Stages of multiple myeloma

Staging describes or classifies a cancer based on how much cancer there is in the body and where it is when first diagnosed. This is often called the extent of cancer. Information from tests is used to find out the size of the tumour, whether the cancer has spread from where it first started and where the cancer has spread. By the time multiple myeloma is diagnosed, the cancer is usually widespread. Your healthcare team uses the stage to plan treatment and estimate the outcome (your prognosis).

Staging multiple myeloma is based on the results of blood and imaging tests. Results of other tests can also help determine the stage depending on the system used.

Doctors use 2 systems to stage multiple myeloma:

• International Staging System (ISS)
• Durie-Salmon staging system

In Canada, multiple myeloma is most often staged using the International Staging System.

For multiple myeloma there are 3 stages. Often the stages 1 to 3 are written as the Roman numerals I, II and III. Generally, the higher the stage number, the larger the amount of the myeloma in the body. Talk to your doctor if you have questions about staging.

The International Staging System uses the results of 2 blood tests to stage multiple myeloma – the albumin level and the beta-2-microglobulin level.

Albumin is the main protein found in plasma. It helps to maintain blood volume. Beta-2-microglobulin is a protein found on the surface of cells that is shed into the blood. It plays a role in the immune response.

The beta-2-microglobulin level is less than 3.5 mg/L.

The albumin level is 35 g/L or more.

The beta-2-microglobulin level is less than 3.5 mg/L.

The albumin level is less than 35 g/L.

Or

The beta-2-microglobulin level is more than 3.5 mg/L but less than 5.5 mg/L and any albumin level.

The beta-2-microglobulin level is 5.5 mg/L or more and any albumin level.

The Durie-Salmon staging system uses the results of blood tests, urine tests and x-rays to determine the stage of multiple myeloma. The Durie-Salmon staging system is based on the amount of:

• hemoglobin in the blood
• calcium in the blood
• bone damage found on x-rays
• monoclonal protein (M-protein) in the blood or urine (as measured by IgG, IgA, free light chains)

A small number of myeloma cells are found.

All of the following features are present:

• Hemoglobin level is 100 g/L or more.
• Blood calcium level is normal (less than 2.8 mmol/L).
• There are no areas of bone damage or there is a solitary plasmacytoma of the bone.
• IgG level is less than 50 g/L.
• IgA level is less than 30 g/L.
• Urine M-protein level is less than 4 g (urine collected over 24 hours).

A moderate number of myeloma cells are found.

The features are between stage 1 and stage 3.

A large number of myeloma cells are found.

One or more of the following features are present:

• Hemoglobin level is less than 85 g/L.
• Blood calcium level is more than 2.8 mmol/L.
• There are several areas of bone damage.
• IgG level is more than 70 g/L.
• IgA level is more than 50 g/L.
• Urine M-protein level is more than 12 g (urine collected over 24 hours).

The stages of multiple myeloma are further divided according to creatinine level in the blood, which shows how well the kidneys are working.

Kidney function is normal. Creatinine level is less than 180 µmol/L.

Kidney function is abnormal. Creatinine level is 180 µmol/L or more.

Relapsed, or recurrent, multiple myeloma means that the cancer has come back after it has been treated. It may come back in the same place that the original myeloma first started or it may come back in another part of the body.