Gamma Knife Radiosurgery in Recurrent Glioblastoma

Abstract

Background: We evaluated Gamma Knife radiosurgery (GKRS) as a treatment option for patients with recurrent glioblastoma. Patients and Methods: 42 patients with histopathologically diagnosed recurrent grade IV tumor were treated with GKRS. All patients had undergone standard multimodal first-line treatment. The average time from diagnosis to GKRS was 17.0 months. The median target volume was 5.1 cm³. The median margin dose was 10 Gy and the median central dose 20 Gy. In a subset of patients, O⁶-methylguanine methyltransferase (MGMT) promoter methylation analysis by pyrosequencing was performed. Results: Most patients did not develop complications after GKRS. Time to radiological progression after initial GKRS was 4.4 months (95% CI: 3.1-5.7 months). Radiological progression mainly occurred beyond the GKRS-irradiated area. The median survival time after initial GKRS was 9.6 months (95% CI: 7.7-11.5 months). The median overall survival time from diagnosis was 25.6 months (95% CI: 21.8-29.3 months). Patients with MGMT promoter methylation survived significantly longer (33.4 months; 95% CI: 21.2-45.5 months) compared to patients without MGMT promoter methylation (16.0 months; 95% CI: 8.0-23.9 months). Conclusion: GKRS seems to be a relatively safe salvage treatment option for recurrent glioblastoma for highly selected patients but must be seen as part of a multimodal treatment algorithm.

Target treatment with stereotactic radiation for recurrent gliomas

“…Although this was a non-randomized study, favorable prognostic factors included smaller tumor volume, younger age, high KPS and lower grade (47). Several other studies found age and performance status to be significantly associated with survival (40,41,45). Two other retrospective reports showed that higher KPS and small tumor volume predicted for increased OS (48).…”

“…One study showed a significant median OS benefit in patients with MGMT promoter methylation (33.4 vs. 16 months). However, only 22 patients had MGMT sequencing at the time of this study (41). Another report had 11 patients with MGMT promoter methylation, but did not find a statistically significant difference between OS in the cohort (40).…”

Guiding Treatment Choices for Elderly Patients with Glioblastoma by a Comprehensive Geriatric Assessment

“…The current practice is to re-evaluate all treatment modalities used in first line for the individual benefit when used in the particular recurrence. In small recurrent GBM, radiosurgery presents a valuable alternative to surgical resection [49].…”

Stereotactic Radiotherapy in Recurrent Glioblastoma: A Valid Salvage Treatment Option

“…Most of the recurrences are observed within the initial tumor bed or irradiated volume [4,5]. The median overall survival (OS) for patients with recurrent GBM reported in the literature ranges between 5.3 and 24 months [6][7][8][9][10][11][12]. There is no standard salvage treatment after recurrence.…”