June 25 (HealthDay News) -- Radiation to the brain isn't necessary for most children with newly diagnosed acute lymphoblastic leukemia, new research has found.

In fact, doctors from St. Jude Children's Research Hospital found that children who had chemotherapy alone had a longer remission period and experienced fewer adverse events than those who, in the past, had also been given radiation treatments.

"Effective chemotherapy can cure up to 90 percent of all children with acute lymphoblastic leukemia without the use of cranial irradiation," said study author Dr. Ching-Hon Pui, chairman of oncology at the hospital, in Memphis, Tenn.

"Survivors of childhood acute lymphoblastic leukemia can now enjoy excellent quality of life, virtually similar to that of the general population," Pui said.

The study is reported in the June 25 issue of the New England Journal of Medicine.

Leukemia, a cancer that begins in the bone marrow and affects blood cells, is the most common type of cancer affecting children and teens, according to the American Cancer Society. Acute lymphoblastic leukemia (ALL) is the most common type of childhood leukemia, affecting about three out of every four children with the disease.

Historically, treatment included chemotherapy plus preventive radiation of the brain, according to Pui. And, though the addition of radiation was believed to improve survival, the treatment had serious side effects, including an increased risk for another cancer, cognitive deficits and growth retardation.

Chemotherapy regimens have improved over time, but fear remained that not giving children radiation would mean that residual cancer cells might be missed, allowing the leukemia to return.

The study included the evaluation of 71 children who, in the past, would have received preventive cranial radiation but now were being treated with systemic chemotherapy or chemotherapy administered intrathecally (through a lumbar puncture). They were compared with 56 youngsters who had been treated with prophylactic cranial radiation for ALL.

The five-year remission rate for the chemotherapy-only group was 90.8 percent, vs. 73 percent for the group also given radiation treatment. Eleven children in the chemotherapy group had central nervous system relapses, but all were able to achieve a second remission.

"With effective chemotherapy, prophylactic cranial irradiation can be safely omitted in all children with acute lymphoblastic leukemia," Pui said.

Dr. A. Kim Ritchey, chief of the division of pediatric hematology/oncology at Children's Hospital of Pittsburgh, said that the study "may not be the final answer, but my personal bias has always been to decrease radiation as much as possible."

"The treatment of leukemia has become more and more individualized, and high-risk patients can get more therapy, sometimes even based on their genotype, and this study makes the point that you can attempt to treat high-risk patients without cranial radiation," he said. "This is the type of data we love to see in pediatric oncology because we're very concerned about the effects of treatment after the cure."

SOURCES: Ching-Hon Pui, M.D., chairman, department of oncology, St. Jude Children's Research Hospital, Memphis, Tenn.; A. Kim Ritchey, M.D., chief, division of pediatric hematology/oncology, Children's Hospital of Pittsburgh; June 25, 2009, New England Journal of Medicine