Long-term tumor control after Gamma Knife radiosurgery for sporadic vestibular schwannoma

J Neurosurg 144:965–971, 2026

This clinical study evaluates long-term tumor control after single-fraction Gamma Knife stereotactic radiosurgery (SRS) for sporadic vestibular schwannoma in 749 adults treated from 2000–2022, reporting Kaplan–Meier control rates of 100%, 98%, 96%, 92%, and 91% at 1, 3, 5, 10, and 15 years respectively. Patient demographics, SRS dosing, and complication rates—including low persistent facial paresis—are summarized with statistical analysis and clear definitions for growth, pseudoprogression, and salvage.

The authors detail three post-SRS tumor behavior patterns, finding 13% pseudoprogression (mostly within 5 years) and 42 salvage treatments (median 3.7 years), and conclude that SRS offers durable control while emphasizing the need for prolonged surveillance and nuanced clinical decision-making about retreatment.

Objective Assess long-term efficacy of single-fraction stereotactic radiosurgery (SRS) as primary treatment for adult, treatment-naïve sporadic vestibular schwannoma (Gamma Knife), treated from 2000–2022.

Cohort 749 adults included; 76% had tumors extending into the cerebellopontine angle (CPA) at SRS; median age 62; 50% women; 99% had House-Brackmann (HB) grade I facial nerve function at SRS.

Long-term tumor control Tumor control after SRS remained high: 100% (1 yr), 98% (3 yr), 96% (5 yr), 92% (10 yr), and 91% (15 yr).

Radiosurgical failure/salvage 42 patients required salvage (35 microsurgery, 7 repeat SRS), median 3.7 years post-SRS; 3 salvage treatments occurred >10 years after SRS, indicating late failures can occur.

Risk factors Age, macrocystic tumor presence, and treated tumor volume were not significantly associated with risk of salvage in univariable analysis.

Post-SRS tumor patterns Three post-SRS behaviors were observed: (1) stability/shrinkage, (2) pseudoprogression (growth then stability/shrinkage), and (3) continued growth without stability at last follow-up.

Pseudoprogression timing 13% experienced pseudoprogression; all but 4 showed it by year 5 post-SRS, though some initial growth occurred later (e.g., 5.1–8.6 years) with subsequent stability on follow-up imaging.

Conclusion/implication SRS provides durable control through 15 years for most patients (91%), but ongoing long-term surveillance is needed because failures may occur even beyond 10 years and pseudoprogression can be seen out to ≥5 years.

Volumetric Growth and Growth Curve Analysis of Residual Intracranial Meningioma

Neurosurgery 92:734–744, 2023

After meningioma surgery, approximately 1 in 3 patients will have residual tumor that requires ongoing imaging surveillance. The precise volumetric growth rates of these tumors are unknown.

OBJECTIVE: To identify the volumetric growth rates of residual meningioma, growth trajectory, and factors associated with progression.

METHODS: Patients with residual meningioma identified at a tertiary neurosurgery center between 2004 and 2020 were retrospectively reviewed. Tumor volumewas measured using manual segmentation, after surgery and at every follow-up MRI scan. Growth rates were ascertained using a linear mixed-effects model and nonlinear regression analysis of growth trajectories. Progression was defined according to the Response Assessment in Neuro- Oncology (RANO) criteria (40% volume increase).

RESULTS: There were 236 patients with residual meningioma. One hundred and thirtytwo patients (56.0%) progressed according to the RANO criteria, with 86 patients being conservatively managed (65.2%) after progression. Thirteen patients (5.5%) developed clinical progression. Over a median follow-up of 5.3 years (interquartile range, 3.5–8.6 years), the absolute growth rate was 0.11 cm3 per year and the relative growth rate 4.3% per year. Factors associated with residual meningioma progression in multivariable Cox regression analysis were skull base location (hazard ratio [HR] 1.60, 95% CI 1.02–2.50) and increasing Ki-67 index (HR 3.43, 95% CI 1.19–9.90). Most meningioma exhibited exponential and logistic growth patterns (median R2 value 0.84, 95% CI 0.60–0.90).

CONCLUSION: Absolute and relative growth rates of residual meningioma are low, but most meet the RANO criteria for progression. Location and Ki-67 index can be used to stratify adjuvant treatment and surveillance paradigms.

Cavernous sinus aneurysms: risk of growth over time and risk factors

J Neurosurg 132:22–26, 2020

Cavernous internal carotid artery (ICA) aneurysms are frequently diagnosed incidentally and the benign natural history of these lesions is well known, but there is limited information assessing the risk of growth in untreated patients. The authors sought to assess and analyze risk factors in patients with cavernous ICA aneurysms and compare them to those of patients with intracranial berry aneurysms in other locations.

METHODS Data from consecutive patients who were diagnosed with a cavernous ICA aneurysm were retrospectively reviewed. The authors evaluated patients for the incidence of cavernous ICA aneurysm growth and rupture. In addition, the authors analyzed risk factors for cavernous ICA aneurysm growth and compared them to risk factors in a population of patients diagnosed with intracranial berry aneurysms in locations other than the cavernous ICA during the same period.

RESULTS In 194 patients with 208 cavernous ICA aneurysms, the authors found a high risk of aneurysm growth (19.2% per patient-year) in patients with large/giant aneurysms. Size was significantly associated with higher risk of growth. Compared to patients with intracranial berry aneurysms in other locations, patients with cavernous ICA aneurysms were significantly more likely to be female and have a lower incidence of hypertension.

CONCLUSIONS Aneurysms of the cavernous ICA are benign lesions with a negligible risk of rupture but a definite risk of growth. Aneurysm size was found to be associated with aneurysm growth, which can be associated with new onset of symptoms. Serial follow-up imaging of a cavernous ICA aneurysm might be indicated to monitor for asymptomatic growth, especially in patients with larger lesions.

 

Correlation of volumetric growth and histological grade in 50 meningiomas

Acta Neurochir (2017) 159:2169–2177

Advances in radiological imaging techniques have enabled volumetric measurements of meningiomas to be easily monitored using serial imaging scans. There is limited literature on the relationship between tumour growth rates and the WHO classification of meningiomas despite tumour growth being a major determinant of type and timing of intervention. Volumetric growth has been successfully used to assess growth of low-grade glioma; however, there is limited information on the volumetric growth rate (VGR) of meningiomas. This study aimed to determine the reliability of VGR measurement in patients with meningioma, assess the relationship between VGR and 2016 WHO grading as well as clinical applicability of VGR in monitoring meningioma growth.

Methods All histologically proven intracranial meningiomas that underwent resection in a single centre between April 2009 and April 2014 were reviewed and classified according to the 2016 edition of the Classification of the Tumours of the CNS. Only patients who had two pre-operative scans that were at least 3 months apart were included in the study. Two authors performed the volumetric measurements using the Slicer 3D software independently and the inter-rater reliability was assessed. Multiple regression analyses of factors affecting the VGR and VDE of meningiomas were performed using the R statistical software with p < 0.05 considered to be statistically significant.

Results Of 548 patients who underwent resection of their meningiomas, 66 met the inclusion criteria. Sixteen cases met the exclusion criteria (NF2, spinal location, previous surgical or radiation treatment, significant intra-osseous component and poor quality imaging). Forty-two grade I and 8 grade II meningiomas were included in the analysis. The VGR was significantly higher for grade II meningiomas. Using receiver-operator characteristic (ROC) curve analysis, the optimal threshold that distinguishes between grade I and II meningiomas is 3 cm3/year. Higher histological grade, high initial tumour volume, MRI T2-signal hyperintensity and presence of oedema were found to be significant predictors of higher VGR.

Conclusion Reliable tools now exist to evaluate and monitor volumetric growth of meningiomas. Grade II meningiomas have significantly higher VGR compared with grade I meningiomas and growth of more than 3 cm3/year is strongly suggestive of a higher grade meningioma. A larger, multi-centre prospective study to investigate the applicability of velocity of growth to predict the outcome of patients with meningioma is warranted.

Keywords

Incidence of growth and rupture of unruptured intracranial aneurysms followed by serial MRA

Incidence of growth and rupture of unruptured intracranial aneurysms followed by serial MRA

Acta Neurochir (2013) 155:211–216

The natural history, including growth and rupture, of unruptured intracranial aneurysms (UIAs) remains unknown. Here, we present the results of serial magnetic resonance angiography (MRA) follow-up study in 111 patients with 136 UIAs.

Method A total of 111 patients with 136 UIAs were followed annually over the past 12 years, using 1.5-Tesla MRA. Follow-up was ended when UIAs were treated surgically, or the patients died of subarachnoid hemorrhage or other causes. Various factors influencing aneurysm rupture or growth were examined statistically.

Results Aneurysm rupture and growth occurred in six and 13 of the 111 patients, respectively. Annual rupture rate was 1.8 % per year and annual growth rate was 3.9 % per year. Aneurysm size was the sole factor influencing rupture(H.R. 1.214, 95 % CI, 1.078–1.368) and multiplicity was the sole factor influencing aneurysm growth (H.R. 5.174, 95 % CI 1.81–14.80).

Conclusions Serial MRA study showed that the incidence of UIA growth was twice as high as that of UIA rupture. As four patients showed aneurysm rupture or growth within 1 year, further investigations are necessary to determine the optimum interval of radiological investigation and to identify which UIAs grow or rupture within a short time.