Leiomyosarcoma occurs when cancerous tumors grow in your dog's smooth muscle tissue. Your dog's internal organs are made up of smooth muscle tissue, and leiomyosarcoma usually occurs in the tissue of the GI tract. Prognosis and treatment varies depending on the location of the tumors.
Symptoms of Canine Leiomyosarcoma
The average age of onset for leiomyosarcoma is about ten years, making this a cancer of geriatric dogs. Symptoms can be vague and difficult to pinpoint. In some cases, you may be able to feel your dog's tumor beneath the skin. But, in most cases, tumors will be located inside the body and you'll need to observe your dog's more general symptoms.
Symptoms of leiomyosarcoma generally include diarrhea, vomiting, weight loss, loss of appetite and lethargy.
Diagnosing Leiomyosarcoma in Dogs
Your vet will need a complete medical history and a thorough physical exam in order to make a diagnosis of leiomyosarcoma. Blood tests and biopsies can help your vet identify the presence of cancer and tumors in your dog. Leiomyosarcoma can cause anemia and it can make your dog's white blood cell count abnormally high.
Most cases of leiomyosarcoma affect the digestive tract, and your vet may be able to feel the tumors during your dog's physical exam. Leiomyosarcoma tumors are white in color, firm to the touch and made up of several smaller lobes (lobulated). In the GI tract, leiomyosarcomas may have a mucousy covering.
Treating Leiomyosarcoma in Dogs
Treatment for leiomyosarcoma will very depending on the location of your dog's tumors. If surgery is an option, your vet will remove the tumor and as much of the surrounding area as he can, to reduce the risk of the cancer returning. If leiomyosarcoma affects your dog's spleen, your vet will remove your dog's spleen.
Chemotherapy or radiation therapy can be used to slow or halt the progress of this cancer if your dog's leiomyosarcoma has already spread to other parts of his body. Pain management for this type of cancer can include non-steroidal anti-inflammatories (NSAIDs) like aspirin and steroid medications to relieve inflammation. Your vet may prescribe mild opioid drugs as well. Because opiods are addictive, so your vet will restrict their use to post-surgical pain relief, however, if your dog's leiomyosarcoma is terminal, your vet may prescribe stronger opiod drugs to ease your dog's pain during the final weeks of his life.
Canine Leiomyosarcoma Prognosis
Most dogs live for about 22 months after being diagnosed with tumors of the GI tract. Dogs with tumors of the spleen live for about eight months after being diagnosed. If leiomyosarcoma affects the liver or other vital organs, your dog may succumb to the cancer within a few weeks. If your dog's leiomyosarcoma affects the liver or is inoperable, your vet may recommend palliative care or euthanasia.
Leiomyosarcomas that develop beneath the skin are the easiest to treat, and dogs who develop this type of leiomyosarcoma often recover and live for many years.