Multiple Myeloma

What Is It?

Multiple myeloma is cancer of the bone marrow that results from uncontrolled growth of plasma cells, a form of white blood cells. Normally, plasma cells make antibodies called immunoglobulins to fight infections. In multiple myeloma, however, plasma cells multiply uncontrollably and make too much of a single type of immunoglobulin. The level of other types of immunoglobulin drops dangerously low, leaving the patient susceptible to infections. The cancerous plasma cells collect in the bones and bone marrow, and sometimes form tumors that destroy the bone tissue, causing the bones to become weak and possibly break.

Multiple myeloma is a fairly rare form of cancer, affecting only three to four out of every 100,000 people in the United States each year. It tends to occur in older people. The average age that this cancer develops is 60. Other risk factors include exposure to radiation, benzene or pesticides.

Symptoms

There may not be any symptoms early in the illness. However, as multiple myeloma progresses, symptoms can include:

• Pain in the bones, especially in the back, ribs, and, sometimes, the arms — Pain occurs when bone is being destroyed by the myeloma cells.
• Frequent infections
• Fatigue
• A tendency to bleed easily, especially from the nose or gums
• Easy bruising
• A general numbness of the skin
• Severe kidney problems
• Loss of appetite
• Nausea and vomiting
• Confusion

Diagnosis

Your doctor will order blood tests to check for anemia, which occurs when plasma cells crowd the bone marrow and prevent the normal production of red blood cells. Blood tests also will reveal unusually high levels of protein, a reflection of the large amounts of immunoglobulin being formed by cancerous plasma cells. You may be asked to collect your urine for 24 hours so that it can be analyzed for abnormal amounts of protein.

Your doctor may order X-rays of the long bones in your body, your skull and chest to help confirm the diagnosis, and to check for bone weakness. A bone-marrow biopsy also will be done to confirm an abnormally high level of plasma cells. This procedure is done under local anesthesia in your doctor's office. A long needle is used to withdraw a small amount of bone marrow so it can be examined under a microscope. Normally, plasma cells account for less than 5 percent of the cells in the bone marrow. However, in patients with multiple myeloma, this percentage increases to 10 percent to 90 percent. Multiple myeloma is diagnosed if a bone-marrow biopsy shows more than 30-percent plasma cells.