RT-1 Treatment results of salvage gamma knife stereotactic radiosurgery and bevacizumab (AVAgamma therapy) for recurrent malignant glioma

Abstract Purpose: We report the treatment results of AVAgamma therapy combining gamma knife (GK) and bevacizumab for recurrent malignant glioma. Subjects: From August 2013 to January 2021, 71 patients (Grade 2:8 patients, Grade3:16 patients, Grade 4:47 patients) with recurrent malignant glioma treated with AVAgamma therapy as salvage therapy at the time of relapse after initial treatment. The average age is 55.7 years, with 44 men and 27 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 the gamma knife was 15 ml or less, the marginal dose was 20 to 26 Gy, and when the irradiation volume was 15 ml or more, the marginal dose was 12 to 15 Gy in two divided doses.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) from AVAgamma treatment, median survival (mOS), and mOS from initial treatment were examined and compared with mOS in the RPA classification of recurrent glioma. Results: In relapsing glioma RPA classification, NABTT CNC class 2 mOS is 17.2 months, class 3 mOS is 3.8 months, class 5 mOS is 5.6 months, class 6 mOS is 6.4 months, but mOS from AVAgamma therapy is 18 months in class 3, 11 months in class 5, 9 months in class 6. The survival time has been extended in class3, class5, class6. 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 malignant glioma and play an important role as salvage treatment.