AVACTA Animal Health is launching a new canine lymphoma blood test (cLBT) at the London Vet Show (stand S50).
The laboratory says that the test has been subjected to a blinded retrospective study on serum collected from 57 dogs over four years. It was found possible to accurately and objectively assess remission status in dogs during and after chemotherapy for lymphoma.
The study found that the test detected recurrence up to two months prior to the appearance of physical signs. Furthermore, it was found that the cLBT data obtained from the pretreatment sample were a good prognostic indicator for the disease.
Figure 1 gives a detailed breakdown of data obtained from 23 dogs undergoing treatment for lymphoma, illustrating the mean cLBT scores obtained at time points prior to the appearance of peripheral lymphadenopathy.
The cLBT ranks the remission status from 0 to 5, where 0 indicates complete remission, 5 equates to active diseases and a score of 3 represents a border line result. The study demonstrated that dogs regularly giving a cLBT score of 2 or lower remained in remission, whereas an increase in the score to 3 or more indicated that the disease was recurring.
Veterinary oncologists have suggested that the test be used on a monthly basis to monitor lymphoma patients in remission. This would facilitate earlier referral of dogs to specialists, thereby providing more time to plan appropriate re-induction or rescue strategies. A typical response for a dog undergoing chemotherapy for lymphoma is shown in Figure 2.
Avacta states: “Lymphoma is one of the most common canine cancers, representing 5% of all malignancies. It has an annual incidence of 25 cases per 100,000 dogs. The disease usually presents as painless swellings in the peripheral lymph nodes. However, diagnosis is complicated by lymphoid proliferation in internal organs such as the alimentary tract, mediastinum and bone marrow.
“Lymphoma is classified as low, intermediate or high grade. Around 80% of cases are intermediate and high grade. These tumours comprise cells with a high mitotic rate and rapid disease development. Patients initially respond well to chemotherapy. However, the disease invariably recurs and second round treatment is more difficult, producing only short-lived results. Close monitoring of dogs after treatment and in remission is therefore important since it is generally considered that reinduction or rescue therapies are more effective when recurrence is detected early.
“Monitoring for disease remission and recurrence is performed by palpation of peripheral lymph nodes, and owners are frequently taught to do this. However, it is a subjective procedure capable of only detecting gross changes in peripheral lymph nodes.
“Biochemical methods which measure circulating markers of the disease have the potential to provide greater objectivity whilst detecting changes that precede peripheral lymphadenopathy.
“It is widely recognised that acute phase protein (APP) levels are increased in response to diseases such as lymphoma. In human medicine, Creactive protein (C-RP) is used routinely in the diagnostic work-up of nonHodgkin’s lymphoma. However, individual APPs lack specificity for diseases such as lymphoma.
“Dramatic improvements in test performance can be achieved by employing a multivariate approach using specifically designed algorithms incorporating levels of several serum proteins along with other parameters. The method is analogous to considering multiple factors such as age, breed, physical signs and biochemistry results when making any diagnosis.
“We therefore investigated the application of CRP and haptoglobin in the monitoring of dogs undergoing chemotherapy treatment for lymphoma.”
