Correlation between clinical variables and overall survival time in dogs with multicentric B-cell lymphoma: a retrospective study in Taiwan.

INTRODUCTION: Multicentric B-cell lymphoma (MBCL) is one of the most commonly diagnosed spontaneous hematopoietic malignancies in dogs. However, few studies have characterized dogs with MBCL in Taiwan, and the prognostic value of clinical variables, including clinical substage and treatment response, remains under investigation. This study aimed to characterize canine MBCL in Taiwan and evaluate associations between selected clinical variables and overall survival time (OST). METHODS: Medical records of 441 dogs diagnosed with lymphoma were retrospectively reviewed. Cases with peripheral lymph node enlargement and uniformly large neoplastic cells on cytology and/or histopathology were included. Immunophenotypes were primarily determined by flow cytometry, with PCR for antigen receptor rearrangement used in a small subset for clonality assessment. Dogs that completed at least one full cycle of CHOP chemotherapy were included in the OST analysis and stratified by clinical variables. RESULTS: Dogs with clinical signs (substage b) had shorter OST (median, 140 days; 95% CI, 126-199) than asymptomatic dogs (substage a: median, 186 days; 95% CI, 164-248). Dogs achieving complete or partial response to CHOP had longer OST (median, 196 days; 95% CI, 151-239) than dogs with stable or progressive disease (median, 182 days; 95% CI, 140-196). No significant differences in OST were observed according to serum calcium concentration (>10.5 mg/dL) or advanced clinical stage (IV-V). Cox proportional hazards analyses indicated that clinical signs (HR, 2.27; 95% CI, 1.04-4.96; p = 0.040) and failure to achieve an objective response (HR, 2.09; 95% CI, 1.06-4.16; p = 0.035) were associated with increased mortality. DISCUSSION: This study provides the first epidemiological and immunophenotypic characterization of canine MBCL in Taiwan. Clinical substage and initial response to CHOP were associated with OST, although further prospective studies are needed to validate these findings and more comprehensively characterize canine lymphoma in Taiwan.