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Signs & Symptoms of Cancer in Dogs

Discovering that your dog has cancer can be an emotional experience. There are various types of cancer in dogs and how they are treated depends on the type and how advanced it is. Our Orange vets discuss the types of cancer in dogs as well as the signs or symptoms and the recommended method of diagnosis and treatment.

Types of Cancer That Can Affect Dogs

Humans are not the only creatures that will experience the various types of cancers, dogs of all types will as well, and with very similar symptoms. Here are some of the most common types of cancer that our vets see in dogs:

Osteosarcoma (Bone Cancer) 

In dogs, this is the most common bone cancer. While any breed of dog can be affected, our vets tend to see this form of cancer most often in larger breeds.


This is a very common form of cancer in dogs and there are a number of treatment options available. Most vets have extensive experience in treating this disease.


Hemangiosarcoma is most commonly found on internal organs and blood vessels, although it may occasionally be found on the skin. These tumors can grow quite large with bleeding into the pericardium. This form of cancer requires emergency treatment, as it can become fatal very quickly.


These skin tumors are typically found in the dog's mouth or on the feet. Melanoma can spread quickly to other areas of your dog's body and tends to be malignant.

Mast Cell Tumor

These tumors are also found on the skin and can be difficult for your vet to remove depending on the location. That said this type of cancer in dogs can be cured if detected and treated early.


This is a slow-spreading form of cancer in dogs but can be difficult to treat. To prevent a recurrence, amputation and radiation are the most common treatment options.

The Common Signs & Symptoms of Cancer in Dogs

Unfortunately, the symptoms of cancer may not make themselves obvious until the disease is already advanced. Even so, there are some easy to spot symptoms that you can keep an eye out for when it comes to cancer in dogs:

If your dog is showing any of the following signs and symptoms, make an appointment to visit your vet as soon as possible. Successful treatment of cancer depends on early diagnosis and treatment.

  • Weight loss
  • Lethargy, depression
  • Difficulty breathing
  • Loss of appetite
  • Strong odor
  • Sores that don't heal
  • Bleeding or discharge
  • Lumps or bumps beneath the skin
  • Pain or difficulty walking, lameness or stiffness
  • Straining when going to the bathroom
  • Difficulties eating or swallowing
  • Swelling

Diagnosis of Cancer in Dogs

It is key to be aware of any changes that happen with your dog, whether it be physically or through their behavior and to contact your vet immediately if your dog is experiencing the above symptoms. 

When diagnosing cancer in dogs, your vet may perform a biopsy or other test that will be sent to our lab for testing, as well as palpate your dog to feel for any lumps. 

Your vet is the only person that can diagnose cancer in your dog and the best chance for survival of cancer in your dog is early detection, always be alert to any changes in your dog's behavior that could indicate that there is a health issue.

Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.

If you notice any potential signs or symptoms of cancer or any other conditions, please contact our Orange vets to book an appointment immediately.

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If you are looking for a veterinarian in Orange contact us at Vet4HealthyPet Animal Hospital today, to schedule your cat or dog's first appointment! Our vets are passionate about what they do and always provide the best possible veterinary care.

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