Staging, the process of finding out how much the cancer has advanced, is important for treatment options and prognosis. Prognosis is a prediction of the course of disease – the outlook for the chances of survival. It depends on the stage of the cancer. 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. Some doctors use a simpler system that relies on 2 factors: levels of albumin and beta-2-microglobulin in the blood. Others use factors such as chromosome changes and tests of the myeloma growth rate. The Durie-Salmon staging 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 red blood cell-producing marrow cells.

There are 3 stages for the classification of the extent of the multiple myeloma. 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 (above 10 grams/deciliter)
bone x-rays appear normal or show only 1 area of bone damage
normal blood calcium levels (less than 12 milligrams/deciliter)
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:
hemoglobin level quite low (below 8.5 g/dl)
high blood calcium level (above 12 mg/dl)
three or more areas of bone destroyed by the cancer
large amount of monoclonal immunoglobulin in blood or urine

Recurrent multiple myeloma: Recurrent disease means that the cancer has come back after treatment. Recurrent multiple myeloma may return in the bone or in another part of the body.

Indolent myeloma: This term is sometimes used for people with myeloma who remain in stage II for a long period of time.

Smoldering myeloma: This term is used to describe people who remain in stage I for a long period of time.

Survival rates by stage

At one time, it was possible to give survival rates by stage. With the new treatments used in myeloma, these are no longer valid, and people are beginning to use other criteria to determine a personÂ’s outlook for survival. These are described below.

Other Prognostic Factors

In addition to bone x-rays and tests to measure levels of the monoclonal immunoglobulin in blood or urine and hemoglobin and calcium in blood, several other tests may be done to help predict a patient's outlook and to determine treatment options.

Some doctors rely on the amount of beta-2-microglobulin in the blood to determine the prognosis of people with myeloma. This protein is produced by the myeloma cells and is probably the single best indicator of the amount of myeloma in the body. High levels of this protein indicate that many myeloma cells are present. Although this protein is not a part of the staging system described above, its level in the blood goes up as the stage gets higher. Beta-2-microglobulin levels also go up if there is kidney damage. Very high levels indicate many cancer cells and significant kidney damage, predicting a poor prognosis.

The blood creatinine level also reflects the kidney's health. This chemical is eliminated from the body by the kidneys. When the kidneys are damaged by the monoclonal immunoglobulin, blood creatinine levels rise, predicting a worse prognosis.

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.

Genetic changes such as those for chromosome 13 are also important. Changes in chromosome 13 as well as in other chromosomes will lower the chances of survival.

Other tests may be done that do not directly examine the cancer but check the patient's general state of health and the condition of certain organs that are particularly sensitive to the side effects of certain drugs used to treat this disease.

Source: American Cancer Society