For Children with Leukemia, Radiation May Be Unnecessary

Adapted from the NCI Cancer Bulletin ¹.

Children with the most common form of leukemia can safely forego radiation therapy to prevent a relapse of the disease if they are treated with chemotherapy regimens tailored to their individual needs. This is the conclusion of a clinical trial involving 498 patients with acute lymphoblastic leukemia (ALL). Nearly 94 percent of the patients were still alive 5 years after treatment, a result that compares favorably with other ALL treatment studies.

The strategies and treatments employed in this trial could be adopted by other medical centers, said researchers from St. Jude Children's Research Hospital in Memphis, who published their results in the June 25, 2009, issue of the New England Journal of Medicine (see the journal abstract ²).

Cranial irradiation has been used since the 1960s as a way to prevent a recurrence of cancer in the brain. First introduced by researchers at St. Jude, it was considered a breakthrough and improved survival rates in the disease to about 50 percent. Thanks to continued improvements in chemotherapy, today 90 percent of children with ALL are cured of their disease.

But with a growing population of survivors and clear evidence that radiation exposure can lead to second cancers and cognitive problems, many centers have limited its use to patients at risk of a relapse. In the trial, Ching-Hon Pui, M.D., and his colleagues tailored chemotherapy regimens for each patient and used the latest techniques for delivering the drugs and monitoring their effectiveness. After several weeks, adjustments could be made if a patient had evidence of residual cancer cells.

Based in part on comparisons with historical data on patients with ALL, the researchers conclude that individualized chemotherapy regimens are preferred over treatments that include cranial irradiation. They even recommend against irradiation for patients considered at risk of relapse. If this group had received radiation therapy in the current study, the researchers explained, 90 percent of the patients would have received radiation unnecessarily.

"The introduction of radiation therapy in the 1960s put the word 'cure' into discussions of ALL," said coauthor and director of St. Jude, William Evans, Pharm.D. "The importance of the current study is that we're now removing radiation from the therapy. And the reason we're able to do this is that we've gotten smarter and better at using chemotherapy."