Neurosurgical resection of a brain metastasis in patients with a diagnosis of cancer may be indicated however the recurrence rate approximates 50% and adjuvant radiotherapy is standard. Single fraction postoperative stereotactic radiosurgery (SRS) has been widely adopted as a standard therapy as it achieves equivalent survival and prevents loss of neurocognitive function as compared with whole brain radiotherapy and improves cavity local control rates as compared with observation. Hypofractionated stereotactic radiotherapy in 3 to 5 fractions (hfSRT) is also used in the postoperative setting.~Nodular leptomeningeal disease (nLMD) is a recognised pattern of failure after postoperative SRS and hfSRT. A 16.9% incidence of nodular LMD was seen after surgery and a similar incidence of 11%-28%is reported following postoperative SRS in retrospective series. These data suggest that postoperative SRS/hfSRT have no significant effect on the development of LMD following surgery.~The incidence of LMD following single fraction preoperative SRS is only 6.1% according to the largest retrospective series. Preoperative SRS takes advantage of the easier delineation of an intact BM and sterilizes tumor cells disseminated at surgery. Side effects are minimized by a smaller planning margin, a dose reduction and resection of the irradiated volume. In addition, there is no delay to systemic therapy due to wound healing/complications. Furthermore, a single fraction offers patient convenience.~This trial will randomise and compare intracranial outcomes between single fraction preoperative SRS and 5 fraction postoperative hFSRT.
The research question is whether a single fraction of preoperative radiosurgery can reduce the incidence of leptomeningeal disease 12 months following resection of a brain metastasis (BM) as compared with 5 fractions of postoperative stereotactic radiotherapy.