Last Modified: February 16, 2003
Dear OncoLink "Ask The Experts,"
Our 15 1/2 year old cat recently has been diagnosed with Multiple Myeloma. Can you tell me a little about the diagnosis and possible treatments?
Lili Duda, VMD, Section Editor of the OncoLink Veterinary Oncology Menu, responds:
Multiple myeloma is an uncommon cancer of a type of white blood cell known as a plasma cell. These white blood cells are the ones that produce antibodies, which fight off infection. In order to diagnose multiple myeloma, at least 2 of four criteria must be met:
Many of the clinical signs of multiple myeloma are caused by the increased amount of globulin protein in the blood. This globulin can cause the blood to become very thick and viscous, which can cause heart problems because it has to work so much harder to pump the blood, and kidney problems because the protein can clog up the kidneys. It can also cause decrease in immune function as well as bone pain. Treatment is aimed at reducing the number of cancer cells and decreasing the amount of globulins in the blood. Chemotherapy is the initial approach, which consists of high dose prednisone (which is chemotherapeutic against cancerous plasma cells) and another chemotherapy drug called melphalan. Specific organ problems are treated symptomatically. While multiple myeloma is probably the most common cause of elevated globulins in the older cat, there are other causes, such as lymphosarcoma or leukemia (which is also a treatable cancer) and a variety of infectious diseases.