Stereotactic radiosurgery (SRS) is the preferred treatment for vestibular schwannoma (VS) in patients with preserved hearing and tumour less than 3cm [1,2]. Linac-based SRS has grown technically more advanced with its ability to utilise IMRT and VMAT techniques, with the possibility of better sparing of OARs, especially the cochlea. Emerging evidence suggests restricting the cochlear dose improves hearing preservation, but limiting the dose to the cochlea at the expense of tumour coverage is not currently recommended [3,4]. This study aims to compare dynamic conformal arc...

Eighteen patients previously treated for VS with SRS, between 2000 and 2015, were included in this retrospective study. Selection criteria included Unilateral vestibular schwannoma Serviceable hearing (pre-treatment pure-tone average less than 50 decibels) Availability of CT and MRI for planning. The original tumour target volume and brainstem OAR volume were retained; as it was not a routine practice to contour cochlea in our institution, the cochlea was newly contoured (Image 1) using the bone window of the planning CT scan. For each case, the radiosurgery...

Mean tumour volume was 2.25 cc (SD 2.26) (Tumour characteristics are provided in Table 1). Mean dose, D2 and D98 to the target were similar across all techniques (Table 2). The conformity index (RTOG and Paddick) was similar for VMAT and DCAT, but was superior to IMRT (Table 3); the Gradient Index was lowest in DCAT compared to VMAT and IMRT (Table 3). VMAT produced 2.12 Gy and 2.32 Gy lower cochlear mean dose (mean difference), 2.56 Gy and 2.42 Gy lower cochlear max (D0.03)...

Radiosurgery with VMAT technique for vestibular schwannoma reduces cochlear and brainstem dose compared to DCAT or IMRT techniques. VMAT technique should be considered for patients with vestibular schwannoma and preserved hearing to maximum cochlear dose sparing.

Tsao MN, Sahgal A, Xu W, De Salles A, Hayashi M, Levivier M, et al. Stereotactic radiosurgery for vestibular schwannoma: International Stereotactic Radiosurgery Society (ISRS) Practice Guideline. J Radiosurg SBRT. 2017;5(1):5-24. Wolbers JG, Dallenga AH, Mendez Romero A, van Linge A. What intervention is best practice for vestibular schwannomas? A systematic review of controlled studies. BMJ Open. 2013;3(2). Goldbrunner R, Weller M, Regis J, Lund-Johansen M, Stavrinou P, Reuss D, et al. EANO guideline on the diagnosis and treatment of vestibular schwannoma. Neuro Oncol. 2020;22(1):31-45....