Synovial cell sarcoma in dogs is a cancerous tumor that grows in your dog's joints. Large breed dogs are more susceptible to this type of cancer than smaller breeds. Synovial cell sarcoma is rare, but is aggressive and often spreads to the lymph nodes and throughout the body from there. Here's what you should know about synovial cell sarcoma.
Symptoms and Diagnosis of Synovial Cell Sarcoma in Dogs
The most common symptoms of synovial cell sarcoma are swelling, pain and lameness in the affected joint. The joint may appear visible deformed. Your dog's symptoms may be quite similar to those of other orthopedic conditions like osteoarthritis or Lyme disease, so synovial cell sarcoma can be difficult to diagnose. Your vet will need a physical exam, a complete medical history and blood tests. He'll also need to perform an immunohistochemistry, which will help him isolate and identify key proteins in the cancerous cells so that he can be sure your dog is suffering from synovial cell sarcoma and not some other type of canine joint cancer.
Your vet may be able to estimate, at the time of diagnosis, how likely your dog's synovial cell sarcoma is likely to spread. Synovial cell sarcomas are graded on levels I through III, with grade I tumors being the least aggressive and least likely to spread, and grade III tumors being the most aggressive and most likely to spread.
Treating Canine Synovial Cell Sarcoma
The recommended treatment for synovial cell sarcoma in dogs is to amputate the affected limb and surgically remove the diseased joint to stop the tumor from recurring. Because synovial cell sarcomas affect the entire joint and its function, the whole joint will have to be removed in order to treat the tumor. Simply removing the tumor isn't enough; it will only grow back again from the cells of your dog's synovial (joint) fluid in the affected joint.
Synovial cell sarcoma is a very aggressive cancer, and it spreads rapidly into the lymph nodes, lungs and even more distant organs. About one third of all cases of canine synovial cell sarcoma have already metastized (spread) by the time a diagnosis is made. Synovial cell sarcomas spread faster than any other soft tissue sarcomas.
If your dog's synovial cell sarcoma has already spread by the time a diagnosis is made, you can increase your dog's chances of survival with chemotherapy treatments. While chemotherapy isn't especially effective in treating this type of cancer, certain types of chemotherapy can have a positive impact.
Your Dog's Prognosis with Synovial Cell Sarcoma
If your dog's synovial cell sarcoma has already metastasized to the lymph nodes or lungs at the time of his diagnosis, chances are he'll survive for no longer than about six months. If your dog's synovial cell sarcoma hasn't metastasized yet, he could survive for as long as 36 months. Dogs who have the affected limb amputated live almost twice as long as dogs who only have the tumor removed.