CLINICAL ARTICLE J Neurosurg 129:928–936, 2018 ABBREVIATIONS CN = cranial nerve; GKS = Gamma Knife surgery; IGKRF = International Gamma Knife Research Foundation; JFS = jugular foramen schwannoma; PFS = progression-free survival; SRS = stereotactic radiosurgery. SUBMITTED November 20, 2016. ACCEPTED May 11, 2017. INCLUDE WHEN CITING Published online November 10, 2017; DOI: 10.3171/2017.5.JNS162894. Stereotactic radiosurgery for jugular foramen schwannomas: an international multicenter study Hideyuki Kano, MD, PhD, 1 Antonio Meola, MD, 1 Huai-che Yang, MD, 2 Wan-Yuo Guo, MD, PhD, 2 Roberto Martínez-Alvarez, MD, PhD, 3 Nuria Martínez-Moreno, MD, PhD, 3 Dusan Urgosik, MD, PhD, 4 Roman Liscak, MD, PhD, 4 Or Cohen-Inbar, MD, PhD, 5 Jason Sheehan, MD, PhD, 5 John Y. K. Lee, MD, 6 Mahmoud Abbassy, MD, 7 Gene H. Barnett, MD, 7 David Mathieu, MD, 8 Douglas Kondziolka, MD, 9 and L. Dade Lunsford, MD 1 1 Department of Neurological Surgery, Center for Image-guided Neurosurgery, University of Pittsburgh, Pennsylvania; 2 Departments of Radiation Oncology and Neurological Surgery, Taipei Veterans Hospital, Taipei, Taiwan; 3 Functional and Radiosurgery Unit, Ruber International Hospital, Madrid, Spain; 4 Department of Stereotactic and Radiation Neurosurgery, Na Homolce Hospital, Prague, Czech Republic; 5 Department of Neurological Surgery, University of Virginia, Charlottesville, Virginia; 6 Department of Neurological Surgery, University of Pennsylvania, Philadelphia, Pennsylvania; 7 Department of Neurological Surgery, Cleveland Clinic, Cleveland, Ohio; 8 Université de Sherbrooke, Centre de Recherche Clinique Étienne-LeBel, Sherbrooke, Quebec, Canada; and 9 New York University Langone Medical Center, New York, New York OBJECTIVE For some jugular foramen schwannomas (JFSs), complete resection is possible but may be associated with significant morbidity. Stereotactic radiosurgery (SRS) is a minimally invasive alternative or adjunct to microsurgery for JFSs. The authors reviewed clinical and imaging outcomes of SRS for patients with these tumors. METHODS Nine participating centers of the International Gamma Knife Research Foundation identified 92 patients who underwent SRS between 1990 and 2013. Forty-one patients had prior subtotal microsurgical resection. The median interval between previous surgery and SRS was 15 months (range 0.5–144 months). Eighty-four patients had preexisting cranial nerve (CN) symptoms and signs. The median tumor volume was 4.1 cm 3 (range 0.8–22.6 cm 3 ), and the median margin dose was 12.5 Gy (range 10–18 Gy). Patients with neurofibromatosis were excluded from this study. RESULTS The median follow-up was 51 months (range 6–266 months). Tumors regressed in 47 patients, remained stable in 33, and progressed in 12. The progression-free survival (PFS) was 93% at 3 years, 87% at 5 years, and 82% at 10 years. In the entire series, only a dumbbell shape (extension extracranially via the jugular foramen) was significantly associated with worse PFS. In the group of patients without prior microsurgery (n = 51), factors associated with bet- ter PFS included tumor volume < 6 cm 3 (p = 0.037) and non–dumbbell-shaped tumors (p = 0.015). Preexisting cranial neuropathies improved in 27 patients, remained stable in 51, and worsened in 14. The CN function improved after SRS in 12% of patients at 1 year, 24% at 2 years, 27% at 3 years, and 32% at 5 years. Symptomatic adverse radiation effects occurred in 7 patients at a median of 7 months after SRS (range 5–38 months). Six patients underwent repeat SRS at a median of 64 months (range 44–134 months). Four patients underwent resection at a median of 14 months after SRS (range 8–30 months). CONCLUSIONS Stereotactic radiosurgery proved to be a safe and effective primary or adjuvant management approach for JFSs. Long-term tumor control rates and stability or improvement in CN function were confirmed. https://thejns.org/doi/abs/10.3171/2017.5.JNS162894 KEY WORDS jugular foramen schwannoma; stereotactic radiosurgery; Gamma Knife J Neurosurg Volume 129 • October 2018 928 ©AANS 2018, except where prohibited by US copyright law Unauthenticated | Downloaded 02/18/22 07:59 AM UTC