RT-3 TREATMENT RESULTS OF AVAGAMMA THERAPY FOR RECURRENT GLIOBLASTOMA COMBINED WITH GAMMA KNIFE AND BEVACIZUMAB

PURPOSE: We report the treatment results of AVAgamma therapy combining gamma knife (GK) and bevacizumab (Bev) for recurrent glioblastoma. SUBJECTS: From August 2013 to July 2022, 56 patients with recurrent glioblastoma treated with AVAgamma therapy as salvage therapy at the time of relapse after initial treatment. When the irradiation volume of GK was 15 ml or less, a single irradiation with a marginal dose of 20 to 26 Gy was performed. More than that received a single marginal dose of 12-15 Gy in two fractions or 8 Gy in three fractions. The mean therapeutic marginal dose was 23.9 Gy. Bev was administered 10 mg / kg or 15 mg / kg 1 to 10 times after GK. METHODS: Median progression-free survival (mPFS) and median survival (mOS) from AVAgamma treatment, and mOS and 5-year survival rate from initial treatment were compared with historical controls (GK group: 30 patients) who received only GK at the time of recurrence. RESULTS: The mPFS from AVAgamma therapy was 6 months, PFS-6m was 39%, OS-6m was 76%, and mOS was 10 months. The mOS from initial treatment was 25 months, which was prolonged compared to 21 months in the GK group (p=0.05). The 5-year survival rate for recurrent glioblastoma was 5% in the GK group and 22% in the AVAgamma group (p=0.04). The 5-year survival rate for glioblastoma with KPS is 70% or more at recurrence was 0% in the GK group and 33% in the AVAgamma group (p=0.017). DISCUSSION: Combined use of Bev with GK was considered to provide local control of recurrent lesions and prolong life prognosis in patients with good KPS at the time of recurrence. CONCLUSION: AVAgamma therapy is thought to prolong the survival of recurrent glioblastoma and play an important role as salvage treatment.