Radiosurgery and Hypofractionated Stereotactic Irradiation with Photons or Protons for Tumours of the Skull Base

Recent technological advances in photon-RT have allowed an improvement in targeting accuracy, dose escalation, delivery of multiple large fractions (hypofractionated stereotactic radiation therapy HSRT) or single fraction stereotactic ablative radiation therapy (radiosur‐ gery SRS). Radiosurgery delivers a single large dose with very steep dose fall-off outside the lesion to very small volumes in order to be tumouricidal through DNA damage or ablative causing necrosis via a vascular endothelial damage [1]. Furthermore, it has been shown that molecular responses to radiation differ based on dose per fraction. More recently, HSRT in two to five sessions has been employed to deliver extremely hypofractionated regimens. Prelimi‐ nary data suggest that HSRT may represent an effective treatment associated with lower risk of radiation-related adverse effects in patients with perioptic or large benign tumours as compared with single fraction SRS, although potential benefits remain to be demonstrated.