What is multiple myeloma?

Multiple myeloma is cancer of the plasma cells in bone marrow. Diseases in which plasma cells become cancerous are known as plasma cell neoplasms. Plasma cells are part of the immune system, a network of specialized cells that make proteins (antibodies) that attack and destroy foreign substances. These substances include viruses, bacteria, fungi and parasites.

The cells of the immune system work together to defend the body from infections and other diseases. The main type of immune system cell is the lymphocyte. The two types of lymphocytes are:

• B lymphocytes (B-cells). B-cells defend the body from invading bacteria and other harmful substances by changing into plasma cells, which produce antibodies. The antibodies then mark the foreign substances for destruction.
• T lymphocytes (T-cells). T-cells recognize the infected cells and destroy them directly.

When B-cells react to an infection, they mature and transform into plasma cells. Mainly located in the bone marrow (the soft, inner component of bone), plasma cells manufacture and release antibodies, also known as immunoglobulins. When these cells grow uncontrollably, they can produce a tumor, which typically develop in the bone marrow. When only one tumor develops, it is known as a solitary plasmacytoma. More frequently, there are numerous tumors or extensive cellular infiltration spread throughout the bone marrow in many bones of the body. This disorder is known as multiple myeloma.

All forms of blood cells are produced in the bone marrow, including:

• White blood cells (WBCs or leukocytes). Cells that fight infection, which include plasma cells.
• Red blood cells (RBCs orerythrocytes). Cells that carry oxygen to tissues throughout the body.
• Platelets (thrombocytes). Cells that help develop blood clots and control bleeding.

In patients with multiple myeloma, the overgrowth of plasma cells can interfere with the bone marrow's ability to produce adequate numbers of normal cells. Over time, this can result in a shortage of white blood cells (leukopenia), red blood cells (anemia), and platelets (thrombocytopenia). Shortages in these types of cells can lead to a decreased ability to fight off infection, fatigue and excessive bleeding. Although many plasma cells are being produced in patients with multiple myeloma, the cells are abnormal. As a result, the antibodies they produce are not useful in fighting infections.

How is it diagnosed?

A physician who suspects that a patient may have multiple myeloma will first take the patient's medical history and perform a physical examination. To diagnose and determine the extent of the disease, a variety of tests may be ordered, including:

Beta-2-microglobulin test. High levels of the protein beta-2-microglobulin in the blood may also indicate myeloma, although it is also elevated in other diseases, such as lymphoma. Blood chemistry tests. These tests measure the level of calcium and other chemicals in the blood. They are used to monitor changes in liver or kidney function caused by myeloma or treatment with certain chemotherapy drugs. Bone marrow biopsy and aspiration. Usually performed at the same time, these procedures may be ordered to confirm a diagnosis of multiple myeloma. A bone marrow aspiration involves using a thin needle to collect a small sample of liquid bone marrow. A bone marrow biopsy uses a larger needle to remove a piece of bone marrow. CAT scan (computed axial tomography). This test allows for multiple x-rays to be taken from different angles around the patient. In multiple myeloma patients, CAT scans (also called CT scans) can detect bone damaged caused by the disease. CAT scans may also be used to guide a biopsy needle into a suspected area. This procedure is known as a CAT-guided needle biopsy. Cytogenetics. This test may be ordered to determine if the cells have too many chromosomes, or if the chromosomes have any translocations (the transfer of DNA from one chromosome to another), deletions (the loss of part of a chromosome), inversions (the rearrangement of DNA in part of a chromosome) or additions (all or part of a chromosome is duplicated and too many copies are found in a cell). Bone density test. This procedure uses a special type of x-ray to measure bone loss.

Multiple myeloma cannot be diagnosed with any one test, according to the ACS. Instead, a physician will consider a number of factors including symptoms, findings from the physical examination, and results of blood, bone marrow, urine and imaging tests. To be diagnosed with the disease a patient must have the appropriate symptoms and at least one major criterion or at least three minor criteria.

Major criteria for the diagnosis of multiple myeloma:

• A biopsy reveals a plasma cell tumor.
• More than 30 percent of cells in the sample of bone marrow are plasma cells.
• The monoclonal immunoglobulin in the blood or urine is above a certain amount.

Minor criteria for the diagnosis of multiple myeloma include:

• Between 10 and 30 percent of cells in the bone marrow sample are plasma cells.
• Imaging tests have detected holes in bones (osteolytic lesions) due to tumor growth.
• There is insufficient normal antibody in the blood.
• Monoclonal immunoglobulin is detected, but not enough to fulfill a major criterion.

How is multiple myeloma treated?

After multiple myeloma has been diagnosed and staged, a treatment plan will be established for the patient. As with all cancers, treatment for multiple myeloma is usually coordinated by a cancer care team, headed by a primary care physician and/or hematologist or oncologist.

There are a variety of methods used to treat multiple myeloma. The National Cancer Institute (NCI) describes this disease as highly treatable but rarely curable. The treatment method chosen for each patient depends on the stage of the disease as well as other factors including the patient's age (survival is higher in younger patients) and overall health. Common treatment methods for multiple myeloma include:

In addition to cancer treatments, patients may receive treatment with medications to control their symptoms. Multiple myeloma can cause bone to dissolve, resulting in weakness and fractures. Bisphosphonates may be prescribed to slow this process. In some cases the drug is given in combination with chemotherapy. Diuretics, which are drugs that increase urination, may be prescribed to help the kidney remove excess fluid, salts and pain relievers from the body. Erythropoietin may also be prescribed to improve anemia and its symptoms.

Plasmapheresis may be recommended to relieve some symptoms of multiple myeloma. This procedure involves removing blood from a patient's vein and separating the blood cells from the blood plasma (the liquid component of blood). The plasma is discarded because it contains the abnormal protein (monoclonal immunoglobulin) produced by the myeloma cells. The plasma is replaced with a salt solution and blood proteins from donors and the remaining components are returned to the patient through another vein. This treatment may be recommended when the buildup of myeloma proteins causes blood to thicken and interfere with circulation.

Following treatment, patients typically require regular visits to their physicians. Frequent checkups enable their physician to detect any changes in health and treat them immediately. Checkups may include a physical examination, blood tests, x-rays and other imaging tests.

Patients are encouraged to report the development of any new symptoms to their physician. They may be a sign of recurrent multiple myeloma (myeloma that has come back after treatment) or side effects of treatment. If a relapse occurs, it can occur in the bone or in another part of the body.

There are no established prevention methods for multiple myeloma because there are no known avoidable risk factors.

Medications

• Anticancer and cortisone drugs (chemotherapy).
• Pain relievers.
• Antibiotics to fight infections.

Decadron (Dexamethasone), Cytoxan (Cyclophosphamide), Leukeran (Chlorambucil), Zyloprim (Allopurinol)

What might complicate it?

Complications include increased risk of infection, destruction of bone tissue that may result in fractures, spinal cord compression with possible neurological impairment, damaged kidneys or renal failure due to increased levels of calcium and immunoglobulin in the blood, and anemia or bleeding disorders.

Predicted outcome

The five-year survival rate for multiple myeloma is estimated at 33 percent by the ACS. Younger patients tend to have a better chance of survival than elderly people. In addition, the five-year survival rate is based on patients who were diagnosed and treated for the disease more than five years ago. Treatment advances may result in a better prognosis for recently diagnosed patients.

Alternatives

Similar symptoms arise from benign situations involving chronic inflammation, sometimes referred to as monoclonal gammopathy of undetermined significance (MGUS). Other diseases with a similar appearance include chronic lymphocytic leukemia, non-Hodgkin's lymphoma and amyloidosis.

Appropriate specialists

Hematologist or oncologist. Depending upon complications; surgeon, orthopedist, cardiologist, nephrologist, and radiation oncologist.

Last updated 5 July 2015