Frameless gamma knife stereotactic radiosurgery for over two hundred vestibular schwannoma patients - a single institution experience.
Gamma Knife radiosurgery (GKRS) as definitive treatment for vestibular schwannomas (VS) provides high rates of tumor control. Traditionally, treatment immobilization necessitated a rigid stereotactic frame. The Gamma Knife Icon (Elekta AB) system enables frameless, mask-based immobilization. This study evaluates tumor control and hearing preservation after single- or five-fraction frameless GKRS for VS.
We reviewed 206 patients with unilateral VS who underwent definitive single- or five-fraction GKRS with frameless immobilization between 2017 and 2024, ultimately including 170 patients with untreated VS. Radiographic follow-up was available for 112 patients, 40 of whom had both baseline and follow-up audiometric follow-up. Tumor control was assessed volumetrically on MRI and categorized as progressive, stable, partial response, complete response, or transient swelling. Serviceable hearing was defined as American Academy of Otolaryngology-Head and Neck Surgery class A or B. Kaplan-Meier methods estimated tumor control and and serviceable hearing preservation, and Cox regression evaluated associations with outcomes.
Among 112 patients with radiographic follow-up (median 2.3 years), 1- and 3-year tumor control rates were 97.1% and 93.7%. At last follow-up, 75.9% demonstrated stable disease or partial response, and 7 patients (6.3%) developed progressive disease. Of 76 patients with baseline serviceable hearing, 40 had audiometric follow-up; serviceable hearing preservation at 1 and 3 years was 71.1% and 33.8%, though 3-year data was limited. No factors were significantly associated with tumor control or hearing preservation.
Frameless GKRS for VS achieves acceptable tumor control that is comparable to historical frame-based series. These findings support the selective use of frameless GKRS, although warrant prospective studies with standardized radiologic and audiologic follow-up.
We reviewed 206 patients with unilateral VS who underwent definitive single- or five-fraction GKRS with frameless immobilization between 2017 and 2024, ultimately including 170 patients with untreated VS. Radiographic follow-up was available for 112 patients, 40 of whom had both baseline and follow-up audiometric follow-up. Tumor control was assessed volumetrically on MRI and categorized as progressive, stable, partial response, complete response, or transient swelling. Serviceable hearing was defined as American Academy of Otolaryngology-Head and Neck Surgery class A or B. Kaplan-Meier methods estimated tumor control and and serviceable hearing preservation, and Cox regression evaluated associations with outcomes.
Among 112 patients with radiographic follow-up (median 2.3 years), 1- and 3-year tumor control rates were 97.1% and 93.7%. At last follow-up, 75.9% demonstrated stable disease or partial response, and 7 patients (6.3%) developed progressive disease. Of 76 patients with baseline serviceable hearing, 40 had audiometric follow-up; serviceable hearing preservation at 1 and 3 years was 71.1% and 33.8%, though 3-year data was limited. No factors were significantly associated with tumor control or hearing preservation.
Frameless GKRS for VS achieves acceptable tumor control that is comparable to historical frame-based series. These findings support the selective use of frameless GKRS, although warrant prospective studies with standardized radiologic and audiologic follow-up.
Authors
Daniell Daniell, Gallitto Gallitto, Li Li, Garcia Camargo Garcia Camargo, Chen Chen, Sedor Sedor, Patel Patel, Xu Xu, Shih Shih, Elliston Elliston, Wang Wang, Sisti Sisti
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