = 0.001). No significant difference was observed in ST between the LHOP and CHOP groups (p = 0.131). Our study findings thus indicate that the LHOP protocol can be used as a first-line chemotherapeutic protocol in canine multicentric lymphoma.