What is myeloma?
Myeloma is a cancer of plasma cells (mature B-lymphocytes), which are a type of white blood cell that form part of the immune system. Myeloma may also be called multiple myeloma or plasma cell myeloma.
Myeloma develops when plasma cells undergo a malignant (cancerous) change and become myeloma cells. These myeloma cells multiply without any proper order, forming tumours that accumulate in different parts of the body, most commonly in the bone marrow and on the surfaces of different bones in the body.
Myeloma cells may secrete chemicals that stimulate other bone marrow cells (osteoclasts) to remove calcium from the bone. As a result, bones can become weaker, more brittle and break more easily.
Under normal conditions, plasma cells produce immunoglobulins (antibodies) that help protect the body from infection and disease. Myeloma cells produce an abnormal type of immunoglobulin called a paraprotein (also known as monoclonal immunoglobulin, M-spike or M-protein). This can be detected in the blood or urine.
As myeloma cells multiply, they crowd the bone marrow and prevent it from making normal numbers of red blood cells, white blood cells and platelets. Myeloma cells can also interfere with the production of normal antibodies.
This can make people with myeloma anaemic, more susceptible to infections and cause them to bleed and bruise more easily. Excess immunoglobulin fragments can also cause damage to the kidneys.
Types of myeloma
The types of myeloma are traditionally subclassified according to the antibodies (immunoglobulins) that the abnormal plasma cells produce. The types of immunoglobulin that can be produced include IgG, IgA, and rarely IgD or IgE.
Each immunoglobulin is made up of a combination of two ‘heavy’ chains and two ‘light’ chains. If excess heavy chains are produced it is termed heavy chain myeloma, and if excess light chains are produced it is called light chain myeloma.
In some people, the amount of paraprotein or light chains produced is so small or undetectable, and these people are classified as having non-secretory myeloma or oligo-secretory myeloma.
Signs and symptoms
The signs and symptoms of myeloma can vary and depend on how advanced the disease is. In the earliest stages, there may be no symptoms, and myeloma may be detected by coincidence during a routine blood test. In other cases, people might experience symptoms that affect their daily living.
Common symptoms include:
- Anaemia (lack of energy, fatigue, weakness, dizziness, shortness of breath and pale skin)
- Increased bleeding or bruising
- Bone pain
- Elevated blood calcium level (hypercalcaemia)
- Frequent or repeated infections
Symptoms of hypercalcaemia may include:
- Feeling sick
- Constipation
- Tiredness or fatigue
- Feeling thirsty
- Confusion.
The acronym CRAB is often used by doctors to describe the effect myeloma can have on different areas of the body:
Calcium elevation (hypercalcaemia)
Renal impairment and changes to kidney function
Anaemia, or bone marrow failure
Bone disease
Causes
The exact cause of myeloma remains unknown. Like other types of blood cancers, myeloma is thought to develop when DNA is damaged during the development of a plasma cell.
We do know that myeloma is not contagious, you cannot catch it from someone else.
Why these mutations (errors) occur in the first place remains unknown but there are likely to be a number of factors involved. Certain factors may put some people at a higher risk of developing myeloma, including exposure to higher than usual doses of radiation and ongoing exposure to certain industrial or environmental chemicals.
Diagnosis
Myeloma affects every person differently, and therefore results from the tests may vary from person to person.
A variety of blood tests are used to help diagnose and monitor myeloma. Blood is taken from a vein in your arm and sent to a laboratory where it is looked at under a microscope. The presence of free light chains and paraprotein can be detected in the blood. They can also do a full blood count (which measures different levels of cells in your blood) and blood chemistry (which looks at the levels of substances in your blood).
A bone marrow biopsy is usually done to test a sample of your bone marrow
Many people require x-rays or other imaging tests as part of being diagnosed with myeloma and for ongoing monitoring.
These may include:
- Chest x-ray: to detect a chest infection or other abnormalities.
- Electrocardiogram (ECG) or echocardiogram (ECHO): to see how well your heart is working.
- Computer-assisted tomography (CT) scan: may be used if there is concern about specific localised involvement or damage caused by myeloma.
- Magnetic resonance imaging (MRI) scan: may be used in diagnosis and monitoring of myeloma to detect early disease-related bone changes.
- Full body X-ray or skeletal survey: may be done to check for any bone damage caused by myeloma.
- Positron emission tomography (PET) scan: a specialised CT scan that uses a radioactive tracer and special cameras to detect areas where there may be increased tissue activity due to myeloma involvement.
Treatment
The main goals of treating myeloma are to destroy the myeloma cells, stop any progression and improve quality of life by treating the symptoms associated with myeloma.
The treatment that your doctor will recommend depends on things like the type of myeloma you have, your age, general health and how well your myeloma is likely to respond to treatment.
Treatment for myeloma may involve one or a combination of the following:
- Active monitoring
- Corticosteroids
- Chemotherapy
- Novel therapy
- Radiotherapy
- Stem cell transplant
