Medline ® Abstracts for References 41,42

Changing definitions and classifications of hematologic malignancies (HMs) complicate incidence comparisons. HAEMACARE classified HMs into groupings consistent with the latest World Health Organization classification and useful for epidemiologic and public health purposes. We present crude, age-specific and age-standardized incidence rates for European HMs according to these groupings, estimated from 66,371 lymphoid malignancies (LMs) and 21,796 myeloid malignancies (MMs) registered in 2000-2002 by 44 European cancer registries, grouped into 5 regions. Age-standardized incidence rates were 24.5 (per 100,000) for LMs and 7.55 for MMs. The commonest LMs were plasma cell neoplasms (4.62), small B-cell lymphocytic lymphoma/chronic lymphatic leukemia (3.79), diffuse B-cell lymphoma (3.13), and Hodgkin lymphoma (2.41). The commonest MMs were acute myeloid leukemia (2.96), other myeloproliferative neoplasms (1.76), and myelodysplastic syndrome (1.24). Unknown morphology LMs were commonest in Northern Europe (7.53); unknown morphology MMs were commonest in Southern Europe (0.73). Overall incidence was lowest in Eastern Europe and lower in women than in men. For most LMs, incidence was highest in Southern Europe; for MMs incidence was highest in the United Kingdom and Ireland. Differences in diagnostic and registration criteria are an important cause of incidence variation; however, different distribution of HM risk factors also contributes. The quality of population-based HM data needs further improvement.

BACKGROUND: Ascertainment of cases and disease classification is an acknowledged problem for epidemiological research into haematological malignancies.

METHODS: The Haematological Malignancy Research Network comprises an ongoing population-based patient cohort. All diagnoses (paediatric and adult) across two UK Cancer Networks (population 3.6 million,>2000 diagnoses annually, socio-demographically representative of the UK) are made by an integrated haematopathology laboratory. Diagnostics, prognostics, and treatment are recorded to clinical trial standards, and socio-demographic measures are routinely obtained.

RESULTS: A total of 10,729 haematological malignancies (myeloid=2706, lymphoid=8023) were diagnosed over the 5 years, that is, from 2004 to 2009. Descriptive data (age, sex, and deprivation), sex-specific age-standardised (European population) rates, and estimated UK frequencies are presented for 24 sub-types. The age of patients ranged from 4 weeks to 99 years (median 70.6 years), and the male rate was more than double the female rate for several myeloidand lymphoid sub-types, this difference being evident in both children and adults. No relationship with deprivation was detected.

CONCLUSION: Accurate population-based data on haematological malignancies can be collected to the standard required to deliver reproducible results that can be extrapolated to national populations. Our analyses emphasise the importance of gender and age as disease determinants, and suggest that aetiological investigations that focus on socio-economic factors are unlikely to be rewarding.