J Neurosurg 145:721–731, 2026
How long should imaging continue after apparently successful radiosurgery for a vestibular schwannoma? This large single-center series follows 878 patients after single-session Gamma Knife treatment, with a median clinical follow-up exceeding 12 years. Patients stable and free of salvage treatment during the first 5 years had very little subsequent true progression. Hearing preservation improved in the more recent treatment era, while delayed cystic and cranial-nerve complications remained uncommon but possible. The findings support less intensive imaging after a decade of stability, not the complete abandonment of individualized clinical follow-up.
Objective
To evaluate the long-term durability, functional outcomes and late adverse events of Gamma Knife surgery for sporadic vestibular schwannoma and determine whether routine imaging intensity can be reduced after prolonged stability.
Methods
This retrospective single-center study included 878 patients treated with single-session Gamma Knife surgery between May 1991 and January 2020. Tumors were classified from intracanalicular disease through severe brainstem compression using a modified Koos-based system. A prespecified subgroup contained 793 patients with at least 5 years of follow-up and no salvage treatment during the first 5 years.
Main results
The median clinical follow-up was 154.5 months. Overall, 7.5% required salvage treatment. Early salvage was more frequent for tumors with severe brainstem compression and fourth-ventricle deviation: 24.7% at 5 years versus 3.6% for less advanced types.
Among patients stable during the first 5 years, cumulative salvage incidence at 15 years was 2.1%, and true progression was identified in only two patients (0.3%). In patients with Gardner–Robertson class I hearing, 10-year serviceable-hearing preservation improved from 48% in the 1991–2004 era to 63% in 2005–2023. Delayed cyst-related complications occurred in 3.1%, trigeminal neuralgia in 1.6%, persistent facial palsy in 0.1% and malignant transformation in 0.2%.
Interpretation
Early anatomical severity predicts the initial need for rescue, but prolonged stability is strongly reassuring. The very low late-progression rate makes indefinite frequent MRI difficult to justify in every stable patient. Nevertheless, the presence of rare delayed effects means that surveillance should transition to a risk-adapted strategy with clear instructions for symptom-triggered reassessment.
Limitations
This was a retrospective experience from one high-volume center over almost three decades. Dose planning, imaging quality, hearing assessment and selection for radiosurgery evolved substantially. The proposal to reduce surveillance is inferred from observed event rates rather than tested prospectively, and the results apply principally to sporadic small- and medium-sized tumors suitable for single-session treatment.
Clinical takeaway
After Gamma Knife surgery, maintain closer imaging during the first years, especially for large tumors with brainstem compression. If control remains stable through 5 years and no concerning symptoms develop, progressively lengthen intervals; after 10 years, consider individualized low-intensity surveillance while preserving access for new hearing, facial, trigeminal, vestibular or hydrocephalic symptoms.
You must be logged in to post a comment.