Staging is the process of determining how far the cancer has spread. It is necessary for a physician to plan treatment and determine the patient’s prognosis. The Durie-Salmon system may be used to stage multiple myeloma. The system is based on four factors:

• The quantity of abnormal monoclonal immunoglobulin in the patient’s blood or urine. The presence of large amounts of monoclonal immunoglobulin suggests that many malignant (cancerous) plasma cells are present and are producing that abnormal protein.
  
  
• The level of calcium in the patient’s blood. High levels of calcium in the blood indicate advanced bone damage.
  
  
• The severity of the patient’s bone damage based on x-rays. Multiple areas of bone damage suggest an advanced stage of multiple myeloma.
  
  
• The level of hemoglobin in the patient’s blood. Hemoglobin is the substance in red blood cells that transports oxygen. Low levels suggest that the cancer cells occupy a large amount of the bone marrow and that there is not enough space for the normal red blood cell-producing marrow cells.

These factors are combined to estimate the amount of myeloma cells in the body. The cancer is then assigned a stage based on the extent of the disease. The stages of multiple myeloma include:

• Stage I. In this stage a small amount of myeloma cells are found. Multiple myeloma is considered in stage I when all of the following features are present:
  
  
• • The level of hemoglobin is only slightly below normal (above 10 grams per deciliter [g/dl]).
    
    
  • Bone x-rays appear normal or detect only one area of bone damage.
    
    
  • The level of calcium in the blood is normal (less than 12 milligrams per deciliter [mg/dl]).
    
    
  • There is only a small amount of monoclonal immunoglobulin in the blood or urine.
    
    
  The term smoldering myeloma may be used to describe the disease in stage I.
  
  
• Stage II. In this stage, a moderate amount of myeloma cells are found. Multiple myeloma is considered in stage II when the patient’s features are between those of stage I and stage III.
  
  
• Stage III. In this stage, a large amount of myeloma cells are found. Multiple myeloma is considered to be at stage III when one or more of the following features are present:
  
  
• • The level of hemoglobin is low (below 8.5 g/dl).
    
    
  • The level of calcium in the blood is high (above 12 mg/dl).
    
    
  • There are three or more areas of bone damage.
    
    
  • There is a large amount of monoclonal immunoglobulin in the blood or urine.
    

According to the American Cancer Society (ACS), the median survival times for patients in the different stages of multiple myeloma include: