LAUSR

Radiotherapy (RT) is a mainstay in the treatment of pediatric brain and spinal cord tumors. Indications for RT include the histological type, the extent of the tumor at diagnosis and/or post-operatively, the availability and utilization of chemotherapy regimens, and the age of the child. The sequelae of RT on the developing CNS have been welldescribed, and it is typically avoided in children under the age of 3. RT is most commonly delivered by fractionated external beam radiotherapy, which includes the modalities of 2D radiotherapy (2DRT), 3D conformal radiotherapy (3DCRT), intensity modulated radiotherapy (IMRT) and proton therapy. Each of these techniques can be considered an improvement on the prior in terms of how precisely the radiotherapy is delivered to the target volume. More conformal radiotherapy techniques result in lower doses to the sensitive surrounding normal tissues, and lower late effects of RT. In the Childhood Cancer Survivor Study, over 80% of 5-year survivors had at least one chronic morbidity, and had higher rates of endocrine disorders, hearing deficits and neurological issues compared with siblings [1]. Moreover, cranial RT was associated with higher risks of cognitive impairment and secondary malignancy. Children who received cranial RT doses over 50Gy had a 7% risk of in-field second malignancy. Cognitive impairment was proportion to the doses used for specific tumor types, and dose of RT to the frontal and temporal lobes was associated with lower rates of employment and marriage. Proton therapy can reduce the dose to normal tissues because these heavy particles have unique physical properties resulting in a very different dose profile in tissue. Protons can penetrate the body to a specific depth, based on their initial energy, and then deposit dose in a sharp, discrete peak with no additional dose in the exit path. These unique beams can dramatically change how radiation dose falls off into normal tissues. There are already a few reports that have demonstrated the superiority of protons relative to photons in vulnerable pediatric populations [2–5]. In general, the radiation oncology community, as well as stakeholders among payors and policy makers, agree that pediatric solid tumors, and specifically pediatric CNS tumors, are ideal indications for the use of protons [4,5]. While proton therapy centers are still uncommon, the accessibility of proton therapy has been expanding geographically. In this report, we used the National Cancer Database (NCDB) to study the patterns of utilization of different radiotherapy techniques for the treatment of pediatric CNS malignancies. Our hypothesis was that utilization of proton therapy has increased significantly over the past 10 years. As secondary endpoints, we examined the relationship between clinical and sociodemographic parameters, with use of advanced RT modality, and overall survival. We also examined the trends of IMRT utilization from 1998 to 2011.