Myeloma is blood cancer of the plasma cells that are made in the bone marrow. Because bone marrow is found throughout the body, myeloma can affect multiple areas at the same time, and the disease is often called multiple myeloma.
Learn more about:
- The blood
- What is blood cancer?
- What is myeloma?
- How myeloma starts
- How is it different from leukaemia?
- What causes myeloma?
- Who gets myeloma?
The blood
Blood is pumped around your body to provide oxygen and nutrients to your organs and tissues, and remove waste. It contains red blood cells, white blood cells and platelets – each with its own job to help the body function.
All three types of blood cells live for a limited time and need to be continually replaced. Most are made in the bone marrow – the spongy centre of the bones. The bone marrow contains stem cells. These are unspecialised blood cells that develop into mature red or white blood cells or platelets. Once mature, blood cells are usually released into the bloodstream to carry out their jobs.
What is blood cancer?
Cancer is a disease of the cells. Cells are the body’s basic building blocks – they make up tissues and organs. The body constantly makes new cells to help us grow, replace worn-out tissue and heal injuries.
Normally, cells multiply and die in an orderly way, so that each new cell replaces one lost. Sometimes cells become abnormal and keep growing. These abnormal cells may turn into cancer.
In solid cancers, such as breast cancer, the abnormal cells form a mass or lump called a tumour. However, myeloma is a blood cancer that starts in the bone marrow. Bone marrow is the spongy centre of the bone where blood cells are produced.
In myeloma, a type of white blood cell, called a plasma cell, changes and becomes abnormal. Healthy plasma cells make antibodies, called immunoglobulins, that protect us from infection.
Without treatment, the bone marrow keeps making more abnormal myeloma cells, leaving less room for normal healthy blood cells. This drop in healthy blood cells and antibodies weakens the immune system and can damage the kidneys. Myeloma can then spread to other parts of the body that contain bone marrow, such as the spine, skull, shoulders, ribs and pelvis.
Most myeloma cells produce an abnormal antibody called paraprotein, which enters the bloodstream. Levels of paraprotein usually build up in the blood, and may be detected on a blood test.
Stem cells
What is myeloma?
Myeloma begins when abnormal plasma cells, known as myeloma cells, start multiplying. Normal plasma cells make different types of antibodies to help the body fight infections. Abnormal plasma cells make an antibody known as paraprotein, M-protein or monoclonal protein. Paraprotein is found in the blood of most people who have myeloma.
Because the myeloma cells crowd out the bone marrow, there is less space for normal blood cells to develop and keep you healthy. As a result, a lack of:
- normal plasma cells and other white blood cells can make a person more likely to get infections
- red blood cells (anaemia) can cause fatigue
- platelets can cause bleeding and bruising.
How myeloma starts
Bone marrow produces three main types of blood cells: red cells, white cells and platelets.
Plasma cells are a special type of white blood cell. Myeloma starts when plasma cells become abnormal and multiply, crowding the bone marrow. They usually also release an antibody (paraprotein) into the blood.
How is it different from leukaemia?
Myeloma and leukaemia are both types of blood cancer, but they affect the body in different ways. Leukaemia is cancer of the white blood cells, which can be detected on a specific blood test.
Myeloma is cancer of the plasma cells, which are found in the bone marrow and not usually detected in the blood.
In rare cases, cancerous plasma cells form a tumour in the bone or tissue, called solitary or multiple solitary plasmacytoma. Unlike myeloma, solitary plasmacytoma produces few or no abnormal plasma cells in the bone marrow. Because it is located in one area, plasmacytoma is usually treated with radiation therapy. Some people may later develop myeloma or another plasmacytoma.
What causes myeloma?
DNA is in all cells and carries instructions for how cells work. Plasma cells become cancerous (myeloma) due to certain DNA changes, but it isn’t always clear what causes these DNA changes.
Most cases of myeloma have no known cause, but things linked to an increased risk include:
- older age and being male (see below)
- exposure to certain toxic chemicals, including dioxins used in industry, benzenes, and some chemical herbicides
- being near high levels of radiation
- certain viruses (such as HIV)
- having monoclonal gammopathy of undetermined significance (MGUS)
- being overweight (research has shown there may be a link)
- a close family member with myeloma (though it is not hereditary).
Who gets myeloma?
In Australia, about 2700 people are diagnosed with myeloma each year. Myeloma accounts for almost 14% of blood cancers and less than 2% of all cancers.
It is most common in people who are aged over 60. Myeloma can still affect younger people, but it is quite rare in people aged under 40. Myeloma is slightly more common in men than in women.
More resources
Dr Ian Bilmon, Haematologist, Westmead Hospital and The Sydney Adventist Hospital (Clinical review); Martin Boling, Consumer; Catherine Bowley, Specialist Myeloma Nurse, Myeloma Australia; Dr Samuel Dickson, Radiation Oncologist, Calvary Mater Newcastle; Rachelle Frith, Clinical Nurse Consultant, Haematology, Prince of Wales Hospital; Dr Wojt Janowski, Haematologist, Calvary Mater Newcastle; Yvonne King, 13 11 20 Consultant, Cancer Council NSW. We would like to thank all the health professionals, consumers and editorial teams who have worked on current and past editions of this title.
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