CHICAGO – Surprising research suggests that childhood cancer is most common in the Northeast, results that even caught experts off-guard. But some specialists say it could just reflect differences in reporting.

The large government study is the first to find notable regional differences in pediatric cancer. Experts say it also provides important information to bolster smaller studies, confirming that cancer is rare in children, but also more common in older kids, especially among white boys.

The study from the Centers for Disease Control and Prevention is based on data representing 90 percent of the U.S. population. It found that cancer affects about 166 out of every million children, a number that shows just how rare childhood cancers are.

The highest rate was in the Northeast with 179 cases per million children, while the lowest was among children in the South with 159 cases per million. Some experts suggested that could mean there is better access to care in the urban centers of the Northeast, leading to more diagnoses.