MONDAY, June 2 (HealthDay News) -- A sweeping government study of childhood cancers has found numerous differences in cancer types depending on a child's age, sex, race and where he or she lives in the United States.

White children had the highest incidence of all cancers, the researchers found, and youngsters in the Northeast were diagnosed with cancer more often than children in other parts of the country.

The study also found that boys were more likely to have a pediatric malignancy than girls, and that adolescents are more likely to have cancer than are younger children.

"We looked at the childhood cancer incidence rate from 2001 through 2003, and further looked at the data by age, sex, ethnicity and U.S. census region," said the study's lead author, Dr. Jun Li, an epidemic intelligence office for the U.S. Centers for Disease Control and Prevention (CDC) in Atlanta.

"We identified 36,446 cases of childhood cancer during these three years, which is about 166 per every million," he said.

Li said the information for the study, which represents more than 90 percent of the U.S. population, came from 39 National Program of Cancer Registries and five Surveillance, Epidemiology and End Results (SEER) databases.

Results of the study are published in the June issue of the journal Pediatrics.

Three cancers accounted for about 60 percent of all childhood cancers. Leukemias were the most common childhood malignancy, affecting just over 26 percent of youngsters with cancer. Central nervous system tumors, such as brain tumors, were the next most common type of pediatric cancer, affecting about 17.6 percent of children with the illness. Lymphomas affected about 14.6 percent of kids with cancer, according to the study.

Overall, boys were more likely to develop cancer than girls. The incidence rate for boys was 174 per million, while the incidence rate for girls was 157 per million. The type of cancer each sex commonly developed also varied. Boys were more likely to have lymphoid leukemia, non-Hodgkin lymphoma, Burkitt lymphoma, hepatoblastoma, osteosarcomas, and more. Girls were more likely to develop kidney cancers, thyroid cancers and malignant melanomas.

The cancer incidence rates for those between 15 and 19 were 210 per million, while the incidence rate in children 14 and under was about 151 per million.

White children were the most likely to have cancer, with an incidence rate of 173 per million. The rate for black children was 118 per million, 131 per million for Asian/Pacific Islanders, and 164 per million for Hispanics. American Indians and Alaska Natives had the lowest rates, with 97 per million.

Geography appeared to make a difference as well. Kids in the Northeastern part of the country are most likely to develop cancer, with an incidence rate of 179 per million. In the Midwest, the rate was 166 per million; in the South, it was 159 per million; and in the West, it was 165 per million. Interestingly, the study also reported that the Northeast, despite having the highest cancer rate, also has the lowest death rate from pediatric cancers.

Li said the researchers weren't able to identify the reasons for the differences in this study, but he believes the data will lay the groundwork for future research. Knowing these differences may help other scientists target their research, he added.

"This is an interesting study, but as a practicing oncologist, I won't be advising families any differently. And, as a father of three sons, I wouldn't have any added concern as a parent living in the Northeast," said Dr. Adam Levy, a pediatric hematologist and oncologist, and director of pediatric neuro-oncology at the Children's Hospital at Montefiore in New York City.

"My fear is that people may over-interpret this study, and parents really don't need added anxiety. We're still talking about very rare pediatric cancers and mild differences. Mostly, this gives epidemiological researchers clues. Parents don't need to become overly worried by this," concluded Levy.

More information

Learn more about childhood cancers from the National Cancer Institute.

SOURCES: Jun Li, M.D., Ph.D., M.P.H., epidemic intelligence officer, U.S. Centers for Disease Control and Prevention, Atlanta; Adam Levy, M.D., pediatric hematologist/oncologist, and director, pediatric neuro-oncology, the Children's Hospital at Montefiore, New York City; June 2008 Pediatrics

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