If your vet suspects that your dog may have Canine Lymphoma, there are two primary ways to test for the disease – Biopsy or Fine Needle Aspiration.
In the past, full surgical biopsy of the potentially affected lymph node was the best and only way to test for Canine Lymphoma. However, in recent years, for the reasons discussed below, Fine Needle Aspiration tests have become increasing prevalent.
A biopsy is a full surgical procedure, under which your vet will sedate your dog, cut into the affected area, and remove the potentially affected lymph node to be tested. This removed lymph node will then (in rare cases) be studied by your vet, or more often will be sent to the pathologist to be evaluated for signs of Canine Lymphoma. The pathologist will then dissect the lymph node and study portions of it under a microscope to determine whether any of the cells show telltale signs of the disease.
Because biopsies are full (though relatively minor) surgical procedures, they can be expensive (costing as much as $500 to $600 or more in many cases) and can put a strain on your dog (as a result of having to undergo general anesthesia and the pain and exhaustion of recovery from being cut open to have the lymph node removed).
[Note: While it’s not necessary to remove the entire lymph node to complete this biopsy test, the preferred practice is to remove the entire node, since this can provide the pathologist with more material to test for the disease, and since there’s no significant disadvantage to removing the entire node instead of just part.]
Fine Needle Aspiration
In recent years, vets have begun to use Fine Needle Aspiration tests much more frequently to test for Canine Lymphoma, to the point where Fine Needle Aspiration is now the primary test used in the majority of cases.
For a Fine Needle Aspiration, your vet will use a needle attached to a syringe, to pierce and draw a few cells out of the potentially affected Lymph Node. In most cases, your vet will perform this procedure several times, in several different parts of the Lymph Node to ensure that he has a representative sample of the tissues for inspection.
These removed tissue cells will then be sent off to a clinical pathologist who specializes in diagnosing Canine Lymphoma, to study the cells under a microscope and determine whether any of the cells appear to be cancerous. This test generally takes 1 to 2 days before results are reported back to your vet.
Note that in some cases, the results of these tests may come back inconclusive (or in certain cases there may be “false negatives”). The reasons for this include: 1) a non-affected lymph node was tested, 2) lymphocytes are really fragile and can rupture during this testing process, making it hard for the pathologist to determine a diagnosis, or 3) it could be really early in the disease process and not enough of a lymph node is affected by the disease to make a confident diagnosis.
Although Fine Needle Aspiration tests may not always be as accurate as a full biopsy (though in most cases they are almost as accurate), there are many advantages to using this type of test over a full biopsy. In particular:
- The Fine Needle Aspiration process is much gentler on your dog. Unlike a full biopsy which requires a full surgical sedation and removal of the potentially affected lymph node, a fine needle aspirate can be done much more quickly and easily, without sedation, and with a significantly easier recovery period.
- Since Fine Needle Aspiration does not require a full surgical procedure it costs much less. For example, while costs can vary significantly from vet to vet and around the country, in Dr. Freeman’s office the cost of a Fine Needle Aspiration test is generally about $200 (compared to an approximate of $500 to $600 cost for a full biopsy procedure)
- Results for a fine needle aspirate are returned within 1 to 2 days versus a biopsy which can take 3 to 5 days for results.
Other Canine Lymphoma tests (primarily to determine staging)
As discussed in the section on Canine Lymphoma Stages, beyond just knowing whether your dog has Canine Lymphoma, it’s often important for your vet to understand the extent that the disease has progressed. This determination is called “staging,” because it determines which of the 5 defined stages of the disease your dog is dealing with. And in many cases, the stage of the disease can help determine how well certain treatments may work for the patient.
Note: While “staging” for Canine Lymphoma can be extremely valuable to help your vet determine the types of treatment available, in certain cases the staging process may be helpful only to determine the prognosis, or likelihood of certain results or the possible length of remission for your dog. In those cases, the recommended Canine Lymphoma treatment may be identical, regardless of the actual determination of Canine Lymphoma stage.
Traditionally the tests required to fully stage a Canine Lymphoma diagnosis include:
- Chest X-Rays
- Abdominal Ultrasound
- Blood Tests (Full Blood Panel)
- Bone Marrow Aspiration
However, many vets, including Dr. Freeman, do not require all of these staging tests for their patients. The reason for this is primarily related to the cost of these tests (it can be really expensive to fully stage a patient – see Canine Lymphoma Treatment Cost) compared to the actual benefits of the information gained from each test. And under certain circumstances (for example in cases of financial hardship, etc.), clients may decide to skip certain tests (or the staging process entirely) to use the funds saved to cover the actual cost of treatment instead.
As noted above, because of the value of staging the disease in many cases, we only recommend this in limited cases where financial hardship makes it difficult for the owner to pay for both the tests and the treatment. You should discuss what tests would be most beneficial for your pet depending on the circumstances.