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How is multiple myeloma staged?


Staging is the process of finding out how much the cancer has advanced. It is important for treatment options and prognosis. Prognosis is a prediction of the course of disease—the outlook for the chances of survival. Knowing all you can about staging lets you take a more active role in making informed decisions about your treatment.

Multiple myeloma may be staged using the Durie-Salmon system. Although some doctors use this system, its value is becoming limited because of newer diagnostic methods. Recently, a new staging system called the International Staging System for Multiple Myeloma has been developed. It relies mainly on levels of albumin and beta-2-microglobulin in the blood. Other factors that may be important are kidney function, platelet count and the patient's age.

The Durie-Salmon staging system

This system is based on 4 factors:
• The amount of abnormal monoclonal immunoglobulin in the blood or urine: Large amounts of monoclonal immunoglobulin indicate that many malignant plasma cells are present and are producing that abnormal protein.
• The amount of calcium in the blood: High blood calcium levels are also related to advanced bone damage. Because bone normally contains lots of calcium, bone destruction releases calcium into the blood.
• The severity of bone damage based on x-rays: Multiple areas of bone damage seen on x-rays indicate an advanced stage of multiple myeloma.
• The amount of hemoglobin in the blood: Hemoglobin is the substance in red blood cells that carries oxygen. Low hemoglobin levels indicate that the myeloma cells occupy much of the bone marrow and that not enough space is left for the normal marrow cells that produce red blood cells.

This system uses these factors to divide myeloma into 3 stages. Stage I indicates the smallest amount of tumor, and stage III indicates the largest amount of tumor:

Stage I

A relatively small number of myeloma cells are found. All of the following features must be present:
• Hemoglobin level only slightly below normal (still above 10 g/dL)
• Bone x-rays appear normal or show only 1 area of bone damage
• Normal blood calcium levels (less than 12 mg/dL)
• Relatively small amount of monoclonal immunoglobulin in blood or urine

Stage II

A moderate number of myeloma cells are present. Features are between stage I and stage III.

Stage III

A large number of myeloma cells are found. One or more of the following features must be present:
• Low hemoglobin level (below 8.5 g/dL)
• High blood calcium level (above 12 mg/dL)
• 3 or more areas of bone destroyed by the cancer
• Large amount of monoclonal immunoglobulin in blood or urine

The International Staging System

This system divides myeloma into 3 stages based only on the serum beta-2 microglobulin and serum albumin levels.

Stage I

Serum beta-2 microglobulin is less than 3.5 (mg/L) and the albumin level is above 3.5 (g/L)

Stage II

Neither stage I or III, meaning that either:
• The beta-2 microglobulin level is between 3.5 and 5.5 (with any albumin level),

OR
• The albumin is below 3.5 while the beta-2 microglobulin is less than 3.5

Stage III

Serum beta-2 microglobulin is greater than 5.5.

Other factors that affect survival

Kidney function

The blood creatinine (Cr) level shows how healthy the kidneys are. Kidneys eliminate this chemical from the body. When they are damaged by the monoclonal immunoglobulin, blood creatinine levels rise, predicting a worse outlook.

Age

Age is also important. In the studies of the international staging system, older people with myeloma do not live as long.

Labeling index

The myeloma cell labeling index, sometimes called the plasma cell labeling index, indicates how fast the cancer cells are growing. This test is done in specialized labs, using myeloma cells from bone marrow samples. A high labeling index can predict a more rapid accumulation of cancer cells and a worse outlook.

Chromosome studies

The bone marrow may be sent for tests to look at the chromosomes in the malignant cells. Certain chromosome changes can indicate a poorer outlook. For example, changes in chromosome 13 will lower the chances for survival. Another genetic abnormality that predicts a poor outcome is an exchange of material from chromosomes 4 and 14. This is called a translocation.

Last Medical Review: 08/04/2011
Last Revised: 07/24/2012

http://www.cancer.org/Cancer/Multipl...yeloma-staging