Stages of Plasma Cell Neoplasms

There are no standard staging systems for monoclonal gammopathy of undetermined significance (MGUS) and plasmacytoma.

After multiple myeloma has been diagnosed, tests are done to find out how much cancer is 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 to find out how much cancer is in the body:

• 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:

• beta-2-microglobulin level is lower than 3.5 mg/L; and
• albumin level is 3.5 g/dL or higher.

Stage II multiple myeloma

In stage II multiple myeloma, the blood levels are in between the levels for stage I and stage III.

Stage III multiple myeloma

In stage III multiple myeloma, the blood level of beta-2-microglobulin is 5.5 mg/L or higher and the patient also has one of the following:

• high levels of lactate dehydrogenase (LDH); or
• certain changes in the chromosomes.

Plasma cell neoplasms may not respond to treatment or may come back after treatment.

Plasma cell neoplasms are called refractory when the number of plasma cells keeps going up even though treatment is given. Plasma cell neoplasms are called relapsed when they have come back after treatment.