ACT-03 Clinical outcome and radiological findings of patients with recurrent glioblastomas treated by bevacizumab

Object: Seven years have passed since the approval of bevacizumab (BEV) in Japan. We retrospectively reviewed the clinical outcome and radiological findings of patients with recurrent glioblastomas (GB) treated by BEV. Method: We reviewed 116 patients, including 27 cases of newly diagnosed GB and 89 cases of recurrent GB, treated by BEV during the study period between 2013 June and 2019 September. Cumulatively, 116 patients received 1672 cycles of BEV. Among those, we focused on 74 patients with newly diagnosed GB treated by BEV at recurrence to examine clinical characteristics, outcome, and radiological findings of T2-circumscribed or double-positive proposed by Nowosieski et al. or Bahr et al., respectively. Result: The study cohort comprised median age of 66.8 years (range 10 to 81), median KPS of 60% (range, 20 to 100), median cycles of administration 11(1 to 59), median period of treatment 172 days (0 to 1413), median post-BEV survivals 266 days, and overall survival 693 days. Patients without progressive disease at 6 months post-BEV MRI (n = 23) presented favorable post-BEV survival of 713 days than those with progressive disease (n = 8) (p=0.0003). The radiological findings varied by patients, tumor lesions, and sequential imaging; thus, it was difficult to correlate with survival. Our data implied that the T2-circumscribed lesion was accompanied by no enhancement at T1 but hyperperfused at arterial spin labeling imaging, indicating that blood-brain barriers were intact and vascularization is activated. Conclusion: Although our cohort included patients with relatively high age, some had prolonged post-BEV survival. T2-circumscribed or double-positive was not useful to predict the survival; however, MRI at 6 months post-BEV can be an indicator for two years of post-BEV survival.