Huntsman Cancer Institute Myeloma Program – Types and Stages of Multiple Myeloma

There are different forms of myeloma-related conditions. Some require treatment, some do not, but all will require regular check-ups to monitor whether the disease is progressing:

Monoclonal gammopathy of undetermined significance (MGUS)
People who have MGUS harbor a small number of myeloma cells in the bone marrow but these cells are not forming a tumor and symptoms of the myeloma are not present. This condition is usually discovered during a routine blood exam that shows unusual levels of protein in the blood.

MGUS is a pre-cancerous condition. Therefore, check-ups should occur every 6 months to monitor the condition and make sure that it does not develop into multiple myeloma, even though this only happens in a small amount of patients.

A diagnosis of MGUS should not be made without having performed chromosome analysis, gene array, MRI, and/or a PET/CT scan.

Asymptomatic (smoldering/indolent) myeloma
Asymptomatic myeloma falls somewhere between MGUS and overt, symptomatic multiple myeloma. In this condition, a person has a greater number of myeloma cells than a person with MGUS. However, the disease does not cause any damage to the body and the typical myeloma symptoms are not present, though patients may exhibit anemia due to causes other than the myeloma.

Asymptomatic myeloma can be stable for many months or years, but it ultimately tends to progress. Treatment will likely be needed at some point. Patients will need to be monitored to see if the disease progresses and if symptoms become evident.

Symptomatic (active) myeloma
This type of myeloma represents overt cancer. A person with symptomatic myeloma has more myeloma cells than a person with asymptomatic myeloma or MGUS.

At this point, the disease is causing damage to the body, like bone damage, anemia, kidney problems, or hypercalcemia (high levels of calcium in the blood).

Staging is the process of finding out the extent of a person’s myeloma. There are two staging systems that myeloma doctors consult:

Durie-Salmon staging
In this system, there are three stages of myeloma: Stage I, Stage II, and Stage III. The stage depends on factors including:

Myeloma can also be further classified into Group A or Group B, based on damage to the kidneys. Group A indicates normal kidney function while Group B indicates abnormal kidney function. A person could be classified, for example, as Stage IIB.

International Staging System (ISS)
This staging system is based on the albumin level (more or less than 3.5 mg/dL) and B2-microglobulin level (< 3.5; 3.5-5 or >5 mg/L). The higher the stage, the poorer the outcome. This staging system is based on outcomes of more than 10,000 cancer cases.

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