Doctors use staging to assess how much leukaemia there is. This helps them know when you may need treatment and which treatment is best for your situation.

There are two staging systems commonly used for CLL – the Binet system and the Rai system. The Binet system is most commonly used in the UK.

Binet staging system

This looks at the number of white blood cells, red blood cells and platelets in the blood. It also looks at how many areas of lymph nodes are enlarged. These areas are in the neck, armpits, groin, liver and spleen. If the lymph nodes in both armpits are enlarged, it’s only counted as one area.

There are three stages in the Binet system:

  • Stage A – There are fewer than three areas of enlarged lymph nodes.
  • Stage B – There are three or more areas of enlarged lymph nodes.
  • Stage C – There are a reduced number of red blood cells, platelets or both.


In a small number of people with CLL, the leukaemia can change and start to grow more quickly. This is called transformation.

In about 10% of people (1 out of 10), CLL may change into another type of leukaemia called prolymphocytic leukaemia. In less than 10% of people, CLL may develop into a type of lymphoma (cancer of the lymphatic system) known as Richter’s syndrome.

Transformation can be found by a blood test that shows a high number of leukaemia cells.

Sometimes, the first sign of transformation is when a person has more symptoms. These include:

  • a high temperature (fever)
  • sweats
  • weight loss
  • a sudden swelling of affected lymph nodes, especially in the tummy (abdomen).

However, there are many other reasons why someone may have these symptoms.

It’s important to remember that transformation is unusual and doesn’t happen for most people with CLL.

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Treating CLL by stage

Stage A CLL often doesn’t need treatment. People with stage B or C CLL usually have chemotherapy and possibly targeted therapy.