How does a veterinarian know what kind of cancer my dog has?

It depends on the location of the cancer, so let's say I find a lump on your dog or your cat. I'm going to either do a punch biopsy or a needle biopsy to hopefully get cells that tell me what type of cancer it is. Depending on what the diagnosis is from a pathologist, it will help me determine what the next plan is going to be.

We’re also going to take X-rays quite often to check the chest and look for Mets and look in the abdomen to make sure nothing is going on there.

So it depends on the cancer. They all have a little bit of different behavior. If we find enlarged lymph nodes, we're going to see if this is lymphoma. And then we're going to look for where that is and what type of lymphoma it is to determine what type of chemotherapies we're going to recommend. On top of the type of cancer, we want to know that cancer’s general behavior, whether it's one that metastasizes or it's just localized cancer, and then we just go from there.

It depends on several things. Sometimes we can figure out what type of cancer a dog has based on a fine needle aspirate, where I stick a needle into a tumor, for instance, and look at it under the microscope. Certain tumors are relatively easy to diagnose that way, like a mast cell tumor in the skin is an easy one to diagnose that way. We can diagnose some of them in the office. For others, we take a biopsy sample. We take a little piece or the whole tumor in some cases and send that to the laboratory. A veterinary pathologist looks at them and does histopathology and gives us that diagnosis.