Leukaemia in children in Papua New Guinea: an unusual pattern

We report data on 110 children aged <15 years diagnosed with leukaemia during two periods covering 13.25 years. The data sets were consistent. The reported incidence of leukaemia was low. Only 34 (31%) of the children were diagnosed with acute lymphoblastic leukaemia (ALL) compared with 54 (49%) children with acute myeloid leukaemia (AML). The overall mean (SD) age was 6.6 (3.5) years, 6.1 (3.5) for ALL and 6.9 (3.5) for AML. There was no evidence of an early childhood peak of ALL. The male : female ratio was 1.2 : 1 for all leukaemias, 1.3 for ALL and 1.25 for AML. Only eight (22%) of those diagnosed with ALL were classified as type L1. Our figures reflect a relative absence of the common (cALL) cell type in early childhood leukaemia and support the role of infection and its effect on the immune system in the aetiology of childhood leukaemia. Our data also revealed an unusually high proportion of chronic myeloid leukaemia (CML).