RTRB-22HYPOFRACTIONATED RADIOTHERAPY VERSUS STANDARD FRACTIONATED RADIOTHERAPY WITH CONCURRENT TEMOZOLOMIDE IN ELDERLY PATIENTS WITH NEWLY DIAGNOSED GLIOBLASTOMA

Abstract

BACKGROUND: Adjuvant hypofractionated radiotherapy (HRT) for elderly patients with newly diagnosed glioblastoma (GBM) is reasonable compared to standard fractionation radiotherapy (SRT). Comparison of HRT in the presence of temozolomide (TMZ) vs SRT with TMZ is unclear. We examined HRT for GBM with TMZ in comparison to SRT with TMZ. METHODS: Retrospective analysis of patients > 60 years-old who received SRT or HRT of newly diagnosed GBM in the post-operative setting from 1994 to 2014. Inclusion criteria included SRT (60 Gy/30 fractions or 59.4 Gy/33 fractions) vs HRT of 40 Gy/15 fractions. RESULTS: 158 patients received SRT vs 26 with HRT. Median survival receiving SRT versus HRT was 430 and 475 days (p = 0.550). 95% of the SRT patients received TMZ vs 100% with HRT. Patients receiving HRT were older (median: 72 vs 66 years). All HRT patients were treated with IMRT technique vs SRT. Multivariate Cox regression showed decreased survival in age > 70 (Hazard ratio [HR] 1.84; 95% confidence interval [CI] 1.23-2.75), lower Karnofsky performance status (HR 5.25; 95% CI 1.73-15.99), biopsy vs. surgical resection (HR 4.18; 95% CI 1.49-11.77), RT planning technique 3D- or 2D-planning vs. IMRT (HR 1.91; 95% CI 1.32-2.76 and HR 3.40; 95% CI 1.60-7.22, respectively). IMRT based planning showed no difference between HRT vs SRT. For patients receiving TMZ, there was no survival difference between HRT and SRT. CONCLUSIONS: Elderly GBM patients receiving HRT or SRT had similar overall survival. Subset analysis patients receiving concurrent TMZ showed no difference in survival between HRT and SRT.