Stereotactic radiotherapy for brain metastases: indications, dose fractionation, technological innovations, and evolving combination strategies - a comprehensive review.

The incidence of brain metastases in cancer patients is increasing due to improved survival from systemic therapies and advancements in diagnostic imaging. Radiotherapy remains a cornerstone in the management of brain metastases. Among the various techniques, stereotactic radiotherapy (SRT) is widely adopted in multidisciplinary treatment owing to its high precision, rapid dose fall-off, high rates of local control, and superior preservation of neurocognitive function. In recent years, significant progress has been made in several areas of SRT, including technological advancements in equipment and radiation quality, its combination with surgery (either pre- or post-operatively), integration with systemic therapy (such as targeted and immunotherapy), and the exploration of new indications (e.g., more than 4 brain metastases, small cell lung cancer). Furthermore, optimization of dose fractionation regimens-including fractionated SRT, low-dose radiotherapy, exploration of maximum tolerated doses, and individualized ultrafractionated adaptive radiotherapy-has been actively investigated. This review synthesizes the evidence from classical literature and recent clinical studies to outline the current landscape and future directions of SRT for brain metastases.