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Bone Cancer in Dogs

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Bone cancer is a scary diagnosis that no dog parent ever wants to hear. While the prognosis can be discouraging, to say the least, there are options available that can extend the dog’s life, especially when the cancer is caught early on. That’s why it’s so important to recognize the signs and seek treatment as soon as possible.

What is Osteosarcoma?

There are different types of dog bone cancer, but osteosarcoma is by far the most common. It typically occurs in the limbs but can also happen in the spine, ribs, skull, or jaw. Canine osteosarcoma is an aggressive malignant tumor that initially develops within the bone. It can be very painful as it grows from the inside out, destroying the surrounding bone as it gets larger.

Osteosarcoma in dogs can also metastasize, which means spread to other organs of the body quite rapidly. This is one of the reasons it can be such a devastating disease. It may have already invaded vital organs like the lungs, heart, liver, and kidneys by the time it’s diagnosed.

No one knows for sure the causes of bone cancer, but there is some speculation that it could be related to issues affecting the bone, such as:

  • Prior fractures
  • Repeated bone injuries
  • An underlying bone disease
  • Previous exposure to radiation

While these factors could have something to do with bone cancer, no studies prove that they are linked.

Bone Cancer in Big Dogs

Dogs of any size and breed are at risk for bone cancer, but it is more prevalent in large and giant breed dogs. These include:

Bone cancer in dogs also seems to happen either early or later in life. Cases of bone cancer tend to occur in puppies around 1-2 years old when there can be a significant growth spurt and in adult dogs who are 7 years old or more.

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Symptoms of Bone Cancer in Dogs

Unfortunately, the symptoms of dog bone cancer can be subtle and hard to detect at first. Since the tumor starts deep within the bone, your dog may not feel any pain or discomfort in the early stages. As the tumor grows and damages surrounding bone and tissue, your dog may start to show signs including:

  • Lameness, which can be intermittent or constant
  • Joint pain
  • Swelling
  • Loss of appetite

You may also notice issues related to the location of the bone cancer. For instance, if the cancer is in the leg, your dog may start limping or babying that limb. If the cancer is in the jaw, your dog might have trouble eating, chewing, or opening the mouth.

Tumors in dogs can also weaken their bones as they get larger, which can cause a fracture or a break. Sometimes a fracture or break is the first indication of bone cancer since the other signs can be missed or mistaken for an injury or a natural effect of getting older.

Diagnosing Bone Cancer in Dogs

If you have any suspicions that your dog has bone cancer, visit your veterinarian as soon as possible. Bone cancer is very aggressive, and early diagnosis and treatment can help extend your dog’s life.

Your veterinarian will examine your dog and typically order X-rays to check for bone cancer, which has a “moth-eaten” look in an X-ray film. Other diagnostic tests, such as blood work, an examination of the tissues in the area (called histopathology), and a fine-needle aspiration or bone biopsy, may also be needed.

Unfortunately, by the time bone cancer is detected, it has often metastasized to the lungs already. X-rays, CT scans, or an MRI of the lungs and other areas may be ordered to determine if and how far it has spread.

Treatment Options

Treatment for bone cancer in dogs depends on factors such as where the tumor is located and whether or not the cancer has metastasized.

Amputation is typically recommended if the bone cancer is in the limb. While amputation sounds drastic, keep in mind that dogs can get along very well on three legs. Humans tend to think about it from their own perspective, but it’s easier to go from four legs to three than two legs to one.

This surgery is often followed by chemotherapy. While chemotherapy won’t completely eliminate the cancer, it can help extend your dog’s life. Radiation is another option, but it is usually used as a palliative treatment to help reduce bone pain rather than eradicate the cancer.

 Depending on the particular situation, some dog parents may decide to forgo surgery and not pursue chemotherapy, primarily if the cancer has spread throughout the body. In these cases, pain management becomes the centerpiece of treatment. Pain medications, vitamins, and supplements might be given to your dog to make any remaining time as comfortable as possible. Remember, it is critical that you never give your dog human pain medications as most are poisonous to canines.

Life Expectancy

It’s sad to say, but dogs with bone cancer do not have a very long life expectancy, especially if the cancer has metastasized. Dogs who have an amputation followed by chemotherapy may live up to a year. However, some dogs have been known to live up to five or six years after treatment.  

Even though you can’t know how long a dog with bone cancer will survive, you can still focus on making the best of the time you have left together. Work with your veterinarian to provide life-extending treatments when appropriate and alleviate your dog’s pain and discomfort. 

And don’t forget to take care of yourself. It can be stressful and upsetting to have a dog with bone cancer. Reach out to friends and family to share your feelings and ask for help when you need it. You can also look into support groups to help connect with dog parents who are in the same situation.

Costs of Treating Bone Cancer

The costs of treating dog cancer can vary depending on your veterinarian’s recommendations, but it is often expensive. There can be expenses for surgery, anesthesia, hospitalization, pain medication, chemotherapy, radiation, and other treatments. In fact, ASPCA Pet Health Insurance customers have submitted claims up to and over $8,000 to help manage the costs of bone cancer.

Learn more about what pet insurance covers.

The information presented in this article is for educational and informational purposes only and does not constitute or substitute for the advice of your veterinarian.


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