A Useful Discussion for Dogs With Cancer

I received a question recently that involves a common situation for guardians coping with a dog cancer diagnosis.

So, to benefit everyone, I am including my answers here, in the hopes that you can apply the information to how you manage your dog with cancer.

This case is Almond, who is a 10 year female mix.  Almond’s guardian was advised to watch a growth to see if it increased in size.

I believe that, since half the dogs over the age of 10 will get cancer, that every mass should be checked with at least a fine needle aspirate.

We cannot tell if a tumor is malignant with the naked eye most of the time.  And we cannot tell if a tumor that is not increasing in size is not sending cells off to internal organs (metastasizing).

Almond’s guardian eventually had the growth removed and biopsied.  Good work. Always get that pathologist’s report so you have some idea of what to expect from this growth. Some are benign too, or some are completely removed with a single surgery.  So always get the biopsy report.

The path report revealed a grade 2 mast cell tumor. Now, it is true that all mast cell tumors have the potential to be malignant. But here we have general guiding information that this is an intermediate grade, meaning some aggressively spread and some do not. So we have a gray zone to deal with in what we can expect.

This can be frustrating. Luckily, for some cancers, there are further tests that can be done to pinpoint more accurately these gray zone path report.

Mast cell tumors, and other cancers, have something called mitotic index. This is the relative number of dividing cells that the pathologist sees on the slide. Higher mitotic index usually means faster growth and more aggressive behavior.

Generally, with grade 2 mast cell tumors, if the mitotic index is 5 or less, these tumors behave in a more benign fashion.

This means that the odds of spread are low after a proper surgery is done.  Having said that, we still need to realize that some of these can surprise us and spread.  But all told, most of these will be cured with a wide excision.

Wide excision means that a large swath of normal appearing tissue is removed around the lump (tumor).  This increases our odds of removing the cancer completely.

If we receive a diagnosis of mast cell tumor, or any cancer that has the potential to be life threatening for that matter, I always advise a wide excision around the tumor site, even if this means a second surgery.  Get the bad cells out if you can.

This would be a good thing for Almond’s mom to consider first, if the surgery was not initially a wide excision.

Almond’s treatment plan was discussed.  One of the first steps in dealing with dog cancer is to define what kind of person are you, as a guardian?  Is your priority life extension or life quality? Both? Most conventional steps, in particular chemotherapy and radiation, have life quality effects that are in proportion to life extension gained.

This means if we get better cancer responses, the odds of treatment side effects go up.

You must define what your priorities are.  Write it down. This will be your guide in how you make treatment decisions.

Next is the topic of what other steps should be taken.  Chemotherapy was brought up (we will get to this in a moment).  However, I wonder what about diet? Apocaps? Other supplements? Life quality enhancement? These are useful measures to take when a dog is producing tumors.

What about chemo? Well, getting data is a good thing.  We have looked at Palladia in a few posts.  By the way, please use the search bar to the right of this screen to search for specific cancer topics.

We see that 42.8% of dogs respond to this chemo drug, and that the response length averages, at most, 4.5 months.  Hm.  To answer whether or not this is a good gain, we must go back to that question: what kind of person am I?

How about side effects? Here is the data submitted to the FDA for approval of Palladia as a New Animal Drug at a dose commonly used in practice:

Dose:  3.5 mg/kg every other day

No of Dogs: 20

Side effects:

Diarrhea : 50%

Anorexia (loss of appetite): 40%

Vomiting: 5%

Fatigue  15%

Hind limb weakness: 15%

Neutropenia: (drop in the numbers of a white cell): 0%

Do these numbers hold for every dog?  Of course not. Twenty dogs were used.  These side effects may not happen, or other side effects could possibly happen that did not occur in these twenty dogs.

And perhaps the doses being used by a given oncologist are lower than the dose assessed here, which also would tend to lower side effects.

However, this is a guide, a starting point to assess what the side effects odds could be.

Now, Almond’s guardian has the data she needs.  Perhaps the benefits of Palladia are sufficient for her to treat her dog, taking into consideration the big picture, or perhaps not.

It all depends on the answer to the question: what kind of person am I?

For more information like this, read The Dog Cancer Survival Guide.

Best,

Dr D