Recent results published in the Practical Radiation Oncology (PRO) journal, the official journal of the American Society for Radiation Oncology (ASTRO), titled “Practice patterns of photon and proton pediatric image guided radiation treatment: Results from an International Pediatric Research Consortium”, evaluated the use of image guided radiation therapy (IGRT) for the treatment planning of pediatric cancers.
IGRT uses frequent imaging during the course of radiation therapy, usually before radiation delivery, to improve the localization of both target and healthy structures, allowing a more precise and accurate radiation delivery.
This technique is commonly used in photon and proton therapy, especially in the treatment of tumors that are located in proximity to sensitive structures or organs, or in specific areas of the body that can change in shape.
Even though IGRT is a common practice to improve treatment accuracy of pediatric tumors, these recent results suggest that consensus recommendations are necessary to guide clinical decisions for its use in pediatric patients.
The team evaluated clinical patterns of pediatric IGRT practice through an international pediatrics consortium of institutions that used either photon or proton radiation therapy.
Of the nine international institutions selected to participate in the consortium, seven completed a 53-item survey evaluating patterns of IGRT use in definitive radiation therapy for patients younger than 21 years of age.
Among the seven institutions, a total of 750 pediatric patients were treated per year, with 5 institutions using photon therapy alone, 1 using proton therapy alone and 1 using both photon and proton therapy.
Researchers found that IGRT was used in tumors of the central nervous system (98%), abdomen or pelvis (73%), head and neck (100%), lung (83%), and liver (69%). Moreover, photon therapy institutions used kV cone beam computed tomography and kV- and MV-based planar imaging for IGRT, and all proton institutions used kV-based planar imaging.
More than half of photon institutions used a specialized pediatric protocol for IGRT that delivers a lower dose of radiation than the standard amount used in adult protocols. Also, the techniques used for patient immobilization varied according to treatment site and institution and IGRT was utilized daily and weekly in 45 and 35% of cases, respectively.
“This study draws attention to the common consensus that the use of low-dose CT scans for image guidance for children is important for quality treatment and to ensure treatment accuracy,” Stephanie A. Terezakis, MD, co-author of the study and assistant professor of radiation oncology and molecular radiation sciences at Johns Hopkins Sidney Kimmel Comprehensive Cancer Center in Baltimore, said in an ASTRO press release. “There was variation in the way the physicians at the consortium institutions were determining the treatment field, particularly in different sites of the body. This data provides us with valuable treatment patterns that can help us determine a standard or best practice that all institutions can apply for the same technique, which will improve the quality of care for children.”