LAUSR

PURPOSE To analyse feasibility, prognostic factors and patterns of recurrence after concurrent reirradiation and bevacizumab for recurrent high-grade gliomas. PATIENTS AND METHODS Between 2009 and 2015, 35 patients (median 57-year-old; 21 men, 14 women) with WHO grade III (n=11) or grade IV (n=24) gliomas were included in this retrospective and consecutive single-centre study. All patients received bevacizumab (median number of treatments: 12) concomitant with reirradiation (median dose: 45Gy, median number of fractions: 18) for recurrence with median 22 months (range: 5.6-123.7 months) from first irradiation (median dose: 60Gy). RESULTS The median follow-up was 9.2 months from reirradiation. The median overall survival from reirradiation was 10.5 months (95% confidence interval [95% CI]: 4.9-16.1) and the progression-free survival from reirradiation was 6.7 months (95% CI: 2.9-10.5). The median overall survival from initial diagnosis was 44.6 months (95% CI: 32-57.1). No grade 3 toxicity or above was reported. Prognostic factors significantly correlated with better overall survival in univariate analysis were: age at least 55 (P=0.024), initial surgery (P=0.003), and 2Gy equivalent dose (EQD2) at least 50Gy at reirradiation (P=0.046). Twenty-two patients bevacizumab-naïve at time of reirradiation had a significantly increased overall survival from reirradiation compared to patients treated with reirradiation after bevacizumab failure (17.7 vs. 5.4 months, P<0.001) as well as overall survival from initial diagnosis (58.9 vs. 33.5 months, P=0.006). This outcome was similar in patients with initial glioblastomas (P=0.018) or anaplastic gliomas (P=0.021). There was no correlation between overall survival and gross tumour volume or planning target volume, frontal localization, or number of salvage therapies before reirradiation (P>0.05). CONCLUSIONS Concomitant reirradiation with bevacizumab in high-grade recurrent gliomas shows encouraging results in terms of survival and toxicities. Our data suggest that reirradiation should be favoured at initiation of bevacizumab, with EQD2 at least 50Gy.