Failure rate of contemporary low-dose radiosurgical technique for vestibular schwannoma Clinical article

Restricted access

Object

The decline in cranial nerve morbidity after radiosurgery for vestibular schwannoma (VS) correlates with dose reduction and other technical changes to this procedure. The effect these changes have had on tumor control has not been well documented.

Methods

The authors performed a retrospective review of 293 patients with VSs who underwent radiosurgery between 1990 and 2004 and had a minimum of 24 months of imaging follow-up (90% of the entire series). The median radiation dose to the tumor margin was 13 Gy. Treatment failure was defined as progressive tumor enlargement noted on 2 or more imaging studies. The mean postradiosurgical follow-up was 60.9 ± 32.5 months.

Results

Tumor growth was noted in 15 patients (5%) at a median of 32 months after radiosurgery. Radiographically demonstrated tumor control was 96% at 3 years and 94% at 7 years after radiosurgery. Univariate analysis revealed 2 factors that correlated with failed radiosurgery for VS: an increasing number of isocenters (p = 0.03) and tumor margin radiation doses ≤ 13 Gy (p = 0.02). Multivariate analysis showed that only an increasing number of isocenters correlated with failed VS radiosurgery (hazard ratio 1.1, 95% CI 1.02–1.32, p < 0.05). The tumor margin radiation dose (p = 0.22) was not associated with tumor growth after radiosurgery.

Conclusions

Distortion of stereotactic MR imaging coupled with increased radiosurgical conformality and progressive dose reduction likely caused some VSs to receive less than the prescribed radiation dose to the entire tumor volume.

Abbreviations used in this paper:CPA = cerebellopontine angle; HR = hazard ratio; IAC = internal auditory canal; IQR = interquartile range; NF2 = neurofibromatosis Type 2; PIV = prescription isodose volume; VS = vestibular schwannoma.

Article Information

Address correspondence to: Bruce E. Pollock, M.D., Department of Neurological Surgery, Mayo Clinic, Rochester, Minnesota 55905. email:pollock.bruce@mayo.edu.

Please include this information when citing this paper: published online May 1, 2009; DOI: 10.3171/2009.3.JNS08949.

© AANS, except where prohibited by US copyright law.

Headings

Figures

  • View in gallery

    Axial post-Gd MR images obtained in a 74-year-old man, showing a right-sided VS. The tumor margin radiation dose was 12 Gy. A: Image obtained 12 months after radiosurgery. B: Image obtained 43 months after radiosurgery. C: Image obtained 58 months after radiosurgery. Along the petrous axis, the tumor measured 18 (A), 20 (B), and 23 mm (C).

  • View in gallery

    Graph showing tumor control rates in patients who underwent VS radiosurgery between January 1990 and March 1997 (88 patients, solid line) compared with those who underwent radiosurgery between April 1997 and December 2004 (205 patients, dashed line).

  • View in gallery

    Images from a dose plan for a patient undergoing radiosurgery for a right-sided VS. Left: Coronal reconstruction of a post-Gd MR image showing the 50% isodose line. Nine isocenters of radiation were used to cover a PIV of 307 mm3. The tumor margin radiation dose was 12 Gy, and the maximum radiation dose was 24 Gy. Right: Coronal reconstruction of the stereotactic CT showing the 50% isodose line shifted ~ 1 mm superior in the z plane. The radiation dose to the inferior portion of the IAC ranges from 6.1–7.1 Gy.

References

  • 1

    Banerjee RMoriarty JFoote RLPollock BE: Comparison of the surgical and follow-up costs associated with microsurgical resection and stereotactic radiosurgery for vestibular schwannoma. J Neurosurg 108:122012242008

    • Search Google Scholar
    • Export Citation
  • 2

    Borden JATsai JMahajan A: Effect of subpixel magnetic resonance imaging shifts on radiosurgical dosimetry for vestibular schwannoma. J Neurosurg 97:5 Suppl4454492002

    • Search Google Scholar
    • Export Citation
  • 3

    Burchiel KJNguyen TTCoombs BDSzumoski J: MRI distortion and stereotactic neurosurgery using the Cosman-Roberts-Wells and Leksell frames. Stereotact Funct Neurosurg 66:1231361996

    • Search Google Scholar
    • Export Citation
  • 4

    Chopra RKondziolka DNiranjan ALunsford LDFlickinger JC: Long-term follow-up of acoustic schwannoma radiosurgery with marginal tumor doses of 12 to 13 Gy. Int J Radiat Oncol Biol Phys 68:8458512007

    • Search Google Scholar
    • Export Citation
  • 5

    Flickinger JCKondziolka DPollock BELunsford LD: Evolution in technique for vestibular schwannoma radiosurgery and effect on outcome. Int J Radiat Oncol Biol Phys 36:2752801996

    • Search Google Scholar
    • Export Citation
  • 6

    Friedman WABradshaw PMyers ABova FJ: Linear accelerator radiosurgery for vestibular schwannomas. J Neurosurg 105:6576612006

  • 7

    Hasegawa TFujitani SKatsumata SKida YYoshimoto MKoike J: Stereotactic radiosurgery for vestibular schwannomas: analysis of 317 patients followed more than 5 years. Neurosurgery 57:2572642005

    • Search Google Scholar
    • Export Citation
  • 8

    Iwai YYamanaka KShiotani MUyama T: Radiosurgery for acoustic neuromas: results of low-dose treatment. Neurosurgery 53:2822872003

    • Search Google Scholar
    • Export Citation
  • 9

    Karpinos MThe BSZeck OCarpenter LSPhan CMai W: Treatment of acoustic neuroma: stereotactic radiosurgery vs. microsurgery. Int J Radiat Oncol Biol Phys 54:141014212002

    • Search Google Scholar
    • Export Citation
  • 10

    Kondziolka DDempsey PKLunsford LDKestle JRDolan EJKanal E: A comparison between magnetic resonance imaging and compued tomography for stereotactic coordinate determination. Neurosurgery 30:4024061992

    • Search Google Scholar
    • Export Citation
  • 11

    Kondziolka DLunsford LDMcLaughlin MRFlickinger JC: Long-term outcomes after radiosurgery for acoustic neuromas. N Engl J Med 339:142614331998

    • Search Google Scholar
    • Export Citation
  • 12

    Lindquist CPaddick I: The Leksell Gamma Knife Perfexion and comparisons with its predecessors. Neurosurgery 61:3 Suppl1301402007

  • 13

    Massager NNissim ODelbrouk CDelpierre IDevriendt DDesmedt F: Irradiation of cochlear structures during vestibular schwannoma radiosurgery and associated hearing outcome. J Neurosurg 107:7337392007

    • Search Google Scholar
    • Export Citation
  • 14

    Miller RCFoote RLCoffey RJSargent DJGorman DASchomberg PJ: Decrease in cranial nerve complications after radiosurgery for acoustic neuromas: a prospective study of dose and volume. Int J Radiat Oncol Biol Phys 43:3053111999

    • Search Google Scholar
    • Export Citation
  • 15

    Myrseth EMoller PPedersen PVassbotn FSWentzel-Larsen TLund-Johansen M: Vestibular schwannomas: clinical results and quality of life after microsurgery or gamma knife radiosurgery. Neurosurgery 56:9279352005

    • Search Google Scholar
    • Export Citation
  • 16

    Niranjan ALunsford LDFlickinger Maitz AKondziolka D: Dose reduction improves hearing preservation rates after intracanalicular acoustic tumor radiosurgery. Neurosurgery 45:7537621999

    • Search Google Scholar
    • Export Citation
  • 17

    Petit JHHudes RSChen TTEisenberg HMSimard JMChin LS: Reduced-dose radiosurgery for vestibular schwannomas. Neurosurgery 49:129913062001

    • Search Google Scholar
    • Export Citation
  • 18

    Pollock BE: Management of vestibular schwannomas that enlarge after stereotactic radiosurgery: treatment recommendations based on a 15-year experience. Neurosurgery 58:2412472006

    • Search Google Scholar
    • Export Citation
  • 19

    Pollock BEDriscoll CLWFoote RLLink MJGorman DABauch CD: Patient outcomes after vestibular schwannoma management: a prospective comparison of microsurgical resection and stereotactic radiosurgery. Neurosurgery 59:77852006

    • Search Google Scholar
    • Export Citation
  • 20

    Pollock BELunsford LDKondziolka DFlickinger JCBissonette DJKelsey SF: Outcome analysis of acoustic neuroma management: a comparison of microsurgery and stereotactic radiosurgery. Neurosurgery 36:2152291995

    • Search Google Scholar
    • Export Citation
  • 21

    Régis JHayashi MPorcheron DDelsanti CMuracciole X: Impact of the model C and Automatic Postioning System on Gamma Knife radiosurgery: an evaluation in vestibular schwannomas. J Neurosurg 97:5 Suppl5885912002

    • Search Google Scholar
    • Export Citation
  • 22

    Regis JPellet WDelsanti CDufour HRoche PHThomassin JM: Functional outcome after gamma knife surgery or microsurgery for vestibular schwannomas. J Neurosurg 97:109111002002

    • Search Google Scholar
    • Export Citation
  • 23

    Van Roijen LNijs HGTAvezaat CJJKarlsson GLinquist CPauw KH: Costs and effects of microsurgery versus radiosurgery in treating acoustic neuroma. Acta Neurochir (Wien) 139:9429481997

    • Search Google Scholar
    • Export Citation
  • 24

    Walton LHampshire AForster DMKemeny AA: Stereotactic localization with magnetic resonance imaging: a phantom study to compare accuracy obtained using two-dimensional and three-dimensional data acquisitions. Neurosurgery 41:1311371997

    • Search Google Scholar
    • Export Citation
  • 25

    Yu CApuzzo MLZee CSPetrovich Z: A phantom study of the geometric accuracy of computed tomographic and magnetic resonance imaging stereotactic localization with the Leksell stereotactic system. Neurosurgery 48:109210982001

    • Search Google Scholar
    • Export Citation

TrendMD

Metrics

Metrics

All Time Past Year Past 30 Days
Abstract Views 261 261 27
Full Text Views 117 73 0
PDF Downloads 54 46 0
EPUB Downloads 0 0 0

PubMed

Google Scholar