Proton radiation therapy for pediatric malignancies: status report.

Proton radiation therapy allows high degrees of conformity of radiation dose around irregular target volumes of variable sizes. Long-term follow-up in adults, and preliminary data for pediatric patients suggest that local control and survival can be improved in histologies requiring high radiation dose, without increased incidence of late toxicities. In the pediatric patient, avoidance of even moderate amounts of irradiation to normal tissues is of paramount importance. Conformal 3-D planned proton irradiation can contribute to this goal. For late effects, one can expect that reduced dose and volume irradiated will reduce radiation effects. However, full expression of late effects may occur in children five to ten years after treatment, or even later. Proton irradiation is therefore also indicated and used at Loma Linda University Medical Center for pediatric solid neoplasms in which conventional dose levels yield satisfactory local control and survival.