Chronic lymphocytic leukaemia is a type of cancer that affects the white blood cells and tends to progress slowly over many years.

It mostly affects people over the age of 60 and is rare in people under 40. Children are almost never affected.

In chronic lymphocytic leukaemia (CLL), the spongy material found inside some bones (bone marrow) produces too many white blood cells called lymphocytes that aren’t fully developed and don’t work properly.

Over time this can cause a range of problems, such as an increased risk of picking up infections, persistent tiredness, swollen glands in the neck, armpits or groin, and unusual bleeding or bruising.

CLL is different from other types of leukaemia, including chronic myeloid leukaemiaacute lymphoblastic leukaemia and acute myeloid leukaemia.

Symptoms of CLL

CLL doesn’t usually cause any symptoms early on and may only be picked up during a blood test carried out for another reason.

When symptoms develop, they may include:

You should visit your GP if you have any persistent or worrying symptoms. These symptoms can have other causes other than cancer, but it’s a good idea to get them checked out.

Read more about diagnosing CLL and complications of CLL.

Treatments for CLL

As CLL progresses slowly and often has no symptoms at first, you may not need to be treated immediately.

If it’s caught early on, you’ll have regular check-ups over the following months or years to see if it’s getting any worse.

If CLL starts to cause symptoms, or isn’t diagnosed until later on, the main treatments are:

  • chemotherapy – where medication taken as a tablet or given directly into a vein is used to destroy the cancerous cells
  • a stem cell or bone marrow transplant – where donated cells called stem cells are transplanted into your body so you start to produce healthy white blood cells

Treatment can’t usually cure CLL completely, but can slow its progression and lead to periods where there are no symptoms. Treatment may be repeated if the condition comes back.

Read more about treating CLL.

Outlook for CLL

The outlook for CLL depends on how advanced it is when it’s diagnosed, how old you are when diagnosed, and your general health.

Younger, healthier people who are diagnosed when CLL is still in the early stages generally have the best outlook.

Although it can’t normally be cured, treatment can help control the condition for many years.

Overall, around three in every four people with CLL will live at least five years after diagnosis, but this can range from 10 years or more if caught early on, to less than a year if caught at a very advanced stage.

Causes of CLL

It’s not clear what causes CLL. There’s no proven link with radiation or chemical exposure, diet or infections. You can’t catch it from anyone else or pass it on.

However, having certain genes can increase your chances of developing CLL. You may be at a slightly higher risk of it if you have a close family member with it, although this risk is still small.

Support groups and charities

Living with a serious and long-term condition such as CLL can be very difficult.

You may find it useful to find out as much as you can about the condition and speak to others affected by it.

The following support groups and charities can offer help and advice for people CLL, their families and their carers:

The Macmillan Cancer Support and Cancer Research UK websites are also good places for CLL information and support.