The annual incidence of CLL varies with the age and sex structure of the population. Whereas in the USA it has been estimated at per 100,000 (males : females ) [2], in the UK estimates of per 100,000 have been reported [3]. However, since in a majority of patients diagnosis is established because of an incidental blood count performed for irrelevant reasons and because of increasing life expectancies, the prevalence should augment in the future. The median age for diagnosis is 70 for males and 74 for females. Caucasian populations have a clearly higher incidence when compared.
