Abstract

Over the past decades, radiotherapy (RT) has received massive improvements that enabled radiation oncologists to escalate the dose to gross tumor volume and, at the same time, spare nearby organs. Nevertheless, local failures still pose a problem and the presence of dose-limiting normal tissue complications precludes further treatment intensification. In this context, ultra-high dose radiotherapy, also known as FLASH-RT, is emerging as a promising technology due to its differential effect on tumor vs. normal tissues. Although first described in 1967, preclinical studies on animal models have only recently confirmed its safety and effectiveness compared to conventional RT. In this short review, we outline the main preclinical data, discuss the case of the first patient that was treated with FLASH-RT and contemplate on the hypotheses regarding its underlying mechanism.

Keywords

FLASH radiotherapy, ultra-high dose radiotherapy, equivalent antitumor effect, therapeutic index, FLASH effect, implementation, pulse level, dose monitoring, radiosensitivity, re-discovered, geometric properties, electronic radiotherapy, immune-related effects, inflammation markers, sparing effect