Multiple myeloma
Introduction
Multiple myeloma is a cancer of your plasma cells. Plasma cells are a type of white blood cell present in your bone marrow — the soft, blood-producing tissue that fills in the center of most of your bones. The exact cause of multiple myeloma isn't known.
Plasma cells usually make up less than 5 percent of the cells in your bone marrow. But if you have multiple myeloma, a group of abnormal plasma cells (myeloma cells) multiplies, raising the percentage of plasma cells to more than 10 percent of the cells in your bone marrow. The result can be erosion of your bones. The disease also interferes with the function of your bone marrow and immune system, which can lead to anemia and infection. Multiple myeloma may also cause problems with your kidneys.
The disease is called multiple myeloma because myeloma cells can occur in multiple bone marrow sites in your body.
If you have multiple myeloma but aren't experiencing symptoms, your doctors may just need to monitor your condition. If you're experiencing symptoms, a variety of treatments are available.
Signs and symptoms
Although multiple myeloma may not cause symptoms early in the disease, it's likely that you'll experience symptoms as the disease progresses.
Signs and symptoms of the disease can vary from person to person. One of the most common symptoms, however, is bone pain. A common sign is the presence of abnormal proteins — which can be produced by myeloma cells — in your blood or urine. These proteins — which are antibodies or parts of antibodies — are called monoclonal, or M, proteins.
Often discovered during a routine exam, monoclonal proteins may indicate multiple myeloma, but also can indicate other conditions.
Another potential sign of multiple myeloma is a high level of calcium in your blood. This can occur when calcium from affected bones dissolves into your blood. As a result, you may experience signs and symptoms such as: Anemia can occur as myeloma cells replace oxygen-carrying red blood cells in your bone marrow, which may lead to another common symptom — fatigue.
Other signs and symptoms of multiple myeloma may include:
- Bone pain, particularly in your back or ribs
- Unexplained bone fractures
- Repeated infections — such as pneumonia, bladder or kidney infection, or sinusitis
- Weight loss
- Weakness or numbness in your legs
Although the exact cause isn't known, doctors do know that multiple myeloma begins with one abnormal plasma cell in your bone marrow. This abnormal cell then starts to multiply. Because abnormal cells don't mature and then die as normal cells do, they accumulate, eventually overwhelming the production of healthy cells. Healthy bone marrow consists of a small percentage of plasma cells, less than 5 percent. But in people with multiple myeloma, the percentage of plasma cells often increases to more than 10 percent.
Because myeloma cells may circulate in low numbers in your blood, they can populate other bone marrow sites in your body, even far from where they began. Uncontrolled plasma cell growth can damage bones and surrounding tissue. It can also interfere with your immune system's ability to fight infections by inhibiting your body's production of normal antibodies.
Experts aren't sure why this process begins. But, researchers are studying the DNA of plasma cells to try to understand what changes occur that cause these cells to become cancer cells. Though they haven't yet discovered the cause of these changes, they have found some common abnormalities in myeloma cells. For example, many myeloma cells are missing all or part of one chromosome — chromosome 13. Cells with a missing or defective chromosome 13 tend to be more aggressive and harder to treat than cells with a normal chromosome 13.
Multiple myeloma sometimes develops from a harmless condition called monoclonal gammopathy of undetermined significance (MGUS). This condition, like multiple myeloma, is marked by the presence of M proteins — produced by abnormal plasma cells — in your blood. However, in MGUS, the amount of the abnormal proteins isn't high enough to cause harm, and no damage to the bones occurs.
Treatment
Generally, if you have multiple myeloma and aren't experiencing symptoms, you don't need treatment. However, your doctors will likely monitor your condition at variable intervals, checking for signs — such as increasing levels of M protein in your blood or urine — that indicate the disease is progressing. If it is, you may need treatment to help prevent symptoms. The average time between diagnosis and the onset of symptoms is two to three years.
If you're experiencing symptoms, treatment can help relieve pain, control complications of the disease, stabilize your condition and slow the progress of the disease.
Standard treatments
Though there's no cure for multiple myeloma, with good treatment results you can usually return to near-normal activity. The appropriate treatment depends on your needs, medical status and general health. Standard treatment options include:
- Chemotherapy. Chemotherapy is the most common treatment for this disease. It involves using medicines — taken orally as a pill or given through an intravenous (IV) injection — to kill myeloma cells. Chemotherapy is often given in cycles over a period of months, followed by a rest period. Often chemotherapy is discontinued during what is called a plateau phase or remission, during which your M protein level remains stable. You may need chemotherapy again if your M protein level begins to rise.
- Stem cell transplantation. This treatment involves using high-dose chemotherapy along with transfusion of previously collected immature blood cells (stem cells) to replace diseased or damaged marrow. The stem cells can come from you or from a donor, and they may be from either blood or bone marrow.
- Radiation therapy. This treatment uses high-energy penetrating waves to damage myeloma cells and stop their growth. Radiation therapy may be used to target myeloma cells in a specific area — for instance, to more quickly shrink a tumor that's causing pain or destroying a bone.
Informations obtained from National Institute of Health.