Outcomes and prognostic factors in canine T cell lymphoma treated with lomustine, vincristine, cyclophosphamide, and prednisone chemotherapy

The most common first-line treatment for canine lymphoma is a chemotherapy protocol that includes cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP). Canine high-grade T-cell lymphoma has been found to have a significantly poorer prognosis than high grade B-cell lymphoma. Several studies have investigated alternative protocols for non-indolent T-cell lymphoma. This retrospective study investigated using a cyclophosphamide, lomustine, vincristine, and prednisone protocol (CLOP) for naïve non-indolent T-cell lymphoma patients. In this retrospective study, medical records of dogs treated for non-indolent T-cell lymphoma at a veterinary teaching hospital from 2017 to 2022 were reviewed. Response rate, toxicity, progression-free survival and survival time were calculated. Factors potentially related to prognosis were statistically analyzed. Twenty-six dogs were included in the study. The median progression-free survival (PFS) time was 166 days (95% CI 119–213). The median overall survival time (OST) for the whole study group was 318 days (95% CI 239–374). Twenty-four dogs experienced gastrointestinal adverse events during the protocol, with 79% of them being grade 1 or 2 as per VCOG-CTCAE v2. This protocol has shown similar median PFS time and OST compared with previous studies for canine non-indolent T-cell lymphoma treated with CHOP, along with minimal toxicity, and suggests the inclusion of lomustine in first-line chemotherapy protocol against canine non-indolent T-cell lymphoma may be beneficial.