Socio-economic and ethnic disparities in childhood cancer survival, Yorkshire, UK.

BACKGROUND: Establishing the existence of health inequalities remains a high research and policy agenda item in the United Kingdom. We describe ethnic and socio-economic differences in paediatric cancer survival, focusing specifically on the extent to which disparities have changed over a 20-year period. METHODS: Cancer registration data for 2674 children (0-14 years) in Yorkshire were analysed. Five-year survival estimates by ethnic group (south Asian/non-south Asian) and Townsend deprivation fifths (I-V) were compared over time (1997-2016) for leukaemia, lymphoma, central nervous system (CNS) and other solid tumours. Hazard ratios (HR: 95% CI) from adjusted Cox models quantified the joint effect of ethnicity and deprivation on mortality risk over time, framed through causal interpretation of the deprivation coefficient. RESULTS: Increasing deprivation was associated with significantly higher risk of death for children with leukaemia (1.11 (1.03-1.20)) and all cancers between 1997 and 2001. While we observed a trend towards reducing differences in survival over time in this group, a contrasting trend was observed for CNS tumours whereby sizeable variation in outcome remained for cases diagnosed until 2012. South Asian children with lymphoma had a 15% reduced chance of surviving at least 5 years compared to non-south Asian, across the study period. DISCUSSION: Even in the United Kingdom, with a universally accessible healthcare system, socio-economic and ethnic disparities in childhood cancer survival exist. Findings should inform where resources should be directed to provide all children with an equitable survival outcome following a cancer diagnosis.

Childhood leukaemia and socioeconomic status in England and Wales 1976-2005: evidence of higher incidence in relatively affluent communities persists over time.

BACKGROUND: Record-based studies have generally reported association of higher childhood leukaemia incidence with higher socioeconomic status (SES), but recent findings are less consistent. METHODS: We examined records from the National Registry of Childhood Tumours for evidence of this association in England and Wales during 1976-2005. All eligible leukaemia registrations (N=11940) were grouped by year of diagnosis in decades centred on census years 1981, 1991 and 2001 (N=3748, 3922, 4270, respectively). Using data from the census appropriate to the decade, SES for each case was measured by the child-population-weighted quintile of the Carstairs deprivation index of the census ward containing the address at diagnosis. RESULTS: In each decade, the age-standardised leukaemia rate in the poorest quintile was ∼90% of the rate in the most affluent. Using Poisson regression, the age-adjusted rate ratio per quintile decrease in SES was 0.96 (95% confidence interval 0.94-0.98; P<0.001 for trend) in 1976-1985, 0.97 (0.95-0.99; P=0.008) in 1986-1995 and 0.97 (0.95-0.99; P=0.009) in 1996-2005. Similar association was evident for lymphoid leukaemia, the major subgroup (N=9588 in total), but not for acute myeloid (N=1868) or other/unspecified leukaemia (N=484). CONCLUSION: Reported childhood leukaemia incidence in England and Wales continues to be higher in relatively affluent communities. Possible explanations include under-diagnosis of leukaemia in children from poorer communities, and/or association of higher SES with hypothesised risk factors, such as population mixing and delayed exposure to infection.

Effect of population mixing and socioeconomic status in England and Wales, 1979-85, on lymphoblastic leukaemia in children.

OBJECTIVE: To examine the effects of migration, diversity of migrant origins, commuting, and socioeconomic status on the incidence of acute lymphoblastic leukaemia in childhood. DESIGN: Poisson regression analysis of incidence rates in relation to the variables of interest. SETTING: The 403 county districts of England and Wales during 1979-85. SUBJECTS: Children aged under 15 years. RESULTS: There were significant trends in the incidence of lymphoblastic leukaemia at ages 0-4 and 5-9 years with the proportion of children in a district who had recently entered the district. While there was no consistent relation between the proportion of recent incomers in the total population of a district and its incidence rate, the combination of higher migration with greater diversity of origins or distance moved was associated with higher incidence in both age groups. Incidence increased significantly at age 0-4 with the level of employment in a district and at age 5-9 with the proportion of households with access to a car. No significant trends were found with commuting. CONCLUSIONS: The results for level of child migration and diversity of total migration provide evidence of an effect of population mixing on the incidence of childhood leukaemia which is not restricted to areas experiencing the most extreme levels of mixing.

International variations in the incidence of childhood lymphomas.

The International Agency for Research on Cancer has coordinated a worldwide study of childhood cancer incidence, with data provided by contributors from over 50 countries. We present here the results on lymphomas from this study and other sources. Hodgkin's disease had a relatively high incidence in North Africa and West Asia and a low incidence throughout East Asia. In populations of predominantly European origin, the highest rates tended to be in warmer countries of lower latitude. In industrialised Western countries, the incidence increased steeply with age and was low in childhood compared with that in young adults whereas elsewhere the increase in incidence between childhood and adults aged 20-34 was much less marked. The age-distribution of Hodgkin's disease in childhood appears to be related to levels of socio-economic development but the total incidence seems to be determined more by ethnic and environmental factors. The highest incidence of Burkitt's lymphoma occurred in tropical Africa and Papua New Guinea. Elsewhere, Burkitt's lymphoma was rare, though the incidence was higher in Spain, North Africa and the Middle East than in other areas. In most Western countries, a third of all non-Hodgkin lymphomas may be Burkitt's. There was no consistent pattern in the incidence of other non-Hodgkin lymphomas except for a tendency towards higher rates around the Mediterranean and in some Latin American registries.