Low-dose Gamma Knife radiosurgery plus whole-brain radiation therapy for patients with 5 or more brain metastases with or without meningeal dissemination

Abstract

Purpose/objective(s): Radiosurgery plus whole-brain radiotherapy (WBRT) has been reported to be useful for patients with ≤ 4 brain metastases (BM), but we hypothesized that similar treatment may be applicable to patients with ≥ 5 BM with or without meningeal dissemination. The purpose of this study was to evaluate the efficacy and toxicity of low-dose Gamma Knife (GK) followed by WBRT for patients with advanced BM. Materials/methods: Major eligibility criteria for this phase II study were: (1) ≥ 5 BM with or without meningeal dissemination and (2) the largest tumor diameter ≤ 4 cm. During 2013–2016, 40 patients (13 men and 27 women) entered the study. Nineteen had meningeal dissemination. The GK dose was 12 Gy at the periphery when the longest diameter was 3–4 cm and 14 Gy when it was < 3 cm. The WBRT dose to the isocenter was 30 Gy in 10 fractions, or 37.5 Gy in 15 fractions for two patients, with an expected survival of > 12 months. The median number of target BM was 17.5. Results: After GK plus WBRT for 40 patients, 31 did not develop further intracranial recurrence until death or last follow-up, whereas 9 developed recurrence. With a follow-up period up to 24 months, the overall survival rate was 36% at 12 months and median survival time was 8 months. The cumulative incidence of intracranial recurrence was 25% at 12 months. Toxicity was considered acceptable. Conclusion: Treatment with low-dose GK followed by WBRT for advanced-stage BM appeared to contribute to local control.