Analysis Of Diffusion Weighted Imaging For Prognosis Of Brain Metastases Treated With Gamma Knife Radiosurgery AND Clinical Analysis Of Gamma Knife Radiosurgery For Treatment Of Cerebellar Metastases

Part 1Analysis of Diffusion Weighted Imaging for Prognosis of Brain Metastases Treated with Gamma Knife RadiosurgeryObjective:The aim of this study is to investigate the relationship between diffusion weighted imaging(DWI)parameters of brain metastases(BMs)and prognosis after gamma knife radiosurgery(GKRS),and moreover,to assess whether DWI parameters accurately predict patient outcomes.Methods:DWI data for 62 patients treated with GKRS for BMs were retrospectively reviewed.Apparent diffusion coefficient(ADC)and normalized ADC(nADC)were calculated from the largest BMs for every patient.Patients were divided into 2 groups according to ADC and nADC parameter.Overall survival(OS)and progression free survival(PFS)were analyzed with ADC and nADC parameter.Results:There is no significant difference between ADC groups or nADC groups.Patients in low-ADC group tend to have longer OS(median 18.3 vs 7.60 months,P=0.0095)and longer PFS(median 8.53 vs 3.93 months,P=0.0480).Two-year survival rate in low-ADC group is higher than high-ADC group(32.26%vs 3.23%,P=0.0057),so as low-nADC group(32.26%vs 3.23%,P=0.0057).Patients in low-nADC group have longer OS(median 18.30 vs 8.53 months,P=0.0043).Conclusions:ADC and nADC may have a prognostic value in BMs patients treated with GKRS.Low ADC/nADC predict longer OS.Part 2Clinical Analysis of Gamma Knife Radiosurgery for Treatment of Cerebellar MetastasesObjective:To report our experience in patients with the cerebellar metastases for single-session,or staged gamma knife radiosurgery(GKRS);and the evaluation of its efficacy.Methods:From January 2017 to October 2018,21 patients with cerebellar metastases>2cm in our hospital treated with single-session or staged SRS.The median age was 64 years(range 42-78 years),and the median Karnofsky performance status(KPS)was 70.Overall survival(OS),SRS related toxicity and KPS were analyzed.Results:The median follow-up time was 13.7 months.The median OS was 7.1 months(range 0.5-23.9).Staged GKRS was performed in 13 patients.The median dose at first and second staged GKRS were 14 Gy(range 8-18 Gy)and 12 Gy(range 6.7-15 Gy),respecctively.The median maximum dose was 30Gy(range 20-53.3 Gy).The median prescribed isodose was 50(range 45-60).7 in 21 patients achieved local partial response with no severe radiation related toxicity.Conclusion:GKRS is an effective for cerebellar metastases≥ 2cm with acceptable treatment-related morbidity.GKRS or staged GKRS may potentially merit being offered to patients with cerebellar metastases≥ 2cm who are in poor condition or are otherwise ineligible for standard care.