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17 August 2010

Multiple myeloma

Multiple myeloma is a type of cancer. It affects certain white blood cells called plasma cells.

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Description

  • Multiple myeloma is a cancer of a specific type of white blood cell, called plasma cells.
  • The main problems that result from multiple myeloma are anaemia, bone pain and fractures, kidney malfunction, frequent infections and high calcium level in the blood.
  • The main treatment methods are chemotherapy, radiotherapy and bone marrow transplantation.
  • The aim of treatment is to stop the cancer getting worse, rather than curing it.

What is multiple myeloma?

Multiple myeloma is a type of cancer. It affects certain white blood cells called plasma cells. To understand multiple myeloma, it is helpful to know about normal cells, especially plasma cells, and what happens when they become cancerous.

The body is made up of many kinds of cells. Each type of cell has special functions. Normal cells are produced in an orderly, controlled way as the body needs them.

Plasma cells and other white blood cells are part of the immune system, which helps protect the body from infection and disease. All white blood cells begin their development in the bone marrow – the soft, spongy tissue that fills the bones. Some of these cells develop into plasma cells when the immune system needs them to fight viruses and bacteria that cause infections in different parts of the body.

Plasma cells produce antibodies – proteins that move through the bloodstream to help the body get rid of harmful organisms such as bacteria and viruses. Each plasma cell responds to only one specific organism by making a large amount of one kind of antibody. These antibodies find and act against that specific substance. Because the body has many plasma cells, it can respond to many substances.

Cancer is a group of diseases in which cells become abnormal and are produced in excessive amounts. Cancerous cells interfere with the growth and functions of normal cells. In addition, they can spread from one part of the body to another.

When cancer involves plasma cells, the body keeps producing more and more of these cells. These are abnormal plasma cells with cancer-like properties, and are called “myeloma cells” and are responsible for the development of the cancer called Multiple Myeloma. The myeloma cells usually produce large quantities of a single kind of antibody. This antibody, however, does not behave like normal antibodies that fight infections. It is abnormal and merely clogs the circulation,sometimes damaging the kidneys and hijacking the the immune system, preventing or limiting the production of normal antibodies.

Myeloma cells tend to collect in the bone marrow. They can also secrete chemicals that cause the calcium to br absorbed back out of the bone. This results in high levels of calcium in the blood and in the development of of small holes known as lytic lesions. These can cause severe pain and and can even result in the bone breaking. Occasionally the plasma cells collect in only one site (usually a bone) and form a single mass, or tumour, called a plasmacytoma.

It is important to keep in mind that cancer is classified by the type of cell or part of the body in which the disease begins. Although plasmacytomas and multiple myeloma can affect the bones, they begin in cells of the immune system. These cancers are different from bone cancer, which actually begins in cells that form the hard, outer part of the bone. This fact is important because the diagnosis and treatment of plasmacytoma and multiple myeloma is different from the diagnosis and treatment of bone cancer.

What causes multiple myeloma?

At this time, we do not know what causes multiple myeloma or how to prevent it. However, we do know that no-one can "catch" multiple myeloma from another person; cancer is not contagious.

Who gets multiple myeloma and who is at risk?

Although scientists cannot explain why one person gets multiple myeloma and another does not, we do know that most multiple myeloma patients are between 50 and 70 years old. The disease affects black people more often than white people and men more often than women.

Symptoms and signs of multiple myeloma

Symptoms of multiple myeloma depend on how advanced the disease is.

In the earliest stage of the disease, there may be no symptoms. When symptoms do occur, they may include bone pain, often in the back or the ribs. There may also be broken bones (fractures), weakness, fatigue, weight loss and repeated infections.

When the disease is advanced, symptoms may include nausea, vomiting, constipation, problems with urination, and weakness or numbness in the legs.

These are not sure signs of multiple myeloma, however – they can be symptoms of several other medical problems. You should see a doctor if these symptoms occur.

Because people with multiple myeloma have an abnormally large number of identical plasma cells, they also have too much of one type of antibody. These myeloma cells and antibodies can cause a number of serious medical problems:

  • Myeloma cells damage and weaken bones, causing pain and sometimes fractures. Bone pain can make movement difficult and impair mobility.
  • When bones are damaged, calcium is released into the blood. This may lead to hypercalcemia – too much calcium in the blood. Hypercalcemia can cause loss of appetite, nausea, thirst, fatigue, muscle weakness, restlessness and confusion.
  • Myeloma cells prevent the bone marrow from forming normal plasma cells and other white blood cells that are important to the immune system. Your body may not be able to fight infection and disease.
  • The cancer cells also may prevent the growth of new red blood cells, causing anaemia. People with anaemia may feel unusually tired or weak.
  • Multiple myeloma may lead to serious kidney problems including kidney failure. Excess antibody proteins and calcium can prevent the kidneys from filtering and cleaning the blood properly.

How is multiple myeloma diagnosed?

Multiple myeloma may sometimes be found as part of a routine physical exam before symptoms of the disease appear.

When you do have symptoms, your doctor will ask about your personal and family medical history and perform a complete physical exam. In addition to checking general signs of health, your doctor may order tests to determine the cause of the symptoms.

If you are experiencing bone pain, x-rays can show whether any bones are damaged or broken. Blood and urine samples are taken to see whether they contain high levels of antibody proteins called M proteins.

Your doctor may also do a bone marrow test (aspiration and trephine biopsy of the bone marrow) to check for myeloma cells. (This test is done with with local anaesthetic and is not as painful as it sounds.) In an aspiration, the doctor inserts a needle into the pelvic bone to withdraw a sample of fluid and cells from the bone marrow.

To do a biopsy, the doctor uses a larger needle to remove a sample of solid tissue from the bone marrow. A pathologist examines the samples under a microscope to see whether myeloma cells are present.

How is multiple myeloma treated?

Multiple myeloma is very hard to cure. Although people with a plasmacytoma (the localised form of myeloma) may be free of symptoms for a long time after treatment, many eventually develop multiple myeloma. For those who have multiple myeloma, treatment can improve quality of life by controlling the symptoms and complications of the disease.

People who have multiple myeloma but no symptoms of the disease (called “smouldering myeloma”) usually do not receive treatment. This is because in these cases, the risks and side-effects of treatment are likely to outweigh the possible benefits.

However, these cases are watched closely, and treatment is begun as soon as symptoms appear or when there is a sign that the disease is progressing (frequently on the basis of blood tests). People who need treatment for multiple myeloma usually receive chemotherapy and sometimes radiation therapy.

Chemotherapy is the use of drugs to treat cancer. It is the main treatment for multiple myeloma. Doctors may prescribe two or more drugs that work together to kill myeloma cells. Many of these drugs are taken by mouth; others are injected into a blood vessel. Either way, the drugs travel through the bloodstream, reaching myeloma cells all over the body. For this reason, chemotherapy is called systemic therapy.

Anti-cancer drugs (chemotherapy) are often given in cycles – a treatment period followed by a rest period, then another treatment and rest period, and so on. Most people take their chemotherapy at home or receive it on an outpatient basis at the hospital. However, depending on your health and the drugs being given, you may require a treatment protocol that necessitates that you stay in hospital during treatment. Recently there have been huge advances in the treatment of myeloma with the development of several new and effective chemotherapy drugs. This has dramatically improved the outcome of treatment. 

There are potential problems with giving chemotherapy, as it can further weaken the immune system. It is very important to listen carefully to your doctor’s instructions. It helps if another member of the family is present during the consultation.

Radiation therapy (also called radiotherapy) uses high-energy rays to damage cancer cells and stop them from growing. In this form of treatment, a large machine aims the rays at the tumor. Treatment with radiation is local therapy: it affects only the cells in the treated area.

Radiation therapy is the main treatment for people who have a single plasmacytoma. They usually receive radiation therapy every weekday for four to five weeks in the outpatient department of a hospital or clinic.

People who have multiple myeloma sometimes receive radiation therapy in addition to chemotherapy. The purpose of the radiation therapy is to help control the growth of tumours in the bones and relieve the pain that these cause. Treatment usually continues for one to two weeks.

Bone marrow transplantation is another method of treatment for multiple myeloma. It involves collecting a special type of cells known as “stem cells”, either from you or from a compatible brother or sister. These stem cells are then kept frozen in storage while you receive a high dose of chemotherapy and/or radiotherapy in the hope that this strong treatment will destroy all the myeloma cells.

As a side-effect of this high-dose treatment, the whole bone marrow gets destroyed. The stem cells are then returned to you (intravenously, using a drip) in order to recover normal blood cell production. Bone marrow transplantation from a sibling is the only potentially curative procedure for multiple myeloma. However it is an extremely risky procedure and is associated with severe side-effects. It is only suitable for a few people who are reasonably young and fit.

Side-effects of treatment

The drugs used to treat multiple myeloma are very powerful. Treatment can help you feel better by relieving symptoms such as bone pain. However, it is hard to limit the effects of therapy so that only cancer cells are destroyed. Because healthy cells may also be damaged, treatment can cause unpleasant side-effects.

The side-effects of cancer treatment vary for each person. They may even be different from one treatment to the next. Doctors try to plan treatment to keep side-effects to a minimum. They also monitor you very carefully so they can help with any problems that occur.

The side-effects of chemotherapy depend on the particular drugs used. In general, anti-cancer drugs affect rapidly growing cells, such as blood cells that fight infection, cells that line the digestive tract, and cells in hair follicles. As a result, side-effects may include decreased resistance to infection, loss of appetite, nausea, vomiting and mouth sores. People given venous chemotherapy drugs may also have less energy and lose their hair. One drug used to treat multiple myeloma, called Prednisone (Cortisone), may cause swelling of the face and feet, heartburn or indigestion, mood swings, restlessness and acne. Some of the newer and most effective drugs can also affect the nerves, causing pins and needles or weakness. These should be reported to your doctor. The side-effects of chemotherapy usually resolve over time after the treatment stops.

During radiation therapy, you may be more tired than usual. Resting is important, but doctors usually advise you to stay as active as far as possible.

Loss of appetite can be a problem for people with multiple myeloma. You may not feel hungry when you are uncomfortable or tired. Some of the common side-effects of cancer treatment, such as nausea and vomiting, can also make it hard to eat. Yet eating well often makes you feel better and increases your energy levels, so good nutrition is important. Eating well means getting enough calories and protein to prevent weight loss, regain strength and rebuild normal tissues. Many people find that having several small meals and snacks during the day works better than having three regular meals. Constipation can also be a real problem and should be reported to your doctor and treated early.  

Supportive Care

People with multiple myeloma frequently have pain caused by bone damage or by tumours pressing on nerves. Doctors often suggest taking pain medication and/or wearing a back or neck brace to help relieve pain.

Preventing or treating bone fractures is another important part of supportive care. Because exercise can reduce loss of calcium from the bones, doctors and nurses encourage people with multiple myeloma to be active, if possible. They may suggest appropriate forms of exercise. If you have a fracture or a breakdown of certain bones, especially those in the spine, a surgeon may need to operate to relieve the pressure that the tumour or bone fragments are putting on the spinal cord. Most patients with myeloma requiring treatment should be given a special drug once a month to protect the bones in addition to their other therapy.

People with hypercalcemia may receive medication to reduce the level of calcium in the blood. They are also encouraged to drink large amounts of fluid every day; some may need intravenous (IV) fluids. Getting plenty of fluids helps the kidneys get rid of excess calcium in the blood. It also helps prevent problems that occur when calcium collects in the kidneys.

If the kidneys aren't working well, dialysis or plasmapheresis may be necessary. In renal dialysis, the blood passes through a machine that removes wastes, and the blood is then returned to the body. Plasmapheresis is used to remove excess antibodies produced by the myeloma cells. This process thins the blood, making it easier for the kidneys and heart to function.

Multiple myeloma weakens the immune system. You must take care to protect yourself from developing infection. It is important to stay out of crowds and away from people with colds or other infectious diseases. Any sign of infection (fever, sore throat, cough) should be reported to the doctor right away. Infections are treated with antibiotics or other drugs, depending on the causative organism.

Anaemia may be treated with transfusions of red blood cells or erythropoietin injections, given under the skin. Transfusions can help reduce the shortness of breath and fatigue often caused by anaemia.

What is the outcome of treatment?

Multiple myeloma is very difficult to cure. The aim of treatment is to stop the advance of the disease, but some of the new therapeutic drugs appear to be significantly improving the outcome. You may be told that you are in:

  • remission, when there is no sign of myeloma, or in
  • a plateau phase, when the myeloma is still present but not progressing. Blood tests and X-rays do not show any deterioration in this phase of the disease.

Can multiple myeloma be prevented?

According to current knowledge, multiple myeloma cannot be prevented.

When to call the doctor

Multiple myeloma frequently gets discovered in patients seeing a doctor for complaints of:

  • Bone pain or fracture (back pain common)
  • Weakness or paleness due to anaemia
  • Frequent chest infections
  • Generally feeling unwell

One has to remember that the above symptoms may not be related to multiple myeloma at all; there are many other diseases that may present with similar symptoms.

Sometimes the myeloma is discovered accidentally on X-ray or blood tests done for other reasons.

Originally reviewed by Dr Adrian Schmidt, MBChB (Pretoria), M Med Internal Medicine (Stellenbosch)

Reviewed by Dr Karen Gunther, MBChB M Med, April 2010.

 
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