Gamma knife radiosurgery for trigeminal schwannoma: a 20-year experience with long-term treatment outcome
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This study evaluated the long-term tumor control rate (TCR) and symptomatic outcomes of patients treated with gamma knife radiosurgery (GKRS) for trigeminal schwannomas (TSs).
Thirty-two patients with TS who underwent GKRS between January 1994 and January 2013 with at least 2 years of follow-up were enrolled in the study. Clinical charts and surgical records were retrospectively reviewed to evaluate factors affecting TCR and symptomatic outcomes. The median patient age was 57.5 years (max = 81, interquartile range [IQR] = 51–67), and the median tumor volume was 3.55 cm3 (max = 25.2 cm3, IQR = 2.0–6.2 cm3). The median marginal and maximum doses were 13.0 Gy (max = 18.0 Gy, IQR = 12.5–15 Gy) and 23.8 Gy (max = 35 Gy, IQR = 21.7–25.0 Gy), respectively.
At a median follow-up of 90.5 months (max = 281 months, IQR = 49–139.75 months), the actuarial 3-, 5-, and 10-year TCR were 93.8, 86.2, and 80.8%, respectively. Our data and multivariate analysis indicated that the target volume was the only significant factor determining TCR and that larger tumors (> 5 cm3) were more likely to progress (p = 0.011). Cystic tumors had a higher incidence of transient enlargement and temporary symptom change compared to those in solid tumors. An unfavorable outcome of symptoms was observed in five patients (15.6%). Complications were observed in two patients (6.25%), including hydrocephalus and radio-induced trigeminal neuropathy, respectively.
GKRS can be a safe and effective treatment modality for TS with long-term follow-up, especially for small tumors. An extended period of follow-up observation is required to conclude the clinical response to GKRS.
KeywordsTrigeminal schwannoma Gamma knife radiosurgery Clinical outcome
Gamma knife radiosurgery
Tumor control rate
There is no personal financial or institutional interest in any of the drugs, materials, or devices described in this article.
Compliance with ethical standards
Conflicts of interest
The authors declare that they have no conflict of interest.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Informed consent was obtained from all individual participants included in the study.
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