Hearing a cancer diagnosis for your pet can be scary and confusing. Therefore, understanding the terms and the science behind various types of cancer can go a long way in creating HOPE and an ability to make informed decisions about treatment options. In this blog, we will be discussing leukemia, which is a cancer that attacks the immune system’s white blood cells.
When the various types of cells within the immune system begin to divide out of control, they become leukemia. Traditionally, this type of cancer is located in the bone marrow or blood and results in the overproduction of white blood cells. The bone marrow is unable to produce healthy cells due to the presence of the cancerous cells overcrowding the marrow.
Leukemia comes in two general forms: acute and chronic. The term “acute” refers to immature cancerous cells, while “chronic” refers to more mature cancerous cells. The acute form tends to be more aggressive, as the immature cells tend to divide rapidly. Acute leukemia unfortunately tends to have poor responses to chemotherapy. This disease process is typically treated with injectable chemotherapy but often has a survival rate of only a couple of months. Chronic leukemias are much more treatable and sometimes do not even require treatment right away.
Symptoms that may indicate your dog has acute leukemia include lethargy, decreased appetite, vomiting, and an elevated temperature. Blood work may show low red and white blood cells and low platelets. Keep in mind, however, that these signs are nonspecific and do not directly indicate leukemia. An exam with your primary care veterinarian is always a recommended first step.
If elevated white blood cells are discovered, your primary care veterinarian may recommend a consult with an oncology specialist, who may recommend a flow cytometry. This diagnostic test involves taking a sample of blood and looking for specific markers on the cells to identify leukemia. Other ‘staging’ tests may be recommended to assess for cancer involvement in other parts of the body as well as concurrent disease. In some situations, an aspirate of the bone marrow may be recommended to obtain a more definitive diagnosis.
Once a diagnosis is obtained, treatment is primarily made up of injectable chemotherapy. There are various protocols; however, the most common treatment option is CHOP, which is composed of four different chemotherapy drugs (cyclophosphamide, doxorubicin, vincristine, and prednisone), or COP (cyclophosphamide, vincristine, and prednisone). Some protocols may also include a chemotherapy agent called cytarabine, which some studies suggest may help with overall survival times. Depending on how aggressive the leukemia is, hospitalization and blood transfusions may be necessary.
There are several different types of acute leukemias that each carry a different prognosis. Unfortunately, the overall survival times range from two weeks to four to six months, even with treatment. Chronic leukemias, on the other hand, can have extended survival times, for potentially years.
Each situation is unique; therefore, you’ll want to seek the guidance of a highly-trained specialist in the field of veterinary oncology.
