Radiation therapy is well established as one of the three primary approaches to treating cancer; however, it comes with a number of issues. Here, Anthony Zietman, MD, of the Massachusetts General Hospital, Boston, MA, discusses these issues, and describes the pros and cons of proton beam therapy in comparison to standard radiotherapy, particularly in a pediatric setting. This video was recorded at the 2017 National Cancer Research Institute (NCRI) Conference, held in Liverpool, UK.