Particle radiation therapy in the management of malignant glioma: Early experience at the Shanghai Proton and Heavy Ion Center

Background The objective of this study was to evaluate the outcomes of patients with high-grade glioma who received treatment with particle radiotherapy. Methods Between June 2015 and October 2018, 50 consecutive and nonselected patients with glioblastoma multiforme (n = 34) or anaplastic glioma (n = 16) were treated at the Shanghai Proton and Heavy Ion Center. Twenty-four patients received proton radiotherapy (at a dose of 60 gray-equivalents in 30 daily fractions), and 26 patients received proton radiotherapy plus a carbon-ion radiotherapy (CIRT) boost in various dose-escalating schemes. All patients received temozolomide because of their age or their O-6-methylguanine-DNA methyltransferase (MGMT) promoter methylation status. Progression-free survival (PFS) and overall survival (OS) rates, as well as treatment-induced toxicities, were analyzed. Results At a median follow-up of 14.3 months (range, 4.8-39.6 months), the 12-month and 18-month OS rates were 87.8% (95% CI, 77.6%-98.0%) and 72.8% (95% CI, 56.7%-88.9%), respectively, and the 12-month and 18-month PFS rates were 74.2% (95% CI, 60.9%-87.5%) and 59.8% (95% CI, 43.1%-76.5%), respectively. Univariate analyses revealed that age (>50 vs <= 50 years), World Health Organization grade (3 vs 4), and Karnofsky performance status (>80 vs <= 80) were significant prognosticators for OS, and IDH mutation and World Health Organization grade were significant for predicting PFS. Furthermore, MGMT promoter methylation, performance status, and age showed a trend toward predicting PFS. No significant predictive factors for PFS or OS were identified in multivariate analyses. Twenty-nine patients experienced grade 1 treatment-related acute adverse effects, and 11 developed grade 1 (n = 6) or grade 2 (n = 5) late adverse effect of radiation-induced brain necrosis. No grade 3, 4, or 5 toxicities were observed. Conclusions Particle radiotherapy produced 18-month OS and PFS rates of 72.8% and 59.8%, respectively, with acceptable adverse effects in patients with high-grade glioma. Particle radiotherapy at a dose >= 60 gray-equivalents appears to be safe and potentially effective.