Systematic review of fractionated brain metastases radiotherapy

Management of brain metastases includes approaches such as fractionated whole brain radiotherapy (WBRT) and single-fraction stereotactic radiosurgery (SRS). Focal, fractionated radiotherapy given alone or in conjunction with WBRT is a potential alternative to radiosurgery that has been explored in the medical literature. Such fractionation carries theoretical radiobiologic advantages by exploiting cell reassortment and reoxygenation. Integration of image-guided radiation therapy and intensity-modulated radiation therapy can provide an accurate, precise, and conformal treatment platform to provide radiosurgery-like dose escalation without the use of invasive stereotactic fixation devices. The use of the simultaneous in-field radiotherapy technique integrating WBRT with contemporaneous treatment of the boost volume can yield important planning and treatment efficiencies. At the same time, the relative efficacy of fractionated lesional boosts compared with other forms of lesional treatment intensification is unclear. The aim of this systematic review is to determine the clinical benefits and toxicity related to fractionated focal brain radiotherapy for lesional dose escalation in accordance with PRISMA guidelines. Review of the literature for lesional dose escalation, with or without sequential/integrated WBRT, suggests the potential for important clinical benefits including overall survival, local control and acceptable toxicity. In general, such approaches provide clinical benefits competitive with traditional radiosurgery approaches, provided that adequate biological equivalent doses are used. However, given the heterogeneity associated with these reports as well as the retrospective nature of most of the published literature, no firm conclusions regarding the clinical indications of such therapy over traditional SRS or WBRT techniques can be made at this time.