Hemangiosarcoma of the spleen, or spleen cancer in dogs, is a cancer that is diagnosed in many canines every year. It is a cancer made up of the cells that line blood vessels, and therefore can be found in any part of the body. However, the most common sites include the spleen, liver and right auricle of the heart. Approximately 2/3rds of masses in the spleen are malignant and of those, 2/3rds are diagnosed as hemangiosarcomas. Splenic hemangiosarcoma is most often diagnosed in older dogs, with German Shepherds, Labrador Retrievers and Golden Retrievers being the most commonly affected breeds.
Splenic hemangiosarcoma in dogs is very dangerous because there are very few signs of the cancer until the spleen either ruptures or the cancer happens to be spotted on a routine abdominal radiograph or ultrasound. This is largely due to the fact that the spleen is deeply seated in the body. In fact, many dogs that are diagnosed with splenic hemangiosarcoma present to their veterinarian on an emergent basis with a history of lethargy, decreased appetite, weight loss, acute collapse, pale to white mucous membranes and/or swelling in their abdomen. Vomiting and diarrhea can also be seen in a small percentage of patients.
Splenic masses can sometimes be seen with abdominal radiographs but are most often diagnosed with an abdominal ultrasound. In either case, once a splenic mass has been detected, it is in the patient’s best interest to undergo further diagnostics (i.e. staging tests) to evaluate for any evidence of metastasis (spread of the cancer to other areas of the body). These tests include an abdominal ultrasound (if not already performed) to evaluate for possible disease in any of the other abdominal organs, chest radiographs determine if there is any evidence of disease in the lungs, blood work that includes a CBC (which checks the red and white blood cells and platelets), a chemistry panel, clotting times and a urinalysis. An echocardiogram of the heart may also be warranted. Studies have shown that a small percentage of patients with splenic hemangiosarcoma can have a mass in the right auricle of the heart at the time of diagnosis.
Surgery is the primary treatment for a splenic mass and we need to keep in mind that not all splenic masses are malignant. The only way to obtain a definitive diagnosis is with removal of the spleen and submitting the sample for biopsy. The hope is to pursue surgery before the mass or masses rupture, but most patients present in a crisis secondary to rupture of the mass leading to emergency surgery. With surgery alone, the median survival time is approximately 1-2 months with patients succumbing to metastatic disease.
Hemangiosarcoma has a high metastatic potential even if the spleen has been removed. Due to the aggressive nature of hemangiosarcomas, chemotherapy may be recommended to try and slow the progression of the cancer. The primary chemotherapy drug used to treat hemangiosarcoma is doxorubicin (also known as adriamycin). Fortunately, most patients tolerate chemotherapy well with minimal side effects. These side effects can include stomach upset (decrease in appetite, nausea, vomiting, diarrhea and lethargy), decrease in white blood cell count and thinning of the fur coat. In addition, doxorubicin has also been shown to have a cumulative toxicity on the heart and because of this, doxorubicin has a lifetime dose in dogs that we do not exceed. In some cases, an echocardiogram may be recommended prior to the first treatment to obtain a baseline of their heart function and then again prior to the 5th or 6th treatment. Doxorubicin is administered intravenously once every 3 weeks for 4-6 treatments. Patients treated with surgery and chemotherapy experience a median survival time of 4-6 months.
In addition to traditional therapy, there are a couple of other treatment options that have shown some promise, but there is limited information regarding their true efficacy. These include I’m Yunity and Yunnan Baiyao. I’m Yunity is an extract of polysaccharopeptide from Coriolus versicolor mushroom (commonly known as the Yunzhi mushroom) that showed some promise in a small study out of the University of Pennsylvania. This study was very small, so it is unknown whether the information gathered in this study is representative of the larger population.
Many oncologists are prescribing the Chinese supplement Yunnan Baiyao. This supplement is thought to help slow down or stop bleeding from some of the cancerous lesions. There is also some data that shows it may also promote healing and possibly has some anti-tumor benefit against hemangiosarcoma. To better understand the benefit of this supplement, clinical studies are needed.
There may be some ongoing clinical trials available to your pet. Clinical trials are most often trying to find a new and possibly better treatment to improve the outcome for dogs with hemangiosarcomas.
Splenic hemangiosarcoma is a very aggressive cancer and, unfortunately, long-term control/survival is difficult to achieve. Our main goal when treating your pet is to provide good quality time for all of you.