Q: Is there a blood test that I can get to see if my pet has cancer?

A: There is not a single blood test that detects all cancers. If such a thing existed, I suspect you and I would be getting the test frequently. There are certain cancers that can be detected using blood tests, but usually we base the need to run those based on abnormalities on physical examination, general blood panels, or suspicious history or genetics.

The most successful treatment of any cancer is to detect it as early as possible. That’s why the American Veterinary Medical Association, American Animal Hospital Association, and American Association of Feline Practitioners all recommend physical examinations every six months and blood testing at least once a year. Each of these organizations also recommends increasing the frequency and thoroughness of laboratory testing in pets when they are the equivalent of 50 to 75-years-old in “human age.” For most pets, that is between seven and fourteen years of age, but it varies based on size. Those are the ages when early detection of cancer and other diseases is most likely to make a difference. During those years, some type of blood panel every six-months is the standard recommendation of every major professional organization.

Most people understand this concept from their own medical care.  Cholesterol screening can lead to treatments that prevent heart attacks.  Regular mammograms, colonoscopy, and prostate evaluations can catch cancer in very early, treatable stages.  Thanks in large part to the success of routine screening, people are living longer, healthier lives than ever before.

When pets enter the “over fifty” crowd, pets should graduate to more thorough laboratory screening tests than younger pets.  In addition to certain cancers, complete blood counts can detect chronic inflammatory conditions, platelet problems, and anemia.  Serum chemistries can detect diabetes, liver conditions, kidney impairment, digestive problems, hormone imbalances and more.  Frequently, a thorough serum chemistry panel will be our best chance of catching illnesses in their earliest stages.  A urinalysis provides important information on kidney function, bladder health, and can even detect liver problems or diabetes. Although these aren’t specifically “cancer tests,” they can alert your veterinarian to a problem that may warrant additional diagnostics, including tests for specific type of cancer.

Q:  When I took my dog in for a vaccine, the veterinarian found a small lump located on her lower shoulder area. It’s only about the size of a blueberry. The doctor took a needle aspirate and told me it is a mast cell tumor. Do you think it is worth having the mass removed and biopsied?


A:  I absolutely recommend removal of the cancerous tumor. Mast cell tumors are very common, accounting for about 15% of all skin lumps in dogs. Although they feel innocent, mast cell tumors can be fatal and could spread through the blood without ever appearing aggressive on the outside. The good news is that many can be cured with surgery alone – but only if caught early.


After removal, it’s important to have the mass biopsied to stage it and to be sure it was all removed. If the biopsy comes back as grade one, then most will be cured with surgery alone. Grade two masses with wide surgical margins also have a good prognosis, although they can return and still have the potential to have already spread. If the surgical margins are not clear by a wide margin, most oncologists recommend additional treatment, including oral medications. Grade three tumors are likely to have already spread and warrant additional diagnostics and treatment.


Three quarters of mast cell tumors are either grade one or grade two. Unfortunately, there is no reliable way to grade the mass ahead of time. They generally look harmless, but certainly can be real trouble.