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J Neurol Surg B Skull Base 2018; 79(04): 335-342
DOI: 10.1055/s-0037-1607968
Original Article
Georg Thieme Verlag KG Stuttgart · New York

Impact of Cochlear Dose on Hearing Preservation following Stereotactic Radiosurgery and Fractionated Stereotactic Radiotherapy for the Treatment of Vestibular Schwannoma

Lawrance K. Chung
1   Department of Neurosurgery, University of California, Los Angeles, California, United States
,
Nolan Ung
1   Department of Neurosurgery, University of California, Los Angeles, California, United States
,
John P. Sheppard
1   Department of Neurosurgery, University of California, Los Angeles, California, United States
,
Thien Nguyen
1   Department of Neurosurgery, University of California, Los Angeles, California, United States
,
Carlito Lagman
1   Department of Neurosurgery, University of California, Los Angeles, California, United States
,
Winward Choy
1   Department of Neurosurgery, University of California, Los Angeles, California, United States
,
Stephen Tenn
2   Department of Radiation Oncology, University of California, California, United States
,
Nader Pouratian
1   Department of Neurosurgery, University of California, Los Angeles, California, United States
2   Department of Radiation Oncology, University of California, California, United States
,
Percy Lee
2   Department of Radiation Oncology, University of California, California, United States
,
Tania Kaprealian
1   Department of Neurosurgery, University of California, Los Angeles, California, United States
2   Department of Radiation Oncology, University of California, California, United States
3   UCLA Jonsson Comprehensive Cancer Center, University of California, Los Angeles, California, United States
,
Michael Selch
2   Department of Radiation Oncology, University of California, California, United States
,
Antonio De Salles
1   Department of Neurosurgery, University of California, Los Angeles, California, United States
,
Quinton Gopen
4   Department of Head and Neck Surgery, University of California, Los Angeles, California, United States
,
Isaac Yang
1   Department of Neurosurgery, University of California, Los Angeles, California, United States
2   Department of Radiation Oncology, University of California, California, United States
3   UCLA Jonsson Comprehensive Cancer Center, University of California, Los Angeles, California, United States
4   Department of Head and Neck Surgery, University of California, Los Angeles, California, United States
5   Department of Neurosurgery, Harbor-UCLA Medical Center, Torrance, California, United States
6   Los Angeles Biomedical Research Institute, Torrance, California, United States
› Author Affiliations
Funding Lawrance Chung was partially supported by the AMA Foundation Seed Grant and the AΩA Carolyn L. Kuckein Student Research Fellowship. Thien Nguyen and John P. Sheppard are recipients of the David Geffen Medical Scholarship. Carlito Lagman was partially supported by the Gurtin Skull Base Research Fellowship. Isaac Yang was partially supported by the UCLA Visionary Ball Fund Grant, the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research UCLA Scholars in Translational Medicine Program Award, the Jason Dessel Memorial Seed Grant, the UCLA Honberger Endowment Brain Tumor Research Seed Grant, and the Stop Cancer! Research Career Development Award.
Further Information

Publication History

12 July 2017

19 September 2017

Publication Date:
10 November 2017 (online)

Also available atMedOne
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Abstract

Objective The objective of this study was to examine the effect of cochlear dose on hearing preservation in stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (fSRT) for vestibular schwannoma (VS).

Design This is a retrospective case–control study.

Setting This study was completed at the Ronald Reagan UCLA Medical Center, a university-affiliated tertiary care center.

Participants Patients who underwent SRS (marginal dose of 12 Gy) or fSRT (marginal dose of 50.4 Gy) procedures for VS were included in the study.

Main Outcome Measures The main outcome measure was hearing preservation. Audiometric data, when available, were used to determine the level of hearing according to the Gardner Robertson scale.

Results A total of 38 patients (14 SRS and 24 fSRT) were analyzed. SRS patients with decreased hearing received a significantly higher minimum cochlear dose (7.41 vs. 4.24 Gy, p = 0.02) as compared with those with stable hearing. In fSRT patients, there were no significant differences in cochlear dose for patients with decreased hearing as compared with those with stable hearing. For SRS patients, who received a minimum cochlear dose above 6 Gy, there was a significant risk of decreased hearing preservation (odds ratio: 32, p = 0.02).

Conclusion Higher minimum cochlear dose was predictive of decreased hearing preservation following SRS. Though the study is low powered, the radiation dose to the cochlea should be a parameter that is considered when planning SRS or fSRT therapies for patients with VS.

Keywords

cochlear dose - hearing - stereotactic radiosurgery - fractionated stereotactic radiotherapy - vestibular schwannoma