Dog Cancer: What You Need To Know About Symptoms & Treatment

dog cancer

Original Article by Dr. Javk Stephens for PetsBest

Cancer is a spine-chilling word, no matter what context it is used in. For pet owners, hearing a veterinarian say their dog has canine cancer is always a bombshell— one that leaves them worried and downhearted. And since canine cancer can be particularly difficult to detect, it’s not uncommon for dog owners to feel a sense of guilt, as though they should have somehow known or had their pet examined sooner.

While these emotions are normal, it is important for pet owners to know that modern-day treatments for dog cancer are highly effective, and that discovering their dog has cancer does not mean they are unable to continue living a full and healthy life.

Thus, in this blog, we’ll be discussing what to do when your dog has cancer, and sharing some helpful information about dog cancer treatments.

Common Types of Cancer in Dogs


This form of dog cancer affects the bones and is most common in large-sized dogs, including St. Bernard’s, Great Danes, and German Shepherds.

Osteosarcoma is caused by abnormal cells that accumulate and form tumors, and most commonly develops in the limbs, but sometimes presents itself in other bones, like the jaw, ribs, or pelvis.

While the prognosis for dogs diagnosed with this type of pet cancer is severe, 28 percent of dogs that receive surgery and chemotherapy treatments survive at least two years after diagnosis.

Oral Melanoma

Did you know that 7% of all malignant canine tumours are found in the oral cavity? For this reason, it is important for pet owners to educate themselves about this specific type of dog cancer.

Oral melanoma is more prevalent in male dogs, and Chow Chow, Golden Retrievers, and Pekingese breeds seem to be especially susceptible to developing oral tumors. As a general rule of thumb, breeds that have darkly-pigmented tongues and oral cavities seem to be diagnosed with oral melanoma more frequently.

On a positive note, the average age for oral melanoma presentation is 11.4 years, and there is now a preventative DNA-vaccine that can protect your pooch by preventing cancerous oral cells from developing.


Lymphoma is a form of rapidly-spreading dog cancer that affects the lymph nodes and/or bone marrow. Presently, there are more than 40 different types of canine lymphoma, each with their own set of symptoms and progression patterns. One of the most recognisable symptoms of canine lymphoma is hardening of the lymph nodes, which become swollen and tender when cancerous cells have amassed inside them.

Lymphoma is most commonly diagnosed in middle-aged and senior dogs, and Bull Mastiffs, Bull Dogs, and Boxers seem to be especially prone to developing cancer of the lymphatic system.

The Symptoms and Signs of Canine Cancer

Determining if a dog has cancer isn’t a straightforward process. Depending on the type of cancer, and what stage of development it is in, symptoms can vary. Additionally, the signs of dog cancer can differ from dog to dog.

With this being said, if you’ve been wondering how to know if your dog has a tumor, or concerned that your pet may have a less-detectable form of pet cancer, there are some indicators that may suggest cancer is present.

Some of these signs and symptoms include:

  • A bloated belly
  • Sudden or excessive weight loss
  • Loss of appetite
  • Increased thirst or urination
  • Unusual swellings, lumps, or bumps
  • Discharge from any orifice of the body
  • Diarrhea or changes in bathroom behaviors
  • Any indication of general pain or discomfort
  • Excessive drooling


If you have noticed any of these symptoms, booking an examination with your veterinarian is the best course of action.

Dog Cancer Diagnosis

It is likely your veterinary professional will order blood work as a first step. While this is routine, there are some forms of cancer that are not immediately detectable via lab work alone. For this reason, there will likely be additional precautions your vet will want to take.

These additional examination procedures include:

1. Screening Tests

Screening tests look for biomarkers that indicate the presence of disease. Some of the most common screening tests for pet cancer include serum TK levels, c-reactive protein (CRP) levels, and miRNAs.

2. Biopsies

Biopsies are most commonly performed in an effort to diagnose tumors or abnormal growths. They are a minimally-invasive surgical procedure that involves removing some or all of the growth, which is then sent for laboratory testing to determine if cancerous cells are present.

3. Fine Needle Aspirate

A fine needle aspirate screening is similar to a biopsy, but instead of surgically removing all (or a portion of) a tumor or bump, your vet will simply insert a needle into the growth and withdraw some of the cells and fluids inside. The sample is then sent for laboratory testing.

Treatment for Dogs with Cancer

Much like in humans, dog cancer treatments vary depending on the type of cancer, and how far along it has progressed.

Typically, your dog will have to undergo some form of surgery to remove any cancerous growths or affected organs.

Chemotherapy may also be needed to prevent the cancer from spreading or advancing any further. Fortunately, there are several chemotherapy methods available for pets, including oral, intravenous, topical, and intratumoral administration. The severity of the side effects your pet will experience depends greatly on the type of chemotherapy they undergo.

Lastly, your pet may require radiation therapy, a treatment that can reduce the size of malignant growths, which prevents them from maturing.

Unfortunately, due to the advanced medical equipment that is required to perform radiation therapy, it can be quite costly, especially if your dog requires follow-up sessions.

Additionally, normal cells can be killed along with cancerous cells during the radiation process, resulting in hair loss, and other potential side effects. It is important to speak to your veterinarian about all possible outcomes in order to make the best decision for your pet.


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