One of the most common malignant cancers seen in feline medicine is the development of lymphosarcoma, which is an abnormal overgrowth of cells of the immune system known as lymphocytes. While certain viruses such as feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) can play a role in at the development of lymphosarcoma, in other cases no known cause is found, although other factors, including excessive exposure to environmental pesticides, chemicals, and over-vaccination may play a role in some pets.
In younger cats, lymphosarcoma most commonly presents with the development of masses in the chest, where symptoms may include difficulty breathing, coughing and/or vomiting. The most common site of involvement in older cats is in the digestive tract; however, development of cancer in other organs including the brain, eyes, nose, kidney and spine may occur.
Symptoms will vary depending on the organ system involved. With the most common digestive tract form, loss of appetite, chronic vomiting, diarrhea and/or weight loss may occur. Lymphosarcoma can mimic many other diseases, including the very common inflammatory bowel disease. Successful treatment outcome depends on early diagnosis through tissue/tumor biopsy and/or staging of the cancer.
The cornerstone of treatment of lymphosarcoma in both cats and dogs remains the use of sequential chemotherapy typically over many weeks or months. While some cats may have side effects with this treatment, many cats tolerate chemo side effects very well. Median survival time in cats with a diagnosis of lymphosarcoma is typically from 6 to 9 months, although occasional longer periods of survival may be seen.
For those clients who can’t afford expensive chemotherapy treatments and/or consultations with veterinary oncologists, I have found that a protocol using oral prednisone and chlorambucil effective in many cats with gastrointestinal lymphosarcoma. Clients may also consider consultation with holistic veterinarians for complimentary therapies, including dietary therapies, nutritional supplements and classical homeopathy.