LYMPHOMA IN DOGS

Lymphoma in dogs is a type of cancer that occurs within the dog’s lymphatic system. This system is an integral portion of the dog’s immune system, which helps fight off infection. When lymphocytes (a specific type of white blood cell) grow abnormally, they will multiply out of control and migrate through the body. Since the lymphatic system is located throughout the entire body, a variety of organs may develop tumors from this disease, including lymph nodes, spleen, liver and bone marrow.

Lymphoma is considered one of the most prevalent forms of canine cancer and it can develop in dogs regardless of their age; however, it is typically diagnosed in middle aged and elderly dogs. A quick progression of this disease often depends on the specific type and stages of the disease; therefore, early detection of lymphoma is crucial for achieving a favorable prognosis.

Causes and Risk Factors

There are various theories regarding what causes lymphoma in dogs. The consensus among veterinarians and researchers is that there are numerous possible causes related to both genetics and environment.

Changes in immune regulation may contribute to lymphoma development, although the exact cause remains unknown. Some breeds appear to have an increased likelihood of developing lymphoma. These breeds include golden retrievers, boxers, bulldogs and rottweilers. There appears to be a genetic link associated with these breeds.

Factors that could contribute to the development of lymphoma in dogs include:

• Genetic predisposition
• Immune system dysfunction
• Environmental exposure to chemicals or toxins
• Chronic inflammation or immune stimulation.

Symptoms

• Swollen lymph nodes
• Reduced energy levels
• Mild loss of appetite
• Noticeable enlargement of multiple lymph nodes
• Vomiting or diarrhea
• Increased thirst and urination
• Difficulty breathing if the chest is affected
• Weakness and muscle loss

Risks and Complications

Lymphoma is a progressive disease that will rapidly move through the entire body and be fatal if left untreated.

Accumulation of lymphoma cells can interfere with the normal function of organs such as the lymph nodes, liver, spleen, bone marrow and other tissues. This obstruction also causes problems when fighting off infection.

Severe weight loss, anemia and organ failure occur in late stages. In most cases, this disease progresses quickly enough to limit a dog’s quality of life and possibly shorten their lifespan if left untreated.

Diagnosis

Confirming abnormal lymphocyte proliferation and identifying progression of the disease are two components of diagnosing lymphoma.

Common Diagnostics Used for Lymphoma

• Physical examination of enlarged lymph nodes
• Fine needle aspiration (FNA) of lymph nodes
• Biopsy for definitive diagnosis
• Blood tests to assess organ function and blood cell counts
• X-rays or ultrasound to check internal organ involvement
• Bone marrow evaluation in advanced cases

These tests help determine the type and stage of lymphoma which guides treatment planning.

Treatment

Lymphoma in dogs does not have a cure; however, the majority of lymphomas are treatable and many dogs will have favorable responses to treatment.

Chemotherapy

Chemotherapy is the most common form of treatment for canine lymphoma. Chemotherapy works by attempting to inhibit the growth rate of tumor cells (i.e., slow down the growth of the cancer), which allows patients to maintain good quality of life while controlling the disease. Overall, dogs tend to tolerate chemotherapy relatively well compared to people, experiencing few side effects. The primary goal of chemotherapy in dogs is to induce clinical remission and maintain that state as long as possible.

Supportive Treatment

Some supportive treatments can be helpful to your dog during the course of chemotherapy:

• Anti nausea medications or vomiting medications
• Appetite stimulants
• Dogs who are severely dehydrated or weak may require fluid replacement
• Pain medication if needed

Steroid Therapy

Corticosteroids may be prescribed to your dog depending upon the specific situation. Steroids can provide temporary relief from the signs associated with lymphoma and they may also slow the progression of the disease in some cases. Steroids may provide temporary improvement in some dogs but generally do not provide the same duration of remission as chemotherapy.

Prognosis

The prognosis will depend upon the specific type of lymphoma, the extent of disease at the time of diagnosis and how responsive the dog is to treatment.

Many dogs treated with chemotherapy will go into remission for a period of time ranging from a few months to one year. If left untreated, the disease typically develops very quickly.

Timely treatment along with prompt identification of disease significantly improves both the quality of life and the length of survival time.

Prevention

Although lymphoma cannot currently be prevented, maintaining good overall health and regular veterinary care can help detect disease earlier.

• Schedule regular visits to your veterinarian
• Seek immediate attention from your veterinarian should you notice unexplained swelling or weight loss
• Limit your pet’s exposure to toxins whenever possible
• Provide your pet with a nutritious diet that supports a strong immune system.