Lymphoma in cats treated with a weekly cyclophosphamide-, vincristine-, and prednisone-based protocol: 114 cases (1998–2008)

Objective—To evaluate the clinical response rate, progression-free survival time, overall survival time, and possible prognostic factors associated with a cyclophosphamide-, vincristine-, and prednisone (COP)-based chemotherapy protocol in cats with lymphoma. Design—Retrospective case series. Animals—114 cats with lymphoma. Procedures—Medical records of cats receiving a weekly COP-based chemotherapy protocol from 1998 to 2008 at the Matthew J. Ryan Veterinary Hospital of the University of Pennsylvania were evaluated for information regarding signalment, anatomic site of involvement, cell morphology, treatment, and outcome. Retroviral status, baseline weight, substage, anatomic location, dose delays, dose reductions, and response to treatment were evaluated for prognostic importance. Results—The majority of cases (94 [82.4%]) were substage b, and the most common anatomic site was the gastrointestinal tract (57 [50%]). Clinical response rate after the first chemotherapy cycle was 47.4%. Response to treatment was significantly associated with progression-free survival time and overall survival time, whereas substage was significantly associated with progression-free survival time. The median progression-free survival time and overall survival time were 65.5 and 108 days, respectively. Compared with nonresponders, responders had significantly longer median progression-free survival time (364 vs 31 days) and median overall survival time (591 vs 73 days). Conclusions and Clinical Relevance—Clinical response after 1 cycle of COP-based chemotherapy was predictive for progression-free survival time and overall survival time in cats with lymphoma; therefore, response after 1 cycle of chemotherapy could be used to guide decisions about further treatment. No new prognostic factors were identified.