For pet owners, there is nothing scarier than having their dogs diagnosed with cancer. Sadly research suggests that almost 60% of pets will develop cancer at some point in their lives.

This number is devastating and emphasizes the importance of prevention and early diagnosis and therapy. Understanding the symptoms of cancer in dogs is of imperative significance for every dog owner.

Lately, dog food supplements like omega 3 fatty acids, probiotics, antioxidants, and CBD oil for dogs are of particular interest due to their ability to mitigate the effects associated with standard cancer therapies. 

Keep reading as this article will reveal everything you need to know about using probiotics in dogs diagnosed with cancer.  

Signs Your Dog Might Have Cancer 

When an otherwise normal body function like breathing or swallowing becomes labored or painful it is time to schedule an appointment with your vet. 

Sudden pain and discomfort are always concerning and need to be thoroughly investigated.

These are some of the most common changes indicating cancer in dogs: 

  • Emergence of lumps and bumps under the skin

  • Persistent sores and wounds that do not heal

  • Swollen lymph nodes 

  • Sudden weight loss

  • Lack of appetite (reluctance to eat regular food) 

  • Chronic vomiting and diarrhea 

  • Abdominal swelling

  • Changes in the bathroom habits

  • Difficulty eating and swallowing

  • Difficulty breathing

  • Loss of stamina

  • Persistent lameness

  • Unusual discharge or bleeding from body openings

  • Lethargy and depression

These red flags are not specific for cancer in dogs. Many other health issues manifest with similar symptoms which is why it is best to have your dog checked as soon as you notice any changes.  

Most Common Cancer in Dogs

Most Common Cancer in Dogs

In dogs, there are many different types of tumor affecting different body systems and exerting different health issues. Some are life threatening and some can be managed.

Because of their prevalence in the dog population, the following cancer types are worth describing. 


Hemangiosarcoma is one of the most aggressive dog cancers. It affects the blood vessel’s endothelial cells. All dogs can develop hemangiosarcoma, but age and breed are risk factors – it is more prevalent among middle-aged and senior dogs and breeds like German Shepherds and Golden Retrievers.

Hemangiosarcoma develops slowly and usually does not cause pain, so it is rarely diagnosed before reaching advanced stages. 

Many dogs with hemangiosarcoma die from internal bleeding before being diagnosed with cancer. Less than half of the dogs that receive treatment survive for more than six months.


Lymphoma is the common type of dog cancer. The cancer cells form in the lymphoid tissues distributed in the lymph nodes, spleen, liver, bone marrow, and mucus layer of the gastrointestinal tract. It can affect both the t cells and the b cells. 

Lymphoma is prevalent among Golden Retrievers, Standard Poodles, and Australian Shepherds. Since lymphoma occurs in dogs between six and nine years old, age is a determined risk factor. 

Lymphoma usually manifests with swollen lymph nodes and breathing and digestive symptoms. If caught early, lymphoma is treatable. 


Osteosarcoma or bone cancer is a particularly common cancer type – it accounts for over 85% of the skeletal system cancers in dogs. It is more common among large and giant breeds.

Osteosarcoma can occur in any part of the body but it usually affects the bones forming the wrist, knee, and shoulder. Its clinical manifestation includes limping and limb swelling. 

Mast Cell Tumors

Mast cells are a type of immune system cells responsible for allergic immune responses. They are distributed in all body tissues but the ones located in the skin are most likely to transform into cancer cells.

The mast cell tumors’ aggressiveness varies from relatively benign to aggressive. Mast cell tumors are very common in Boxers.


Melanoma is the most common form of malignant oral tumor. Alternatively, instead of the dog’s mouth, it can develop in the toenail beds.

In both cases, the tumor spreads to the lungs long before signalizing its presence thus making the surgical removal impossible. 

Diagnosing and Treating Your Dog

Diagnosing and Treating Your Dog with cancer

As mentioned, early diagnosis is one of the key management aspects. Early diagnosis and prompt treatment initiation can positively influence the prognosis in certain types of cancer. 

Diagnosing Cancer

Vets diagnose cancer through a series of tests including blood analysis, x-rays, ultrasound, biopsy, MRI, and CT scans.

Sometimes, even the initial physical examination is enough to set the suspicion for cancer. However, definitive diagnosis and staging (determining the cancer’s malignancy and spreading) requires additional tests. 

Treatment Options 

When tailoring the individual therapy plan, the vet will take several things into consideration, including:

  • Age and general health of the dog.

  • Tumor type, biological behavior, and stage.

The therapy options for dogs are similar to human cancer therapies. 


The cornerstone for addressing cancer in pets is surgery. Although oldest, this approach is the most efficient in many situations, especially if the cancer cells are not spread to other body systems.  

Based on the exact circumstances, it can be used alone or combined with other approaches, such as chemo and radiation. 


Chemo refers to the administration of specific chemicals to destroy the cancer cells while sparing the healthy cells in the body. This approach alone is not enough which is why vets combine it with surgery or radiation. 

It should be noted that most chemotherapy drugs trigger side effects in dogs. Plus, not all cancers in pets respond to this type of therapy. 


Popularly known as x-ray therapy or cobalt therapy, radiation is one of the most frequently used treatment options for both people and dogs. It is also combined with other approaches. 

Radiation kills the cancer cells without damaging the healthy ones. This is because radiation targets cells that divide and multiply at a high pace. 

Holistic Therapy 

Most holistic therapies are based on using dietary supplements like fish oil, coconut oil, CBD oil, omega 3 fatty acids, omega 6 fatty acids, probiotics, different herbs, and special foods and diets. 

The goals of these supplements are to reduce pain and discomfort, minimize nausea, prevent inflammation and boost the dog’s immune system function.  

All in all, cancer requires a multimodal approach and it is best if several strategies are used together. 

Probiotics in Dogs with Cancer 

First things first – probiotics are not a cure per se. However, they can help mitigate the side effects associated with chemotherapy and other conventional cancer therapies. 

The use of probiotics in this field of veterinary medicine is relatively new but so far the results are promising.  

What are the Benefits of Probiotics?

Using a probiotic product is the answer to many gut issues. Probiotics are in fact live bacteria (and sometimes yeasts) that restore the microbiome balance in the intestines and promote better digestion. The bacteria in the probiotics are of the “good” kind. 

Considering that an important portion of the immune system is located within the gastrointestinal system, the “good” bacteria promoting gut health also promote healthy immune system function.  

In general, these are the benefits probiotics offer:

  • Improved GI health

  • Enhanced digestion and nutrient absorption 

  • Immune system modulation 

  • Decreased risk of allergic reactions

  • Prevention of urinary tract infections

Are there Any Risks?

After reviewing the benefits, it is time to say a word or two about the risks. In some dogs that have never used probiotics, these supplements can make the digestive issues worse before achieving improvement. 

Additionally, a dog with an extremely weakened immune system, due to old age or disease, can experience issues if receiving probiotics. Namely, certain probiotic strains can overgrow and cause systemic infection. 

Finally, it is estimated that one in a million dogs can develop an allergic reaction to probiotics. Although probiotic-related allergies are extremely rare they are worth mentioning. 

Generally speaking, the risk of developing any adverse effects is more significant when using low-quality probiotics. 

Using Probiotics for Dogs in a Cancer Treatment Plan 

Using Probiotics for Dogs in a Cancer Treatment Plan 

Dogs who receive chemotherapy drugs almost always suffer from gastrointestinal inflammation, resulting in issues like decreased or absent appetite, nausea, severe diarrhea, and weight loss. This specific inflammation is popularly called a “leaky gut.”

This is particularly critical as dogs with cancer need high-quality nutrition to support their immune systems and promote overall health. Even the best diet will not do the trick if the dog cannot consume it or if diarrhea prevents adequate nutrient absorption.

“Leaky gut” is the most common reason dog owners decide to terminate their dogs’ chemo treatments.

Adding probiotic supplements to the dog’s food improves gut health and promotes better nutrient absorption. Probiotic supplements achieve this by reducing inflammation and restoring balance in the gut bacteria.

The implementation of oral probiotic products for dogs is something that needs to be discussed with vets. 

Although most oral probiotic supplements are available over-the-counter, a vet must approve whether they are compatible with the rest of the drugs the dog is receiving.

How to Use Probiotics for Dogs

Most probiotics for dogs come in powder forms that can be easily sprinkled on top of the food. 

Probiotics can be used daily and either alone or combined with other supplement products like omega 3 fatty acids and CBD oil. 

Omega 3 Fatty Acids  

Omega fatty acids are vital for dogs undergoing cancer therapy because of several reasons:

  • Inhibit the pro-inflammatory chemicals that promote inflammation in the body

  • Help prevent the muscle wasting associated with most cancer types

  • Protect the healthy cells during radiation

However, for the omega acids to exert their benefits, the levels of omega 3 fatty acids should be higher than the level of omega 6 fatty acids. Pets fed dry foods (kibble) have inadequate omega 3 to omega 6 ratio. 

To restore the normal ratio and ensure higher levels of omega 3 fatty acids dogs with cancer need supplementation. Fish oil is the best source of omega fatty acids. 


Another way of supporting your dog’s overall health is adding CBD oil to its pet food. CBD oil can help alleviate the pain and discomfort, decrease dizziness and increase appetite, modify the immune system function, and improve the overall quality of life.


When using probiotics for dogs, it is best to add prebiotics too. Prebiotics are a specific type of dietary fibers that promote the growth of the “good” bacteria in the intestines. 

In simple words, prebiotics are food for probiotics. Prebiotics can be found in many high-fiber foods, like pumpkin. 

Our Final Thoughts

dog and owner enjoying sunset

Just like in people and cats, cancer is a common cause of death among dogs. Considering cancer’s multifactorial nature, prevention can be quite a challenge. Therefore, vets are urging dog owners to be diligent when it comes to regular checkups.

The introduction of holistic approaches as part of cancer management in dogs and pets is increasingly popular. More and more vets recommend implementing supplements – herbs, oils, and probiotics to mitigate the effects of either cancer itself or its therapy.

The use of probiotics is of particular interest. Probiotics have been used to support gut health and healthy immune function in people for years, but their use in pets is relatively new. 

Frequently Asked Questions

How do I help my dog with cancer?

Following your trusted vet’s advice and implementing holistic methods to improve your dog’s quality of life are the best way of helping your dog. 

Can CBD help with cancer in dogs?

Yes, CBD can help dogs with cancer in terms of alleviating pain and discomfort, decreasing dizziness and increasing appetite, modifying the immune system function, and improving the overall quality of life.

Why is cancer so common in dogs?

Because they are exposed to many proven carcinogens – from household chemicals and air pollution through tobacco smoke to pet food ingredients and ultraviolet radiation.