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Cancer in Dogs - Signs & Symptoms

Our Tucson vets understand that discovering an unexplained lump on your dog can be alarming. While not all lumps and bumps are cancerous, having suspicious lumps found on your dog checked out by your vet can give you peace of mind and may give your dog their best shot at recovery.

Types of Cancer in Dogs

You may be surprised to learn that dogs can get many of the same types of cancer that people do, and with similar symptoms. The following are some common types of cancer seen in dogs:

  • Melanoma - Skin tumors are often found in the feet and mouth of dogs. Melanoma may quickly spread to other areas of your dog's body and tends to be malignant. 
  • Mast Cell Tumor - These tumors can also be found on the skin and may be difficult to remove, depending on the location. However, this type of cancer can often be cured - if the tumor is detected early and fully removed. 
  • Osteosarcoma (Bone Cancer) - The most common type of bone cancer found in dogs. Osteosarcoma can affect any breed, though larger breeds tend to be impacted more often. 
  • Lymphoma/Lymphosarcoma - This form of cancer is highly common in dogs, and quite a few treatment options are available. Many vets are experienced in treating this disease. 
  • Hemangiosarcoma - Your dog may require emergency intervention for this form of cancer, which can quickly be fatal. Hemangiosarcoma is most often found in blood vessels and on internal organs, though it is occasionally found on the skin. These tumors may grow to be quite large, with bleeding into the pericardium. 
  • Fibrosarcoma - This slow-spreading form of cancer in dogs can be tricky to treat. To prevent recurrence, radiation and amputation may be necessary.

Signs & Symptoms of Cancer in Dogs

Unfortunately, you may not know by looking at your dog that he or she is ill. In fact, certain types of cancers may not even be detected with blood work. However, there are some symptoms you can watch for that may indicate cancer is developing. 

If your dog is showing any of these signs, you'll want to make an appointment with your veterinarian as soon as possible. When it comes to cancer, early detection is key to positive treatment outcomes. 

  • Sores that don't heal
  • Bleeding or discharge
  • Lumps or bumps beneath the skin
  • Loss of appetite
  • Unexplained Weight loss
  • Lethargy, depression, disinterest in exercise
  • Difficult or painful breathing or coughing
  • Straining when going to the bathroom
  • Strong odor
  • Challenges when eating or swallowing
  • Swelling
  • Pain or difficulty walking, lameness or stiffness


It's critical to be aware of changes in your dog's behavior and to pay attention to any lumps or bumps you may feel while petting your dog. If your canine companion is displaying one or more of the symptoms listed above, make an appointment to see your vet immediately.

Your vet may perform a biopsy or other test that will be sent to a lab for testing, as well as palpate your dog to detect any lumps. Ultimately, only your vet will be able to determine if your dog has cancer. Your dog's best chance for survival is early detection, so be sure to pay close attention to any changes.

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.

Concerned that your dog may have cancer? Contact our Tucson vets to book an appointment immediately.

Cancer in Dogs - Signs & Symptoms

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