New research shows that childhood cancers in the US vary by geographical region, age, race, ethnicity and gender, and that the findings could be used to better understand and track childhood cancers.

The study is the work of researchers from the US Centers for Disease Control and Prevention (CDC) and the Office of Workforce and Career Development, both based in Atlanta, Georgia, and is published in the 2nd June online issue of the journal Pediatrics.

Although cancer is the number 1 cause of disease-related deaths among 1 to 19 year old Americans, little is known about its demographic and geographic variation.

For the research, lead author Dr Jun Li, from the Division of Cancer Prevention and Control of the National Center for Chronic Disease Prevention and Health Promotion at the CDC, and colleagues, studied nearly 36,500 cases of childhood cancer in persons aged 0 to 19 from 2001 to 2003 and sorted them by age, gender, race, ethnicity and geography.

The cases came from 39 National Program of Cancer Registries and 5 Surveillance, Epidemiology, and End Results statewide registries, which together represent over 90 per cent of the US population.

The results showed that: The age adjusted incidence rate of childhood cancer was 166 per million.
Consistent with known data, leukemia was the most common childhood cancer.
For all cancers combined, boys were more likely to be diagnosed with the disease than girls, adolescents (15 to 19 year olds) more than children (0 to 14) and white children more than any other race.
Boys were most often diagnosed with lymphoid leukemia and non-Hodgkin's lymphoma.
Girls were more likely to be diagnosed with kidney cancers.
Children living in the northeast of the United States had the highest incidence for all census regions, which the authors suggest is probably due to the significantly higher incidence rate for central nervous system neoplasms and lymphomas in this region. The authors concluded that:

"This study is the first to demonstrate substantial regional differences in the incidence of childhood cancer. It also shows that incidence varies according to gender, age, race, and ethnicity."

They recommended that the findings could be useful for "prioritizing future childhood cancer research needs".

Experts commenting in various media said they were perplexed by the fact the South of the US appeared to have a lower incidence of childhood cancers.

A children's cancer physician at Ochsner Medical Center in New Orleans, Dr Rafael Ducos, told the Associated Press that the low rates in the South could be due to under-reporting.

In a telephone interview reported by Bloomberg, lead author Li said the risk of cancer in a region could be affected by radiation levels, and, echoing the comment made by Ducos, there could be more cases in the Northeast because they have "good- quality health-care facilities".

"Cancer Incidence Among Children and Adolescents in the United States, 2001-2003."
Jun Li, Trevor D Thompson, Jacqueline W Miller, Lori A Pollack, and Sherri L Stewart.
Pediatrics, Vol 121, No 6, pp e1470-e1477, Published online 2nd June 2008.
DOI: 10.1542/peds.2007-2964

Click here for Abstract.

Source: journal abstract, Associated Press, American Academy of Pediatrics, Bloomberg.

: Catharine Paddock, PhD