Stereotactic Radiosurgery of Cavernous Sinus Meningiomas

Technical note: Enhanced radiosurgical planning for cavernous sinus tumors using T1 SPACE sequences with Motion-Sensitized Driven Equilibrium (MSDE)

BACKGROUND AND OBJECTIVE

Radiosurgery can serve as a primary, adjuvant, or salvage treatment modality for cavernous sinus tumors (CST), providing high tumor control. However, particularly with cavernous sinus expansion, there may be insufficient distance from the optic apparatus to perform radiosurgery safely. The internal carotid artery adjacent to the distal dural ring (ICAddr), when enhancing similarly to the CST, can be difficult to delineate, and can lead to over-contouring of target volume near the optic nerve and therefore increasing the risk of radiation-induced optic toxicity. To evaluate the efficacy and safety of 3D T1-weighted Turbo Spin-Echo (TSE) MR sequence with the Motion-Sensitized Driven Equilibrium (MSDE) technique in accurately delineating the internal carotid artery adjacent to the distal dural ring (ICAddr) to minimize the risk of radiation-induced optic toxicity during radiosurgery for cavernous sinus tumors (CST).

METHODS

Nine patients were treated for CST with Gamma Knife radiosurgery from 2021 to 2023, utilizing a 3D T1-weighted Turbo Spin-Echo (TSE) MR sequence with the Motion-Sensitized Driven Equilibrium (MSDE) technique. Improved delineation of the ICAddr from the lesion facilitated precise dosimetry near the optic nerve.

RESULTS

At a median follow-up of 15 months, all patients demonstrated stable disease with no reported tumor progression. The use of the T1-weighted TSE MR sequence with MSDE significantly improved the delineation of the ICAddr from the cavernous sinus tumors. Only one patient experienced a transient episode of diplopia. No additional visual deficits were reported.

CONCLUSION

The use of T1 SPACE sequence has enhanced the radiosurgical planning process for CST, allowing for more precise contouring of the lesion near the ICAddr and optic nerve and reducing radiation dose to the ipsilateral optic nerve. Integration of these techniques into standard practice may offer significant benefits for the radiosurgical management of CST.

Resection of Meningiomas Invading the Cavernous Sinus: Treatment Strategy and Clinical Outcomes

Background/Objectives: Resection of tumors invading the cavernous sinus (CS) carries a risk of injury to the cranial nerves and internal carotid artery. Therefore, radical surgery involving lesions around the CS remains challenging, especially for lesions invading the CS, optic sheath, and oculomotor cave. Here, we describe a surgical strategy for meningiomas invading these structures and report on the clinical outcomes. Methods: Surgical resection was indicated in patients with neurological symptoms or rapid tumor growth for the restoration of cranial nerve function. We investigated 13 patients who had preoperative images of CS invasion, underwent surgical resection, and were followed-up with magnetic resonance imaging for at least 1 year between July 2017 and July 2024. Their preoperative symptoms, postoperative course, adjuvant therapy, postoperative complications, degree of resection, and recurrence were evaluated. Results: The mean patient age was 59.1 years (range, 23-73 years), and 10 were female. Major preoperative symptoms included oculomotor nerve paresis in 8 patients (61.5%), abducens nerve paresis in 6 (46.2%), visual disturbance in 7 (53.8%), and brain swelling in 3 (23.1%). These symptoms improved at least partially after surgery in 7 (87.5%), 5 (83.3%), 7 (100%), and 3 (100%) patients, respectively. Major postoperative complications included contralateral visual deterioration in 1 patient (7.7%) and brief transient slight hemiparesis caused by internal carotid vasospasm or dissection in 2 (15.4%). Four patients with residual atypical meningioma in the CS underwent intensity-modulated radiotherapy (IMRT). The lesions in 6 patients recurred or regrew, resulting in additional treatment with stereotactic radiosurgery in 2 patients, IMRT in 3, and resection in 1. Conclusions: Our surgical strategy for the surgical resection of meningiomas in and around the CS for the restoration of cranial nerve function is safe and effective, with only transient acceptable injuries. Even if the tumor in the CS is too stiff to be removed, it is important to open the optic nerve sheath and oculomotor cave widely to effectively remove the tumor.

The safety and efficacy of robotic radiosurgery and radiotherapy in the management of skull base tumors: a systematic review and meta-analysis

Stereotactic radiosurgery (SRS) and radiotherapy (SRT) have gained prominence as both adjuvant and primary treatment options for patients with skull base tumors that are either inoperable or present as residual or recurrent lesions post-surgery. The object of the current study is to evaluate the safety and efficacy of robotic-assisted SRS and SRT across various skull base pathologies. The study was conducted under PRISMA guidelines and involved a comprehensive evaluation of databases, including PubMed, Scopus, Embase, Web-of-Science, and the Cochrane Library. The data collection period was extended up to 30 September. Statistical analyses were executed using Comprehensive Meta-Analysis software. Furthermore, Cochran's Q test assessed statistical heterogeneity within the findings. From an initial pool of 1,792 articles, 69 studies were included in the systematic review, with 60 qualifying for meta-analysis, encompassing 3,046 participants. Meta-analysis revealed tumor control rates were significantly enhanced with the use of CyberKnife (95% CI: 0.901-0.928, p < 0.001) and robotic Gamma Knife radiosurgery (GKRS) (95% CI: 0.897-0.959, p < 0.001). Meningiomas and schwannomas exhibited higher treatment responsiveness (ES: 0.960 and 0.949, respectively), whereas chordomas displayed lower responsiveness (ES: 0.743). The overall major adverse event rate was between 5.6% and 8.3% (95% CI: 0.056-0.083, p < 0.001). Adverse events exhibited a higher incidence in patients with adenomas (95% CI: 0.122-0.217, p < 0.001), while they were least prevalent in those with schwannomas (95% CI: 0.019-0.041, p < 0.001). Robotic SRS and SRT, employing both gamma-knife and cyber-knife, have demonstrated promising outcomes characterized by high efficacy and safety in managing various skull base tumors.

Functional and Radiographic Outcomes of Cavernous Meningiomas Based on Treatment Modality

Introduction  Cavernous sinus meningiomas (CSMs) are challenging given their proximity to neurovascular structures. Treatments include surgery, radiation, or observation. There are little data comparing outcomes based on treatment. This study presents the radiographic and functional outcomes of patients with CSMs treated with either radiation, surgical resection ± radiation, or radiographic surveillance. Methods  This is a retrospective review of adults diagnosed with CSMs between 2009 and 2016. Patient and tumor characteristics and outcomes were obtained from chart review. Categorical and continuous variables were compared via nonparametric tests. Results  Sixty-four patients were diagnosed with CSMs between 2009 and 2016. Thirty-four had radiation. Thirteen had surgical resection with adjuvant radiation and 14 underwent observation. Fifty-four patients had a pretreatment deficit (84.4%). Radiographic control rates were 100% in the surgery group, 97.1% in the radiation group, 69.2% in the surgery + adjuvant radiation, and 90.9% in the observation group ( p  = 0.035). The radiotherapy group had complete improvement of symptoms in 32.4% and partial improvement in 23.1% ( p  = 0.022). In the surgery group, one patient had complete resolution of symptoms (6.3%), eight had partial improvement (50.0%), and seven patients had no improvement ( p  = 0.002). Surgery was more likely to lead to progression of symptoms posttreatment (odds ratio: 5.16, confidence interval: 1.309-20.34) ( p  = 0.019). Conclusion  Radiation has an excellent rate of radiographic control. Surgery is an option for large or symptomatic lesions. The role of surgery is primarily for vision preservation, decompression of cranial nerves, and tumor debulking and patients should be counseled extensively regarding treatment goals and expectations prior to surgery.

Evaluating the Efficacy and Safety of CyberKnife for Meningiomas: A Systematic Review

This systematic review aims to evaluate CyberKnife (Accuray, Madison, WI, USA) radiosurgery's efficacy, safety, and outcomes in treating meningiomas, focusing on tumour control rates, symptom relief, survival rates, quality of life, and adverse events. A comprehensive literature search was conducted across PubMed, EMBASE, Web of Science, Google Scholar, and Cumulative Index to Nursing and Allied Health Literature (CINAHL), covering studies published in the last 20 years and available in English. The inclusion criteria targeted studies involving patients with meningioma treated with CyberKnife radiosurgery, reporting on specific outcomes of interest. Quality assessment was performed using the Newcastle-Ottawa Scale for observational studies, and a narrative synthesis approach was adopted for data analysis. Twenty-one studies met the inclusion criteria, encompassing various design types and patient demographics. The review highlights CyberKnife's effectiveness in managing benign and atypical meningiomas and specific challenging cases like perioptic lesions and large cranial base tumours. Key findings include high tumour control rates, preservation or improvement of visual functions in perioptic lesions, and promising results in benign spinal tumours and supratentorial meningiomas. Comparative analyses suggest better radiographic tumour control and a lower incidence of post-treatment complications with stereotactic radiotherapy over stereotactic radiosurgery. Long-term outcomes and safety profiles underline the viability of CyberKnife as a treatment option, with minimal permanent side effects reported. CyberKnife radiosurgery is a highly effective and safe treatment modality for meningiomas. It offers significant benefits in tumour control, symptom relief, and maintaining the quality of life with minimal adverse effects. The precision and adaptability of CyberKnife technology make it a valuable addition to the treatment arsenal for meningiomas. It necessitates further research and adoption in clinical practice, especially in regions like the United Arab Emirates, where its use is emerging.

Survey of Skull Base Surgeons' Approach to Carcinomas Involving the Cavernous Sinus

Objectives  Carcinomas involving the cavernous sinus are challenging to resect without compromising important neurovascular structures. Given the morbidity and mortality of these operations, radiotherapy, chemotherapy, and immunotherapy are more often utilized. Although limited to case reports and small series, radical resection of the cavernous sinus has been proposed. We aimed to study surgeons' willingness to perform cavernous sinus exenteration (CSE) under different clinical scenarios. Design, Setting, Participants, Main Outcome Measures  We conducted an online survey from April to July 2021 among members of the Skull Base Congress and the North American Skull Base Society. Descriptive statistics were used to analyze the main outcome measure of willingness to perform CSE . Results  The analytic sample ( n  = 112) included 54% otolaryngologists and 43% neurosurgeons. Eighty-six percent practiced in an academic setting. Surgeons' willingness to perform CSE was low (6-16% under different clinical scenarios), citing a belief that they could not obtain oncologic margins and the procedure's morbidity. Forty-five percent had at least one patient undergo CSE with 72% of patients surviving no more than 2 years. Complications included chronic intractable pain, cerebrospinal fluid leak, cerebrovascular accident, and/or intraoperative/postoperative death within 30 days. Sixty percent agreed that the availability of immunotherapy and genomic sequencing has affected their willingness to offer CSE. Conclusion  Overall, most of the surgeons surveyed were unwilling to offer CSE for carcinomatous cavernous sinus invasion, whether for primary disease or recurrence. Given the rarity of these tumors and the limited data on CSE, these results may provide more information for clinicians and patients for these treatment decisions.

Long-term Experience of LINAC Single-Dose Radiosurgery for Skull Base Meningiomas: A Retrospective Single-Center Study of 241 Cases

BACKGROUND AND OBJECTIVES

Stereotactic radiosurgery (SRS) is increasingly applied to treat meningiomas, attributable to their increased incidence in older individuals at greater surgical risk. To evaluate the effectiveness of treatment with linear accelerator (LINAC)-based stereotactic radiosurgery in skull base meningiomas as either primary treatment or postresection adjuvant therapy.

METHODS

This study included 241 patients diagnosed with skull base meningiomas treated by single-dose SRS, with a median age of 59 years. SRS was primary treatment in 68.1% (n = 164) and adjuvant treatment in 31.9% (n = 77), using LINAC (Varian 600, 6 MeV). The median tumor volume was 3.2 cm 3 , and the median coverage dose was 14 Gy. Bivariate and multivariate analyses were performed to determine predictive factors for tumor progression, clinical deterioration, and complications. Kaplan-Meier analysis was used for survival analysis.

RESULTS

After the median follow-up of 102 months, the tumor control rate was 91.2% (n = 220). Progression-free survival rates were 97.07%, 90.1%, and 85.7% at 5, 10, and 14 years, respectively. Clinical improvement was observed in 56 patients (23.2%). In multivariate analysis, previous surgery (hazard ratio 3.8 [95%CI 1.136-12.71], P = .030) and selectivity (hazard ratio .21 [95%CI 0.066-0.677], P = .009) were associated with tumor progression and increased maximum dose (odds ratio [OR] 4.19 [95% CI 1.287-13.653], P = .017) with clinical deterioration. The permanent adverse radiation effect rate was 6.2% (n = 15) and associated with maximum brainstem dose >12.5 Gy (OR 3.36 [95% CI .866-13.03], P = .08) and cerebellopontine angle localization (OR 3.93 [95% CI 1.29-11.98], P = .016).

CONCLUSION

Treatment of skull base meningiomas with single-dose SRS using LINAC is effective over the long term. Superior tumor control is obtained in patients without previous surgery. Adverse effects are related to localization in the cerebellopontine angle, and maximum brainstem radiation dose was >12.5 Gy.

Outcomes and predictors of response to fractionated radiotherapy as primary treatment for intracranial meningiomas

Background

Surgery is the primary treatment for most meningiomas. However, primary fractionated radiotherapy (fRT) remains an option for patients with larger meningiomas in challenging anatomic locations or patients at prohibitively high surgical risk. Outcome prediction for these patients is uncertain and cannot be guided by histopathology without available tumor tissue from surgery. Therefore, we aimed to assess the clinical factors that contribute to treatment failure in a large cohort of meningiomas consecutively treated with fRT as primary therapy, with the goal of identifying predictors of response.

Methods

Patients treated with primary fRT for intracranial meningiomas from 1998 to 2017 were reviewed. Those who received primary surgical resection, radiosurgery, previous fRT, or had <6 months of clinical follow-up were excluded. We applied logistic regression and Cox regression modeling to ascertain key predictors of treatment failure, progression-free survival (PFS), and adverse events (AE) following fRT.

Results

Our cohort included 137 meningiomas, 21 of which progressed after fRT (median PFS 3.45 years). Progressive meningiomas had a larger median gross tumor volume (GTV) compared to those that remained stable (19.1 cm³ vs 9.6 cm³, p = 2.86 × 10^-2). GTV > 11.27 cm³ was independently predictive of progression and larger GTV was associated with higher risk of significant (grades 3/4) AE following fRT. Cavernous sinus and optic nerve sheath meningiomas had overall excellent outcomes post-fRT.

Conclusions

We present a large cohort of meningiomas treated with primary fRT and find GTV and anatomic location to be key predictors of outcome, adding to the complex treatment considerations for this heterogeneous disease.

Pseudoprogression of Vestibular Schwannoma after Stereotactic Radiosurgery with Cyberknife®: Proposal for New Response Criteria

(1) Background: Transient increase in volume of vestibular schwannomas (VS) after stereotactic radiosurgery (SRS) is common and complicates differentiation between treatment-related changes (pseudoprogression, PP) and tumor recurrence (progressive disease, PD). (2) Methods: Patients with unilateral VS (n = 63) underwent single fraction robotic-guided SRS. Volume changes were classified according to existing RANO criteria. A new response type, PP, with a >20% transient increase in volume was defined and divided into early (within the first 12 months) and late (>12 months) occurrence. (3) Results: The median age was 56 (range: 20-82) years, the median initial tumor volume was 1.5 (range: 0.1-8.6) cm³. The median radiological and clinical follow-up time was 66 (range: 24-103) months. Partial response was observed in 36% (n = 23), stable disease in 35% (n = 22) and PP in 29% (n = 18) of patients. The latter occurred early (16%, n = 10) or late (13%, n = 8). Using these criteria, no case of PD was observed. (4) Conclusion: Any volume increase after SRS for vs. assumed to be PD turned out to be early or late PP. Therefore, we propose modifying RANO criteria for SRS of VS, which may affect the management of vs. during follow-up in favor of further observation.

Hypofractionated Radiosurgery for Large or in Critical-Site Intracranial Meningioma: Results of a Phase 2 Prospective Study

PURPOSE

Radiosurgery is a well-known, safe, and effective technique used in the treatment of intracranial meningiomas. However, single-fraction radiosurgery can lead to high toxicity rates when large-volume or critically located lesions are targeted. Multisession-also called hypofractionated-radiosurgery (hypo-RS) might overcome these limitations. Accordingly, we carried out a prospective phase 2 trial, aiming to establish whether a fractionated RS schedule of 25 Gy in 5 fractions would be safe and effective in treating large (≥ 3 cm) and/or critically located (<3 mm from critical structures) grade 1 intracranial meningiomas. The main aim was to evaluate the safety of hypo-RS in terms of absence of adverse events. The secondary aim was to evaluate tumor response in terms of local control, defined as stability or reduction of lesion volume.

METHODS AND MATERIALS

We prospectively enrolled patients with diagnoses of grade 1 meningiomas, large size and/or critically located lesions, either histologically diagnosed or imaging defined. Additional inclusion criteria were signed informed consent, an age of ≥18 years, and Karnofsky Performance Status ≥70.

RESULTS

Between 2011 and 2016, 178 patients were consecutively enrolled. The median follow-up was 53 months (range, 4-101 months). Overall, the toxicity rate was 12.7% (21 of 166 patients). At a 5-year minimum follow-up, the patients' toxicity rates were 11.7 % (9 of 77 patients). Symptom evaluation at both 3-year and last follow-up showed an improvement in most of the patients. Five-year local tumor control was 97% (95% confidence interval, 92%-99%).

CONCLUSIONS

Hypo-RS schedule of 25 Gy in 5 fractions is a well-tolerated option in the treatment of large-volume and/or critically located benign meningiomas. Early results suggest favorable local control, although longer-term follow-up is needed.

Stereotactic Therapies for Meningiomas

Although surgery remains the mainstay of treatment for most meningiomas, radiotherapy, specifically stereotactic radiosurgery, has become more commonplace as first-line therapy for select meningioma cases, particularly small meningiomas in challenging or high-risk anatomic locations. Radiosurgery for specific groups of meningiomas have been found to provide local control rates comparable to surgery alone. In this chapter stereotactic techniques for the treatment of meningiomas such as stereotactic radiosurgery by using Gamma knife or Linear Accelerator-based techniques (modified LINAC, Cyberknife, etc.) as well as stereotactically guided implantation or radioactive seeds for brachytherapy are introduced.

Identification and Management of Aggressive Meningiomas

Meningiomas are common primary central nervous system tumors derived from the meninges, with management most frequently entailing serial monitoring or a combination of surgery and/or radiation therapy. Although often considered benign lesions, meningiomas can not only be surgically inaccessible but also exhibit aggressive growth and recurrence. In such cases, adjuvant radiation and systemic therapy may be required for tumor control. In this review, we briefly describe the current WHO grading scale for meningioma and provide demonstrative cases of treatment-resistant meningiomas. We also summarize frequently observed molecular abnormalities and their correlation with intracranial location and recurrence rate. We then describe how genetic and epigenetic features might supplement or even replace histopathologic features for improved identification of aggressive lesions. Finally, we describe the role of surgery, radiotherapy, and ongoing systemic therapy as well as precision medicine clinical trials for the treatment of recurrent meningioma.

Stereotactic radiosurgery for treating meningiomas eligible for complete resection

BACKGROUND

For meningiomas, complete resection is recommended as first-line treatment while stereotactic radiosurgery (SRS) is established for meningiomas of smaller size considered inoperable. If the patient´s medical condition or preference excludes surgery, SRS remains a treatment option. We evaluated the efficacy and safety of SRS in a cohort comprising these cases.

METHODS

In this retrospective single-centre analysis we included patients receiving single fraction SRS either by modified LINAC or robotic guidance by Cyberknife for potentially resectable intracranial meningiomas. Treatment-related adverse events as well as local and regional control rates were determined from follow-up imaging and estimated by the Kaplan-Meier method.

RESULTS

We analyzed 188 patients with 218 meningiomas. The median radiological, and clinical follow-up periods were 51.4 (6.2-289.6) and 55.8 (6.2-300.9) months. The median tumor volume was 4.2 ml (0.1-22), and the mean marginal radiation dose was 13.0 ± 3.1 Gy, with reference to the 80.0 ± 11.2% isodose level. Local recurrence was observed in one case (0.5%) after 239 months. The estimated 2-, 5-, 10- and 15-year regional recurrence rates were 1.5%, 3.0%, 6.6% and 6.6%, respectively. Early adverse events (≤ 6 months after SRS) occurred in 11.2% (CTCEA grade 1-2) and resolved during follow-up in 7.4% of patients, while late adverse events were documented in 14.4% (grade 1-2; one case grade 3). Adverse effects (early and late) were associated with the presence of symptoms or neurological deficits prior to SRS (p < 0.03) and correlated with the treatment volume (p < 0.02).

CONCLUSION

In this analysis SRS appears to be an effective treatment for patients with meningiomas eligible for complete resection and provides reliable long-term local tumor control with low rates of mild morbidity.

Stereotactic radiosurgery of benign brain tumors in elderly patients: evaluation of outcome and toxicity

BACKGROUND

Stereotactic radiosurgery (SRS) is widely accepted as a therapeutic option for meningiomas (M) and vestibular schwannomas (VS). However, data on outcome and toxicity in the elderly population have rarely been reported in detail.

METHODS

All patients aged ≥ 65 years with M or VS who underwent single fraction SRS were included. Patient data were analyzed in terms of clinical tumor control and incidence of early and late treatment related complications, which were graded according to the Common Terminology Criteria for Adverse Events (CTCAE), RESULTS: We identified 245 patients with benign brain tumors (129 M and 116 VS, median tumor volume 2.9 ml, range 0.1-28). The median age was 71 years (range 65-86) and the mean follow-up times were 42 months (range 2-181). Tumors were irradiated with a median dose of 12.4 Gy. Actuarial clinical and radiological tumor control rates at 2, 5, and 10 years after SRS were 98%, 93%, and 88%, respectively. Recurrent tumors after previous treatment had a higher probability of post-radiosurgical progression (p < 0.001). Permanent toxicity (CTCAE I/II) were noted in 5.7%. No severe adverse events were observed during early and late follow up, although patients > 70 years had a slightly higher risk for toxicity (p = 0.027). The presence and extent of co-morbidities had no significant influence on local tumor control or toxicity.

CONCLUSION

SRS provides favorable tumor control with low risk for treatment-related severe complications. Thus, SRS should always be considered as treatment option for benign intracranial tumors (meningiomas, schwannomas), especially in the group of elderly patients.