Stereotactic Radiosurgery for Vestibular Schwannoma in Neurofibromatosis Type 2: An International Multicenter Case Series of Response and Malignant Transformation Risk

Abstract

BACKGROUND:Vestibular schwannomas (VSs) related to neurofibromatosis type 2 (NF2) are challenging tumors. The increasing use of stereotactic radiosurgery (SRS) necessitates further investigations of its role and safety.OBJECTIVE:To evaluate tumor control, freedom from additional treatment (FFAT), serviceable hearing preservation, and radiation-related risks of patients with NF2 after SRS for VS.METHODS:We performed a retrospective study of 267 patients with NF2 (328 VSs) who underwent single-session SRS at 12 centers participating in the International Radiosurgery Research Foundation. The median patient age was 31 years (IQR, 21-45 years), and 52% were male.RESULTS:A total of 328 tumors underwent SRS during a median follow-up time of 59 months (IQR, 23-112 months). At 10 and 15 years, the tumor control rates were 77% (95% CI: 69%-84%) and 52% (95% CI: 40%-64%), respectively, and the FFAT rate were 85% (95% CI: 79%-90%) and 75% (95% CI: 65%-86%), respectively. At 5 and 10 years, the serviceable hearing preservation rates were 64% (95% CI: 55%-75%) and 35% (95% CI: 25%-54%), respectively. In the multivariate analysis, age (hazards ratio: 1.03 [95% CI: 1.01-1.05]; P = .02) and bilateral VSs (hazards ratio: 4.56 [95% CI: 1.05-19.78]; P = .04) were predictors for serviceable hearing loss. Neither radiation-induced tumors nor malignant transformation were encountered in this cohort.CONCLUSION:Although the absolute volumetric tumor progression rate was 48% at 15 years, the rate of FFAT related to VS was 75% at 15 years after SRS. None of the patients with NF2-related VS developed a new radiation-related neoplasm or malignant transformation after SRS.

In Reply: Stereotactic Radiosurgery for Vestibular Schwannoma in Neurofibromatosis Type 2: An International Multicenter Case Series of Response and Malignant Transformation Risk

“…We read with great interest the commentary provided by Hannan et al 1 regarding our article "Stereotactic Radiosurgery for Vestibular Schwannoma in Neurofibromatosis Type 2: An International Multicenter Case Series of Response and Malignant Transformation Risk." 2 We appreciate the opportunity to respond to the thoughtful comments of our esteemed colleagues from the United Kingdom.…”

“…We affirm the necessity of stringent and meticulous criteria in evaluating the potential for RRM in patients with NF2, as highlighted in various studies. 1,12,13 Although the study cited by the authors reported an estimated 5% RRM risk, in some cases, identifying RRM hinged on the radiological observation of rapid tumor growth-a characteristic not uncommon in aggressive NF2 cases. 14,15 If tumors were indeed malignant, its swift growth would likely necessitate surgical resection and subsequent histological diagnosis.…”

“…We read with great interest the commentary provided by Hannan et al 1 regarding our article "Stereotactic Radiosurgery for Vestibular Schwannoma in Neurofibromatosis Type 2: An International Multicenter Case Series of Response and Malignant Transformation Risk." 2 We appreciate the opportunity to respond to the thoughtful comments of our esteemed colleagues from the United Kingdom. Their ongoing commitment to the scientific studies related to neurofibromatosis type 2 (NF2), as demonstrated by their coordinated work across multiple centers, is a testament to their dedication to understand this disorder and its impact.…”

Letter: Stereotactic Radiosurgery for Vestibular Schwannoma in Neurofibromatosis Type 2: An International Multicenter Case Series of Response and Malignant Transformation Risk

“…We read with interest the recent publication by Bin-Alamer et al 1 which reported the results of a multi-institutional retrospective cohort study assessing the outcomes of stereotactic radiosurgery (SRS) NF2-schwannomatosis (NF2-SWN)–associated vestibular schwannomas (VS). The authors described the results of SRS treatment of 328 VS in 267 patients, with a median follow-up duration of 59 months.…”

Vestibular Schwannoma Stereotactic Radiosurgery in Octogenarians: Case Series

“…3 Given the minimally invasive nature of stereotactic radiosurgery (SRS) and its safety and efficacy in the management of VS, we sought to better understand the outcomes when VS SRS was performed in octogenarians. [3][4][5] In this study, we examined tumor control, need for additional tumor management and survival after SRS for VS in octogenarians.…”