Favorable prognosis in patients with high-grade glioma with radiation necrosis: the University of Colorado reoperation series.

Abstract

To analyze the pathology, outcomes, and prognostic factors in patients with high-grade glioma undergoing reoperation after radiotherapy (RT). Fifty-one patients with World Health Organization Grade 3-4 glioma underwent reoperation after prior RT. The median dose of prior RT was 60 Gy, and 84% received chemotherapy as part of their initial treatment. Estimation of the percentage of necrosis and recurrent tumor in each reoperation specimen was performed. Pathology was classified as RT necrosis if ≥80% of the specimen was necrotic and as tumor recurrence if ≥20% was tumor. Predictors of survival were analyzed using log-rank comparisons and Cox proportional hazards regression. The median interval between the completion of RT and reoperation was 6.7 months (range, 1-59 months). Pathologic analysis showed RT necrosis in 27% and recurrence in 73% of cases. Thirteen patients required a reoperation for uncontrolled symptoms. Among them, 1 patient (8%) had pathology showing RT necrosis, and 12 (92%) had tumor recurrence. Median survival after reoperation was longer for patients with RT necrosis (21.8 months vs. 7.0 months, p=0.047). In 7 patients with Grade 4 tumors treated with temozolomide-based chemoradiation with RT necrosis, median survival from diagnosis and reoperation were 30.2 months and 21.8 months, respectively. Patients with RT necrosis at reoperation have improved survival compared with patients with tumor recurrence. Future efforts to intensify local therapy and increase local tumor control in patients with high-grade glioma seem warranted.