RT-01 Treatment results of salvage gamma knife and bevacizumab (AVAgamma therapy) for recurrent glioblastoma

Abstract Purpose: We report the treatment results of AVAgamma therapy combining gamma knife (GK) and bevacizumab for recurrent glioblastoma. Subjects: From August 2013 to April 2020, 44 patients (88 lesions) with recurrent glioblastoma treated with AVAgamma therapy as salvage therapy at the time of relapse after initial treatment. The average age is 61.5 years, with 26 men and 18 women. The tumor volume is 150 ml or less, and KPS is 40% or more as the indication of AVAgamma therapy. When the irradiation volume of GK is 15 ml or less, a single irradiation with a boundary dose of 20 to 26 Gy was performed, and when the irradiation volume was 15 ml or more, a single irradiation boundary dose was divided into two divided irradiations of 12 to 15 Gy. The mean therapeutic borderline dose was 24 Gy. Bevacizumab was administered 10 mg / kg or 15 mg / kg 1 to 10 times after GK. Methods: Median progression-free survival (mPFS), 6-month progression-free survival (PFS-6m), 6-month survival (OS-6m), median survival (mOS) from treatment with AVAgamma Considered mOS from initial treatment. Results: The mPFS from AVAgamma therapy was 5 months, PFS-6m was 37%, OS-6m was 79%, and mOS was 9 months. The mOS from initial treatment were 25 months. In relapsing glioma RPA classification, NABTT CNC class 5 mOS is 5.6 months, class 6 mOS is 6.4 months, but mOS from AVAgamma therapy is 9 months in class 5, 9 months in class 6. The survival time has been extended. Discussion: By AVAgamma therapy, it was thought that recurrent lesions were locally controlled and life prognosis was prolonged. Conclusion: AVAgamma therapy is thought to prolong the survival of recurrent glioblastoma and play an important role as salvage treatment.