Staging myeloma is something that can be done at diagnosis, as the same tests that are used to identify myeloma can also be used to determine the prognosis and extent (stage) of the disease.
The doctor will use certain criteria to classify myeloma on a scale from 1 to 3. People with stage 3 disease have signs of more advanced disease, such as kidney failure.
A common classification system for myeloma is the International Staging System (ISS). This system uses the results from two additional blood tests for staging.
The first test is called Beta-2 microglobulin (β2M). β2M is a small protein that is released by all lymphocytes, including plasma cells, as part of their life cycle. Elevated levels indicate an increase in the number of plasma cells, even if the M- protein is not significantly increased. Normal β2M values are less than 2.5µg/mL.
The second test is blood albumin. Albumin is a protein found in the blood that helps to regulate blood volume. Low albumin levels may indicate kidney damage. Normal values for albumin are 35- 50g/L (or 3.5- 5.0 g/dL).
The below table summarizes staging of myeloma.
The staging of myeloma is important to physicians because it gives them information about the extent and spread of the disease, prognosis, as well as options for treatment.
Kyle, Robert and Rajkumar, S. Vincent "Multiple Myeloma" Blood 15 March 2008 111:2962-2972.
Lin, Pei "Plasma Cell Myeloma" Hematology/ Oncology Clinics of North America 2009 23:709-727.
Nau, Konrad and Lewis, William "Multiple Myeloma: Diagnosis and Treatment" American Family Physician 1 October 2008 78:853-859.
Stages may be subclassified as A (normal kidney function) or B (abnormal kidney function). No matter what stage of the myeloma, the prognosis may be worse if the cancer has affected kidney function.