Elderly Patients With Recurrent High-Grade Glioma Derive Similar Benefit From Re-Irradiation As Younger Patients

Although there is no standard of care for recurrent high-grade glioma (HGG), treatment options include a combination of local and systemic therapies. This question is particularly notable in the elderly population as they tend to do worse than younger patients. We set out to determine if there was a benefit to elderly patients (≥65 years) by treating with re-irradiation. A retrospective review was conducted on all patients with recurrent HGG treated at our institution with re-irradiation from January 2013 to July 2019. Patients were stratified by age (≥65 and <65) and overall survival (OS) was estimated based using the Kaplan-Meier method and compared using the log-rank test. Patients were also stratified by histology, KPS at presentation, tumor location, extent of initial resection, MGMT and IDH status, and systemic therapy. Their effect on OS was compared using the same technique as well as Cox Proportional-Hazard Model. 118 patients were included in the current study, 91 (77%) had GBM, 26 (22%) had recurrent anaplastic gliomas. 26 (22%) were elderly and 92 (78%) were < 65 years at diagnosis. Majority of the patients, 106 (90%) pts were treated with concurrent temozolomide (TMZ) and 92 (78%) were treated with adjuvant TMZ with initial radiation treatment. Median time to recurrence was 12 (range 3-246) months. Median dose for re-irradiation was 35 Gy in 10 fractions. Unmethylated MGMT was more common (59.6%). There was no significant difference between elderly and younger groups. Elderly patients have significantly worse OS from diagnosis (2 years survival was 53% vs. 68% in younger patients, 1.85; 95% CI 1.1-3.09; p = 0.018). However, OS from re-irradiation was similar in both group (19% vs. 12%; HR 1.17 95% CI 0.7-1.95). IDH or MGMT status, extent of resection, type of chemotherapy prescribed at recurrence, tumor location, or presenting symptoms did not predict for survival in this population. There was no difference observed in patients receiving bevacizumab-containing regimens vs. systemic therapy without bevacizumab. Only two patients had grade 3 or higher toxicities. One patient had grade 3 cerebral edema and another patient had grade 4 seizures. There were no instances of grade ≥ 3 radionecrosis. Our study confirmed worse overall survival for elderly patients with HGG from diagnosis as compared to younger patients. However, in the recurrent setting, elderly patients had similar OS from re-irradiation as younger patients. The treatment is well tolerated, indicating a role of re-irradiation in elderly population.