Tumors in Dogs – What Causes them?

Just like humans, dogs may also suffer from cancers and tumors. And just like cancers in humans, early detection can save your pet’s life. Here are important things to take note of cancer and tumors in dogs.

There are five most common cancers in dogs

Cancer can affect dogs but are most common in older dogs. The five common cancers in dogs are 

  • Mast cell tumors, a form of skin cancer
  • Melanoma which is a malignant growth in a dog’s mouth
  • Lymphoma is cancer in the blood cell lymphocytes, as well as an abnormal growth in the lymphoid tissues.
  • Bone cancer or osteosarcoma 
  • Hemangiosarcoma is malignant cancer that causes tumors in the entire body, including the heart and the spleen.   

Some breeds are more susceptible to tumor growths:

Some dog breeds are more susceptible to cancer and tumors. Breeds like Golden Retrievers, German Shepherds, Rottweilers, and Poodles are known are more prone to developing tumors while Bloodhounds, Bullmastiffs, Airdale Terriers, and Scottish Terriers are less prone. If your dog belongs to any of these breeds or is a mixed breed, consult your vet about cancer screening.

Early signs and symptoms of tumors in dogs:

No matter what breed your dog is, you should be mindful of the early signs and symptoms of tumors. Here are the most common to watch out for: 

  • Abnormal swelling that moves or grows – this refers to any growth or swelling on any part of the body. Try to gently touch it and see if it moves slightly. Monitor the size and the shape of the growth. 
  • Lameness – a pet that’s reluctant to move or has lost its energy can be due to a tumor in the lungs or heart. 
  • Loss of appetite – any growth that’s found in the intestine can lead to loss of appetite, and in fact, almost all illnesses can cause poor appetite.
  • Sores that will not heal – if your pet has an open sore or wound that won’t heal with oozing pus or bleeding can be a sign of cancer. 
  • Loss of weight – sudden and unexplained loss of weight can be due to a tumor in the digestive tract. 
  • Problems with eating and swallowing – a tumor along the neck or the esophagus can make it hard for your pet to chew and swallow. 
  • Problems with breathing, defecating, and urinating – there may be tumors on the lungs, digestive tract, and the bladder respectively.
  • Bleeding in any part of the body – bleeding in the nose, ears, or mouth may not immediately indicate cancer, but it is one of the most common signs. 
  • Any offensive odor – tumors found in the lower part of the large intestine and in the anus can lead to pus and terrible odors. 

Average survival time is shorter in dogs:

Unfortunately for our little pals, when a tumor or cancer has been diagnosed, the average survival time is only two months. However, your pet’s life can be prolonged by cancer treatment or chemotherapy, but not all tumors may respond to cancer treatment. 

Causes of cancer in dogs:

The cause of cancer is still unknown in animals. But there are known carcinogens that can contribute to cancer in dogs. Ultraviolet radiation, viruses, extended exposure to the sun, ingestion of pesticides, herbicides, and insecticides, and second-hand smoke are known factors that can cause cancer.

And according to experts, you can prevent cancer in your pet dog by spaying or neutering, reducing sun exposure, avoiding the ingestion of toxins, and quitting smoking to prevent second-hand smoke. Also, cancer may be hereditary in dogs, and thus neutering or spaying can prevent a dog from passing cancer to its offspring.

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Lovelia Horn

I’m a certified crazy dog mom, a physical therapist (for hoomans), writer, animal rescuer, and foster home provider. Together with my hubby Ryan, I’ve fostered and helped look for forever homes for over a hundred shelter dogs in the Southern Illinois area. I mostly work with Puppy Rescue 911, Inc., a certified animal rescue organization based out of Chester, IL (home of Popeye!)

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