Population-Based Age- and Sex-Specific Incidence Rates in the 4 Main Types of Leukaemia

Abstract

Due to recent developments in clinical hematology, 98.8% of all 1980 cases of leukemia reported to the Danish Cancer Registry during the period of 1973-1976 could be subclassified into the 4 main types of leukemia. Thus, it has been possible to characterize each of these types more accurately than before regarding age- and sex-specific incidence rates, relative frequency, male/female ratio and median age at diagnosis. Chronic lymphatic leukemia constituted 38% and chronic myeloid leukemia 15% of the cases. These figures are larger and smaller, respectively, than these previously reported. The median age of all cases combined was 67 yr, and the median age in cases of acute nonlymphocytic leukemia was 64 yr with 59% of the latter patients > 60 yr of age. In childhood myeloid leukemia, an early incidence peak, not previously described, was observed before the age of 2 yr. Analysis of Danish leukemia incidence rates from 1943 and onwards shows no increase over 3 decades in patients < 75 yr of age. The observed increase in incidence from 5866-9942/100,000 during the period studied in limited to the very oldest age groups and is probably due to improved diagnostic efforts.