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The radiation oncologist's perspective on stereotactic radiosurgery
1University of Kentucky, Department of Radiation Medicine, 800 Rose Street, Lexington KY 40536-0293, USA. wilregi@pop.uky.edu
Technology in Cancer Research & Treatment
|March 5, 2003
Summary
Fractionated stereotactic radiosurgery (SRS) may better treat unfavorable gliomas than single-fraction SRS by exploiting tumor kinetics. Whole brain radiation therapy (WBRT) for brain metastases impacts cognition; SRS alone may increase recurrence risk and deficits.
Area of Science:
- Radiation Oncology
- Neurosurgery
- Neuro-oncology
Background:
- Single-fraction stereotactic radiosurgery (SRS) is historically based on arteriovenous malformation (AVM) treatment, not optimal for tumor cell kinetics.
- Whole brain radiation therapy (WBRT) for brain metastases carries neurocognitive risks, and its omission may increase recurrence.
- The role of SRS in brain metastasis management is increasing, necessitating evaluation of associated risks and benefits.
Purpose of the Study:
- To review the use of fractionated (F) SRS and split-course FSRS for unfavorable gliomas, exploiting tumor and normal tissue kinetics.
- To evaluate the risk of symptomatic brain tumor recurrence and neurologic deficit in patients treated with Gamma Knife SRS alone for brain metastases.
- To discuss the implications of brain metastasis control on Mini-Mental State Examination (MMSE) scores and the role of WBRT in conjunction with SRS.
Main Methods:
- Review of unique experience with split-course FSRS in patients with unfavorable gliomas.
- Evaluation of 36 patients with newly diagnosed unresected brain metastases treated with Gamma Knife SRS alone, followed by observation.
- Secondary analysis of a randomized phase III study comparing accelerated hyperfractionation (AH) versus standard accelerated fractionation (AF) for brain metastases.
Main Results:
- Fractionated SRS may allow for normal tissue sparing and counteract accelerated tumor growth and repopulation.
- Among 36 patients treated with SRS alone for brain metastases, 47% recurred, with 71% symptomatic and 59% experiencing neurologic deficit.
- Control of brain metastases significantly impacted MMSE scores, with declines observed only in patients with uncontrolled disease.
Conclusions:
- Fractionated SRS, particularly in a split-course fashion, offers a potential advantage for treating unfavorable gliomas by optimizing cell kinetics and sparing normal tissues.
- SRS alone for brain metastases may be associated with a significant risk of symptomatic recurrence and neurologic deficits, warranting careful consideration.
- Brain metastasis control is crucial for maintaining neurocognitive function, highlighting the need to discuss the complementary role of WBRT with SRS.