CLL Overview

What is CLL?

Chronic Lymphocytic Leukaemia (CLL) is a type of cancer that affects white blood cells.

Under normal circumstances healthy white blood cells help our bodies fight infection and disease. In CLL, the bone marrow produces too many white blood cells, called lymphocytes, which aren’t fully developed, and which don’t work properly. Over time, these cells accumulate in the blood and outnumber the normal cells. As well as the blood and bone marrow, white blood cells are also found in large numbers in the lymphatic system, the spleen and other body tissues. This may give rise to enlarged lymph nodes and spleen.

When the abnormal cells accumulate mainly in the lymph nodes rather than the blood, it is called Small Lymphocytic Lymphoma (SLL).

CLL can behave very differently in different people. The term ‘chronic’ means that in most cases this type of cancer develops or progresses very slowly over months or years. Around a third of CLL patients may never need treatment. However, in some cases the disease progresses more rapidly and the options for treatment will need to be considered.

How common it is?

CLL is the most common form of leukaemia in adults in Western countries.

Approximately 4,220 adults are diagnosed with CLL in the UK each year. It is more common in white people and is rarely seen in children.

What causes CLL?

The exact causes for CLL are not known, but research is ongoing to find out more. It is not thought to be caused by lifestyle.

Factors that can increase the risk of CLL are:

  • Age – The risk of developing CLL increases with age. Only about 10% of CLL patients are under 55 years of age.
  • Gender – Men are about twice as likely as women to develop CLL. The reasons for this are not clear.
  • Family History – 5% of patients who have CLL also have a relative with CLL. Over 20 genes have been identified which predispose people to developing CLL, however it is not considered a hereditary disease.

Signs and Symptoms

CLL usually develops slowly and more than half of all patients don’t have any symptoms at the early stages of the disease.

Because people with CLL don’t always feel unwell at first, it’s often found when they have a routine blood test for some other medical reason. As the disease develops, the abnormal cells (known as B-lymphocytes) grow steadily and accumulate in the bone marrow, lymph nodes and blood. This means that the bone marrow may not be able to produce the normal numbers of healthy blood cells as it becomes swamped.

Over time, CLL patients may experience increasing symptoms which can include:

  • Tiredness, sometimes increasing to extreme fatigue.
  • Swollen lymph nodes, especially in the neck, armpits or groin. This might lead to discomfort as the nodes increase.
  • Frequent or more severe infections.
  • Breathlessness, tiredness and headaches caused by anaemia (lack of red blood cells).
  • Bruising or bleeding easily, for example bleeding from the gums.
  • Swollen abdomen due to spleen enlargement or enlarged nodes.

Other symptoms can include: frequent, severe night sweats, unexplained weight loss, and/or fevers (high temperatures) in the absence of any infections.

Tell you doctors about any new symptoms, or any that seem to be getting worse.

It might be worth recording these in a diary. This will allow you to look at the pattern of these symptoms, which you can then show your doctor.