Stages of Multiple Myeloma and Other Plasma Cell Neoplasms
After multiple myeloma and other plasma cell neoplasms have 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:
- X-ray: 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).
- CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
- PET scan (positron emission tomography scan): A procedure to find malignant tumor cells in the body. A small amount of radionuclide glucose (sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the body. Malignant tumor cells show up brighter in the picture because they are more active and take up more glucose than normal cells do.
- Bone densitometry: A procedure that uses a special type of x-ray to measure bone loss.
Certain tests may be repeated to see how well the treatment is working.
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 the surface of plasma cells. Albumin makes up the biggest part of the blood plasma. It keeps fluid from leaking out of blood vessels, brings nutrients to tissues, and carries hormones, vitamins, drugs, and other substances, such as calcium, throughout the body. The amount of beta-2-microglobulin is increased and the amount of albumin is decreased in the blood of patients with multiple myeloma.
The following stages are used for multiple myeloma:
Stage I multiple myeloma
In stage I multiple myeloma, the blood levels are as follows:
- beta-2-microglobulin level is lower than 3.5 g/mL; and
- albumin level is 3.5 g/dL or higher.
Stage II multiple myeloma
In stage II multiple myeloma, the blood levels are as follows:
- beta-2-microglobulin level is lower than 3.5 g/mL and the albumin level is lower than 3.5 g/dL; or
- beta-2-microglobulin level is as high as 3.5 g/mL but lower than 5.5 g/mL.
Stage III multiple myeloma
In stage III multiple myeloma, the blood level of beta-2-microglobulin is 5.5 g/mL or higher.
The stages of other plasma cell neoplasms are different from the stages of multiple myeloma.
Isolated plasmacytoma of bone
In isolated plasmacytoma of bone, one plasma cell tumor is found in the bone, less than 5% of the bone marrow is made up of plasma cells, and there are no other signs of cancer.
Extramedullary plasmacytomaOne plasma cell tumor is found in the soft tissue but not in the bone or the bone marrow.
There is no standard staging system for macroglobulinemia.
Monoclonal Gammopathy of Undetermined Significance
In monoclonal gammopathy of undetermined significance (MGUS), less than 10% of the bone marrow is made up of plasma cells, there is M protein in the blood, and there are no other signs of cancer.
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Source: National Cancer Institute, www.cancer.gov