CLL can be a very slow growing cancer. It often remains inactive, or smouldering, for years. During this time the only sign of the disease is a higher than normal number of white cells in the blood.

Several studies have looked at whether it is better to treat people, who have CLL but no symptoms, immediately or to delay treatment until symptoms develop. The results showed that people who waited until symptoms appeared before starting treatment lived just as long as people who were treated early.

As a result of these studies specialists recommend that treatment for CLL isn't given until symptoms develop or blood tests show the leukaemia is becoming more active. This means that for as long as people aren't having any problems from CLL they don't have to put up with the side-effects or inconvenience of treatment.