The hallmarks of cancer and the radiation oncologist: updating the 5Rs of radiobiology.

A comprehensive, mechanistic understanding of radiobiological phenomena that can be integrated within the broader context of cancer biology offers the prospect of transforming clinical practice in radiation oncology. In this review, we revisit the six established biological hallmarks of cancer and examine how they have provided insights into novel therapeutic strategies. In addition, we discuss the potential of two emerging hallmarks to continue to expand our understanding beyond the narrow confines of the traditional 5Rs of radiobiology.