Leiomyosarcoma in Dogs

Diagnosis

• You might not be able to tell if your dog has leiomyosarcoma unless the tumor is below the skin and palpable. Otherwise, your dog might appear lethargic, have little appetite, diarrhea, vomiting and weight loss. Your vet can make a definitive diagnosis with lab work, biopsies or diagnostic tests. Leiomyosarcomas are sometimes discovered during other surgical procedures.

Identification

• Leiomyosarcomas in the gastrointestinal tract are white nodes that are firm to the touch and have multiple small lobes (lobulated). In the gastric system, leiomyosarcomas are round and smooth, with a mucous-like covering. If the leiomyosarcoma is in the spleen, it can cause leukocytosis (elevated white blood cell count) and anemia. The vet can sometimes palpate the splenic tumor during a physical exam.

Treatment

• The typical treatment is surgical excision of the tumor and a wide swath of surrounding healthy tissue. The surgeon needs to take a wide margin in order to remove all the cancer cells. With splenic leiomyosarcomas, the spleen is usually removed. The spleen filters out toxins and eliminates old blood cells, but the liver can perform the same functions. If the tumor has metastasized (spread) to other areas of the body, chemotherapy or radiation might occasionally be on option. Usually, if surgery isn't an option, the vet will suggest palliative care to address symptoms and ease your dog's suffering.

Pain Management

• In the past, vets tended to overlook or disregard pain management for dogs diagnosed with cancer. That attitude has changed, and now pain management goes hand-in-hand with cancer treatment. Gastrointestinal tumors are extremely likely to be painful, so you should ask your vet about pain relief options if she doesn't mention them. Depending on the pain levels and progression of the leiomyosarcoma, your dog can use one or a combination of several drugs. NSAIDs (non-steroidal anti-inflammatory drugs) like aspirin or Rimadyl are used for inflammation. Steroids can be prescribed to reduce swelling and inhibit pain receptors. Opiods are addictive and generally aren't used long-term. Your vet might dispense weak opiods after surgery or if the tumor is in a particularly painful spot. Strong opiod medicines, such as morphine, are usually reserved for palliative comfort and used at the end of life.

Prognosis

• The median survival time after surgery for gastrointestinal tumors is about 22 months and eight months for splenic leiomyosarcomas. When the tumors are under the skin, the prognosis is excellent, and the dog usually survives several years following treatment. Liver leiomyosarcomas are the most serious. The dog will rapidly degenerate and usually die within a matter of weeks. Some vets recommend euthanasia immediately if the leiomyosarcoma is in the liver. Others will offer pain relief, anti-nausea medications and supportive care to reduce symptoms. Rarely will a vet suggest surgery to excise a leiomyosarcoma in the liver. The surgery often proves more traumatic than beneficial to the dog, without increasing the odds of it surviving longer.