The potential advantages and drawbacks of pencil beam scanning proton therapy in the management of paediatric, teenage and young adult malignancies

Pencil beam scanning (PBS) proton therapy is a new radiation modality which is increasingly used for childhood teenage and young adult malignancies due to its ability to minimise dose to surrounding organs, which in turn translates to reduced late toxicity. However, its dosimetry is extremely sensitive to anatomical changes, density changes and motion. Research on its benefits, drawbacks, clinical efficacy and side effects is therefore required for clinical teams to understand the best way and situation to use this modality in the clinic. Neuroblastoma is a childhood cancer most commonly arising within the abdomen. Radiotherapy to the primary tumour bed is part of the multimodality management for high risk patients. This collection of work investigates the benefits and detriments of PBS in abdominal neuroblastoma alongside the associated dosimetric impact from uncertainties such as set up variation, gastrointestinal tract density variability and intra-field motion. Methods of managing the uncertainties are also examined. Teenage and young adults are a unique and challenging group of patients with complex psychosocial needs. The efficacy and late effects of PBS in this age group with brain and skull base tumours is detailed with analysis of their employment status during survivorship