November 29, 2010

Race Is The Case In Neuroblastoma

(Ivanhoe Newswire) -- Neuroblastoma is the most common extracranial solid cancer in childhood and the most common cancer in infancy, with an annual incidence of about 650 new cases per year in the United States.  Close to 50 percent of neuroblastoma cases occur in children younger than two years old.  A recent study has revealed that African American, Asian, and Native American children are more likely than Caucasian and Hispanic children to die after being treated for neuroblastoma.  The study "“ of more than 3,500 patients with the disease "“ is the largest ever to look at racial disparities in risk and survival for the most common solid cancer found in young children.

Furthermore, the study found that African American and Native American children are more likely to have the high-risk form of the disease all the while demonstrating signs of resistance to modern treatment.  Those biological characteristics suggest that genetic factors contribute to the outcome disparities found for neuroblastoma.

"Disparities in outcome according to race do exist in neuroblastoma," which Susan Cohn, MD, professor of pediatrics at Comer Children's Hospital at the University of Chicago Medical Center and senior author of the study, was quoted as saying.  "There are racial cohorts of patients who do more poorly than the white population."

Since neuroblastoma is a rare cancer "“ with only 650 new cases each year in the United States "“ an alliance was formed with Children's Oncology Group (COG) in an effort to follow a sufficient amount of racially diverse patients.

A subject pool of 3,500 children diagnosed between 2001 and 2009 enabled a research group led by Cohn and Tara Henderson, MD, MPH, Assistant Professor of Pediatrics, to compare children of different races on neuroblastoma risk and survival.  Whereas 75 percent of Caucasian and Hispanic patients survived five years after diagnosis, only 67 percent of African American patients, 63 percent of Asian patients, as well as 39 percent of Native American patients survived to that point.

Patients diagnosed with neuroblastoma are classified as having low-risk, intermediate-risk, or high-risk disease based on numerous clinical and biological factors.  African American children in the study had a higher prevalence of high-risk disease (57 percent) compared to Caucasian children (44 percent).  African American patients also displayed individual predictors of high-risk disease more frequently, such as older age at diagnosis, stage 4 disease, and inauspicious histology.

The study moreover offers a potentially inimitable example of a discrepancy due chiefly to biological, rather than socioeconomic factors.  In many adult cancer types, the survival gap between Caucasian and minority patients is often attributed to factors such as diminished access to health care, delayed diagnosis, and poorer quality treatment.

However, in neuroblastoma this is less likely to be an issue.  Low-risk cancers seldom progress to a higher risk with time, Cohn said, making a delayed diagnosis less likely to affect outcome.  What's more, treatment for high-risk neuroblastoma "“ including intravenous chemotherapy, stem cell transplant, and radiation "“ is fundamentally administered in a hospital setting, removing the effect of compliance, such as missing oral doses of medications at home.

"In many cancers, disparities in outcome appear to be largely due to differences in socio-economic status and environment.  For example, the lack of ability to be seen by a doctor in a timely manner and get appropriate care significantly impacts survival," Cohn concluded.  "While multiple factors are also likely to contribute to the disparities we observed in children with neuroblastoma, genetic factors are likely to contribute to the increased prevalence of high-risk tumors in the black cohort, which is quite unique."

SOURCE: Journal of Clinical Oncology, 22 November 2010