Reirradiation of gliomas under stereotactic conditions: Prognostic factors for survival without relapse or side effects, a retrospective study at Tours regional university hospital (France)

Abstract Purpose To search for factors correlated with relapse-free survival following stereotactic reirradiation in patients with recurrent glioma following radiochemotherapy and evaluate tolerance to this treatment. Patients and methods Initial radiotherapy was given according to the protocol of Stupp and al. Reirradiation was performed using the CyberKnife ® system. Patients could have had surgical resection initially and at the time of recurrence. We analysed 13 patients treated between July 2010 and September 2014. The median age was 55 years. The doses delivered ranged from 20 to 36 Gy, in one to ten fractions. Results Median survival after stereotactic radiotherapy was 14 months. Survival without relapse was 3.7 months. Factors significantly influencing duration of relapse-free survival were: age ( P  = 0.04), total dose ( P  = 0.02), dose per fraction ( P  = 0.04) and number of fractions ( P  = 0.01). We found no correlation between gross tumour volume, clinical target volume, grade of tumour or prescription isodose and relapse-free survival following radiochemotherapy. Three patients developed radionecrosis. Conclusion Reirradiation under stereotactic conditions is well tolerated. A dose of more than 30 Gy delivered in 5 or more fractions seems to prolong relapse-free survival.