Osteosarcoma, the most prevalent type of bone cancer found in dogs, usually strikes the long bones of a dog's limbs and is very aggressive. Though a dog of any age or size may be diagnosed with osteosarcoma, the disease tends to affect older dogs, as well as large and giant breed dogs.
Breeds at Risk
Among the large breed dogs prone to the disease are Labradors, golden retrievers, rottweilers, greyhounds, doberman pinschers, weimeraners, Irish setters and German shepherds. Siberian huskies, samoyeds, akitas and boxers also are vulnerable. Giant breed dogs at risk for the disease include Scottish deerhounds, great Danes, Saint Bernards, mastiffs, great Pyrenees, Irish wolfhounds, Newfoundlands and Bernese mountain dogs.
Big Dogs, Big Risk
Size seems to matter in this serious disease. According to VCA Animal Hospitals, dogs weighing more than 80 pounds have been shown to be 60 times more likely to have osteosarcoma than dogs weighing under 75 pounds. The National Canine Cancer Foundation notes a giant breed dog, such as a great Dane, has as much as 200 times the risk of developing osteosarcoma than a toy or small breed dog. A dog who has experienced a blunt bone injury also may have a greater risk of the disease, according to PetMD.com. Though the disease is uncommon in small breeds of dogs, any dog can develop this cancer.
Symptoms Don't Discriminate Among Breeds
The basics of osteosarcoma are the same, regardless of the breed. Though it can affect the bones in a dog's head and trunk, his limbs are at greater risk, particularly the bones near his shoulder, wrist and knee. Lameness is the classic sign of osteosarcoma; it may come and go or become worse over time. A dog may have swelling and pain in his joints or bones, as well as feel lethargic and uninterested in eating. Sometimes the affected bone may break from minor trauma. X-rays, bone biopsy and blood tests are part of the diagnostic process.
Comfort is Key
Treatment is focused on keeping the cancer from spreading further and making the dog as comfortable as possible. In most cases, amputating the affected limb is recommended, though sometimes the tumor is removed from the site. Chemotherapy often is part of the treatment, to keep the spread of the cancer in check. Anti-inflammatories are used typically as pain-controlling agents. The prognosis for a dog with osteosarcoma isn't favorable, and depends on if and how extensively the cancer has spread. Generally, about half of diagnosed dogs survive a year with standard treatment protocols; fewer than 30 percent survive two years and less than 10 percent make three years. Research, which is ongoing, has yet to show why large breed dogs are prone to osteosarcoma or what causes the disease. As well, there's no way to prevent the cancer.
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