Chemotherapy Superior to Radiation Therapy for Treating Childhood Acute Lymphoblastic Leukemia

Researchers at St Jude are asserting that radiation therapy can be eliminated as a treatment for childhood acute lymphoblastic leukemia (ALL), according to a press release at www.stjude.org.

Childhood ALL treated with a personalized chemotherapy regimen effectively reduced relapse without the cranial radiation currently used for high-risk patients, according to a study in the June 25, 2009, issue of the New England Journal of Medicine. About 20 percent of the estimated 3,400 cases of childhood ALL diagnosed in the United States each year are treated with radiation, said Ching-Hon Pui, M..D., chair of the St. Jude Department of Oncology and one of the study’s authors.

“Cranial radiation was an invaluable treatment when it was introduced by St. Jude oncologists in the mid-1960s,” said Dr. Pui in the St. Jude press release. “It controlled CNS leukemia and boosted the cure rate for ALL from only 4 percent to 50 percent. But radiation’s side effects led to the steady reduction of dosages and limited use to the highest-risk patients.”

Those side effects include second cancers, stunted growth, hormone imbalances and cognitive deficits. The study involved 71 out of 498 patients treated for ALL at St. Jude and Cook Children’s Medical Center in Forth Worth, Texas, between 2000 and 2007. The remission rates of 71 patients who would have qualified for radiation therapy were compared to those of 56 patients who had received cranial radiation for ALL in the past.

The researchers determined the relapse risk by measuring residual leukemia cells present after remission induction treatment, the press release stated. A personalized therapy regimen based on the molecular genetics of ALL achieved a projected cure rate of 90 percent, the best reported for the disease so far.

“In a way, these findings represent coming full circle,” said William Evans, M.D., St Jude director and CEO and a coauthor of the paper. “St. Jude was the first to introduce cranial radiation as a treatment strategy that advanced the cure of childhood ALL to 50 percent. Now St. Jude is the first to show that we can successfully eliminate irradiation by optimizing chemotherapy.”