Leukaemia describes a number of diseases of differing aetiology and clinical course. The four main subtypes are chronic lymphocytic leukaemia (CLL), chronic myeloid leukaemia (CML), acute lymphocytic leukaemia (ALL) and acute myeloid leukaemia (AML). The commonest of these (about 40% of all cases) is CLL (National Cancer Registry, 2010a). All leukaemias combined formed the tenth most common cancer in Ireland, accounting for 2.4% of all malignant neoplasms, excluding non-melanoma skin cancer, in women and 3.2% in men (Table 13.1). The average number of new cases diagnosed each year was 243 in women and 348 in men. During 1995-2007, the number of new cases diagnosed showed a small overall increase of 1% per annum. However, the numbers decreased slightly in NI, while increasing at approximately 2% per annum in RoI.
The risk of developing leukaemia up to the age of 74 was 1 in 170 for women and 1 in 98 for men and was higher in RoI than in NI. At the end of 2008, 847 women and 1,196 men aged under 65, and 663 women and 924 men aged 65 and over, were alive up to 15 years after their leukaemia diagnosis.
Table 13.1 Summary information for leukaemia in Ireland, 1995-2007
| Ireland | RoI | NI |
| females | males | females | males | females | males |
% of all new cancer cases | 1.7% | 2.3% | 1.8% | 2.4% | 1.6% | 2.0% |
% of all new cancer cases excluding non-melanoma skin cancer | 2.4% | 3.2% | 2.5% | 3.4% | 2.1% | 2.8% |
average number of new cases per year | 243 | 348 | 172 | 256 | 71 | 92 |
cumulative risk to age 74 | 0.6% | 1.0% | 0.6% | 1.1% | 0.5% | 0.8% |
15-year prevalence (1994-2008) | 1510 | 2120 | 1115 | 1614 | 395 | 506 |
In contrast to most other cancers leukaemia was more common at the extremes of age—47% of women and 38% of men were aged either under 50 or over 79 years at diagnosis (Figure 13.1). Approximately one quarter of all new cases presented in the age group 70–79 years. The pattern of age at diagnosis was similar in RoI and in NI.
Figure 13.1 Age distribution of leukaemia cases in Ireland, 1995-2007, by sex
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