J Neurol Surg B Skull Base 2018; 79(06): 580-585
DOI: 10.1055/s-0038-1651504
Original Article
Georg Thieme Verlag KG Stuttgart · New York

Toxicity of Gamma Knife Radiosurgery May Be Greater in Patients with Lower Cranial Nerve Schwannomas

Rawee Ruangkanchanasetr
1   Department of Diagnostic and Therapeutic Radiology, Faculty of Medicine, Ramathibodi Hospital, Bangkok, Thailand
,
John Y.K. Lee
2   Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania, United States
,
Suneel N. Nagda
3   Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
,
Geoffrey A. Geiger
3   Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
,
James D. Kolker
3   Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
,
Douglas C. Bigelow
4   Department of Otolaryngology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
,
Michael J. Ruckenstein
4   Department of Otolaryngology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
,
MacLean Nasrallah
5   Department of Pathology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
,
Michelle Alonso-Basanta
3   Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
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Weitere Informationen

Publikationsverlauf

04. September 2017

08. März 2018

Publikationsdatum:
10. Mai 2018 (online)

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Abstract

Objective Gamma Knife stereotactic radiosurgery (GK-SRS) is a preferred treatment option for tumors of the jugular foramen. We hypothesized that GK-SRS toxicity is higher for lower cranial nerve schwannomas than for glomus jugulare tumors despite anatomically similar locations.

Methods We performed a retrospective review of all patients who received GK-SRS for glomus jugulare tumors and lower cranial nerve schwannomas at our institution between 2006 and 2014. Because of small sample sizes, Fisher's exact tests and logistic regression techniques were employed using SPSS.

Result We identified 20 glomus jugulare tumors and 6 lower cranial nerve schwannoma patients with a median follow-up of 17 months. Median marginal dose was 16 Gy (range 13–18 Gy) and 12.5 Gy (range 12–14 Gy), respectively. All except one patient had tumor control at last follow-up visit. No worsening of pre-existing neurological deficits was observed. There were seven patients who developed any new neurological deficit after GK-SRS, four from the glomus group, and three from the schwannoma group (20 and 50% of each group, respectively). Only two of seven patients had permanent new neurological deficits. Both of them were in the schwannoma group. Univariate analysis showed that only a diagnosis of schwannoma had a greater risk of permanent new cranial nerve complication after GK-SRS compared with diagnosis of glomus jugulare (p = 0.046).

Conclusion Although the marginal dose for glomus jugulare is greater, our study suggests that the risk of a new permanent neurological deficit after GK-SRS was higher in the schwannoma group compared with the glomus group.