Hemangiosarcoma of the Bone in Cats

Bone Cancer in Cats Caused by Hemangiosarcoma

Hemangiosarcoma is a type of cancer in cats that arises from blood vessels and can occur almost anywhere in the body. It is a highly metastatic form of cancer, meaning it spreads readily to other tissues. Usually when hemangiosarcoma occurs in bone it is due to metastasis from another site, although rarely, it may actually arise in the bone; the bone is then referred to as the primary site.

This tumor affects the bone much more rarely than osteosarcoma, but when it occurs in bone it can sometimes be very difficult to distinguish from the osteosarcoma. The cause of hemangiosarcoma is largely unknown. In people this type of cancer has been linked to exposure to vinyl chloride, a chemical agent.

The bone form of hemangiosarcoma is rare in cats, but can occur as a local extension of tumors of the soft tissues. It can affect the axial skeleton, which includes the bones of the spine, pelvis and skull, as well as the appendicular skeleton, which includes the arms and legs.

This is a lethal form of cancer in your pet. Average survival rate in animals with this type of cancer, even with treatment, is only months. In most cases, the tumor has already spread widely or will spread widely throughout the body, despite therapy and will continue to grow. When it primarily affects the bone, it can cause lameness and general debilitation of your pet during its development and progression.

What to Watch For

Diagnosis of Hemangiosarcoma of the Bone in Cats

Diagnostic tests are necessary to diagnose the tumor and define the extent of disease. Tests that your veterinarian may wish to perform include:

Treatment of Hemangiosarcoma of the Bone in Cats

Treatment may include the following:

Home Care and Prevention

Your veterinarian will most likely prescribe pain medication to ensure your pet’s comfort. These medications may be given prior to definitive diagnosis and/or after surgery. Medication will usually be in the form of pills or narcotic pain patches that are placed on the skin to release a constant level of medication across the skin.

You should limit your cat’s activity to minimize pain and to prevent what is called a pathologic fracture, which is an abnormal breaking of the bone due to the cancer weakening the bone. Your pet should not run, jump or play during this time. You should watch your cat carefully and give assistance when he climbs stairs.

Have your veterinarian evaluate promptly any unexplained bump or lameness that develops. Lameness is more likely to be associated with arthritis or injury to ligaments and tendons than cancer, but it is worth having your cat evaluated nonetheless.

If your cat does not improve with rest or anti-inflammatory drugs, radiographs of the affected part of the body may be indicated to exclude bone cancer as a cause of the lameness or pain.

Hemangiosarcoma, like other cancers, is not currently preventable.

In-depth Information on Hemangiosarcoma of the Bone in Cats

Hemangiosarcoma is a type of cancer that most commonly affects the spleen, liver and heart and typically causes bleeding from the ruptured tumor. Although it can arise in bone initially, this is rare. Most often when it occurs in bone, the tumor has spread there from another site in the body. Thus, if your cat is diagnosed with bone hemangiosarcoma it is vitally important that other more common sites of this tumor are excluded as the primary site.

As with most forms of cancer, very little is known about what causes hemangiosarcoma to develop. It is a highly lethal form of cancer and thus the diagnosis and treatment should be prompt and aggressive.

It is important to distinguish tumors that have spread from other tissues to bone from those that arise in bone initially because the treatment differs. For metastatic tumors an attempt is made to determine the site of the primary cancer. If your pet is diagnosed with cancer, your veterinarian may wish to consult with an oncologist or cancer specialist to understand the specific behavior and treatment of the cancer.

Diagnosis In-depth

Medical tests are needed to establish the diagnosis, exclude other diseases and determine the impact of hemangiosarcoma on your cat. Tests that your veterinarian may wish to perform include:

Treatment In-depth

One of the most commonly utilized drugs for hemangiosarcoma is adriamycin (Doxorubicin). However, every oncologist has a preference and may select certain drugs, or combinations of drugs, based on your pet’s general health and the extent of disease. The common side effects include a decrease in white blood cell count approximately seven to 10 days after each treatment, nausea, vomiting and/or diarrhea. Each of these drugs may also have unique side effects which your oncologist will discuss with you.

Follow-up Care for Cats with Bone HemangiosarcomaOptimal treatment of your cat requires a combination of home and professional veterinary care. Follow-up can be critical, especially if your cat does not improve rapidly.

You should limit your cat’s activity to minimize pain and to prevent a pathologic fracture prior to definitive therapy. Your cat should not run, jump or play during this time and you should watch him carefully and provide assistance when climbing stairs or getting in and out of the car.

Administer all prescribed medications as directed. Alert your veterinarian if you are experiencing problems treating your cat. Your veterinarian should prescribe pain medications to ensure your pet’s comfort either prior to definitive diagnosis and/or in the aftercare period from surgery. This can be through the use of pills or narcotic pain patches that are placed on the skin and release a constant level of pain medication across the skin.

After surgery, you will need to limit your cat’s activity for at least 10 to 14 days or until the surgical site heals and the sutures or staples are removed. During this time, your cat should not climb stairs unattended, jump or play. You will also need to keep the surgical site clean and dry. Most cats go home on some form of pain control. Any questions you have about your cat during the postoperative period should be addressed with your veterinarian immediately.

Once healing has occurred, your cat can get back to exercising gradually. It may surprise you how quickly your pet begins to move about after surgery, but many feel so much better once the cancer is removed that they are up and acting normal within two to three days after surgery.

Whenever your pet has been diagnosed with hemangiosarcoma, you should be aware of the potential of the cancer recurring somewhere else in the body. Your pet may also suffer bleeding episodes if one of these tumors ruptures. If this happens you should be prepared for the possibility of weakness and an acute collapse.