Objectives: Feline primary laryngeal or tracheal lymphoma (PLTL) is an uncommon extranodal presentation. Information on long-term survival is scarce, although some small case series describe this being achieved with multiagent protocols; an accurate outcome for cats with PLTL is yet to be determined. The aim of this study was to gather information on the clinical presentation, response to treatment and outcome in a large case series of feline PLTL.
Methods: This retrospective multicentre study included cats with a cytological or histopathological confirmation of PLTL. Histopathology samples, when available, were reassessed for grade and immunophenotype. Clinical (age, signalment, retroviral status, presence of anaemia, clinical signs, location and therapy type) and outcome (response, progression-free survival [PFS] and overall survival [OS]) variables were recorded. Survival analyses to assess the impact of variables on PFS and OS were performed.
Results: Twenty-three cases were included; cats had a median age of 11 years (range 2-16) and the male:female ratio was 3.6:1. Common clinical signs at presentation included increased respiratory effort (74%) and abnormal upper respiratory tract sounds (48%). Immunophenotyping was performed in 48% of cases and all were B cell. Debulking surgery was performed in 26% of cases. All cats received chemotherapy, COP (cyclophosphamide, vincristine and prednisolone; 39%), CHOP (cyclophosphamide, vincristine, doxorubicin and prednisolone; 44%) and other protocols (17%); 35% had a partial response and 65% a complete response. Median PFS and OS were 909 days (range 23-1484) and 909 days (range 23-2423), respectively. Complete response was associated with longer PFS (P <0.001) and OS (P = 0.012). Pretreatment with steroids was associated with longer OS (P = 0.003). No other variable was found to be significant.
Conclusions and relevance: PLTL in cats is mostly of a B-cell phenotype, could be of a low-to-medium grade, and may respond to surgical and medical treatment with a longer survival time than has previously been reported.
Keywords: Feline lymphoma; chemotherapy; immunophenotype; prognosis.