Multiple myeloma is a type of cancer that develops in cells in the bone marrow, called plasma cells. Plasma cells help protect the body by making antibodies that recognize and attack harmful organisms like bacteria. Plasma cells may transform into malignant cells causing multiple myeloma. As myeloma cells grow and divide in the bone marrow, they often crowd out other healthy cells that produce red blood cells, platelets, and other normal white blood cells. Myeloma cells produce abnormal antibodies, which are proteins, that can collect in and damage other organs, such as the kidney. In addition, these abnormal antibodies do not function normally to help prevent or reduce infections. A high level of these antibodies, called M proteins, found in the blood or in the urine, is a hallmark of multiple myeloma. Accurate diagnosis, however, depends on several factors including physical evaluation, symptoms, diagnostic testing, and patient history.
It is unclear what causes multiple myeloma; however, it may be genetic and usually affects elderly patients. Multiple myeloma is more common in males than females and black people are twice as likely to develop it as white people. A medical history that includes the condition of monoclonal gammopathy of uncertain significance (MGUS) is also a significant predictor of multiple myeloma.
While occasionally a patient may experience no symptoms during early stages of multiple myeloma (called asymptomatic myeloma), common symptoms vary and may include:
- Bone pain (especially in the spine and ribs)
- Broken bones
- Frequent infections
- Weakness or numbness (especially in the legs)
Complications of multiple myeloma include recurrent infections, bone fractures or osteoporosis, reduced kidney function or kidney failure, and anemia.
The prognosis of patients with multiple myeloma is improving due to research and development of many new effective drugs. Multiple myeloma is a very treatable cancer and new therapies being developed at a very rapid rate. Current therapies include:
- Proteasome inhibitors
- Immunomodulatory drugs
- Monoclonal antibodies
- New targeted agents, such as histone deacetylase inhibitors
- Stem cell transplants (using blood-forming stem cells)
- Bisphosphonates (slows advancement of bone disease, reduces bone pain and fractures)
- Radiation therapy