Survival analysis of 97 cats with nasal lymphoma: a multi-institutional retrospective study (1986-2006)

Abstract

BACKGROUND: Feline nasal lymphoma (NLSA) is a condition for which no standard of care exists. HYPOTHESIS: There is no difference in survival times of cats with NLSA treated with single or multimodality therapy. ANIMALS: Records from 97 cats diagnosed with NLSA were examined. METHODS: The purpose of this retrospective study was to compare the survival times of cats with NLSA treated with radiation therapy (RT) alone, chemotherapy alone, or RT + chemotherapy and identify potential prognostic variables that affected survival. Cats were grouped according to therapy: RT + chemotherapy (n = 60), RT alone (n = 19), or chemotherapy alone (n = 18). RESULTS: Survival was calculated with 2 methods. The 1st survival analysis (method A) included all cats, but counted only deaths caused by progressive NLSA. The median survival time (MST), regardless of therapy modality, was 536 days. The 2nd survival analysis (method B) also included all cats and counted all deaths, regardless of cause, as events. The overall MST calculated for all deaths was 172 days. A negative independent prognostic variable identified was anemia (P < .001), and positive independent prognostic variables were a complete response to therapy (P < .001) and total radiation dose >32 Gy (P= .03). CONCLUSIONS AND CLINICAL IMPORTANCE: There were no significant differences in survival times among the 3 treatment groups but these results suggest that the addition of higher doses of RT to a cat's treatment protocol may control local disease and therefore influence survival.