Hypofractionated Radiotherapy with Helical Tomotherapy Improved the Efficacy of Multiple Brain MetastasesLong-term Follow-up Results of a Phase II Trial

Abstract

Abstract Purpose: Multiple brain metastases (BMs) remain a therapeutic challenge. Helical tomotherapy (HT) is a novel equipment which has shown favorable dosimetric properties in previous studies. The aim of this single institutional phase II trial was to investigate the feasibility and toxicity of hypofractionated radiotherapy (HFRT) with or without simultaneous whole brain radiotherapy (WBRT) by HT in treating patients with multiple BMs. Methods:Patients with at least 3 BMs were enrolled. All the patients were treated with HT. The prescribed dose was 40 Gy in 20 fractions for WBRT and 60 Gy in 20 fractions for BMs simultaneously. For patients who had prior WBRT or refusing WBRT, focal HFRT for the lesions with optimized doses based on tumor volumes and locations were given. The primary endpoint was 1y-intracranial progression free survival (IPFS). Results: Between September 2014 and June 2017, 69 patients were enrolled and finally been analyzed. The median follow-up time was 40.1 months. The 1-year IPFS rate was 80.5%. The median survival time was 18.1 months (95% CI, 15.5- 20.7). The 1-year local control, overall survival and brain metastasis-specific survival rates were 96.4%, 71.0% and 94.6%, respectively. The 2-year rates were 87.6%, 51.1% and 39.1%, respectively. Only 1 patient (1.4%) had Grade 3 hematological toxicity and the radiation necrosis rate was 2.9%. Conclusion: Helical tomotherapy was well tolerated and could significantly extend IPFS compared with historical controls in multiple BMs.