Recurrent low-grade gliomas: the role of fractionated stereotactic re-irradiation

Purpose: To assess the effectiveness of re-irradiation in recurrent low-grade gliomas (LGG). Patients and methods: Sixty-three patients were treated with fractionated stereotactic re-irradiation in the case of recurrent gliomas. At primary diagnosis of the tumor, the histology was grade II astrocytoma, oligodendroglioma or oligoastrocytoma. Fifty-two (82.5%) recurrences were in-field, three (4.8%) were localized at the field border, and eight (12.7%) tumors were localized completely out-field of the former RT field, respectively. Using three to four irregular non-coplanar fields formed with a multi-leaf-collimator, we applied a median total dose of 36 Gy (range 15 - 62 Gy) with a weekly fractionation of 5 x 2 Gy/week depending on the size and the location of the lesion. No concomitant chemotherapy was applied. Results: Radiation was well tolerated by all patients. No severe side effects occurred. Median overall survival was 111 months (range 12 - 240 months). Extent of neurosurgical resection significantly influenced overall survival (P = 0.02). Median interval between the first radiation therapy and re-irradiation was 50 months (range 5 204 months). From the time point of re-irradiation, median survival was 23 months. Median progression-free survival from the time point of re-irradiation was 12 months (range 2 - 63 months). No prognosticators could be identified for survival from re-irradiation and progression free survival. Conclusion: Our retrospective data suggest that stereotactically guided fractionated re-irradiation in recurrent glioma represents an effective treatment option with good results and few complications. However, further investigation is warranted to consolidate these results and to combine radiation with chemotherapy in the case of recurrent LGG.