Types & Stages
Doctors can detect various levels of myeloma-related changes in the marrow, including small changes that do not amount to cancer. Here are different forms of myeloma-related conditions:
MGUS, or monoclonal gammopathy of undetermined significance—In this condition, there are some myeloma precursor cells in the bone marrow, but the percentage is low. The cells do not form a tumor or cause any disease or symptoms, and no treatment is needed. Usually doctors discover this condition when a routine blood test detects unusual levels of protein in the blood. MGUS is not cancer, and it rarely turns into myeloma. If you have MGUS, it’s important to see your doctor about every 6 months to be sure it’s not progressing.
Asymptomatic myeloma, also called smoldering or indolent myeloma—In this condition, there are more myeloma cells than in MGUS. But there are still not enough to damage the body or cause symptoms. This form of myeloma may worsen over time, in some cases very slowly. Some people live symptom-free for many years. As with MGUS, there’s no immediate need to treat this type of myeloma. But it’s important to have regular exams to check whether the condition is getting worse. When the condition becomes symptomatic, then treatment will be started.
Symptomatic myeloma, also called active myeloma—There are usually more myeloma cells in symptomatic myeloma, and they are causing one or more of these forms of damage: high levels of calcium in the blood (hypercalcemia), kidney (renal) problems, anemia (low red blood count) or bone damage. (These signs are sometimes referred to as CRAB, an acronym for Calcium elevation, Renal problems, Anemia and Bone damage.) Active myeloma causes symptoms, and requires treatment.
Stages of Myeloma
The doctor will also determine the stage of your disease, or how far along it is. By the International Staging System, there are three stages for myeloma, referred to as stage I, II and III. The stage depends on the amount of myeloma cells in your body and the amount of damage they have caused, and average survival correlates with the stage, with the longest survival for stage I and the shortest for stage III.
Specifically, the doctor will measure and consider the levels of the proteins beta-2 microglobulin and albumin in your blood to determine the stage.