There are no standard staging systems for monoclonal gammopathy of undetermined significance (MGUS), macroglobulinemia, and plasmacytoma.
After multiple myeloma has been diagnosed, tests are done to find out the amount of cancer in the body.
The process used to find out the amount of cancer in the body is called staging. It is important to know
the stage in order to plan treatment. The following tests and
procedures may be used in the staging process:
- Skeletal bone survey: In a skeletal bone survey, x-rays of all the bones in the body are taken. The x-rays are used to find areas where the bone is damaged. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
- MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body, such as the bone marrow. This procedure is also called nuclear magnetic resonance imaging (NMRI).
- Bone densitometry: A procedure that uses a special type of x-ray to measure bone density.
The stage of multiple myeloma is based on the levels of beta-2-microglobulin and albumin in the blood.
Beta-2-microglobulin and albumin are found in the blood. Beta-2-microglobulin is a protein found on plasma cells. Albumin makes up the biggest part of the blood plasma. It keeps fluid from leaking out of blood vessels. It also brings nutrients to tissues, and carries hormones, vitamins, drugs, and other substances, such as calcium, all through the body. In the blood of patients with multiple myeloma, the amount of beta-2-microglobulin is increased and the amount of albumin is decreased.
The following stages are used for multiple myeloma:
Stage I multiple myeloma
In stage I multiple myeloma, the blood levels are as follows:
Stage II multiple myeloma
In stage II multiple myeloma, the blood levels are as follows:
- beta-2-microglobulin level is lower than 3.5 mg/L and the albumin level is lower than 3.5 g/dL; or
- beta-2-microglobulin level is between 3.5 mg/L and 5.4 mg/L.
Stage III multiple myeloma
In stage III multiple myeloma, the blood level of beta-2-microglobulin is 5.5 mg/L or higher.