Long‐term clinical outcomes of stereotactic radiosurgery and hypofractionated stereotactic radiotherapy using the CyberKnife^® robotic radiosurgery system for vestibular schwannoma

Abstract

Aim The study aimed to evaluate the long‐term clinical outcomes of patients with vestibular schwannoma (VS) treated with stereotactic radiosurgery (SRS) and hypofractionated stereotactic radiotherapy (HSRT) with frameless robotic whole‐body radiosurgery system (CyberKnife®). Methods This retrospective analysis of prospectively collected data included 123 consecutive patients with VS treated at the Radiosurgery center, Ramathibodi Hospital, Bangkok, Thailand. SRS was recommended for patients with unserviceable hearing and Koos grade I–III tumors, and HSRT for patients with serviceable hearing or Koos grade III–IV tumors. Between March 2009 and December 2015, 23 patients (19%) were treated with SRS, whereas 100 (81%) received HSRT. The commonly used regimen was 12 Gy in one fraction for SRS and 18 Gy in three fractions for HSRT. Results After a median follow‐up of 72 months (range: 12–123 months), the 5‐year and 8‐year progression‐free survival (PFS) rates for the whole cohort were 96% and 92%, respectively. The PFS was not significantly different between the SRS and HSRT groups (p = 0.23). Among 28 patients with serviceable hearing in the HSRT group, the 5‐year and 8‐year hearing preservation rates were 87% and 65%, respectively. The rate of nonauditory complications was 14%. Koos grade III/IV was a predictor of disease progression and was associated with nonauditory complications. Conclusion SRS and HSRT with the CyberKnife® system provided excellent long‐term tumor control with a low rate of nonauditory complications. HSRT may result in acceptable hearing preservation rates.

Stereotactic radiotherapy in acoustic neuroma cases: Tumor control and clinical results

“…In a meta-analysis published in 2017, the mean LCR was 96.3%, according to the results of 11 studies involving 800 patients in which CK-SRT was applied [21]. In another recently published study examining 123 patients who underwent CK-SRT with a median extended follow-up of 6 years, 5-y, and 8-y progression-free survival was reported to be 96% and 92% [22]. In light of these studies, it is possible to say that there are similar and excellent LCR in terms of both GK and CK-based radiosurgery.…”

“…Tamura et al [29] suggested that serviceable hearing can be preserved in patients with good hearing function at the beginning, under the age of 50, and whose cochlea dose did not exceed 4 Gy. Hearing protection was reported to be over 50% in CK SRT studies [19,21,22]. However, these results may be misleading due to the small number of patients, the relatively small tumor diameter, and the inadequacy of audiogram examinations.…”

Long-term clinical outcomes of stereotactic radiotherapy for bilateral vestibular schwannomas in neurofibromatosis type 2 patients

“…Fractionated dosing is theoretically safer for the vestibulocochlear nerve and cochlea than a single large radiosurgical dose and might improve treatment outcomes, particularly hearing and facial/trigeminal nerve function outcomes. Although treatment of sporadic VSs using HSRT has been previously reported [11], the role of HSRT for treating VS-NF2 is unclear. To the best of our knowledge, this is the rst study to report long-term clinical outcomes of HSRT treatment of VS-NF2.…”

Hearing Function after CyberKnife for Vestibular Schwannoma: A Systematic Review

“…The 46 remaining articles had their full text read, and 33 were excluded due to the following reasons: the hearing classification system specified in the eligibility criteria was not used or it was used inadequately (for example: considering GR grade III or AAO-HNS class C as serviceable hearing); [15][16][17][18][19] inadequate study design; [20][21][22][23] incomplete study; [24][25][26][27][28][29][30][31][32][33][34] use of another radiation source; 35,36 same population from others studies; [37][38][39][40][41] and inadequate data report [42][43][44][45][46][47] (the corresponding authors of these studies were contacted to request additional information, but there was no response). Then, a total of 13 studies [48][49][50][51][52][53][54][55][56][57][58][59][60] we...…”