LMAP-10 RE-IRRADIATION FOR RECURRENT ADULT DIFFUSE GLIOMA

OBJECTIVE: To investigate the efficacy of re-irradiation and prognosticators for recurrent adult diffuse glioma diagnosed per 2022 WHO diagnostic criteria for central nervous system tumors. METHODS: Patients older than 18 years with recurrent diffuse glioma confirmed by functional imaging or secondary surgical histopathology in Guangdong Sanjiu Brain Hospital from January 1, 2016, to December 31, 2022, were retrospectively analyzed. All patients were re-diagnosed per the 2022 WHO classification of central nervous system gliomas. All patients received re-radiotherapy after tumor recurrence, including conventional fractionation, hypofractionation, and stereotactic radiosurgery. RESULTS: A total of 61 patients were included in this analysis, male to female ratio was 34:27, median age of 45 (ranging from 18-64) years. There were 35 cases of grade IV glioblastoma, 5 cases of grade IV astrocytoma, 3 cases of grade III astrocytoma, 13 cases of grade II astrocytoma, 3 cases of grade III oligodendroglioma, and 2 cases of grade II oligodendroglioma. Twenty-four patients (39.3%) underwent re-operative surgery after recurrence. Forty-one patients (67.2%) received concurrent re-irradiation and chemotherapy, and 26 (42.6%) received concurrent bevacizumab. The median interval from the first to the second radiotherapy was 19 months. The median overall survival (OS) of 61 patients was 47 months, and the median OS following re-irradiation was 13 months. Univariate analysis showed that WHO grading (p = 0.007), IDH status (p = 0.026), reoperation after recurrence (p = 0.019), re-irradiation with or without concurrent chemotherapy (p = 0.026), maintenance chemotherapy (p = 0.038), and antiangiogenic therapy (p = 0.011) were the significant prognosticators. CONCLUSIONS: Re-radiotherapy is feasible and safe for recurrent adult diffuse glioma. Re-irradiation subsequent to the re-operative surgery after recurrence combined with other therapies are favorable prognosticators. Patients with IDH mutation could benefit more from re-irradiation after recurrence.