Stereotactic radiosurgery (SRS) is an established treatment modality in the management of intracranial metastases (1, 2). However, it can be challenging to achieve the goal of SRS, which is to deliver maximal effective dose to the tumour whilst maintaining a low risk of acute and late toxicity (2). Fractionation is a strategy proposed to balance tumour control and adverse effects (3). While data is emerging (4-12), evidence on the incidence of radiation necrosis (RN) and risk factors that could potentially be used to predict the...

Background RN is a potentially serious late complication of SRS. It is being increasingly recognized, which may be a consequence of patients with brain metastases living longer due to improvement in the efficacy of systemic therapies. Patients generally present with new onset neurological deficits or asymptomatic lesions identified on routine follow-up scans. While histologically benign, RN could lead to significant limitation to quality of life or even become life-threatening depending on its site and extent. The overall published data suggest an incidence of RN of...

A total of 200 individual lesions were treated during the study period. 77 patients [38 females, 39 males, median age: 60 years (range 28 – 84 years)] with 93 lesions met the inclusion criteria (Figure 1). 47 patients (51%) were symptomatic from the brain metastases and 7 (8%) presented with seizures (Figure 2). Patients were followed up for a median of 12 months (Range: [6 - 30 months]) (Figure 4). The mean PTV of lesions treated with fractionated SRS was 7.3 cm3 and the me(Range:...

The cumulative incidence of RN was 13.64% in our cohort, which is comparable to the published data for single-fraction SRS (4-12).The lack of higher incidence of RN is somewhat reassuring in this high-risk population. A common practice used based on previous guidelines is dose reduction for lesions greater than 2-3 cm when treated with single fraction SRS to avoid RN (6). With fractionation, large and complex lesions may be treated with equivalent effective biological dose, while maintaining RN rates similar to single-fraction treatments for smaller...

Minniti G, Clarke E, Lanzetta G, Osti MF, Trasimeni G, Bozzao A, et al. Stereotactic radiosurgery for brain metastases: analysis of outcome and risk of brain radionecrosis. Radiation Oncology. 2011;6(1):48 Kirkpatrick JP, Soltys SG, Lo SS, Beal K, Shrieve DC, Brown PD. The radiosurgery fractionation quandary: single fraction or hypofractionation? Neuro-Oncology. 2017;19(suppl_2): ii38-ii49. Putz F, Weissmann T, Oft D, Schmidt MA, Roesch J, Siavooshhaghighi H, et al. FSRT vs. SRS in Brain Metastases—Differences in Local Control and Radiation Necrosis—A Volumetric Study. Frontiers in Oncology. 2020;10(1791)....