Cancer in Dogs: The Signs, Symptoms, and Treatments for Dog Cancer

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veterinarian checking doberman pinscher for cancer in dogs

Cancer in dogs is becoming more and more prevalent. About one in three dogs will be diagnosed with cancer in their lifetime. There are many different types of cancer found in dogs: Soft tissue sarcomas, bladder cancer, squamous cell carcinoma, prostate cancer, and lung cancer. There are also many different treatment options available.

Fortunately, with the increase in veterinary research and clinical trials, there is a better prognosis for dogs with cancer each year.

A Brief Look at What Cancer Is

So, what exactly is cancer? Cancer is the umbrella term for a collection of diseases. These diseases all have one thing in common. Their start point is a group of cells that start dividing uncontrollably. These cells might grow to form a mass called a tumor. This growth could be benign or malignant. A cancerous or malignant tumor can grow and spread to other parts of the body. A benign tumor can grow but will not spread.

4 Potential Causes of Cancer in Dogs

In order to understand more about this disease, it’s important to know what causes it. If you know what the potential causes are, your chances of preventing it are much better.


Cancer occurs more frequently in older dogs. There could be two reasons for this. Firstly, as a dog ages, there is a greater likelihood of cells dividing incorrectly and producing a ‘faulty’ cell that could lead to a tumor. Another possible reason is that the longer an animal lives, the more exposure it has to environmental carcinogens.


There is very little understanding of how genes can predispose an animal to cancer. Yet, there do seem to be strong correlations between genetics and cancer prevalence. There are certain breeds that seem to be more predisposed to cancer. Also, certain breeds are more likely to develop specific types of cancer.

Environmental Factors

Known carcinogens that may contribute to the development of cancer in animals include:

  • Extended exposure to the UV rays of the sun.
  • Exposure to pesticides, herbicides, and insecticides.
  • Air pollution and smog in developed areas.
  • Substances such as asbestos, benzene, uranium, cadmium, nickel, and vinyl chloride.


Some viruses are known to cause cancer in pets. For example, oral papilloma (cancerous wart in the mouth) in dogs is caused by a virus.

golden retriever with dog skin cancer

Are Some Dog Breeds More Prone to Get Cancer?

According to animal statistics, Bernese Mountain Dogs, Boxers, and Golden Retrievers are the dog breeds most likely to develop cancer.

Goldens, Standard Poodles, and Australian Shepherds are the likeliest candidates for lymphoma. While hemangiosarcoma is most prevalent in Golden Retrievers (GRs) and German Shepherds (GSDs). Mast cell tumors occur mostly in Boxers, Beagles, Boston Terriers, Schnauzers, and Labrador Retrievers.

From Lymphoma to Osteosarcoma: The Most Common Types of Dog Cancer

Let’s look at some of the most common cancers that dogs fall prey to!


This is a cancer of the cells that line the blood vessels. Hemangiosarcoma is a highly metastatic disease. Because it is blood-based, it can spread rapidly through the body, especially to the lungs, spleen, brain, kidneys, skeletal muscles, and bone.


It presents as swollen glands (lymph nodes) that can be seen or felt under the neck, behind the knees, or in front of the shoulders. Lymphoma can sometimes affect lymph nodes that are not visible from the outside of the dog’s body. These can cause digestive troubles and breathing difficulties.

Osteosarcoma: Bone Cancer in Dogs

This is cancer of the bone. While osteosarcoma can be present in any bone, it is most often found in the limbs. Symptoms of this cancer include swelling and lameness. Osteosarcoma commonly affects larger breeds of dog such as Great Danes, Rottweilers, Dobermans, Irish Setters, GSDs, and GRs.

Melanoma: Skin Cancer in Dogs

This is a type of skin cancer. It can be found around the mouth, in the eyes, foot pads and nail beds. Malignant melanoma tumors are very metastatic.

Dog Skin Cancer: How Serious Can Lumps on Dogs Be?

This is where giving your dog a once over during your routine grooming sessions is so very important. Lumps on or under your dog’s skin might not be too serious, but rather safe than sorry.

Contact your Vet to get a proper diagnosis.

Mammary Cancer: Breast Cancer in Dogs

Mammary cancers are most common in female dogs that are not spayed. Approximately half of all mammary tumors have metastasized and spread to other parts of the body.

Mast Cell Tumors

This form of cancer is common in older dogs. A skin lesion is usually the first symptom of a mast cell tumor.

Liver Cancer in Dogs

Liver cancer in dogs such as hepatocellular carcinoma is the most common and affects a lower amount of animals every year compared to other types of cancers. Early detection is very important in curing liver cancer. For the most part, tumors on or in the liver are surgically removed.

Bladder Cancer in Dogs

Transitional cell carcinoma is one of the worst types of bladder cancer in dogs and can be very painful. This type of cancer often presents as UTI, so if this is a condition your dog suffers from, ask your vet to check that the condition ends at urinary tract infection.

Lung Cancer in Dogs

Adenocarcinoma, lung cancer in dogs, is not as common as skin or bone cancer but still should be seen as just as serious. One of the most common and successful treatments for lung cancer in dogs is surgical removal of the lung lobe that has the tumor.

Prognosis: Is There a Cure?

This depends on several factors. The type of cancer, how early the cancer is detected, and the overall health of the dog, all play a role in how treatable the disease is.

Early cancer detection is key. A tumor detected early on will mean that there is less chance of the disease spreading to other parts of the body. A smaller growth will have done less damage to surrounding tissues. It will also be easier to operate and remove a smaller tumor.

A healthy dog will respond better to cancer treatment and bounce back from the negative effects of surgery (if necessary) and cancer therapies.

Some cancers, such as hemangiosarcoma, have a very low prognosis. While mammary cancers and mast cell tumors have a good cure rate.

golden retriever having surgery for hemangiosarcoma in dogs

Treatment Methods: Surgical and Non-Surgical Options

The treatment for cancer in dogs is very much like humans. The treatment options include:

  • Chemotherapy
  • Radiation therapy
  • Surgery
  • Herbal (or holistic) therapy

The mode of therapy that you choose will depend on factors such as the type and stage of cancer, the age of the dog, and the dog’s health. Discuss the diagnosis and various treatment options in detail with your veterinary oncologist.

Prevention is Better Than a Cure

Some breeds of dog are simply more predisposed to canine cancer than others. There are however steps that you can take to help prevent cancer.

The Best Course of Action for Those Pups with Dog Cancer

You cannot always prevent something as heartbreaking as cancer in dogs. But sometimes, it is possible. Here are a few tips that can help Fido live a longer and healthier life!

Physical Examination

Make a whole-body check of your pet part of your daily cuddle session. Check your pooch for bumps and lumps or areas where there is heat, swelling, discomfort, or lesions.

If you do see something out of the ordinary, keep an eye on it. If it doesn’t clear bring the symptoms to the attention of your veterinarian. On that note, don’t skip annual check-ups. Allowing your vet to give your canine a thorough once over every 6 – 12 months is a great way of catching diseases early.

What’s in the Bowl?

Make sure to feed your four-legged friend a well-balanced, veterinarian-approved diet. Focus on whole foods rather than processed foods. Take the time to read the ingredients list. To have a strong immune system and a healthy body, your pup needs the right balance of proteins, fats, vitamins, and minerals.

Slim and Trim

More than 50 % of American pets are overweight or obese. Excess weight contributes to the body’s overall level of inflammation. This promotes the growth of cancer cells. Balance the correct quantity of food for your pet with a good dose of daily exercise.

Reduce Daily Exposure to Toxins

Make sure that there are no toxic substances in your house or yard that are accessible to your pet. Clean your home and pet’s bedding with pet-safe cleaning products. Do not allow your pet to roam in outdoor areas treated with herbicides or pesticides.

golden retriever getting surgery for dog bone cancer

Common Questions About Cancer in Dogs?

Is there a cure for canine cancer?

Which breeds are more likely to get cancer?

What are the most common types of cancer in dogs?

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