Radiation Raises Risk of Repeat Tumors in Children

Radiation exposure may increase the risk of brain and spinal column tumors in survivors of childhood cancer, according to new research.

Survivors of childhood cancer are at an increased risk for developing second cancers, but the risk of these cancers differs based on the original cancer, age, a first cancer diagnosis, and primary cancer therapy received. Secondary tumors of the central nervous system (CNS) can have especially debilitating consequences and have been associated with earlier treatment for childhood leukemia and brain tumors, according to a study published in the November 1, 2006, issue of the Journal of the [U.S.] National Cancer Institute.

In the study, Joseph P. Neglia, M.D., a pediatric oncologist and researcher from the University of Minnesota Medical School and Cancer Center (Minneapolis, MN, USA) and colleagues identified secondary CNS tumors in a group of 14,361 5-year survivors of childhood cancer. They also gathered information regarding the patients' exposure to radiation and the chemotherapy used to treat the first cancer.

The investigators discovered that 116 survivors of childhood cancer developed subsequent CNS tumors. Childhood radiation exposure was linked with a higher risk of developing both malignant brain tumors like glioma and benign tumors like meningiomas. The risk of a second tumor increased as the dose of radiation used to treat the first cancer increased. Children under age five were particularly susceptible to the development of secondary gliomas. The scientists suggested that the increased tumor incidence in children exposed at an early age may indicate that the developing brain is very susceptible to radiation's toxic effects.

"Prolonged follow-up of all childhood cancer survivors, particularly those exposed to radiation, is crucial to the early detection of these tumors and should be considered part of the effective therapy of the primary disease,” the scientists wrote in their article.

In an accompanying editorial in the same issue, Elaine Ron, Ph.D., from the U.S. National Cancer Institute (NCI; Bethesda, MD, USA) stated, "By identifying persons at high risk of long-term treatment effects, it may be possible to reduce the growing number of patients who develop secondary malignancies by individualizing treatment.”



Related Links:
University of Minnesota Medical School and Cancer Center