Radiotherapy to the brain: what are the consequences of this age-old treatment?

Radiotherapy (RT) has been widely used in the management of benign and malignant brain tumors for decades. However, complications can develop as a result of adjacent structures being exposed to radiation. As such, careful selection of patients and deciding on the most suitable modality of RT are crucial to minimize complications. In general, complications can be subdivided based on its timeline of onset; acute (few days to weeks), early delayed (1-6 months) and late (>6 months). Late complications such as cognitive decline and radiation necrosis can be debilitating and negatively impacts quality-of-life. New strategies to reduce RT-related complications such as with hippocampal sparing-WBRT, memantine, and focal RT (e.g., stereotactic radiosurgery) have had promising results and are being adopted in clinical practice. This review will focus on RT-related complications in the brain, with a focus on WBRT or SRS-related late adverse events, as well as measures to mitigate these complications.