Multiple myeloma, a cancer of the bone marrow that causes certain cells to grow out of control and break down bone, is the most common type of bone cancer, according to the University of Maryland Medical Center. The word 'stage' is used to describe how far the cancer has advanced. Multiple myeloma is divided into three stages. The early forms, including stage I and smoldering myeloma, are slow-growing with no noticeable symptoms. They require careful monitoring but no treatment, reports the Multiple Myeloma Research Foundation. The advanced stages, stages II and III, warrant immediate treatment. Unlike people with early-stage disease, patients with stage II and III multiple myeloma have active symptoms and complications, such as bone fractures.
The Two Staging Systems
Doctors use two methods to stage multiple myeloma: The Durie-Salmon staging system, which has been around since 1975, and the International Staging System, which was introduced by an international expert panel in 2005, reports the "Journal of Clinical Oncology." Both classify myelomas as stage I, stage II, or stage III. The Durie-Salmon system uses four factors: the M protein, degree of bone damage, amount of calcium and hemoglobin, according to Caring4Cancer. HIgh levels of M protein, an abnormal antibody, show that many cancer cells are present. Both calcium levels and bone tumors increase as the cancer advances. Finally, hemoglobin, a measure of red blood cells, decreases as myeloma grows. The International Staging System uses just two measures to stage myeloma: the amount of beta-2-microglobulin, a protein that is released by myeloma cells, and serum albumin, a blood protein made in the liver.
Stage II Multiple Myeloma
People with stage II multiple myeloma have an intermediate number of cancer cells in their bodies. The International Staging System classification of Stage II myeloma has beta-2-microglobulin levels between 3.5 and 5.5 with an albumin level or as both albumin and beta-2-microglobulin below 3.5. The International Staging System measures stage II disease are between indices for stage I and III disease, reports the Multiple Myeloma Research Foundation..
Stage III Multiple Myeloma
In the Durie Salmon staging system, stage III multiple myeloma has a blood calcium level more than 12 mg/DL, three or more bone tumors, a high level of M protein in the blood, and a hemoglobin level below 8.5 g/dL. These parameters show that a large amount of myeloma cancer cells are in the patient's body, reports the American Cancer Society. The International Staging System uses one measure to define stage III multiple myeloma: a beta-2 microglobulin more than 5.5 This marker was selected after its accuracy was confirmed in large international study, explains the "Journal of Clinical Oncology."
Subclassifications According to Kidney Function
The Durie-Salmon staging system also classifies multiple myeloma according to how well the kidneys are working, explains the Multiple Myeloma Research Foundation. This is done by measuring the amount of serum creatinine, a chemical that is removed by healthy kidneys. The "A" designation, a serum creatinine less than 2.0 mg/dL, means that the kidney is behaving fairly normally. The "B" designation, serum creatinine equal to or more than 2.0 mg/dL, means that kidney function is abnormal and that treatment must be started immediately. Patients can have IIA or IIB disease, or, if it is more progressed, IIIIA or IIIB myeloma.
References
- University of Maryland Medical Center: Bone Cancer
- Caring4Cancer: What Are the Classifications and Stages of Multiple Myeloma?
- Multiple Myeloma Research Foundation: Current and Emerging Trends in the Treatment of Multiple Myeloma.
- "Journal of Clinical Oncology"; International Staging System (ISS) for Multiple Myeloma; Greipp et al; 2005
