Social Inequalities Along the Childhood Cancer Continuum: An Overview of Evidence and a Conceptual Framework to Identify Underlying Mechanisms and Pathways

Abstract

Inequalities in health according to social conditions are regarded as unnecessary and unjust. There is a large body of evidence on inequalities in adult cancer, observable throughout the societies on a national level as well as on a global scale. Socioeconomic influences on health matter at all ages including childhood, for which childhood cancer is the leading cause of disease related death in high-income countries (HICs). Substantial differences in the reported incidence of childhood cancers have been observed globally by socioeconomic development of a population. This is reflected in the higher incidence rates reported for HICs, particularly for acute lymphoblastic leukemia, and for cancer in infants (below 1 year), compared to low- and middle-income countries (LMICs). Considerable inequalities between populations and degree of socioeconomic development are also noted for survival from childhood cancer, with substantially lower survival rates seen in most LMICs compared to HICs. With respect to inequalities by socioeconomic position (SEP) within countries, findings of an association between SEP and childhood cancer risk are diverse and limited to studies from HICs. On the contrary, observations on social inequalities in survival within countries are accumulating and indicate that survival inequalities do not only concern resource-poor countries but also high-income populations including European countries. In turn, a childhood cancer diagnosis in itself may have implications on the parents' socioeconomic situation as well as on the later socioeconomic life after having survived the disease. The underlying mechanisms and causal pathways of these empirically demonstrated social inequalities are poorly understood, although it is of significant public health relevance for any actions or strategies to reduce childhood cancer-related inequity. We propose a conceptual framework on potential underlying mechanism and pathways specifically addressing social inequalities in childhood cancer and after childhood cancer to (i) illustrate potential pathways by which social determinants may create health inequities at different points of the childhood cancer continuum; (ii) illustrate potential pathways by which a childhood cancer diagnosis may impact the socioeconomic situation of the concerned family or the later life of a childhood survivor; and (iii) point out how major determinants may relate to each other.

Area deprivation is associated with poorer overall survival in children with acute lymphoblastic leukemia

“…The mechanisms underlying the association between neighborhood socioeconomic disadvantage and ALL survival are likely multifactorial 8 . Area SES may be an indicator of access to care and could impact time from onset of symptoms to start of therapy, choice of treatment center, or clinical trial participation.…”

“…Survival has improved dramatically over the past several decades but racial and ethnic disparities persist, with outcomes remaining poorer among Hispanics and non‐Hispanic Blacks than non‐Hispanic Whites 2‐7 . Prognostic features including cell lineage, age at diagnosis, and cytogenomics differ by race/ethnicity, and socioeconomic and environmental characteristics also contribute to disparities through their impacts on health care access and adherence to therapy 7‐10 . Importantly, recent evidence suggests that disparities are wider for childhood cancers with high treatment amenability, including ALL 3 .…”

Patient and health service factors associated with delays in cancer treatment for children without social security in Mexico

“…Children from LMICs and low socioeconomic groups have higher cancer incidence, less access to specialized care, and worse survival rates 21‐23 . We observed that residents of the poorest and highest socioeconomic level regions have an increased likelihood of prolonged PRT.…”

Management of neuroblastoma in limited-resource settings

“…Management protocols focus on administering risk-based treatments after identification of the classification of each patient yet many patients were treated on the basis of stage[ 39 ]. LMICs concluded that optimal treatment was doubtful due to the suboptimal classification of tumours[ 9 , 15 , 19 ]. The International Neuroblastoma Risk Group classification and the Children’s Oncology Group classification rely on histological and genetic information (mitosis-karyorrhexis index, MYCN amplification, 11q aberration and DNA ploidy) to determine classification[ 11 ], which is not available in many resource-limited settings.…”

“…Because of the variability of NB symptoms, they can easily be misdiagnosed as infections, bone marrow failure, neuropathology and obstructive enteropathies in LMICs by primary health care workers. Nurse-led primary care clinics or general practitioners may not have the expertise to recognise rare diseases in children and are often the first contact versus HICs where the first contact is usually more experienced health care workers[ 9 ].…”