The word “osteosarcoma” comes from “osteo” for bone (like in the word osteoporosis) and “sarcoma” which means malignant tumor. In short, it is bone cancer. The bone where this cancer is most likely to appear is in the leg and most oftentimes it is just found in one leg, The tumor grows within the bone. It is rare for osteosarcoma to be in another bone, but it can happen.
Osteosarcoma Symptoms in Dogs
Pain is the number one sign with this cancer, as the tumor will grow and cause swelling. This often causes the dog to limp. Sometimes you are able to see the protrusion of the tumor if it is on the lower leg where there is less muscle.
As the tumor continues to grow as the cancer advances, it can cause the bone to break just from normal activity like walking, which puts weight on the weakened bone.
Other symptoms may include problems in the lungs or other areas of the body, as well as decreased appetite resulting in weight loss.
Osteosarcoma Causes in Dogs
There are certain brreds that seem to develop osteosarcoma more often than others: Greyhounds, Rottweilers, Irish Wolfhounds, and other big breed dogs that are over 75 lbs; dogs of this size are two times more likely to develop this cancer than their smaller breed counterparts.
Rare risk factors include previous bone fractures where a bone plate was used, if a bullet was lodged in a dog’s bone, and previous infections. Again, these are rare but the fact that these things all cause inflammation cannot be ignored. Inflammation is sometimes seen has spurring cancer on.
Osteosarcoma in Dogs Treatment & Prognosis
Unfortunately, osteosarcoma often metastasizes. This means that the cancer spreads to other areas. These small cancer cells that spread are called micrometastastis and they cannot be seen by an X-Ray or other body scan. The cells may be lying dormant until it grows enough to cause another tumor. This makes the cancer tough to treat. It is said that potentially 90% of dogs diagnosed with osteosarcoma already have micrometastasis.
Osteosarcoma in dogs occurs most frequently in the legs
Amputation if the osteosarcoma is in the leg is the typical surgical choice. If just surgery is performed, the prognosis can be 4-5 months. About 11% of dogs will leave for a year and around 2% will make it for two years. Combining the surgery with chemotherapy can increase the survival time to 6-13 months, approximately longer. The veterinarian will decide which course of chemotherapy drugs to administer. Pain meds will also be given to keep the discomfort at bay. Radiation can also help with pain management but not as an approach to get rid of the osteosarcoma. It is important to consider the pain medication and radiation as supplying the dog with a better quality of life.
There are always new technologies underway for surgery, chemotherapy and radiation. As always, bring your dog to the vet immediately whenever there is a medical issue.
