Cancer Risk Assessment allows for early detection of cancer and inflammation in dogs, resulting in better outcomes.
Canine cancer is unfortunately a disease that can stay well-hidden for a long time before becoming clinically evident, far into development. With a majority of dogs getting some type of cancer in their lifetime, developing a way to screen for cancer has high value. With this in mind, VDI developed the Cancer Risk Assessment – a dual-marker panel for the early detection of cancer and inflammation in dogs. Early detection of cancer leads to early intervention, access to more options, and better outcomes.
Role of inflammation on cancer
Cancer is an inflammatory disease. While acute inflammation is a critical process to fight pathogens and heal tissue damage, when it becomes chronic it creates an environment that stimulates, promotes, and propagates tumor growth. This makes identifying and resolving non-clinical inflammation critical especially in apparently healthy animals.
Proliferation – a hallmark of cancer
Cancer is a proliferation disease. Under normal conditions cells grow, exist, and die in a controlled manner. When aberrations arise, these cells can begin to proliferate in an uncontrolled way. This is a hallmark of cancer – dysregulated, uncontrolled cellular proliferation. Finding early indications that abnormal cell division is occurring is a feature of early cancer detection.
Developing the Cancer Risk Assessment
The Cancer Risk Assessment (CRA) was developed as a result of recognizing that while transient acute inflammation defends, chronic inflammation is the root cause of many illnesses and actually propagates cancer. As much as the CRA is designed to detect cancer early, it has greater value in detecting chronic inflammation which can be managed before serious diseases develop.
The Cancer Risk Assessment was developed from a large clinical study out of the University of Missouri.2 The initial intent of the study was to examine TK1 and CRP could be used to detect cancer in otherwise apparently healthy dogs but was expanded to look at overall health. In a large cohort of 360 dogs of high risk breeds followed for up to one year, both cancer and serious disease were identified.
Cancer incidence with CRA scores
CRA score: cancer incidence
0.0 – 5.4 : 0.6%
5.5 – 8.9: 19%
9.0 – 10.0: 40%
Mortality increases with CRP level:
CRP (mg/mL): Death Incidence
0.0 – 2.0 : 3%
2.0 – 4.0: 5%
4.0 – 10: 19%
Cancer Risk Assessment Score
Taking the data from the clinical study, the CRA score was developed. CRA is a unitless index from 0 to 10 where 0 is a perfectly healthy, no cancer no inflammation dog, and 10 is a perfect score for cancer. As systemic inflammation increases and abnormal cell replication appears, cancer risk increases.
Using CRA in clinical practice
The Cancer Risk Assessment serves two main purposes: identify risk of cancer and evaluate if chronic inflammation exists. Early detection in apparently healthy dogs leads to early management and intervention.
When to recommend a CRA test:
- Apparently healthy dogs
- Over the age of 5
- High Risk Breeds (e.g. Golden Retrievers)
- Dogs with history of cancer in the line
How often to test:
- For best outcomes CRA should be evaluated every four months
- Six months is a good compromise as 82% of cancers in the study were detected six months prior to clinical signs.
- Annual testing at minimum – anything beyond six months does not hold statistical value and is not included in the risk assessment.
Screening not diagnostics
CRA is a screening test meant for the apparently healthy dog with no signs of cancer. Low, Elevated, and Highly Elevated Risk are not diagnostic and should not be taken as Code Red. Screening tests are designed to be sensitive not specific, so there are chances for false positives. Next steps may include more thorough physical exam, supplementary bloodwork, or serial testing for identifying trends.
The CRA is not a diagnostic test. It is not intended to confirm cancer in a dog but assess risk for cancer developing in the next four to six months. For diagnostic rule-in of cancer, other tests, imaging, or pathology should be used.
1Selting, K.A., Ringold, R., Husbands, B. and Pithua, P.O. (2016), Thymidine Kinase Type 1 and C-Reactive Protein Concentrations in Dogs with Spontaneously Occurring Cancer. J Vet Intern Med, 30: 1159–1166.
2Selting, K. A., Sharp, C. R., Ringold, R. and Knouse, J. (2013), Serum thymidine kinase 1 and C-reactive protein as biomarkers for screening clinically healthy dogs for occult disease. Veterinary and Comparative Oncology