Children with leukema helped by dropping risky brain radiation

Children treated for leukemia survived more often when radiation therapy to the head was omitted, a study found.

Their five-year survival rate was 93.5 percent in the research published online in the New England Journal of Medicine, compared with an average 87.5 percent rate among similar U.S. children with radiation from 2000 to 2004, lead author Ching-Hon Pui said. Tailoring chemotherapy treatment enabled doctors to avoid radiation therapy to the head, a strategy that may prevent long-term side effects including second cancers and hormone imbalances, the researchers said.

Acute lymphoblastic leukemia is the most common cancer in children younger than 15 years old, according to the National Cancer Institute. About 100 children each year are diagnosed initially with this form of leukemia in the brain and spine, and hundreds of others with a high-risk form of the disease receive radiation to their brains preventatively, he said.

"We can eliminate a very toxic component of treatment and not only preserve the good outcome from prior trials, but improve upon it," said study author William Evans, chief executive officer of St. Jude Children's Research Hospital in Memphis, Tenn. "We have better outcomes and less toxicity and that is very encouraging."

Researchers studied 498 patients treated for acute lymphoblastic leukemia from 2000 to 2007 at St. Jude and at Cook Children's Medical Center in Fort Worth, Texas. Doctors then modified doses of chemotherapy drugs based on each individual child to avoid over-treating or under-treating. They also identified which patients needed more drugs or intensified treatments such as bone marrow transplants.

The results showed the overall five-year survival rate was 93.5 percent for the 498 children.

"This is the first study that pushes the cure rate to 90 percent - the best ever," said Pui, chair of the oncology department at St. Jude. Patients are considered cured of leukemia if they survive without relapse for 10 years or more, he said.

To determine if cranial radiation would have made a difference in relapse of the disease in the brain and spine, they compared the outcomes of 71 patients whose leukemia would've qualified them for radiation with those of 56 patients who received radiation in the past. The 71 patients fared "significantly better" with higher survival rates and better quality of life than the 56 patients, the researchers found.

Cranial radiation was introduced by St. Jude doctors in the mid-1960s. It boosted the cure rate for acute lymphoblastic leukemia to 50 percent from 4 percent, Pui said. Eventually radiation was limited to the highest-risk patients because of its side effects. About 20 percent of the 3,400 cases of childhood acute lymphoblastic leukemia diagnosed in the U.S. each year are treated with radiation, he said.

A study by St. Jude researchers in the July 1 issue of the Journal of the National Cancer Institute found that people who survived childhood brain cancer were more likely than healthy siblings to suffer from neurological difficulties including impaired attention or problems with organization and regulating their emotions, depending on their type of tumor. The research linked some of the neurocognitive problems to radiation treatment for their cancer.