[Reirradiation of head and neck cancers].

Locoregional relapse in previously irradiated region for head and neck tumours is associated with a bad locoregional and distant prognosis. Reirradiation might be exclusive, or feasible in addition with surgery and/or chemotherapy, according to histopronostic factors. Data show that reirradiation is feasible with some severe toxicity due to the bad prognosis of this situation. Hyperfractionnated regimen with split course or normofractionnated regimen without split course are possible with similar efficacy. If tumour size is small, stereotactic ablative radiotherapy may be considered, and if the treatment centre has proton therapy, it could be proposed because of better organs at risk sparing. There is no standard regarding reirradiation schedules and several trials have to be done in order to determine the best technique. Nevertheless, it is agreed that a total dose of 60Gy (2Gy per fraction) is needed. Other trials testing the association with new systemic agents have to be performed, among them agents targeting the PD1/PD-L1 axis.