Article
Re-irradiation of Recurrent Astrocytomas withFractionated Stereotacic Radiotherapy (FSRT)
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Published: | March 20, 2006 |
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Introduction: Treatment options for recurrent gliomas are often limited since most therapeutic alternatives have been applied after primary diagnosis.
Re-Irradiation with modern precision techniques such as Fractionated Stereotactic Radiotherapy (FSRT) enables the application of radiotherapy to a defined target while sparing normal tissue. We treated 172 patients with recurrent gliomas with FSRT for re-irradiation.
Patients and Methods: Between 1990 and 2004, 172 patients with recurrent gliomas were treated with FSRT at our institution. Seventy-one patients were diagnosed with WHO Grade II astrocytoas, and WHO grade 3 and 4 tumors were present in 42 and 59 patients, respectively. The median time interval between primary radiotherapy and re-irradiation was 10 months for glioblastoma multiforme (GBM), and 32 and 48 months for anaplastic astrocytomas (AA) and low-grade gliomas (LGG), respectively. FSRT was performed in a rigid mask fixation system made of Scotch cast, a median dose of 36 Gy was prescribed in a median conventional fractionation of 5x2Gy/week.
Results: FSRT was well tolerated and could be completed withouth interruptions in all patients. Only one patient developed radiographically diagnosed and histologically confired radiation-induced necrosis. The median overall survival after primary diagnosis was 21 months for patients with GBM, 50 months for patients with AA and 111 months for patients with LGG. Histology was the strongest predictor for overall survival together with the extent of neurosurgical resection and age at primary diagnosis. Median survival after re-irradiation was 8 months for patients with GBM, 16 months for patients with AA, and 22 months for patients with LGG. Only time to progression and histology were significant in influencing survival after re-irradiation. Progression-free survival after FSRT was 5 months for GBM, 8 months for AA, and 12 months for LGG.
Conclusion: FSRT is very well tolerated and effective in a subgroup of patients with recurrent gliomas. For smaller lesions, Stereotactic Radiosurgery (SRS) offers a non-invavie alternative, which is performed in a single fraction.