Childhood cancer and ethnic group in Britain: a United Kingdom children's Cancer Study Group (UKCCSG) study.

We present here the results of the largest study of childhood cancer and ethnic group in Britain, based on 7,658 children treated at paediatric oncology centres throughout the country. Incidence rates could not be calculated and so relative frequencies were analysed by the log-linear modelling method of Kaldor et al. (1990) with allowance made for regional variations in the ages and diagnostic groups of the children included in the study. Children of Asian (Indian sub-continent) and West Indian ethnic origin had similar patterns of incidence for acute lymphoblastic leukaemia to White Caucasians. There was a significant excess of Hodgkin's disease among Asian children compared with Caucasians with an estimated relative risk (RR) of 2.09; this excess was greatest in the 0-4 age group (RR = 6.67). There were significant deficits of Wilms' tumour and rhabdomyosarcoma among Asian children, each with a frequency around half that among Caucasians, whereas West Indians had a significant excess of Wilms' tumour (RR = 2.55). Asian and West Indian children each had a non-significant twofold RR for unilateral retinoblastoma. The results suggest that the incidence of childhood acute lymphoblastic leukaemia is associated with environmental determinants in the country of residence which are most likely to relate to lifestyle factors. The occurrence of retinoblastoma, Wilms' tumour and Hodgkin's disease in early childhood is apparently related more to ethnicity than to geographical location and may reflect genetic factors or environmental exposures specific to the lifestyle of particular ethnic groups.