Ionising radiation and leukaemia potential risks: review based on the workshop held during the 10th Symposium on Molecular Biology of Hematopoiesis and Treatment of Leukemia and Lymphomas at Hamburg, Germany on 5 July 1997

Acute lymphoblastic leukemia incidence during socioeconomic transition: selective increase in children from 1 to 4 years

Pre-school acute lymphoblastic leukemia (ALL) peak is consistent in developed but not in developing countries and its magnitude apparently correlates with the socioeconomic status. A population-based study describing ALL incidence during socioeconomic transition has been lacking. Central European post-communist countries (with very low foreign migration and centralized statistics) offer reliable data for the period before and during major socioeconomic changes. Population-based data on Czech ALL patients younger than 18 years were taken from two independent Czech national registries partially overlapping in time (1980-1998, n = 1236 and 1991-1999, n = 570). During the 1980s and 1990s, ALL incidence among children 1-4 years increased 1.5 times (P = 0.01). This increase was more prominent in females than in males (slopes 0.13 and 0.09, P values 0.03 and >0.05, respectively). No significant change was observed in other age groups (0, 5-9, 10-14, 15-17 years or all others combined). We discuss possible underlying socioeconomic factors including infant care and breast-feeding, hygiene, birth order, industry and pollution. Moreover, we try to pinpoint the immunophenotypic/molecular-genetic subsets of ALL that might be socioeconomically affected. Selective increase of ALL in children 1-4 years old provides epidemiological evidence that etiology and/or trigger mechanisms are different for a considerable proportion of these children and that these mechanisms are exogenous.

Epidemiology of leukemia and lymphoma

The causes of acute leukemia and lymphomas are still largely unknown. These malignancies account for approximately 6% of cases of cancer in the US population, and active research efforts are now underway to define etiologically important genetic or environmental factors for these conditions. Recent epidemiologic studies have focused on international variations, secular trends, genetic syndromes, familial aggregation, chromosomal abnormalities, environmental exposures, and unique subgroups defined either demographically or biologically.