Abstract

The Lymphocyte-to-Monocyte Ratio (LMR) has been described as a useful prognostic marker for human patients with various cancers and dogs with diffuse large B-cell lymphoma. The objective of this study was to determine whether the LMR could predict disease outcome as measured by the Time To Progression (TTP) and Overall Survival (OS) of dogs with different types of high-grade lymphoma. The medical records of 43 dogs diagnosed with high-grade lymphoma at the Veterinary Medical Center of Obihiro University of Agriculture and Veterinary Medicine between 2013 and 2018, were retrospectively analyzed. Receiver Operating Characteristic (ROC) curve analysis was used to determine the optimal LMR cutoff values. The prognostic influence of the LMR and other clinicopathological data on TTP and OS was studied by Kaplan-Meier curves. To identify the independent prognostic factors, univariate and multivariate Cox proportional analyses were used. The optimal cutoff value of the LMR was 0.7, which corresponded to the maximum sensitivity (0.727) and specificity (0.762) of the LMR for predicting the median days of OS with ROC analysis (area under the curve, 0.794). Log-rank tests showed that dogs with a high LMR had significantly longer TTP and OS than dogs with a low LMR. Moreover, immunophenotype, body weight, treatment regimen and response to treatment were significantly associated with TTP and OS. In multivariate analysis, treatment and response to treatment were independent risk factors for TTP. Moreover, the LMR, treatment regimen and response to treatment were independent predictors of OS.