OSTEOSARCOMA (BONE CANCER)

WHAT IS IT?

Bone cancer can strike relatively young dogs, even as young as 5 years.

While it can affect any bone in the body, 75% to 85% of these cancers are found on the legs at the shoulder, wrist or knee joints as shown in the illustration.

The disease begins inside the bone, initially causing an intermittent lameness but eventually causing constant, deep and severe pain after just a short period (1-3 months, most likely).  The bone weakens and can eventually break with minimal trauma or pressure (a "pathological" fracture).

The following x-rays illustrate the bone changes caused by osteosarcoma

HOW IS IT DIAGNOSED?

Your vet will very likely recommend an x-ray to distinguish the different causes.  Depending on the stage of the osteosarcoma, the x-ray itself can be diagnostic.  Early cases may be more ambiguous and require a follow-up x-ray in a few weeks.

If there is doubt, the definitive diagnosis can usually be obtained through bone biopsy. Other diseases causing similar changes on an x-ray include some bone infections, other types of bone tumors, and fungal infections of the bone.

CAN IT BE TREATED?

Osteosarcoma is a terrible disease and managing it requires a strong commitment, both financially and emotionally.

Treatment addresses two aspects of the disease: the pain and the cancer itself.  The pain of bone cancer is thought to be greater than almost any other disease, and it is continuous, non-stop, relentless, and never-ending.  Even the strongest pain medications can fail to control this kind of pain, so it is imperative that you and your vet aggressively manage this part of the disease. Together, you must recognize when pain is no longer controlled, so you can make an appropriate quality-of-life decision.

TREATMENT OPTIONS

Medical pain relief only - combinations of pain medications to control pain, followed by euthanasia when they fail to do so. The caution here is the difficulty in objectively judging pain.  It's hard to know how much our pets are really suffering, and it's easy to think because they don't scream, they don't hurt.  MOST DOGS SUFFER SEVERE PAIN IN SILENCE.  With this treatment option, life expectancy is 4 months, although pain control may well fail long before that.  You must find the courage to face appropriate timing of euthanasia.

Amputation and pain relief - while seemingly drastic, amputation provides pain relief to 100% of the dogs who receive it.  With amputation alone, the life expectancy remains at an average of 4 months, but the quality of life is improved.

Amputation and chemotherapy - this improves the life expectancy, although does not cure the disease.  With this the average life expectancy is 1 year.

Limb sparing surgery - a new technique adapted from human medicine and done at some referral centers.  The cancerous bone is removed and replace with grafted bone, and the nearest joint is fused.  This is only done on the wrist area at this time.

Radiotherapy to control pain - the tumor is irradiated and this can provide about 4 months of pain relief in about 65% of the patients.

Euthanasia - eventually it is likely that treatment will fail, the pain will overcome your Greyhound again, and the cancer will prevail. When that day comes, the final gift you can give your pet is to relieve him/her of an impossible struggle.  Euthanasia is the beginning of your grief, but it is the end of their suffering, and with this disease it is something that must be faced.

THE FUTURE

Studies are underway to try to understand and treat this disease more effectively.  One aspect of this is a genetic study being done at the University of Michigan.  If your Greyhound develops osteosarcoma, please consider the donation a small blood sample to this study.  We need all the information we can get to eventually be able to cure these cancer victims.

http://www.grassmere-animal-hospital.com/osteosarcoma.htm