A study published online November 22, 2010, in the Journal of Clinical Oncology finds that black and Native Americans children with neuroblastoma were more likely to have high-risk, aggressive disease than white children.

The analysis included more than 3,500 children with neuroblastoma. 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.

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They found that blacks and Native Americans were more likely to have high-risk disease (57% and 68%, respectively) than whites (43%). Only 43% of Hispanic children were also high risk. The five-year event-free survival was 67% for whites, 69% for Hispanics, 62% for Asians and 56% for blacks. Native Americans had the lowest: 37%. 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% and 63%, respectively. Native Americans again had the lowest survival: 39%.

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.?
BR>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.

Commenting on the study, Lisa Diller, MD, Member of ASCO?s Cancer Communications Committee noted: ?These results shed light, for the first time, on neuroblastoma among different racial groups and the potential impact of race on both stage and outcome. The results suggest that there may be genetic differences in chemotherapy responsiveness, and that these differences might account for reductions in long-term, event-free survival in black patients.?

For more information:
Henderson TO, Bhatia S, Pinto N, London WB, McGrady P, Crotty C, Sun CL, Cohn SL Racial and Ethnic Disparities in Risk and Survival in Children With Neuroblastoma: A Children’s Oncology Group Study. J Clin Oncol. 2010 Nov 22. [Epub ahead of print]

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What is Neuroblastoma

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