Extreme hypofractıonated radiosurgery in recurrent inoperable High-Grade Ultra-Large gliomas

To elucidate the efficacy and toxicity of brain re-radiotherapy for recurrent large inoperable gliomas using radiosurgery.

Between 2014 and 2018, extreme hypofractionated radiosurgery was performed using Accuray’s Cyberknife® system on 14 lesions (12 patients)  grade 4 recurrence lesions of 6 patients with anaplastic astrocytoma and 6 patients with glioblastoma who had previously undergone surgery and cranial radiotherapy and had a local-regional recurrence. Six patients (8 lesions) were given a biologic effective dose (BED10) of 48 Gy and lower, and six patients were given a BED10 of 59.5 Gy and higher. The Response Assessment in Neuro-Oncology Criteria (RANO) were used for tumor response, and the Common Terminology for Adverse Events (CTCAE) was used for adverse effect assessment. The primary endpoint was determined as overall survival, and first treatment and salvage treatment time.

The median age of the patients was 43 years, and the median Karnofsky Performance Status (KPS) was 70. The median time from the first radiotherapy to death was 34 months. The median time from the previous radiotherapy was 29.5 months (R:17-40). The median survival was 10 months for those with recurrence before 29.5 months and 11 months for those with recurrence after 29.5 months. The median total tumor volume was 29.224 mL (~30 mL). One grade 4 toxicity was observed.

Radiosurgery can be used effectively as salvage therapy in ultra-large inoperable gliomas.