Brain cancer is the deadliest childhood cancer in the United States, now ahead of leukemia, a result of improved leukemia treatment and a frustrating lack of progress on brain cancer, The Associated Press reports.

Government statisticians reported the change in rankings Sept. 16, 2016, drawing from a review of 15 years of death certificates.

“I think most people, when they think of childhood cancer, think of leukemia,” said Sally Curtin of the Centers for Disease Control and Prevention. “This is kind of a changing of the guard.”

Cancer is the fourth leading cause of death for children overall, accounting for about 1 in 10 childhood deaths in 2014. About a quarter these cancer deaths, or 534, were due to brain cancer. There were 445 leukemia deaths.

There are still more new cases of leukemia each year than new cases of brain cancer, but it no longer accounts for the most deaths. That's due to advances in leukemia treatment over the past few decades and because leukemia is easier than brain cancer to treat, experts said.

In 2014, the brain cancer death rate was about 0.7 per 100,000 children ages 1 through 19. The leukemia death rate was about 0.6. The overall pediatric cancer death rate dropped by about a fifth between 1999 and 2014, the CDC reported, helped by the reduction in leukemia deaths.