By Lisa Rapaport
(Reuters Health) – Black and Hispanic children may be less likely than white kids to survive certain childhood cancers at least in part due to differences in socioeconomic status, a U.S. study suggests.
Researchers examined data on 31,866 black, Hispanic, and white children who were diagnosed with 12 types of cancer between 2000 and 2011 when they were no more than 19 years old. Through the end of 2012, rates of death from all causes ranged from 5.2 percent among kids with Hodgkin lymphoma, an immune system cancer, to 33.8 percent among children with acute myeloid leukemia, a cancer of the blood and bone marrow.
For nine cancers, black children were significantly more likely to die that white kids, with an increased risk ranging from 38 percent with neuroblastoma, a form of brain cancer, to 95 percent with astocytoma, a different type of brain cancer.
With six cancers, Hispanic kids were more likely to die than white children, with an increased risk ranging from 31 percent with neuroblastoma to 65 percent with non-Hodgkin lymphoma, an immune system cancer.
“Racial and ethnic differences in childhood cancer survival have long been known, and there has been some research indicating that socioeconomic status could explain disparities,” said lead study author Rebecca Kehm, of the Columbia University Mailman School of Public Health in New York City.
“However, our study is the first to use statistical methods that put numbers to the relative contribution of SES to survival disparities for different types of childhood cancer,” Kehm, who completed the research at the University of Minnesota School of Public Health, said by email.
Socioeconomic status is a measure of class or standing in society that often includes income, education and occupation. For kids, it’s often based on their parents’ circumstances.
When researchers accounted for socioeconomic status in the current study, it explained much of the difference in survival rates for acute lymphoblastic leukemia, a form of bone marrow cancer; acute myeloid leukemia, a different bone marrow cancer; neuroblastoma; and non-Hodgkin lymphoma.
For black children compared with white kids, factoring in socioeconomic status reduced the original association between race and survival for these four cancers by 44 percent, 28 percent, 49 percent and 34 percent, respectively, the study found.
For Hispanic children, socioeconomic status reduced the original association between ethnicity and survival for these four cancers by 31 percent, 73 percent, 48 percent and 28 percent, respectively.
“Race is a socially constructed taxonomy that does not in itself cause health. However, there are a number of factors that are associated with one’s race that can influence health,” Kehm said.
“For example, exposure to racial discrimination can cause a physiological stress response and a weathering effect on one’s health. There are also genetic variants that are associated with ancestry that have been linked with different health outcomes, including certain types of cancer.”
The study wasn’t a controlled experiment designed to prove whether or how socioeconomic status might directly impact survival odds for childhood cancer patients, researchers note in the journal Cancer. It’s possible that for some types of childhood cancer, the biology of drug processing or tumor biology that differs by ancestry might be more important than socioeconomic status, the study authors write.
Still, the findings add to the large body of evidence linking factors like limited education, low income and issues with the access and affordability of care to worse survival rates for cancer, said Dr. Adam Green, an associate professor at the University of Colorado School of Medicine and a pediatric oncologist at Children’s Hospital Colorado in Aurora.
“Socioeconomic factors like poverty do make it harder for black and Hispanic children to survive some of the most common childhood cancers,” Green, coauthor of an accompanying editorial, said by email. “And it’s doubly important that we address these factors, because there seem to be other factors beyond socioeconomic status that make survival for these groups harder as well, which may be harder to change.”