Multiple myeloma (myelo- + -oma, "marrow" + "tumor"), also known as plasma cell myeloma, myelomatosis, or Kahler's disease (after Otto Kahler), is a cancer of plasma cells, a type of white blood cell normally responsible for producing antibodies. In multiple myeloma, collections of abnormal plasma cells accumulate in the bone marrow, where they interfere with the production of normal blood cells. Most cases of multiple myeloma also feature the production of a paraprotein—an abnormal antibody which can cause kidney problems. Bone lesions and hypercalcemia (high blood calcium levels) are also often encountered
Multiple myeloma is diagnosed with blood tests (serum protein electrophoresis, serum free kappa/lambda light chain assay), bone marrow examination, urine protein electrophoresis, and X-rays of commonly involved bones.
Multiple myeloma is considered to be incurable but treatable. Remissions may be induced with steroids, chemotherapy, proteasome inhibitors, immunomodulatory drugs such as thalidomide or lenalidomide, and stem cell transplants. Radiation therapy is sometimes used to reduce pain from bone lesions.
Multiple myeloma develops in 6.1 per 100,000 people per year. It is more common in men and, for unknown reasons, is twice as common in African-Americans as it is in European-Americans. With conventional treatment, median survival is 3–4 years, which may be extended to 5–7 years or longer with advanced treatments. Multiple myeloma is the second most common hematological malignancy in the U.S. (after non-Hodgkin lymphoma), and constitutes 1% of all cancers. The five year survival rate is 45%.Signs and symptoms
Because many organs can be affected by myeloma, the symptoms and signs vary greatly. A mnemonic sometimes used to remember some of the common symptoms of multiple myeloma is CRAB: C = Calcium (elevated), R = Renal failure, A = Anemia, B = Bone lesions. Myeloma has many other possible symptoms, including opportunistic infections (e.g., pneumonia). CRAB symptoms and proliferation of monoclonal plasma cells in the bone marrow are part of the diagnostic criteria of multiple myeloma.