Multiple Myeloma
Multiple myeloma is a disorder in which plasma cells are produced in an uncontrolled and invasive (malignant) fashion. Plasma cells develop from lymphocytes, a type of white blood cell. They are found primarily in the bone marrow and lymph nodes.
Plasma cells are responsible for helping the body fight infection. They produce antibodies that circulate in the blood and recognize markers, called antigens, on the cells of invading organisms like bacteria. These antibodies defend the body against foreign organisms.
Multiple myeloma occurs when the plasma cells in the bone marrow begin reproducing uncontrollably. While normal bone marrow contains less than 5% plasma cells, bone marrow in a patient with multiple myeloma contains over 10% plasma cells.
Multiple myeloma tends to be a disease of the elderly. The average patient is 68 years old when diagnosed. During the last 10 years, doctors have seen an increase in cases of multiple myeloma occurring at younger ages, but patients are usually over age 40. Men have a slightly increased chance of having multiple myeloma, and African-Americans are twice as likely as Caucasians to develop the disease.
Although the exact cause of multiple myeloma has not been determined, researchers believe that it may be linked to exposure to certain environmental substances such as radiation and chemicals.
Bone pain is an extremely common symptom among patients with multiple myeloma. About 70% of all patients report bone pain as their first symptom. This pain is caused by plasma cells growing in number within the bone marrow, replacing normal marrow and putting pressure on the bone. Plasma cells also produce chemicals called osteoclast activating factors (OAF). OAF encourage special cells called osteoclasts to break down bone. In healthy people this process is balanced by the building up of new bone by cells called osteoblasts. In multiple myeloma, however, excess OAF are produced and bone is eaten away by overly active osteoclasts. Bones become weak (causing osteoporosis) and may break.
The antibodies that are over-produced in multiple myeloma function abnormally. Furthermore, other types of antibodies are under produced. Destruction of circulating antibodies also increases. This results in an increased chance of developing serious bacterial infections. The most common types of infections include pneumonia and kidney infections.
Abnormalities in the structure and function of kidney cells are extremely common in multiple myeloma. About half of all patients have kidney problems. These problems occur because of high levels of calcium in the blood (due to bone breaking down), protein build-up, and increased circulating uric acid. Increased strain on the kidney to eliminate large amounts of the broken down products of antibodies and proteins may cause kidney damage or kidney failure.
Other problems are common in multiple myeloma. Because plasma cells take up space within the bone marrow, other cells normally produced there decrease and are sometimes defective in shape and function. Red blood cells decrease, resulting in anemia in about 80% of all people with multiple myeloma.
Circulating antibodies may interfere with clotting, resulting in an increased risk of bleeding. Abnormally thick blood may interfere with blood circulation anywhere in the body, but particularly in the fingers, toes, ears, and nose. Blood thickening may also cause headache, fatigue, and vision problems. Excess calcium in the blood may cause patients to feel weak, depressed, and confused. Sometimes, the plasma cells create a tumor called a plasmacytoma. Plasmacytomas may press on bone, causing fractures. Fractured bones may place unusual pressure on nearby nerves, resulting in nerve damage, pain, burning, tingling, and weakness of the affected muscle.
Diagnosis of multiple myeloma involves examination of blood, urine, bone marrow, and bones. Blood tests will reveal abnormalities, including anemia with abnormal red blood cells. Blood calcium will be high in about 33% of all patients. A specialized test called electrophoresis can be used to show an increased amount of antibodies in the blood and urine.
Examination of the bone marrow requires a test called a bone marrow aspiration. A long, thin needle is placed into the hip, and a sample of bone marrow is withdrawn. In multiple myeloma, the bone marrow has a significantly increased percentage of plasma cells, usually well over 10%.
Because the treatments for multiple myeloma can be very damaging, and because the disease often progresses slowly, many patients are not treated until measurements of antibodies in the blood reach a particularly high level. Chemotherapy agents used in multiple myeloma include melphalan, cyclophosphamide, chlorambucil, and prednisone. These may be given over four to seven days in four to six week intervals. Chemotherapy may be given for several years. The disease usually recurs within a year after treatment has stopped. Chemotherapy can be given again, but each time the disease reappears it is less responsive to treatment.
Bone pain is often treated with radiation directed at the problem area. High blood levels of calcium may respond to treatment with prednisone. High blood levels of uric acid may improve with allopurinol. When anemia causes symptoms, blood transfusions may be necessary.
One general recommendation for alternative cancer treatment includes dietary supplementation with beta-carotene, vitamin B6, vitamin C, vitamin E, selenium, and zinc as antioxidant protection. Other recommendations include reducing stress through techniques such as biofeedback training, guided imagery, and meditation. These same techniques are useful for pain relief.
About 15% of patients with multiple myeloma die within three months of diagnosis. About 60% of all patients respond to treatment and live for an average of two and a half to three years after diagnosis. About 23% of all patients die of other illnesses associated with advanced age.
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