Multiple Myeloma Facts
What is Myeloma?
Myeloma, or multiple myeloma, is cancer of a certain type of white blood cell called a plasma cell, which is part of your immune system. Myeloma begins in the bone marrow, where blood cells are made.
What Happens in Healthy Bone Marrow
Bone marrow is found in the soft, spongy center of certain bones. Myeloma can affect any bones where marrow is active. Usually in adults marrow is active only in the skull, shoulders, spine, ribs, pelvis, and hips. (It’s not active lower in the arms, hands, legs or feet.)
Healthy bone marrow produces the three major types of blood cells our bodies need.
- White blood cells fight infection.
- Red blood cells carry oxygen.
- Platelets make the blood clot and stop bleeding.
Normally when bacteria or viruses enter your body, white blood cells called B lymphocytes, or B cells, turn into plasma cells. Then these plasma cells make antibodies to destroy the specific type of microorganism that entered your body. Antibodies, also called immunoglobulins, are complex proteins.
What Happens in Myeloma
In myeloma, plasma cells don’t reproduce normally. Instead, they become cancerous, and they divide and grow out of control. The cancerous plasma cells, also called myeloma cells, build up in the marrow and crowd out other healthy blood cells. This can increase your risk of infection (due to low white blood cells), anemia (due to low red blood cells) and blood-clotting problems (due to low platelets).
Also, myeloma cells don’t make effective antibodies. So people with myeloma have lower immune function than normal.
Instead of making effective antibodies, myeloma cells produce and release an abnormal protein, called M protein (M stands for monoclonal), and other chemicals. These substances can damage the immediate area, and they can travel through the bloodstream and damage other parts of the body.
For instance, some of the chemicals interact with bone cells, causing the hard, structural areas of bone to dissolve. These damaged areas are called osteolytic lesions. Lesions weaken the bone and can lead to fractures. Typically, bone damage is one of the main effects of myeloma. When bone dissolves, calcium is released into the bloodstream. A high level of calcium in the blood (hypercalcemia) can cause health problems, such as confusion and dehydration, and it can damage the kidneys.
M protein can also cause kidney damage, such as by damaging the small tubes inside these organs, and cause circulation problems because these proteins tend to stick to each other and to other tissues (like blood cells), which can thicken the blood.
Why it’s Called “Multiple” Myeloma
Most people with myeloma have myeloma tumors in several places in their body. That’s why this disease is often called “multiple myeloma.”
Some people with myeloma have only a single tumor. A single myeloma tumor is called a plasmacytoma. “Plasma-” refers to the type of cell affected. “-Cyte” is a general term for cell. “-Oma” means tumor. A plasmacytoma can form in a bone (called intramedullary disease) or in soft tissue outside the bone (called extramedullary disease). People with a single plasmacytoma in a bone often develop multiple myeloma later on.
Even though myeloma commonly affects the bones, it’s not a form of bone cancer. Myeloma begins in bone marrow cells, so it is a hematologic malignancy. The bone marrow cells give rise to all the mature blood cell types.
Types of Myeloma
Doctors can detect various levels of myeloma-related changes in the marrow, including small changes that do not amount to cancer. Here are different forms of myeloma-related conditions:
- MGUS, or monoclonal gammopathy of undetermined significance—In this condition, there are some myeloma precursor cells in the bone marrow, but the percentage is low. The cells do not form a tumor or cause any disease or symptoms, and no treatment is needed. Usually doctors discover this condition when a routine blood test detects unusual levels of protein in the blood. MGUS is not cancer, and it rarely turns into myeloma. If you have MGUS, it’s important to see your doctor about every 6 months to be sure it’s not progressing.
- Asymptomatic myeloma, also called smoldering or indolent myeloma—In this condition, there are more myeloma cells than in MGUS. But there are still not enough to damage the body or cause symptoms. This form of myeloma may worsen over time, in some cases very slowly. Some people live symptom-free for many years. As with MGUS, there’s no immediate need to treat this type of myeloma. But it’s important to have regular exams to check whether the condition is getting worse. When the condition becomes symptomatic, then treatment will be started.
- Symptomatic myeloma, also called active myeloma—There are usually more myeloma cells in symptomatic myeloma, and they are causing one or more of these forms of damage: high levels of calcium in the blood (hypercalcemia), kidney (renal) problems, anemia (low red blood count) or bone damage. (These signs are sometimes referred to as CRAB, an acronym for Calcium elevation, Renal problems, Anemia and Bone damage.) Active myeloma causes symptoms, and requires treatment.
Symptoms
Symptoms of myeloma come from the build-up of myeloma cells in the marrow, and from the M protein and chemicals that the myeloma cells release. People with asymptomatic myeloma may remain symptom-free for many years.
Once symptoms do begin, these symptoms are typical:
- Weakness and fatigue caused by anemia
- Kidney damage, which may cause swelling in the legs or weakness
- Bone pain from build-up of myeloma cells, often in the back or ribs
- Bone lesions, most often in the skull, spine or hips
- Bone fracture, which may compress nerves or the spinal cord
- Confusion, tiredness, weakness, dehydration, unusual thirst, nausea, constipation or frequent urination caused by high levels of calcium in the blood (released when bone breaks down)
- More frequent infection, or trouble recovering from infection
- Excessive bleeding, including from minor injuries
The same symptoms can also be caused by other conditions. So it’s important to see a doctor if you have these symptoms.
Diagnosis
To find out whether you have myeloma, your doctor will first do a thorough physical exam and ask about your health history. Next the doctor will probably perform a series of blood tests to tell whether any blood cells are unhealthy and, if so, which type. Common blood tests to check for myeloma include the following:
- Complete blood count, or CBC: to determine how many cells of each type (white and red bloods cells and platelets) are circulating in the bloodstream
- Blood chemistry: to look for chemicals in the blood that can be abnormal in people who have myeloma
- Protein testing: to tell whether there is abnormal protein in the blood or urine, what type and how much
For a clear diagnosis and to learn more about the prognostic features of the myeloma, your doctor will perform a bone marrow aspiration and biopsy. A small area of skin over the pelvis (the bone that makes up part of the hip) will be cleaned and numbed. Then a needle will be used to remove a small amount of bone marrow and a small piece of bone. The marrow will be examined under a microscope for involvement by the cancer. A biopsy also helps doctors tell the percentage of myeloma cells in your marrow.
The main way to tell whether myeloma has damaged or weakened your bones is to have X-rays taken. This is the standard imaging technique used in myeloma. If your doctor needs more detailed images, he or she may arrange for you to have other imaging procedures, such as magnetic resonance imaging (MRI), computed tomography (CT) scan, positron emission tomography (PET) scan.
Your doctor may also use the tests described on this page to monitor your condition and your response to treatment.
Stages
The doctor will also determine the stage of your disease, or how far along it is. By the International Staging System, there are three stages for myeloma, referred to as stage I, II and III. The stage depends on the amount of myeloma cells in your body and the amount of damage they have caused, and average survival correlates with the stage, with the longest survival for stage I and the shortest for stage III.
Specifically, the doctor will measure and consider the levels of the proteins beta-2 microglobulin and albumin in your blood to determine the stage.
Risk Factors
Doctors do not know what causes the cellular changes that lead to myeloma. The disease occurs only in adults, seldom before the age of 40 and usually after age 65. It’s more common in men than women, and it’s twice as common in African-Americans as in white Americans. It’s less common in people of Asian or Hispanic descent.
Certain factors are linked to higher risk in some cases. For instance, exposure to some farming chemicals or radiation may increase risk for myeloma. But in the vast majority of people, doctors are not able to link the disease to any particular risk factors.
Some families have more than one person with myeloma. But this is extremely unusual. So it does not appear that myeloma runs in families.