[Radiotherapy for sarcoma: hadrontherapy, for whom and what for?].

The radiobiological properties of the hadrons (neutrons, protons, carbon ions) led to their therapeutic use in sarcomas, as a referent therapy or as an alternative to photon therapy. An extensive review of the literature has been conducted to assess the present indications and the perspectives for hadrontherapy. Compared to photons, neutrons are characterized by a higher biological efficiency that is on particular importance for these tumours usually considered as radio-resistant. Neutrons have been considered as a standard therapy for sarcoma' patients, contra-indicated for surgery or with a definitive R2 resection, but their indications and use have been restricted due to the occurrence of late severe toxicities related to their poor ballistic' properties. Thanks to their physical properties (Bragg Peak), protons are characterized by a higher conformity index compared to photons (and neutrons) with optimal organs at risk preservation that permits a dose escalation. Protontherapy is to date the standard of care for base of skull, spinal and paraspinal sarcomas. Carbon ions combined both advantages from protons and neutrons. Literature data permits to consider this radiation modality as a referent therapy for unresectable sarcomas. The ongoing diffusions of protons and carbon ions radiotherapy facilities will permit to offer these therapies to more patients and to conduct studies that are warranted to determine their indications and their results.