Prospective evaluation of clinically relevant type B hyperlactatemia in dogs with cancer

Background: Cancer is considered a cause of type B hyperlactatemia in dogs. However, studies evaluating cancer as a cause of clinically relevant type B hyperlactatemia (>2.5 mmol/L) are lacking. Cancer cells have a higher lactate production because of increased aerobic glycolysis, known as the “Warburg effect.” The mechanisms through which aerobic glycolysis occurs are not well elucidated, but neoplasia may cause type B hyperlactatemia via this process. Objectives: To determine if malignant tumors of dogs are associated with clinically relevant type B hyperlactatemia (>2.5 mmol/L). Animals: Thirty‐seven client‐owned dogs with malignant tumors: 22 with hematopoietic and 15 with solid tumors. Methods: Histology was used to confirm the diagnosis (cytology was considered adequate for diagnosis of lymphoma). Confounding conditions associated with hyperlactatemia were excluded. Lactate measurements were immediately performed on free‐flow jugular whole blood samples using the LactatePro analyzer. Results: All dogs had lactate concentrations <2.5 mmol/L. Mean blood lactate concentration was 1.09 mmol/L. Mean blood lactate concentrations for solid and hematopoietic tumors were 0.95 and 1.19 mmol/L, respectively. Dogs with lymphoma (n = 18) had a mean blood lactate concentration of 1.15 mmol/L. Conclusions: Malignant tumors were not considered a cause of clinically relevant type B hyperlactatemia. Therefore, cancer‐related type B hyperlactatemia in dogs is uncommon, and hyperlactatemia should prompt careful investigation for causes other than cancer.