Myeloma
What is myeloma?
Myeloma is a cancer of the plasma cells. Plasma cells are mature lymphocytes (a type of white blood cell) that help fight infection by producing special proteins known as antibodies or immunoglobulins. Immunogblobulins (Ig) are produced by plasma cells in response to bacteria, viruses and other harmful substances found in the body.
Myeloma develops when plasma cells undergo a cancerous or malignant change and become myeloma cells. These myeloma cells multiply without any proper order and form collections known as tumours that accumulate in different parts of the body, especially in the bone marrow and on the surfaces of different bones in the body. These tumours 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.
As myeloma cells multiply, they crowd the bone marrow and prevent it from making normal numbers of red cells (causing anaemia), white cells (increasing your susceptibility to infections) and platelets (increasing your susceptibility to bleeding and bruising). Myeloma cells can also interfere with the production of normal antibodies. Myeloma cells produce an abnormal type of immunoglobulin called paraprotein (also known as monoclonal immunoglobulin, myeloma protein, or simply M protein). Sometimes an excessive number of fragments of immunoglobulin known as light chains are produced. These light chains can be detected in the blood and they also appear in the urine. Light chains detected in the urine are called Bence-Jones protein.
What are the stages and types of myeloma?
Knowing the exact stage of your disease is important because it provides more information about the likely course of your disease (prognosis) and the best way to treat it. Myeloma can be classified according to how the disease is distributed in your body. The International Staging System (ISS) is based on two tests and defines three stages of myeloma:
- Stage I is early disease
- Stage II is in between Stage I and Stage III
- Stage III is advanced disease, where there is a large amount of myeloma in the body.
The CRAB criteria is often used to identify whether a person has active myeloma, which may require treatment. The acronym CRAB consists of: (C) increased calcium level (R) renal (kidney) problems (A) anaemia and (B) bone changes (lytic lesions or bone loss). One or more of these CRAB symptoms indicates symptomatic myeloma, which requires treatment. In the majority of cases myeloma is found in multiple bone marrow sites at diagnosis, which is why the disease is often called multiple myeloma. Sometimes an isolated collection of myeloma cells is found in only one site. When this happens the disease is described as a solitary myeloma or solitary plasmacytoma. Plasmacytomas can sometimes be successfully treated using radiotherapy alone – read more about them here.
Some people have an increased number of plasma cells in their bone marrow, but do not fit the criteria for a diagnosis of multiple myeloma. Their disease may be classified as ‘MGUS’ or smouldering myeloma:
- Monoclonal gammopathy of undetermined significance (MGUS) – is a non-malignant (non-cancerous) condition related to myeloma. It also involves the production of paraprotein by plasma cells. MGUS does not cause any symptoms and it is usually picked up during a routine blood or urine test. People diagnosed with MGUS do not require any treatment apart from regular follow-up by their doctor, usually on a yearly basis to have their protein levels checked. Over time a small number of people with MGUS will develop myeloma. Read more about MGUS here.
- Smouldering myeloma – is a very early phase of myeloma with no symptoms, but a bone marrow biopsy shows definite evidence of myeloma. People diagnosed with smouldering myeloma do not need treatment straight away. Treatment is given at a later stage, when the disease progresses after some months or years.
How common is myeloma?
Who gets myeloma?
What causes myeloma?
What are the symptoms of myeloma?
More information about myeloma
Myeloma diagnosis Myeloma treatment and side effects Solitary plasmacytoma Monoclonal gammopathy of unknown significance (MGUS) Bisphosphonates Other Myeloma ResourcesLast updated on April 26, 2022
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