Low socioeconomic status is associated with worse survival in children with cancer: a systematic review

Abstract

Background: While low socioeconomic status (SES) has been associated with inferior cancer outcome among adults, its impact in pediatric oncology is unclear. Our objective was therefore to conduct a systematic review to determine the impact of SES upon outcome in children with cancer.

Methods: We searched Ovid Medline, EMBASE and CINAHL from inception to December 2012. Studies for which survival-related outcomes were reported by socioeconomic subgroups were eligible for inclusion. Two reviewers independently assessed articles and extracted data. Given anticipated heterogeneity, no quantitative meta-analyses were planned a priori.

Results: Of 7,737 publications, 527 in ten languages met criteria for full review; 36 studies met final inclusion criteria. In low- and middle-income countries (LMIC), lower SES was uniformly associated with inferior survival, regardless of the measure chosen. The majority of associations were statistically significant. Of 52 associations between socioeconomic variables and outcome among high-income country (HIC) children, 38 (73.1%) found low SES to be associated with worse survival, 15 of which were statistically significant. Of the remaining 14 (no association or high SES associated with worse survival), only one was statistically significant. Both HIC studies examining the effect of insurance found uninsured status to be statistically associated with inferior survival.

Conclusions: Socioeconomic gradients in which low SES is associated with inferior childhood cancer survival are ubiquitous in LMIC and common in HIC. Future studies should elucidate mechanisms underlying these gradients, allowing the design of interventions mediating socioeconomic effects. Targeting the effect of low SES will allow for further improvements in childhood cancer survival.

Figure 1. PRISMA flow diagram.

Figure 2. Associations between socioeconomic measures and event-free and overall survival in low- and middle-income countries.

A. Measures of material possession, family composition, insurance status, immigrant status, and health care accessibility. B. Measures of education and occupation. C. Measures of income. Positive = lower socioeconomic status associated with inferior outcome; Negative = lower socioeconomic status associated with superior outcome. Magnitudes of association are not plotted. Statistically significance is denoted in red. Data points with a number above represent multiple socioeconomic variables.

Figure 3. Associations between socioeconomic measures and event-free and overall survival in high-income countries.

A. Ecologic measures B. Measures of material possession, family composition, insurance status, immigrant status, and health care accessibility. C. Measures of education and occupation. D. Measures of income. Positive = lower socioeconomic status associated with inferior outcome; Negative = lower socioeconomic status associated with superior outcome. Magnitudes of association are not plotted. Statistically significance is denoted in red. Data points with a number above represent multiple socioeconomic variables. 3* indicates 2 non-significant associations and one significant association.

Figure 4. Mechanisms linking socioeconomic status domains to both general and childhood cancer specific health outcomes.

Domains and general mechanisms are adapted from the work of Galobardes et?al., Braveman et?al., Krieger et?al. and Marmot. Several childhood specific mechanisms are suggested by Bhatia et?al., Gage, Viana et?al. and Gupta et?al. These mechanisms are often theoretical with little empiric basis.