Prognostic significance of morphotypes in canine lymphomas: A systematic review of literature.

Correlation between morphotypes and prognosis of canine lymphomas presented discordant results in literature, leading to some dilemma for application in clinical practice. The aim of this study was to present a systematic review of literature on the prognostic significance of morphotypes in canine lymphomas. Standardized Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria were applied. Retrospective and prospective studies were included. Level of evidence was determined for each study. Some acceptable evidence suggested a significant prognostic impact of morphotypes in canine lymphomas. However, the evidence is not sufficiently robust to determine with precision the most appropriate classification scheme. Updated Kiel and World Health Organization (WHO) classifications seem to remain the most appropriate classification systems with regards to the number of available studies and their levels of evidence. Limitations included lack of randomized control trial, and relative lack of prospective studies available. Current recommended classification of canine lymphoma is the systematic determination of morphotype in each new case. The Updated Kiel and the WHO classifications adapted to dog both remain the schemes with the most valuable interest. Prospective studies in larger population, and international consensus to define precisely each morphotype, are warranted, with application of standardized staging method and treatment.