Researchers from the St. Jude Children’s Research Hospital have reported that children with acute lymphoblastic leukemia (ALL) who are treated with effective, risk-adjusted chemotherapy regimens have good outcomes and may safely be able to avoid preventive radiation therapy to the brain. These results were published in the New England Journal of Medicine.

Over the past 40 years, the cure rates for childhood ALL have steadily increased. This means that a relatively large number of children with ALL will survive into adulthood and be taken care of by physicians who were not involved in their initial treatment. It is therefore important to define the long-term consequences of the intensive treatment to which these patients are subjected. For many years the primary method of preventing CNS recurrences was cranial or cranial and spinal radiation. Over the past decade, it has been recognized that CNS radiation leads to long-term complications; current CNS prophylactic regimens for childhood ALL do not include irradiation and instead rely on systemic and intrathecal chemotherapy.

To confirm that preventive radiation therapy to the brain can be safely omitted, researchers conducted a study among 498 patients, 71 of whom would have been candidates for radiation therapy to the brain by conventional standards. Patients were treated with intrathecal and systemic chemotherapy, with treatment intensity based on the risk features of each patient. Patients did not receive preventive radiation therapy to the brain.

• Five-year progression-free survival was 86%.
• Overall five-year survival was 94%.
• The five-year risk of an isolated relapse in the central nervous system was 2.7%.
• Compared with a past group of patients who received radiation therapy to the brain, the 71 patients in this study who traditionally would have been candidates for radiation therapy had better cancer-free survival.

Comments: These results suggest that with appropriate, risk-adjusted chemotherapy, it may be possible to safely omit preventive radiation therapy to the brain in children with ALL. This would spare children from the long-term side effects of radiation to the brain.

Reference: Pui C-H, Campana D, Pei D et al. Treating childhood acute lymphoblastic leukemia without cranial irradiation. New England Journal of Medicine. 2009;360:2730-41.