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

Is There A Reason For All This Dog Cancer, part 2

Updated: May 15th, 2024

Reasons for Dog Cancer

What are the possible causes of my dog’s cancer?

In my last post, we looked at some of the connections between the environment, diet, and cancer development. We also examined how similar cancer is to the body’s reaction to an injury, as if it were healing a damaged or wounded organ in a deranged way.

Today, I’ll continue some of my thoughts about why the cancer rates are so high these days, for dogs, humans, and other animals.

We have discussed in the Guide and here on this blog the effects of estrogen disruptors, which are chemicals that mimic the effects of hormones, most commonly estrogens.  Estrogen is a pretty common stimulatory signalling molecule for cancers, especially when other things are also stimulating cancer growth. Its is odd that these compounds like BPA which are found in many plastics (food containers, plastic liners of cans, etc), pesticides, unmetabolized birth control pill residues from water treatment plants, work their harmful magic in low doses instead of high doses.  And there is now yet another resurgence in interest about the effects of estrogen disruptors.

Then we have the old fatty acid issue. The short story is this: too much of certain fats (omega-6 fatty acids) create inflammation, increase cancer, and suppress the immune system. These are found in grain fed cow products (red meat, fat, lard), corn, and vegetable oil. It seems the corn feeding of farmed meat animals increases the omega 6 content of the meat, as opposed to grass feeding.  Omega 3 fatty acids tend to offset the effects of excessive omega 6 fatty acids, which is why we discuss fish and krill oil in the Guide. 40,000 years ago, based on fossil evidence anyway, our intake of these two kinds of fats was about equal. In other words, we consumed about equal amounts of omega 3 and omega 6 fatty acids. But now humans take in about 10 times as much omega 6 as omega 3, and dogs consume even more. There is a definite link between cancers and microscopic inflammation.

More dietary issues for you to contemplate. Carbs. Very briefly, carbohydrate excess, at least those starches that are converted to sugars easily, feed developing cancer cells. One of the hallmarks of cancers are their preference and need for simple sugars for fuel. This is so common that there is a name for this trait: the glycolytic phenotype. Its also called the Warburg effect.  So eating a lot of starch in diets, in short, is like fertilizer for cancer cells.  And let’s not forget obesity, affecting about 53% of dogs (which parallels humans btw), leaving them without adequate supplies of adiponectin, an important anti-cancer hormone.

We should not ignore the old immune system. Here we have cancer, a disease characterized by immune compromise, growing in bodies that have crummy immune systems. That’s a bad mix. And why are bodies in the modern world immune compromised? I’d argue its our lifestyles combined with our mental state. Why is this, you might ask? First, we are up, and so are our dogs, often late at night, when we should be sleeping. Light on the retina, particularly blue light late at night, lowers one of the bodies most important cancer-fighting signalling molecules, melatonin. One of the nice things about melatonin is it aids the immune system.

Chronic stress? Of course. Stress hormones, which I believe (but have not measured, so this is speculation) are probably high in dogs as well as humans, suppress the immune system in high amounts. Epinephrine and norepinephrine, signals that are released in the body under high stress conditions, stimulate cancer cells directly.

How about crops? Over the last 40 years, the content of vital trace minerals necessary for normal immune function has slowly dropped, decade by decade. The reason is that the fertilizers used these days usually stimulate bulky rapid growth but lack trace minerals. So repeat growth in plots of land leaches the soil of nice minerals like selenium and zinc which the immune system really needs. So more immune compromise.

Finally, and this is likely a big player, we humans, our dogs, and other pets don’t take in adequate apoptogens. These are phytonutrients, or nutrients from plants, that increase cell death of cancer cells. The ones in the diet are called the dietary apoptogens.  There are over 200 studies in humans and over 20 studies in animals that show eating vegetables and fruits lower cancer rates. There are also many studies in animals that show the dietary apoptogens are chemopreventive, meaning they act like natural preventative chemotherapy. A paper showed that Scotties fed apoptogen-rich vegetables had less bladder cancer (transitional cell carcinoma, which they are prone to).

How would a dog, that does not eat a large amount of vegetables or fruits in its natural diet, get dietary apoptogens (aside from Everpup, that is)? Most of these accumulate in fat, and it turns out that dogs consume the innards of their prey species first, before eating other body parts. Dogs usually consume animals that eat a lot of vegetables, and these animals collect apoptogens in the fat of internal organs, such as the liver.

Even though most have not heard about apoptogens, I have been pushing for their use (for example, by using Apocaps) in dogs with cancer. Slowly, slowly the idea is catching on, and recently James Watson, one of the Nobel prizewinners for his work in discovering the structure of DNA, recently published an article that argued cancer medicine should go in this direction too.

So, how can we pull all of this together?  There has been a lot of information in the last two posts, and to be honest I did not even cover everything for fear that the readers of this post would not only be bored, but also depressed.  Thus we will cut to the chase at this stage, and summarize my thinking at this time.

First, cancer appears very much like a body healing from an injury in an uncontrolled manner. Bodies are exposed to substances in the air, water, and diet that injury body cells. Whole body inflammation is increased by diet fats and obesity, when normally inflammation should occur in injured body areas. So we have not only ongoing microscopic injury occurring for years and years, but we also have things creating a body that seems like it is injured by mimicking injury physiology. Cell growth control is lost not only because one of the areas damaged are growth genes, but probably more importantly, the environment within the body appears injured, and the signals to heal are turned on excessively.

If we look at the risk factors for cancer, most if not all of them can be reduced to elements of an actual acute injury, chronic injury, or the body’s response to injury, directly or indirectly. This is a critical point in understanding this unified way of looking at cancer. But since the “injury” is not in a single location, there is no actual single wounded area, and the entire body is involved, there is no tissue organization in the activated tissue (cancer) growth. It is chaotic, out of control, and progressive. This systemic injury idea of mine is a key point that is being largely ignored right now in current research.

I hope these last two blog posts are helpful in understanding more about why cancer rates are so high right now.


Dr D







Leave a Comment

  1. Amber Drake on December 20, 2017 at 3:46 am

    Hello, Caitlin.

    Yes, a decreased dosage of Apocaps CX still has benefits to your dog. It’s better to have a decreased dosage, than not provide Apocaps CX at all.

    We hope this helps.

    Sending warm wishes and cuddles to you and your boy.

  2. L C Leveson on May 4, 2013 at 9:03 am

    Dear Sir
    My dog a Germansheperd/cross bordercollie,was diagnosed with liver cancer on April 10th and given steroids for appetite.This week within five days the tumour had grown and yesterday May 3rd was put to sleep.I just gave him
    asprin for pain, but my doubts are this did nothing.apart from this,he would always have fresh meat fish lasagne.i would like to know how these tumours manifest themselves,and become agressive which no medication can halt or reduce.He was 11years 11months 3 days old and never had an ilness in his life

  3. Jean on April 29, 2013 at 4:21 am

    I have a Parvo survivor. I moved and had to start with a new vet for the vaccinations. I told the nurse she was a Parvo survivor. She needed her gland releaved so the nurse took her in the back to do this. While she was in the back they administered the vaccines. When we arrived home, later in the day my dog began sneezing repeatedly. I couldn’t think what could be the problem because she was fine before the visit. When I looked over the bill I saw they administered Bordetella Intranasal. I called and asked why they would do that (to me that is usually not part of annual shots for a 3 yr old dog) especially one who had Parvo. This was April 24 in June her behavior started to change, Dec. her eye was red (no reason) Jan. a bump appeared above left eye, Feb she was diagnosed with Osteosarcoma. I feel it was the Intranasal vaccine that caused this, especially due to her Parvo history. Thank you for your advise and hopefully more people can avoid harm to their dog’s through your information.

  4. David Day on April 26, 2013 at 1:01 pm

    Dr. Dressler,

    Our 9 year old field Golden Retriever, Thor was diagnosed with lymphoma on Easter. We chose to not do traditional treatments and opted to follow your diet and supplements with Prednisone. We have followed your recommendations for dosing on Apocaps used with prednisone. Thor has gained weight on the diet <80lbs to now 89lbs. Two weeks ago…approx one week after beginning the diet and supplements Thor's liver levels were off the chart. Today his blood work was much improved however his red blood cell count is still low. He is very active and retrieves everyday. Is there anything we can do to increase red blood cells?

    • Dr. Demian Dressler on May 9, 2013 at 3:37 pm

      Hi David,
      I assume your vet told you that pred will increase liver markers? Not sure if it was the pred or the cancer but don’t forget about that. You should be sure that the anemia is caused by the cancer and not some other reason first (blood parasite, GI parasite, blood loss, other problems…)
      Under veterinary supervision you might try Cordyceps and possibly I3C. I3C is outside the box and would be considered experimental. Cordyceps is not that rarely used. Be sure to have veterinary supervision. Could throw a little panax ginsing in there and as a last resort winstrol. Don’t forget to add iron, zinc, red meat to diet, under veterinary supervision.
      Dr D

  5. Jennifer Heim on April 17, 2013 at 9:31 am

    Dr. Dressler,
    I’m still giving my 13 yr old Maltese the dog cancer diet with Apoptogens, fish oil,
    K-9 immunity,ever-pup etc. After a year and half she is still doing well after stage III mast cell tumor removal that had dirty margins. I feel the diet and supplements have been key in her well being and longevity after the dire prognosis. I have a question for you. I had to put my other 12 yr old Maltese to sleep after he became very sick overnight with pancreatitis, diabetes, COPD, heart condition, he went blind overnight from the diabetes, all due to a misdiagnosis of collapsing trachea treated with steriods. I was overwhelmed and devastated with caring for him for three months until he died (he was previously a healthy happy 5 lb dog) I was looking for some dietary advise but there was nothing out there. Do you think you will ever develop a guide like your cancer book to help other conditions like diabetes, or other inflammatory conditions or just an all around how to keep you dog heathy book? If you do, I’ll definitely buy it, dogs owners like myself are in need of guidance. Thank you for the cancer guide!

    • Dr. Demian Dressler on April 24, 2013 at 12:58 pm

      Hi Jennifer,
      I’m so sorry to hear about your other little boy’s passing. Sorry 🙁
      I’m glad your other Maltese is doing well with the steps you are taking. Sounds great! Definitely beating the odds.
      As to another book…well, one of these days I plan on a general health book, so yes, there is a plan for that. But I cannot promise it soon as these things (books) are loooonnng projects! But I do think I will in time. Thanks for the encouragement!
      Dr D

  6. Irene on April 16, 2013 at 10:30 am

    Hi Doc,

    Thanks for all you’ve done, I am grateful you have taken this difficult subject head on. I recently downloaded your book and am reading through it now.

    My dog has recently had a splenectomy with the biopsy coming back as hemangiosarcoma. She is a mix, Shepard, Malmute, Chow about 45 lbs.
    She doesn’t have any other tumors as of yet and is recovering well from the surgery.
    We are giving her the mushroom supplement Im-Yunnity as we read it can be as effective as chemo for this particular type of cancer with no side effects.
    We’re giving her sardine/anchovy oil supplement, and spirulina (from Hawaii) and changed her water from Brita filtered to Alkaline water.
    She’s being fussy about the low cooked healthy food, so for now we’re integrating grain free kibble (which she’s had most of her life) with canned Halo. We’re hoping for as much quality time as possible with our Monkey, as well as the (small) chance ‘it’ disappears completely. There is a chance after all & we’re going to do what we can.

    My question is, what is your opinion of the Apocaps in addition to or instead of the Im-Yunnity mushroom supplement?
    Mahalo for your time,

    • Dr. Demian Dressler on April 24, 2013 at 11:06 am

      Hi Irene,
      sorry to hear about what is going on with your dog.
      I’m Yunity and apocaps are quite complementary, and I use a similar combination frequently. I would definitely finish reading the book and get your action plan further refined! (I am not sure I’d be going with the s.pacifica, btw…but probably won’t hurt much..I’m very familiar with it)
      I’d pulse the water 5 days on and 3-4 days off (the kidneys will start to block the water effects after a while if this is not done)
      Best Dr D

  7. Claire T on April 16, 2013 at 1:59 am

    This is all so very interesting, it all makes sense! Unfortunatly we lost our boy at 8years old to cancer so quickly, I am now scared about what to feed the next dog we get. Scared to use cleaners etc.. I have started buying natural products for the whole house, but for sure, I will be giving our new pup (when we get one!) a totally different diet. Thank you.

    • Dr. Demian Dressler on April 24, 2013 at 11:02 am

      Thanks Clair, glad to help.
      It’s important to be proactive, but also not go crazy. Be safe, protect your dog, but remember they also sense your emotions. Also, I would most definitely be getting some Everpup for you new dog (this is the second time I’m talking about this today but seems people have the same comments, so there you go).
      Thanks for your input-
      Dr D

    • Dr. Susan Ettinger on April 28, 2013 at 11:28 am

      I understand your concerns. I wrote about this also:
      Thanks for reading!
      Dr Sue

  8. D. McHaffie on April 15, 2013 at 10:45 am

    What fruits and vegetables do you suggest we feed dogs?

    • Dr. Demian Dressler on April 24, 2013 at 10:59 am

      Hi D.McHaffie
      Discuss with your vet:
      mainly the ones in the dog cancer diet. Avoid onions, grapes, raisins. Feed pureed, dark colored (green, orange-yellow) leafy greens, brassica (brussels sprounds etc), kale, cabbage, peppers, a few berries, all varying without giving too much of a single one. this is covered in the last chapter in the Guide as well (cancer prevention).
      And for health dogs Everpup., defintely, which is designed to provide necessary concentrations of the benefical apoptogens found in plant material.
      I hope this helps
      Dr D

  9. Anders on April 15, 2013 at 2:43 am

    Terrific 2-part post. Very logical (common sense) based on scientific discoveries. I appreciate your writing as it is very contrite, understandable and effective about communicating your findings. I hope it becomes more mainstream so it helps more people, our planet and our beloved pets. Thank you.

    • Dr. Demian Dressler on April 24, 2013 at 10:37 am

      Thanks Anders.
      It’s odd how common sense, especially if connected to the natural world and governing principles within it, finally seem to be supported by science. So there is this big loop that apparently must be traveled to get back to a more primordial understanding of basic truths. Gotta feed that hungry intellect I suppose.
      Thanks again

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