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

Purpose: To analyze the pathology, outcomes, and prognostic factors in patients with high-grade glioma undergoing reoperation after radiotherapy (RT).

Methods And Materials: 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.

Results: 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.

Conclusions: 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.