Lymphoma in Ferrets
Lymphoma is a malignant cancer that involves the lymphoid system. In a healthy animal, the lymphoid system is an important part of the immune system's defense against infectious agents such as viruses and bacteria. Lymphoid tissue is normally found in many different parts of the body including lymph nodes, liver, spleen, gastrointestinal tract and skin.
Lymphoma is one of the most common types of cancer in the ferret and is considered by many to be the number one cancer affecting young ferrets. Most often, one lymph node is affected, primarily the popliteal. This lymph node is located on the back legs, behind the knee.
Lymphoma is classified according to the location in the body in which the cancer begins. These include:
- The multicentric form that occurs in the lymph nodes
- The gastrointestinal form that occurs in the stomach, intestines, liver and lymph nodes in the abdomen
- The mediastinal form that occurs in the mediastinum. Lymphoid tissue in the mediastinum is found in front of the heart in an organ called the thymus. Hence this form of lymphoma sometimes is called thymic lymphoma.
- Acute lymphoblastic leukemia that occurs when the disease starts in the bone marrow
What to Watch For
- Enlargement of external lymph nodes
- Loss of appetite
- Weight loss
- Difficulty breathing
Diagnostic tests are needed to identify lymphoma and exclude other diseases. These tests may include:
- Complete blood count (hemogram or CBC) to identify anemia, low platelet count or abnormal lymphocytes in the circulation
- Serum biochemistry to evaluate the general health of your pet and to determine the effect of lymphoma on other organ systems
- Urinalysis to evaluate kidney function and identify urinary tract infection
- Chest X-rays to evaluate for mediastinal lymphoma or enlargement of lymph nodes in the chest
- Abdominal X-rays to evaluate for enlargement of the liver and spleen which may be infiltrated with malignant lymphocytes
- Abdominal ultrasound to evaluate for enlargement of the liver, spleen or lymph nodes in the abdominal cavity
- Fine needle aspirate and microscopic analysis of an enlarged lymph node
- Biopsy of a lump or enlarged lymph node
- Endoscopy and biopsy of the gastrointestinal tract
- Fine needle aspiration and microscopic analysis of bone marrow to evaluate for invasion of malignant lymphocytes into the bone marrow
Treatment for lymphoma may include one or more of the following:
Chemotherapy is the most commonly recommended treatment. An animal is said to be in remission when clinical evidence of the cancer disappears after treatment. Achievement of remission by chemotherapy does not mean that the animal is cured, and cancer is likely to return if treatment is discontinued.
Several different drugs alone or in combination have been used with varying degrees of success.
The commonly used drugs include:
- Prednisone (a cortisone-like drug)
- Vincristine (Oncovin®)
- Cyclophosphamide (Cytoxan®)
- Doxorubicin (Adriamycin®)
- Asparaginase (Elspar®)
Depending upon the drug, treatment can be given by injection under the skin (subcutaneously), intravenously or by mouth (orally). Combinations of these drugs work better than a single drug.
Several different protocols have been used to treat lymphoma in ferrets, and actual treatment may vary from veterinarian to veterinarian. In addition, adjustments to the protocol may be made depending upon the patient.
In rare circumstances, radiation therapy may be recommended in addition to or instead of chemotherapy. A full course of radiation involves a total of 10 to 16 treatments given 3 to 5 times a week. Adverse effects vary depending upon the region of the body treated and the number of treatments given. Animals must anesthetized for each treatment to prevent movement during radiation exposure.
Surgery rarely is used in the treatment of lymphoma, and is more commonly used to make a diagnosis of lymphoma (i.e. to obtain biopsy specimens for examination by a veterinary pathologist).
Home Care and Prevention
As with other cancers, prevention is not possible. Seek veterinary care promptly if you detect lumps below your pet's skin in the neck, shoulders, armpits, or back legs or if your pet has vague symptoms of illness such as loss of appetite, lethargy, and weight loss.
During treatment, watch your pet for vomiting, diarrhea or development of infections.
For ferrets that respond to treatment, remission may occur and may last from 3 months up to 5 years. Unfortunately, not all ferrets respond to treatment and some succumb to the cancer. At this time, there is not a lot of statistical information available about the success rate of ferrets undergoing chemotherapy.