Many people have not heard of multiple myeloma when they are first diagnosed, which makes it vitally important to learn as much as possible about this type of hematologic (blood) cancer that affects plasma cells. It is usually managed as a chronic condition because multiple myeloma is not often cured, but research is making great progress, offering hope to many.
It helps to know a little bit about plasma cells when learning about multiple myeloma. Plasma cells are produced in the bone marrow. They make different types of antibodies to help fight germs and viruses, and stop infection and disease. Antibodies are proteins created as a reaction to foreign substances, such as bacteria, in the body. As a type of white blood cell, plasma cells are an important part of the immune system, a network of cells that work together to defend your body against infections.
Multiple myeloma begins when the blood’s plasma cells multiply uncontrollably. When abnormal plasma cells grow out of control, they prevent healthy plasma cells from producing antibodies, weakening the immune system and affecting the body’s ability to fight infection. These abnormal, cancerous plasma cells are called myeloma cells, and, like normal plasma cells, myeloma cells also make antibodies.
Myeloma cells produce too much of the same antibody called the M-protein, which does not fight infection and may cause the following:
- Myeloma cells can damage the kidneys or other organs.
- They can overcrowd the bone marrow, which suppresses the growth of healthy cells that produce blood.
- When bone marrow cannot produce enough healthy cells, it can lead to anemia, bleeding and infection.
- Myeloma cells can cause tumors in bones, leading to fractures.
The accumulation of myeloma cells usually occurs in multiple areas of bone in the body, giving the disease its name, “multiple myeloma.” When myeloma cells collect in bone marrow, they slow down the growth of healthy white blood cells, red blood cells and platelets. Myeloma cells collect in solid bone, causing holes called lytic lesions. The majority of people with multiple myeloma have lytic lesions when their disease is diagnosed. People with multiple myeloma may or may not have symptoms, which can make it difficult to recognize. As a result, the disease may be at an advanced stage when it is diagnosed.
Making a Diagnosis
To determine whether you have multiple myeloma, your doctor may order blood and urine tests as well as a bone marrow biopsy and imaging tests, which may include magnetic resonance imaging (MRI) and positron emission tomography combined with computed tomography (PET/CT), and X-rays.
Tests on a sample of your bone marrow provide information for staging or determining whether your multiple myeloma is high-risk. The tests may include cytogenetic analysis, fluorescence in situ hybridization (FISH) and flow cytometry.
Your doctor may order a biopsy of fat from around your stomach to check for amyloidosis, which is a buildup of amyloid, an abnormal protein. Amyloidosis may be either primary (with no known cause), secondary (caused by multiple myeloma) or hereditary (passed down from parents to children). Differentiating between amyloidosis and multiple myeloma may be part of the diagnostic process.
Only two precursors to multiple myeloma are known to exist: monoclonal gammopathy of undetermined significance (MGUS) and smoldering myeloma. MGUS occurs when abnormal plasma cells produce too many copies of an identical antibody. Most cases of multiple myeloma are preceded by MGUS, but it is unknown whether MGUS is always present before diagnosis.
Smoldering myeloma, also called asymptomatic multiple myeloma, is an early stage of myeloma. Preventive treatments to delay smoldering myeloma from progressing to multiple myeloma are being studied in clinical trials. Another type of myeloma is called a solitary plasmacytoma. It is an early, isolated form of multiple myeloma and may develop into active multiple myeloma.
The exact cause of multiple myeloma remains unknown, but research is helping doctors learn more about it and how it develops. Treatments are improving as newer therapies and drug combinations are developed and approved. As a result, many more patients are living healthy, active lives.
The Common Signs of Multiple Myeloma
The most common signs of multiple myeloma, which are attributed to the same factors used to stage multiple myeloma (see Staging), can be described with the CRAB acronym:
Calcium level – the disease may cause elevated calcium levels in the blood
Renal (kidney) function – kidney failure may result from damage to the kidneys caused by the multiple myeloma protein
Anemia – low red blood cell counts may be caused by cancer cells slowing the growth of healthy bone marrow cells
Bone lesions – multiple myeloma cells can cause bone damage (lytic lesions), thinning of the bones (osteoporosis) or a compression fracture of the spine