Myeloma affects a type of white blood cell called plasma cells, which are involved in the production of antibodies. These proteins circulate in the blood, attacking viruses and bacteria. When there is an infection, the bone marrow produces more plasma cells, which in turn produce antibodies to attack the source of the infection. In a myeloma patient, however, this process gets out of control and the myeloma cells fill up the bone marrow and interfere with the production of normal white blood cells, red blood cells, and platelets. This process might also cause bone thinning, resulting in pain and fractures.
Myeloma accounts for approximately one percent of all cancers and 10 percent of all hematological (blood) cancers. It can manifest itself in a variety of types, depending on which antibodies are affected. The type of myeloma does not often change the treatment, but it can influence how the disease will affect individuals. The most common type of myeloma is IgG, followed by IgA. The least common types are IgM, IgD, and IgE.
Approximately one in three people with myeloma have light chain myeloma, or Bence Jones myeloma. This is a type of myeloma wherein these light chains of protein can affect the kidneys and are often found in the urine. A rare type of myeloma, called non-secretory myeloma, produces few or no antibodies.
To identify whether an individual has active myeloma, doctors use a set of criteria referred to as CRAB. This consists of:
- C: increased calcium level.
- R: renal (kidney) problems.
- A: anemia.
- B: bone changes (lytic lesions or bone loss).
The presence of one or more of these symptoms indicates active myeloma, which requires treatment.
Since there is no cure, but remission is possible, treatment is aimed at reducing symptoms. In addition, there might be a need to control symptoms such as pain or nausea, and to prevent or treat complications of the disease such as hypercalcemia (elevated levels of calcium in the blood), bone fractures, and kidney failure.
Treatment options include:
- Stem cell transplantation
In cases of relapsed or refractory myeloma, treatment options are thalidomide, lenalidomide (a derivative of thalidomide), or bortezomib. These drugs can be used alone or in combination with corticosteroids and chemotherapy.