The Evolving Role of Proton Beam Therapy for Sarcomas.

As an alternative to conventional photon-based radiotherapy, radiation with protons is recognised to offer considerable advantages. Today, central nervous system tumours, various sarcomatous tumours, childhood cancer and head and neck tumours are commonly treated with proton therapy. This review evaluates current data from clinical and dosimetric trials on the treatment of selected sarcomatous tumours like rhabdomyosarcoma, osteosarcoma, chordoma, chondrosarcoma and Ewing sarcoma. Special considerations for paediatric tumours and future prospects of proton therapy are outlined. Proton therapy is already an internal part in the multidisciplinary management of childhood sarcomas in contiguity to sensitive structures, especially at the base of skull, spine and pelvis. It offers special advantages for tumours requiring high-precision radiotherapy, particularly when total resection seems not feasible. Previous and ongoing research is generating evidence for the benefit of protons in sarcoma patients. Up to now, proton therapy has been safely applied with encouraging results. For future research, prospective, multi-institutional, large registries are required to answer open questions. Modern radiotherapy techniques, such as pencil beam scanning and intensity modulation are increasingly established in proton therapy. More research is needed to understand protons' limitations and potential.