An analysis of more than 3,500 children with neuroblastoma showed that blacks and Native Americans were more likely to have high-risk, aggressive disease than whites. Both groups also had worse survival – both overall and living disease-free without recurrence.
In addition, neuroblastoma recurred at a higher rate in blacks compared to whites among high-risk patients who remained disease-free for two or more years after diagnosis. In contrast, the prevalence of high-risk neuroblastoma among Asian and Hispanic populations was not much different from whites.
“This is the largest neuroblastoma cohort ever analyzed for outcome disparities, and the first to show that blacks and Native Americans have significantly worse survival than white children,” said lead author Susan Cohn, MD, professor of pediatrics at the University of Chicago.
“We found that black children are more likely than white children to have clinically aggressive, high-risk neuroblastoma, and to relapse or have disease progression two or more years after diagnosis. This increased prevalence of high-risk disease was surprising and suggests that these patients may have a genetic predisposition that contributes to the development of high-risk disease.”
Neuroblastoma, a disease of specialized nerve cells, 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 in the United States. The disease can be varied, and is categorized into high-, intermediate- and low-risk groups based on disease characteristics and biology.
Cohn and her colleagues analyzed data collected on 3,539 patients with neuroblastoma enrolled in the Children’s Oncology Group ANBL00B1 biology study. The research was conducted between 2001 and 2009 and aimed at collecting information on patients and their tissue samples to determine prognosis and appropriate therapy.
They found that blacks and Native Americans were more likely to have high-risk disease (57 percent and 68 percent, respectively) than whites (43 percent). Only 43 percent of Hispanic children were also high risk.
The five-year event-free survival was 67 percent for whites, 69 percent for Hispanics, 62 percent for Asians and 56 percent for blacks. Native Americans had the lowest: 37 percent. Seventy-five percent of both white and Hispanic children lived at least five years, whereas black and Asian children had a five-year survival of 67 percent and 63 percent, respectively. Native Americans again had the lowest survival: 39 percent.
According to Cohn, the higher recurrence rate seen after two years in the black children after they initially responded to their treatment “suggests that the black population is more resistant to chemotherapy and that there was disease that failed to completely respond to initial treatment which led to relapse.
We hypothesize that blacks may have a higher prevalence of chemotherapy-resistant minimal disease following therapy than whites, leading to a higher number of late-occurring events.”
Specific inherited gene variations have been shown to play an important role in the racial and ethnic differences in drug effectiveness and toxicity. As one next step, Cohn is planning to collaborate with researchers from the University of Chicago and Children’s Hospital of Philadelphia to analyze data from more than 3,600 black and white children with neuroblastoma for the presence of snippets of DNA called single nucleotide polymorphisms that have been shown to be associated with resistance to certain chemotherapy drugs in a laboratory cell-based model and compare these results to patient outcomes.
Source: ASCO