MGUS (monoclonal gammopathy of undetermined significance)

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What's the connection between MGUS and blood cancer?

What’s my risk of progression?

How do I know it’s MGUS and not myeloma?

Are there any changes I should look out for?

The chance of someone with MGUS developing blood cancer is known as their risk of progression. Research suggests that each year about one in a hundred people (1%) with a diagnosis of MGUS will develop blood cancer.

If MGUS progresses, it usually develops into a blood cancer called myeloma. There’s no cure for myeloma yet, but it is treatable. Most people with myeloma will have periods of treatment followed by periods of remission, where there’s a low level of cancer cells and they feel well.

Sometimes MGUS can develop into another blood cancer, a type of lymphoma called Waldenström macroglobulinaemia (WM). People with certain type of paraprotein (IgM) tend to develop WM rather than myeloma. WM is a treatable blood cancer.

It’s important to remember that very few people with MGUS go on to get blood cancer.

Your personal level of risk depends on the level and type of paraprotein in your blood.

Doctors will look for these things, known as risk factors:

• the level of paraprotein in your blood
• the type of paraprotein in your blood
• whether there is an abnormal ratio (proportion) of kappa and lambda light chains in your blood.
• the number of abnormal plasma cells in your bone marrow (the spongy material inside some of your bones where blood cells are made). However, most people with MGUS won't have a bone marrow test unless other tests show cause for concern.

Ask your hospital team or GP about your level of risk and what this means for you. For example, it may affect who monitors your condition, and how often you need a check-up. Many people find it reassuring to know they will be monitored regularly. It means that if your doctor sees signs the MGUS is progressing, it will be picked up early.

You may feel anxious about developing blood cancer, even if your risk of progression is low. This is completely understandable.

Some people find it helpful to talk through their worries with someone they’re close to. Others find it easier to talk to someone they don’t know, who is trained to listen and provide emotional support. Our Support Service is here at 0808 0208 888 or [email protected] if you’d like to talk things through.

There are two main types of myeloma:

• Smouldering myeloma – this has no symptoms and doesn’t need treatment but will be regularly monitored.
• Active myeloma – this will usually need treatment to control the myeloma and ease the symptoms.

Doctors will look at a range of things when deciding whether the diagnosis is MGUS, smouldering myeloma or active myeloma. The main ones are:

• the level of paraprotein in your blood
• the number of abnormal plasma cells in your bone marrow
• whether there are signs of damage in your body, in particular kidney or bone damage.

We have more online information about myeloma and a printed booklet you can order for free.

Usually with MGUS you won’t have any symptoms. But if you notice any changes in how you feel, tell your doctor. The main things to look out for are:

• pain in your back, ribs or hips for no apparent reason
• breathlessness
• extreme tiredness
• repeated infections
• generally feeling unwell or unable to do things you usually can.

If you have any of these symptoms, you may need more tests to find out whether it’s caused by a change in the MGUS or something else.