Clinical Practice Patterns of Pediatric Image Guided Radiation Treatment: Results From an International Pediatric Research Consortium

Abstract

Image-guided radiation treatment (IGRT) has become standard practice for multiple tumor types in the adult population. IGRT has not been well-studied in the pediatric population and concern for additional radiation dose as a result of on-treatment imaging has made its use controversial in children. We evaluated clinical patterns of pediatric IGRT practice through an international Elekta pediatrics consortium. A formal survey of 53 questions was distributed to five international institutions with dedicated pediatric expertise evaluating institutional patterns of image-guided clinical practice for children. A total of approximately 500 pediatric patients were treated yearly across all institutions. Two institutions use proton therapy for children and all others use IG-IMRT. IGRT was used in the definitive setting in 98% of children with CNS tumors, 100% with head and neck tumors, 100% with lung tumors, and 67% with abdominopelvic tumors. All institutions used IGRT for treatment of medulloblastoma, ependymoma, and sarcomas and three institutions utilized IGRT for neuroblastoma. One proton therapy institution used KV imaging exclusively. All other institutions used cone-beam CT scan (CBCT) for IGRT. One institution used both CBCT and MV imaging. All institutions aligned to bone for CNS and head and neck tumors. A combination of bone and soft tissue matching were used at institutions using CBCT for abdominopelvic and lung tumors. Three institutions utilize daily IGRT while two institutions used weekly IGRT. All but one institution used a specific lower dose pediatric protocol for on-treatment imaging. PTV margin ranged from 3 mm-1 cm depending on treatment site and institution with no consensus. Use of IGRT in the pediatrics population was prevalent at all consortia institutions. There was close agreement on the indications and methods for pediatric IGRT and no consensus on the optimum PTV margin to use for organ site and by IGRT protocol. IGRT carries potential benefits of improved accuracy and a decreased margin for set up error; however, additional radiation dose must be considered. Prospective studies to evaluate and standardize IGRT methods in children are warranted and will be the subject of further activity from this group.