Outcome of cats with low-grade lymphocytic lymphoma: 41 cases (1995-2005)

Objective-To evaluate factors associated with response to treatment, remission duration, and survival in cats with low-grade lymphoma affecting various organ systems. Design-Retrospective case series. Sample Population-41 cats with histologically confirmed low-grade lymphocytic lymphoma. Procedures-Medical records and biopsy specimens of cats with histologically confirmed low-grade lymphocytic lymphoma of various organ systems treated with prednisone and chlorambucil between 1995 and 2005 were reviewed. The Kaplan-Meier method was used to estimate remission duration and survival. Factors potentially associated with prognosis were compared. Results-Common clinical signs were weight loss (83%), vomiting (73%), anorexia (66%), and diarrhea (58%). Seventy-eight percent of cats tested had low serum cobalamin concentrations. Lymphoma was confined to the gastrointestinal tract in 68% of cats. Fifty-six percent of cats achieved a complete response to treatment, and 39% achieved a partial response. Five percent of cats had no response. No association was found between any risk factors (including anatomic site) and response to treatment. Partial response was associated with shorter remission duration, compared with complete response; median remission duration was 428 days for cats achieving a partial response, compared with 897 days for cats achieving a complete response. No other factors were associated with remission duration. Overall median survival time was 704 days. No factors were significantly associated with survival time. Conclusions and Clinical Relevance-Most cats with lymphocytic lymphoma responded to treatment with prednisone and chlorambucil, and most factors evaluated were not associated with outcome.