Lymphoma is a cancer of the lymphatic system. The lymphatic system is responsible for filtering debris from the body. This debris may include bacteria and dead cells, from areas of infection or inflammation, that are carried to the lymph nodes where they are engulfed, digested and removed from the body. The lymphatic system also helps with the body’s normal immune system by producing antibodies (immune proteins made in response to a foreign substance). A tumor that affects the lymphatic system can prevent these normal functions and may affect multiple organs throughout the body. Lymphosarcoma is one of the most common cancers seen in the ferret.
When a pet is diagnosed with cancer, owners often ask where it came from, how the pet got it or how it started. Exactly what transforms an apparently healthy cell into a cancerous cell is not known. Many studies are being done in the field of cancer research to determine this and may include genetic makeup, environmental influences and exposure to certain drugs or toxins.
Clinical signs of the disease vary depending on what organs or body tissues are involved and how extensive the disease is. There are two general forms of lymphosarcoma in the ferret. The lymphoblastic form is a rapidly progressive form that affects primarily young ferrets under 2 years of age. The lymphocytic form is a chronic disease of slow onset that usually affects older ferrets.
The clinical signs of the lymphoblastic form of lymphosarcoma may be vague making diagnosis difficult. Signs of this rapidly progressive disease depend on which organs are involved. Usually the affected ferret is inactive and has lost its appetite resulting in weight loss. At times the liver or spleen may be infiltrated resulting in abdominal swelling or enlargement. With liver involvement marked elevations in liver enzymes may be seen on blood analysis. Another presentation is breathing difficulty due to enlargement of the thymus gland or lymph nodes in the chest that produces fluid and compresses the lungs. Lymphoblastic lymphosarcoma should always be ruled out in any young ferret with serious illness.
The lymphocytic form is usually seen in older ferrets, where it may cause visible enlargement of the peripheral lymph nodes (lymph nodes located just below the skin) that your veterinarian will assess upon physical exam. The early stage of this disease is often subtle in nature and the ferret may not appear sick. As the disease progresses, single or multiple lymph nodes may be affected and these ferrets may show firm swellings beneath the skin, most commonly at the neck, shoulders, rear legs or groin. Internal lymph nodes can also be affected. Late in the course of the disease, organs such as the liver, spleen, kidneys and lungs are infiltrated, resulting in organ failure and death if untreated.
Lymphosarcoma can be a difficult disease to diagnose. Definitive diagnosis requires interpretation of a biopsy or needle aspirate from an affected lymph node or body organ. This requires the expertise of a pathologist or experienced practitioner. Treatment should not be initiated until a definitive diagnosis is obtained.
Although the disease cannot be cured, there are varied treatment options. Treatment is aimed at prolonging and maintaining a good quality of life for the pet. The most effective treatments involve chemotherapy or radiation. Chemotherapy can involve the use of a single drug or a combination of several drugs.
Combination drug therapy is usually more effective than single drug therapy. Several protocols have been published for the treatment of ferret lymphosarcoma and your veterinarian will discuss the various options available. In some cases surgery or radiation treatment may also be recommended.