title: Low-dose radiosurgery or hypofractionated stereotactic radiotherapy as treatment option in refractory epilepsy due to epileptogenic lesions in eloquent areas - Preliminary report of feasibility and safety.
abstract: OBJECTIVE
  The eradication of epileptogenic lesions (e.g. focal cortical dysplasia) can be used for treatment of drug-resistant focal epilepsy, but in highly eloquent cortex areas it can also lead to a permanent neurological deficit. In such cases the neuromodulation effect of low-dose high-precision irradiation of circumscribed lesions may represent an alternative therapy.
  
  
  METHODS
  A total of 10 patients with eloquent localized lesions causing pharmacoresistant focal epilepsy were prospectively identified. After informed consent, six patients agreed and were treated with risk adapted low-dose radiosurgery (SRS) or hypofractionated stereotactic radiotherapy (hfSRT). Comprehensive data concerning treatment modalities and outcome after short-term follow up (mean=16.3 months) were prospectively collected and evaluated.
  
  
  RESULTS
  From the six patients, two patients were treated with hfSRT (marginal dose 36 Gy) and four with SRS (marginal dose 13 Gy). Clinical target volume (CTV) ranged from 0.70 ccm to 4.32 ccm. The short-term follow-up ranged from 6 to 27 months. There were no side effects or neurological deficits after treatment. At last available follow-up two patients were seizure-free, one of them being off antiepileptic drugs. The seizure frequency improved in one and remained unchanged in three patients.
  
  
  CONCLUSIONS
  Treatment of eloquent localized epileptogenic lesions by SRS and hfSRT showed no adverse events and an acceptable seizure outcome in this small prospective patient series. The relatively short-term follow-up comprises one of the study's drawbacks and therefore a longer follow-up should be awaited in order to evaluate the neuromodulation effect of the treatment. These preliminary results may however justify the initiation of a larger prospective trial investigating whether focused low-dose stereotactic irradiation could be an option for lesions in eloquent brain areas.
authors.affiliation: Department of Radiosurgery and Stereotactic Radiotherapy, MediClin Robert Janker Clinic and MediClin MVZ Bonn, Villenstrasse 8, 53129 Bonn, Germany; Department of Neurosurgery, University Hospital of Bonn, Sigmund-Freud-Strasse 25, 53105 Bonn, Germany. Electronic address: Jan.Bostroem@mediclin.de.
authors.forename: Jan P
authors.initials: JP
authors.lastname: Boström
authors.affiliation: Department of Neurosurgery, University Hospital of Bonn, Sigmund-Freud-Strasse 25, 53105 Bonn, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Delev
authors.affiliation: Department of Epileptoloy, University Hospital of Bonn, Sigmund-Freud-Strasse 25, 53105 Bonn, Germany.
authors.forename: Carlos
authors.initials: C
authors.lastname: Quesada
authors.affiliation: Department of Epileptoloy, University Hospital of Bonn, Sigmund-Freud-Strasse 25, 53105 Bonn, Germany.
authors.forename: Guido
authors.initials: G
authors.lastname: Widman
authors.affiliation: Department of Neurosurgery, University Hospital of Bonn, Sigmund-Freud-Strasse 25, 53105 Bonn, Germany.
authors.forename: Hartmut
authors.initials: H
authors.lastname: Vatter
authors.affiliation: Department of Epileptoloy, University Hospital of Bonn, Sigmund-Freud-Strasse 25, 53105 Bonn, Germany.
authors.forename: Christian E
authors.initials: CE
authors.lastname: Elger
authors.affiliation: Department of Epileptoloy, University Hospital of Bonn, Sigmund-Freud-Strasse 25, 53105 Bonn, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Surges
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000502:physiology* / Q000601:surgery; D015331:Cohort Studies; D004307:Dose-Response Relationship, Radiation; D000069279:Drug Resistant Epilepsy / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology / Q000601:surgery*; D004569:Electroencephalography; D004827:Epilepsy / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D065703:Malformations of Cortical Development, Group I / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*; D000069473:Radiation Dose Hypofractionation; D016634:Radiosurgery / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult
keywords: Epileptogenic lesion; Epileptogenic zone; Focal cortical dysplasia; Radiosurgery; Stereotactic radiotherapy