A Retrospective Review of Re-irradiating Patients' Recurrent High-grade Gliomas

After radical treatment, most high-grade gliomas (HGG) recur locally. Upon recurrence, no standard treatment exists. Options include re-resection, salvage systemic therapy and re-irradiation. This retrospective study evaluated patients who underwent re-irradiation for recurrent HGGs and assessed prognostic factors and their influence on management.

Eighty-two patients who underwent re-irradiation for HGG from 2009 to 2014 were retrospectively identified. Re-irradiation consisted of either standard three-dimensional conformal, intensity-modulated radiotherapy or highly conformal stereotactic radiotherapy using mostly volumetric modulated arc therapy. Patient survival from re-irradiation was the primary end point. Survival was estimated via the Kaplan-Meier method with differences assessed using the Log-rank test; hazard ratios were estimated using Cox regression analysis.

The median overall survival from re-irradiation was 9.5 months. Re-irradiation, to a median dose of 35 Gy in 10 fractions, was well tolerated: 4% developed grade 3 toxicity, no patients experienced grade ≥4 or radionecrosis. In the multivariate analysis, factors significantly associated with increased survival included: longer duration from initial radiotherapy, better performance status at re-irradiation of 0-1 versus ≥2, unifocal versus multifocal recurrence and higher total re-irradiation dose (≥35 Gy versus <35 Gy). Re-resection, salvage systemic therapy and age were unrelated to survival.

Patients with recurrent HGG tolerated re-irradiation well with minimal toxicity. Those patients in good prognostic groups, including good performance status can achieve durable control, suggesting managing patients with regular magnetic resonance imaging surveillance post-radical treatment, identifying early radiological progression and instituting salvage therapy when performance status is best.