Skip to content
Featuring Demian Dressler, DVM and Susan Ettinger, DVM, Dip. ACVIM (Oncology), authors of The Dog Cancer Survival Guide

Is Dog Cancer Treatment the Same as Prevention?

Updated: October 4th, 2018

I’ve been thinking about a distinction that deserves way more attention from those who want to be their dogs’ primary health advocate.

Why are distinctions important? One meaning of distinction is, “the act of making or keeping distinct”.  So there is action implied in distinctions.  Many time actions are built in to words because they are useful.

How does this relate to dog cancer?  Well, let’s look at a distinction that has gotten practically no attention among dog lovers, but should: dog cancer treatment versus prevention.

Why is this distinction significant?  We have to go back to the origin of cancer to answer that question.  In The Dog Cancer Survival Guide, there is a truckload of information on this topic for those that want it. But let’s skim the surface as a refresher…

Cancer gets going once there are a number of things that have gone wrong. First, there is enough DNA injury to mess up cell growth genes to get them stuck in the “on” position.  Cell growth genes stuck in “on” makes cells multiply uncontrollably.  Second, the immune system weakens so much it cannot react to the cancer cells to eliminate them. Third, the environment in the body is deranged to the point where it literally favors the growth of cancer.

These things piled on top of each other yield cancer. However, this is a long road, sometimes taking generations to finally become full-fledged cancer.

Okay, let’s switch gears for a little bit. If I were to suggest that doxorubicin, a common chemotherapy drug, should be given to dogs to prevent cancer, people would rightfully say I was nuts. You don’t give a cancer treatment drug to a healthy dog!

Why is that? Well, by the time cancer is really rolling, things are have become monstrous.  Conventional care uses big guns to try to overcome these monstrous changes. Not only are the changes massive, they are self-propelled.  It is this fact that helps explain why (at this moment) we do not have a cure for systemic cancers.

Now here’s where it gets a little fuzzy.  There is a common perception that the stages leading up to cancer are the same as those after the cancer cells start multiplying.  This is a misconception.

Some of the little tiny steps leading up to cancer development (and there may in reality be thousands or millions of these, which is another story) can be derailed.  When a little step is blocked, we have prevented that little step on the road to cancer. This is what you call cancer prevention.

Now, there are certain things that, at least in test tubes, petri dishes, and sometimes in living bodies, seem to be able to derail some of these steps. For example, one old idea was that free radicals damage DNA, and DNA injury can yield a growth gene stuck in “go” mode.  You provide an antioxidant, the free radical load can go down, and the old thinking was that this could maybe help prevent cancer (but not necessarily in reality…there is data now that cancer rates or recurrences may actually be higher in people who take antioxidant vitamins.

Let’s focus on a different scenario altogether now. If you provide  an antioxidant effect to an existing cancer cell (with no other effects), and there is a decent theoretical argument that this nasty little cell will be happier.

If one were to buy the old argument that antioxidant vitamin supplementation helps prevent cancer, and was blurring the distinct concepts of prevention and treatment, this would seem very surprising.

Wait, did I just write that? Yes, you read correctly.  Cancer cells are extremely busy cells. They produce a lot of free radicals within them, and they are not that good at quenching these damaging by-products, at least not like healthy cells can, with their much lower free radical loads.

So a cancer cell filled with free radicals might really like it (again, theoretically) if you provided it with a way to get rid of all those damaging free radicals it is producing.  If one were to buy the old idea that antioxidants prevent cancer, given this information, you might also need to buy that antioxidants help make existing cancer cells happier.

It gets quickly apparent that if you treat cancer prevention as if it were cancer treatment, things can get pretty confusing.

The point here is that many in the alternative medicine community suggest cancer prevention steps for dogs that already have clinical cancer.  This is an error and needs attention.

Cancer treatment and cancer prevention are different.

Bottom line?  If someone gives you some data supporting the use of a therapy in cancer prevention,  ask about data for cancer treatment.  Although there is overlap, these really are not the same issues.


Dr D

Discover the Full Spectrum Approach to Dog Cancer

Leave a Comment

  1. adventuresofabeautyqueen on October 31, 2017 at 12:13 pm

    Hello Doc, my dog had a lumpectomy a month and a half ago and the biopsy showed it was an MCT.

    Now my question: Do I stick to cancer prevention now that the lump has been taken out or do I focus on cancer treatment since my dog has had a cancerous tumor?

    Thank you

  2. Dog Cancer Vet Team on February 21, 2010 at 9:58 pm

    The RSS feed is fine. If you would like to subscribe via RSS, please go to

Scroll To Top