[Childhood acute lymphoblastic leukemia in Norway 1992-2000]. / Akutt lymfatisk leukemi hos barn i Norge 1992-2000.

BACKGROUND: Acute lymphoblastic leukemia is the most common malignancy in childhood. The survival rate has increased steadily over the last 40 years. MATERIAL AND METHODS: All children aged 0-15 years and diagnosed in Norway in the period 1992-2000, were included in the study (n = 301). The patients were followed up until 1.1. 2005. RESULTS AND INTERPRETATION: The diagnosis was made in 301 children, 33 new cases per year (range 24 to 40) on average. The peak incidence was between 2 and 5 years. Four of 6 infants with acute lymphoblastic leukemia and all 4 with mature B-cell leukemia are alive. Two of the remaining 291 children died before treatment was started. 289 were all treated according to the common Nordic NOPHO-ALL 1992 protocol. All children achieved remission (99.7%), except for one who died before remission was achieved. 55 children (19%) relapsed. Radiation to the brain as part of central nervous system prophylaxis was given to just 10% of the children. The 10-year event-free survival (p-EFS) was 76%, and 244 of 289 (84%) were alive 4-13 years after the diagnosis was made. The data are comparable with the best international results.

Age- and sex-specific incidence of childhood leukemia by immunophenotype in the Nordic countries.

BACKGROUND: Studies from various countries have found an increasing incidence of childhood leukemia in recent decades. To characterize time trends in the age- and sex-specific incidence of childhood acute leukemia during the last 20 years in the Nordic countries, we analyzed a large set of population-based data from the Nordic Society of Paediatric Haematology and Oncology (NOPHO) in their acute leukemia database covering a population of approximately 5 million children aged 0-14 years. METHODS: Temporal trends in acute myeloid leukemia and acute lymphoblastic leukemia incidence rates overall and for acute lymphoblastic leukemia immunophenotypes and for specific age groups were analyzed by Poisson regression adjusting for age, sex, and country. All statistical tests were two-sided. RESULTS: We identified 1595 girls and 1859 boys diagnosed with acute lymphoblastic leukemia between January 1, 1982, and December 31, 2001, and 260 girls and 224 boys diagnosed with de novo acute myeloid leukemia between January 1, 1985, and December 31, 2001. No statistically significant change was seen in the overall incidence rate for acute lymphoblastic leukemia during the 20-year study (annual change = 0.22%, 95% confidence interval [CI] = -0.36% to 0.80%). The incidence rate of B-precursor acute lymphoblastic leukemia remained unchanged (annual change = 0.30%, 95% CI = -0.57% to 1.18%) from January 1, 1986, through December 31, 2001. A somewhat lower incidence in the first years of the study period indicated an early increasing incidence of B-precursor acute lymphoblastic leukemia that corresponded to a simultaneous decreasing incidence of unclassified acute lymphoblastic leukemia. Incidences of T-cell acute lymphoblastic leukemia (annual change = 1.55%, 95% CI = -1.14% to 4.31%) and acute myeloid leukemia (annual change = 0.58%, 95% CI = -1.24% to 2.44%) were stable during the study period. CONCLUSION: Incidences of acute myeloid leukemia overall, acute lymphoblastic leukemia overall, and specific acute lymphoblastic leukemia immunophenotypes have been stable in the Nordic countries over the past two decades.