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Pet Cancer Treatment – 11 Common Myths

I’m sure y’all remember me talkin’ about my sister Sadie before. She was here before me, but made the trip to Rainbow Bridge before I came here to live.

Sadie’s cancer had spread so far that it was just to late.

She passed on two days after Christmas last year.

In Sadie’s memory, we have some really good information on pet cancer treatment from the folks at  The Center for Animal Referral and Emergency Services (CARES) in Langhorne, PA.

It seems that pet cancer is the leading natural cause of death in dogs and the second leading cause in cats!

That means that about 50% of all dogs and 30% of cats will be affected by a tumor in their lifetimes.

There are a lot of things you hear about pet cancer, but I wanted to highlight these common myths about pet cancer and pet cancer treatment.

Pet Cancer Treatment – 11 Common Myths

11 Myths About Pet Cancer Treatment

1. Cancer doesn’t occur in dogs and cats.

Unfortunately, animal cancer is common. It’s the leading natural cause of death in dogs and the second leading cause in cats.

Around 50% of all dogs and 30% of cats will be affected by a tumor in their lifetimes, and one report shows that 50% of dogs over the age of 10 will die from cancer.

Estimates indicate that cancer occurs at least as frequently in veterinary patients as in human patients.

2. There’s way more pet cancer now than before.

Yes and no. The incidence of some cancers has increased both in humans and in pets, but the perception that pet cancer rates have increased is most likely because most pets now receive better healthcare and live longer lives.

While cancer can occur at any age, it most commonly affects older patients, and since cats and dogs live longer now, more cancer is diagnosed.

3. The environment/my neighbors/commercial dog food/tap water caused my dog’s cancer.

Cancer is a complex disease with both genetic and environmental effects at play.

Because of inbreeding, genetic factors most likely play a much larger role in veterinary medicine, as borne out by the fact that there are breed predispositions towards particular cancers.

But genetics certainly can’t account for all tumors, and environmental exposures may also contribute.

Associations have been evaluated with environmental exposures such as secondhand smoke, herbicides, exposure to paint solvents, urban living, and so on.

We strongly recommend that you not smoke (and not smoke around your pet).

If you have concerns, you may also test for other exposures (tap water, asbestos, radon). However, please know in advance that whatever caused your pet’s cancer most likely will remain unknown.

The best you can do for your pet is to feed a high quality dog food as the main diet, keep your pet’s weight within normal range, provide a safe and loving environment, provide daily exercise, and perform regular checkups and health care as appropriate for your pet’s age.

4. There’s no reason to treat cancer in pets. They’re just going to die from it anyway. Isn’t treatment just delaying the “inevitable?”

Well, aren’t we all just delaying the “inevitable?” That’s just life.

Seriously though, while cancer is often thought of as one disease, it actually is a large and varied group of diseases that all have different outcomes, expectations, and treatment options.

Some tumors are very aggressive, and treatment for these may be unrewarding. But others can be cured.

Most are treated as chronic diseases in veterinary medicine. This means that a patient may eventually go on to succumb to the disease, but treatment is targeted to give the patient a good-to-great quality of life for a substantially longer time period than would otherwise be possible. For many pet owners, this benefit is well worth it. Certainly, it pays to seek advice as early as possible in the course of the disease and to learn what is possible for a particular cancer.

5. I’ve read a lot of books written by veterinarians who seem to know a lot about pet cancer and they’ve recommended treatments. So why do I need to go to a veterinary oncologist? Won’t he or she just charge me more and recommend toxic treatments?

There are veterinarians who have spent a considerable amount of time reading and writing about cancer; however, this experience in no way compares to the training undertaken by a board-certified specialist.

A veterinary cancer specialist has completed 4 years of veterinary school, 1-3 years of internship training, and 3 years of residency training specific to oncology.

A specialist has performed and published research in the peer-reviewed veterinary literature and has also passed a series of examinations both in general internal medicine and in the more specific field of veterinary oncology.

Requirements to pass these examinations include knowing all of the major human and veterinary oncology texts and also the last 10 years of all of the veterinary and major human oncology studies published.

In my time, it meant taking 24 total hours of additional examinations above and beyond those required to become a general veterinarian.

If the information you are reading is not written by a board-certified veterinary cancer specialist, the information may not be as accurate or rigorous as it should be.

Given their extensive knowledge and experience with pet cancer, board-certified veterinary cancer specialists should be your most trusted source of information.

As for treatment, veterinary cancer specialists recommend first what is known to be most effective for a particular patient.

For many pet cancers, recommendations may include cytotoxic (cell killing) drugs and radiation.

This is because the goal of treatment is to either remove or kill tumor cells so that normal cells can survive and thrive instead.

However, please note that every case is different, and if effective alternative options are available, they can also be discussed.

Oncologists recommend treatments known to be effective or potentially effective, and they are the best people to evaluate other recommendations you may have received to determine whether they have any merit or whether they will simply be a waste of your time and money.

6. My dog has cancer, but he seems fine. It’s okay to watch and wait, right?

Not usually. For less aggressive or benign tumors, a watch and wait approach may be okay, but it’s a gamble.

But for the VAST majority of tumors, it’s the wrong way to proceed.

As a tumor grows or spreads, treatment becomes exceedingly more expensive, complicated, and ineffective.

The patient becomes sicker, which means side effects are also more likely as well.

The best chance an owner has of ensuring their pet’s long term survival is to diagnose early and treat quickly and thoroughly.

7. A needle aspirate or biopsy diagnosis is not important prior to surgery, since the tumor is getting removed anyway, right?

Wrong. A diagnosis will help to plan the surgical approach needed to successfully remove a tumor.

Different tumors behave differently, and it’s best to understand the tumor’s nature before removal, particularly for larger tumors or those in difficult spots.

A biopsy is also performed after removal to further confirm the diagnosis and receive a piece of tissue for tumor grade.

8. Why do you need to biopsy after surgery if you already know or suspect the diagnosis?

The biopsy reveals some of the most useful information about a tumor.

It shows whether the margins are clean.

It shows the grade of the tumor. Some say if it’s worth removing, it’s worth a biopsy, and we believe this to be true.

It’s one of the most important pieces of information we have about a particular tumor.

9. My dog will go bald.

It depends on the breed and the treatment.

Even in the worst case, it usually occurs only partially.

This can occur in non-shedding breeds, such as the Bichon Frise, the Old English Sheepdog, and the Poodle.

Hair loss is non-painful and purely cosmetic. It will also grow back after treatment.

10. My pet is too old for treatment.

Age is not a disease.

Most pet cancer patients are older, and statistics provided to the owner generally refer to the effectiveness and tolerability of treatment in older patients.

More important than age is whether a patient is systemically healthy.

11. Traditional chemotherapy will make my pet sick, and my pet will suffer and have a miserable life if I opt for treatment.

Please remember that our goal is your goal – to give your pet a great quality of life for as long as we possibly can and to prevent distress and suffering.

We don’t like it when our patients are sick either! In a quality of life survey performed at the University of Pennsylvania, owners rated their pet’s quality of life while on chemotherapy as an average of 8.9 out of 10, with 1 being the worst and 10 being the best possible quality of life.

Thus, we treat much differently in veterinary medicine than they do in human medicine.

We use many of the same drugs that are used in human oncology, but we use them at much lower doses and do not give as many at the same time to reduce risks of side effects.

In veterinary cancer treatment, less than 1/4 experience adverse side effects, and less than 5% suffer effects serious enough to require hospitalization.

If hospitalization is required, the patient usually improves in 24-72 hours.

The likelihood of a chemotherapy-associated fatality is less than 1 in 200.

If toxicity occurs, we substitute drugs, lower doses, or add in medications to prevent illness from happening again.

For more information on pet cancer, visit The Cancer Center at CARES at

There you can learn about caring for a pet with cancer, read our cancer dictionary, find out all of the treatment options available, read patient tales of pets who have undergone cancer treatment at CARES, and more.

pet cancer

About The Center for Animal Referral & Emergency Services (CARES)

CARES is a full service, specialty referral, 24-hour emergency and critical care veterinary hospital with one clear goal: to provide a gold standard of care for your pet.

The highly trained and compassionate team of veterinarians at CARES collaborate between specialties as well as with referring veterinarians to optimize the care of your pet.

CARES ensures the latest, most advanced and best treatments available. Specialty and referral services include: Anesthesiology, The Cancer Center at CARES, Cardiology, Clinical Pathology, Internal Medicine, Neurology, Ophthalmology, Radiology and Surgery.

Specialty cases are seen by referral from your primary care veterinarian.

CARES also offers 24-hour emergency care. For more information, visit

You can also find CARES on Facebook at

My Lady said she had a lot of questions when she found out Sadie had cancer.

So, we hope this article might help clear up some of the questions and myths about pet cancer treatment for you.

Beyond Comps

Sunday 17th of April 2022

I hope my pet never gets cancer, such a cruel disease.

Dana Rodriguez

Tuesday 10th of March 2020

So sad that our furry friends can get this as well. One of our friends found out her father in law has lung and bone cancer. This was just last week. Then she found out 2 days later her 9 year old boxer has renal cancer and that he wasn't going to last very long with or without surgery. Just heartbreaking.

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