Edema following Gamma Knife radiosurgery for parasagittal and parafalcine meningiomas

Predictors of salvage therapy for parasagittal meningiomas treated with primary surgery, radiosurgery, or surgery plus adjuvant radiotherapy

OBJECTIVE

Parasagittal meningiomas (PM) are treated with primary microsurgery, radiosurgery (SRS), or surgery with adjuvant radiation. We investigated predictors of tumor progression requiring salvage surgery or radiation treatment. We sought to determine whether primary treatment modality, or radiologic, histologic, and clinical variables were associated with tumor progression requiring salvage treatment.

METHODS

Retrospective study of 109 consecutive patients with PMs treated with primary surgery, radiation (RT), or surgery plus adjuvant RT (2000-2017) and minimum 5 years follow-up. Patient, radiologic, histologic, and treatment data were analyzed using standard statistical methods.

RESULTS

Median follow up was 8.5 years. Primary treatment for PM was surgery in 76 patients, radiation in 16 patients, and surgery plus adjuvant radiation in 17 patients. Forty percent of parasagittal meningiomas in our cohort required some form of salvage treatment. On univariate analysis, brain invasion (OR: 6.93, p < 0.01), WHO grade 2/3 (OR: 4.54, p < 0.01), peritumoral edema (OR: 2.81, p = 0.01), sagittal sinus invasion (OR: 6.36, p < 0.01), sagittal sinus occlusion (OR: 4.86, p < 0.01), and non-spherical shape (OR: 3.89, p < 0.01) were significantly associated with receiving salvage treatment. On multivariate analysis, superior sagittal sinus invasion (OR: 8.22, p = 0.01) and WHO grade 2&3 (OR: 7.58, p < 0.01) were independently associated with receiving salvage treatment. There was no difference in time to salvage therapy (p = 0.11) or time to progression (p = 0.43) between patients receiving primary surgery alone, RT alone, or surgery plus adjuvant RT. Patients who had initial surgery were more likely to have peritumoral edema on preoperative imaging (p = 0.01). Median tumor volume was 19.0 cm3 in patients receiving primary surgery, 5.3 cm3 for RT, and 24.4 cm3 for surgery plus adjuvant RT (p < 0.01).

CONCLUSION

Superior sagittal sinus invasion and WHO grade 2/3 are independently associated with PM progression requiring salvage therapy regardless of extent of resection or primary treatment modality. Parasagittal meningiomas have a high rate of recurrence with 80.0% of patients with WHO grade 2/3 tumors with sinus invasion requiring salvage treatment whereas only 13.6% of the WHO grade 1 tumors without sinus invasion required salvage treatment. This information is useful when counseling patients about disease management and setting expectations.

The Efficacy and Tolerability of Radiosurgery in Treating Benign Meningiomas: A Dose Comparison Study from a Single-Center Analysis

This retrospective study aimed to evaluate the impact of radiation dose on the outcomes of stereotactic radiosurgery (SRS) for benign meningiomas and determine an optimal dosing strategy for balancing tumor control and treatment-related toxicity. Clinical data of 147 patients with 164 lesions treated between 2014 and 2022 were reviewed. Primary outcomes included progression-free survival (PFS), local control rate (LCR), and radiation-induced toxicity, with secondary outcomes focusing on LCR and radiation-induced peritumoral edema (PTE) in two dose groups (≥14 Gy and <14 Gy). The results revealed a median follow-up duration of 47 months, with 1-year, 2-year, and 5-year PFS rates of 99.3%, 96.7%, and 93.8%, respectively, and an overall LCR of 95.1%. Radiation-induced toxicity was observed in 24.5% of patients, primarily presenting mild symptoms. Notably, no significant difference in LCR was found between the two dose groups (p = 0.628), while Group 2 (<14 Gy) exhibited significantly lower PTE (p = 0.039). This study concludes that SRS with a radiation dose < 14 Gy demonstrates comparable tumor control with reduced toxicity, advocating consideration of such dosing to achieve a balance between therapeutic efficacy and safety.

Upfront stereotactic radiosurgery versus adjuvant radiosurgery for parasagittal and parafalcine meningiomas: a systematic review and meta-analysis

Parafalcine and parasagittal (PFPS) are common locations for meningiomas. Surgical resection for these tumors, the first-line treatment, poses challenges due to their proximity to critical structures. This systematic review investigates the use of stereotactic radiosurgery (SRS) as a treatment for PFPS meningiomas, aiming to elucidate its safety and efficacy. The review adhered to PRISMA guidelines. Searches were conducted on MEDLINE, Embase, and Cochrane. Inclusion criteria involved studies on SRS for PFPS meningiomas, reporting procedure outcomes and complications. Tumors were presumed or confirmed to be WHO grade 1. Data was systematically extracted. Meta-analysis was performed where applicable. The review included data from eight studies, 821 patients with 878 lesions. Tumor control was achieved in greater than 80% of cases. Adverse radiation effects were reported in 7.3% of them. Recurrence and further surgical approach were observed in 17.1% and 9.2% of cases, respectively. Symptom improvement was noted in 33.2% of patients. Edema occurred in approximately 25.1% of patients. A subgroup of 283 patients had upfront SRS, achieving tumor control in approximately 97% of such cases. SRS is a safe and effective treatment for PFPS meningiomas, both as an adjuvant therapy and as an upfront treatment for often smaller tumors. Post-SRS edema can typically be managed medically and usually does not require further surgical intervention. Further studies should provide more specific data on PFPS meningiomas. The use of single and hypofractionated SRS for larger volume PFPS meningiomas should be more explored to better define the risks and benefits.

Predictors of recurrence after surgical resection of parafalcine and parasagittal meningiomas

PURPOSE

Owing to their vicinity near the superior sagittal sinus, parasagittal and parafalcine meningiomas are challenging tumors to surgically resect. In this study, we investigate key factors that portend increased risk of recurrence after surgery.

METHODS

This is a retrospective study of patients who underwent resection of parasagittal and parafalcine meningiomas at our institution between 2012 and 2018. Relevant clinical, radiographic, and histopathological variables were selected for analysis as predictors of tumor recurrence.

RESULTS

A total of 110 consecutive subjects (mean age: 59.4 ± 15.2 years, 67.3% female) with 74 parasagittal and 36 parafalcine meningiomas (92 WHO grade 1, 18 WHO grade 2/3), are included in the study. A total of 37 patients (33.6%) exhibited recurrence with median follow-up of 42 months (IQR: 10-71). In the overall cohort, parasagittal meningiomas exhibited shorter progression-free survival compared to parafalcine meningiomas (Kaplan-Meier log-rank p = 0.045). On univariate analysis, predictors of recurrence include WHO grade 2/3 vs. grade 1 tumors (p < 0.001), higher Ki-67 indices (p < 0.001), partial (p = 0.04) or complete sinus invasion (p < 0.001), and subtotal resection (p < 0.001). Multivariable Cox regression analysis revealed high-grade meningiomas (HR: 3.62, 95% CI: 1.60-8.22; p = 0.002), complete sinus invasion (HR: 3.00, 95% CI: 1.16-7.79; p = 0.024), and subtotal resection (HR: 3.10, 95% CI: 1.38-6.96; p = 0.006) as independent factors that portend shorter time to recurrence.

CONCLUSION

This study identifies several pertinent factors that confer increased risk of recurrence after resection of parasagittal and parafalcine meningiomas, which can be used to devise appropriate surgical strategy to achieve improved patient outcomes.

Radiotherapy and radiosurgery for meningiomas

Meningiomas comprise a histologically and clinically diverse set of tumors arising from the meningothelial lining of the central nervous system. In the past decade, remarkable progress has been made in deciphering the biology of these common neoplasms. Nevertheless, effective systemic or molecular therapies for meningiomas remain elusive and are active areas of preclinical and clinical investigation. Thus, standard treatment modalities for meningiomas are limited to maximal safe resection, radiotherapy, or radiosurgery. This review examines the history, clinical rationale, and future directions of radiotherapy and radiosurgery as integral and effective treatments for meningiomas.

Peritumoral edema in meningiomas: pathophysiology, predictors, and principles for treatment

Meningiomas is a tumor of the meninges and is among the most common intracranial neoplasms in adults, accounting for over a third of all primary brain tumors in the United States. Meningiomas can be associated with peritumoral brain edema (PTBE) which if not managed appropriately can lead to poor clinical outcomes. In this review, we summarize the relevant pathophysiology, predictors, and principles for treatment of PTBE. The results of various case-reports and case-series have found that meningioma-associated PTBE have patterns in age, tumor size, and hormone receptor positivity. Our study describes how increased age, increased tumor size, tumor location in the middle fossa, and positive expression of hormone receptors, VEGF, and MMP-9 can all be predictors for worse clinical outcomes. We also characterize treatment options for PTBE such as glucocorticoids and VEGF inhibitors along with the ongoing clinical trials attempting to alleviate PTBE in meningioma cases. The trends summarized in this review can be used to better predict the behavior of meningioma-associated PTBE and establish prognosis models to identify at risk patients.

A Survey on Prophylactic Corticosteroids Use in Stereotactic Radiosurgery Treatments From Ibero and Latin America Centers

Introduction Radiosurgery is a treatment in which a high dose of ionizing radiation is administered to a small field with high-precision techniques, and is a common treatment for tumors and other diagnoses. A typical complication is the development of radiation-induced edema that can progress to radiation necrosis in some cases. The administration of corticosteroids has been used empirically as a prophylaxis in patients who will be treated by stereotactic radiosurgery with intracranial tumors and other pathologies with the intention to prevent radiation-induced edema and or necrosis. Objective The aim of our study is to describe the actual use of corticosteroids in hospitals that perform stereotactic radiosurgery treatments in Latin America and Spain through a survey applied to neurosurgeons and radiation oncologists and expose the implications of the results, as well as to analyze the available literature on it. Methods  We designed a questionnaire of 15 items related to the use of corticosteroids as prophylaxis in patients who will be treated with radiosurgery. The questionnaire was answered by 121 Ibero-Latin Americans through Google Drive considering a database from the Iberolatinoamerican Radiosurgery Association. Results We found that the preference for the use of corticosteroids as prophylaxis for radiosurgery is associated with informal training in radiosurgery, and it was more used by radiation oncologists compared to neurosurgeons (p=0.023). Side effects can exceed the benefit of its use. Conclusions There is practically no literature on the use of corticosteroids as prophylaxis for radiation necrosis in stereotactic radiosurgery. This is a controversial inter- and intra-specialty issue, and its empirical use has a relatively high prevalence, making us reconsider the value of experience in a medical environment that should be fundamentally guided by evidence-based medicine.

Radiotherapy for Meningioma

Meningiomas are the most common primary intracranial brain tumor, and have a heterogeneous biology and an unmet need for targeted treatment options. Existing treatments for meningiomas are limited to surgery, radiotherapy, or a combination of these depending on clinical and histopathological features. Treatment recommendations for meningioma patients take into consideration radiologic features, tumor size and location, and medical comorbidities, all of which may influence the ability to undergo complete resection. Ultimately, outcomes for meningioma patients are dictated by extent of resection and histopathologic factors, such as World Health Organization (WHO) grade and proliferation index. Radiotherapy is a critical component of meningioma treatment as either a definitive intervention using stereotactic radiosurgery or external beam radiotherapy, or in the adjuvant setting for residual disease or for adverse pathologic factors, such as high WHO grade. In this chapter, we provide a comprehensive review of radiotherapy treatment modalities, therapeutic considerations, radiation planning, and clinical outcomes for meningioma patients.

A Pathophysiological Approach to Reduce Peritumoral Edema with Gamma Knife Radiosurgery for Large Incidental Meningiomas

Background: Peritumoral edema may be a prohibitive side effect in treating large incidental meningiomas with stereotactic radiosurgery. An approach that limits peritumoral edema and achieves tumor control with SRS would be an attractive management option for large incidental meningiomas. Methods: This is a retrospective cohort study of patients with large incidental meningiomas (≥2 mL in volume and/or 2 cm in diameter) treated with gamma knife radiosurgery (GKRS) between 2000 and 2019 in Taiwan and followed up for 5 years. The outcomes of a pathophysiological approach targeting the dural feeding artery site with a higher marginal dose (18–20 Gy) to enhance vascular damage and the parenchymal margin of the tumor with a lower dose (9–11 Gy) to reduce parenchymal damage were compared with those of a conventional approach targeting the tumor center with a higher dose and tumor margin with a lower dose (12–14 Gy). Results: A total of 53 incidental meningiomas were identified, of which 23 (43.4%) were treated with a pathophysiological approach (4 cases underwent a two-stage approach) and 30 (56.7%) were treated with a conventional approach. During a median follow-up of 3.5 (range 1–5) years, tumor control was achieved in 19 (100%) incidental meningiomas that underwent a single-stage pathophysiological approach compared with 29 (96.7%) incidental meningiomas that underwent a conventional approach (log-rank test: p = 0.426). Peritumoral edema developed in zero (0%) incidental meningiomas that underwent a single stage pathophysiological approach compared to seven (23.3%) incidental meningiomas that underwent a conventional approach (log-rank test: p = 0.023). Conclusions: Treatment of large incidental meningiomas with a pathophysiological approach with GKRS achieves similar rates of tumor control and reduces the risk of peritumoral edema. GKRS with a pathophysiological approach may be a reasonable management strategy for large incidental meningiomas.

Pseudoprogression and peritumoral edema due to intratumoral necrosis after Gamma knife radiosurgery for meningioma

Peritumoral cerebral edema is reported to be a side effect that can occur after stereotactic radiosurgery. We aimed to determine whether intratumoral necrosis (ITN) is a risk factor for peritumoral edema (PTE) when gamma knife radiosurgery (GKRS) is performed in patients with meningioma. In addition, we propose the concept of pseudoprogression: a temporary volume expansion that can occur after GKRS in the natural course of meningioma with ITN. This retrospective study included 127 patients who underwent GKRS for convexity meningioma between January 2019 and December 2020. Risk factors for PTE and ITN were investigated using logistic regression analysis. Analysis of variance was used to determine whether changes in tumor volume were statistically significant. After GKRS, ITN was observed in 34 (26.8%) patients, and PTE was observed in 10 (7.9%) patients. When postoperative ITN occurred after GKRS, the incidence of postoperative PTE was 18.970-fold (p = 0.009) greater. When a 70% dose volume ≥ 1 cc was used, the possibility of ITN was 5.892-fold (p < 0.001) higher. On average, meningiomas with ITN increased in volume by 128.5% at 6 months after GKRS and then decreased to 94.6% at 12 months. When performing GKRS in meningioma, a 70% dose volume ≥ 1 cc is a risk factor for ITN. At 6 months after GKRS, meningiomas with ITN may experience a transient volume expansion and PTE, which are characteristics of pseudoprogression. These characteristics typically improve at 12 months following GKRS.

Meningiomas

Meningiomas arise in various locations. Convexity tumors are relatively simple to remove. Skull base tumors and tumors adjacent to the major cerebral veins and venous sinuses can be very difficult to extirpate. Attempts at radical resection can lead to serious morbidity. The combination of bulk reduction using microsurgery followed by GKNS gives greatly improved survival and very low morbidity. With smaller tumors, GKNS may be used as the primary treatment. Increasing numbers of asymptomatic meningiomas are demonstrated either as an unexpected finding or as a residual or recurrent tumor after surgery. In all of these situations, GKNS gives a better result than observation or reoperation.

The positive effects of surgery on symptomatic stereotactic radiation-induced peritumoral brain edema: A report of three cases

Background

Peritumoral brain edema is an uncommon but life-threatening side effect of brain tumors radiosurgery. Medical therapy usually alleviates symptoms until edema spontaneously disappears. However, when peritumoral brain edema endangers the patient's life or medical therapy fails to guarantee an acceptable quality of life, surgery might be considered.

Case Description

Our report focuses on three patients who developed extensive peritumoral brain edema after radiosurgery. Two were affected by vestibular schwannomas and one by a skull-base meningioma. Peritumoral brain edema worsened despite maximal medical therapy in all cases; therefore, surgical removal of the radiated lesion was carried out. In the first patient, surgery was overdue and resulted in a fatal outcome. On the other hand, in the latter two cases surgery was quickly effective. In all three cases, an unmanageable brain swelling was not found at surgery.

Conclusion

Surgical removal of brain tumors previously treated with radiosurgery was safe and effective in resolving shortly peritumoral brain edema. This solution should be considered in patients who do not respond to medical therapy and before worsening of clinical conditions. Interestingly, the expected brain swelling was not confirmed intraoperatively. In our experience, this magnetic resonance finding should not be considered a criterion to delay surgery.

Long-term survival in patients with long-segment complex meningiomas occluding the dural venous sinuses: illustrative cases

BACKGROUND

Invasive sagittal sinus meningiomas are difficult tumors to cure by resection alone. Stereotactic radiosurgery (SRS) can be used as an adjuvant management strategy to improve tumor control after incomplete resection.

OBSERVATIONS

The authors reported the long-term retrospective follow-up of two patients whose recurrent parasagittal meningiomas eventually occluded their superior sagittal sinus. Both patients underwent staged radiosurgery and fractionated radiation therapy to achieve tumor control that extended to 20 years after their initial surgery. After initial subtotal resection of meningiomas that had invaded major cerebral venous sinuses, adjuvant radiosurgery was performed to enhance local tumor control. Over time, adjacent tumor progression required repeat SRS and fractionated radiation therapy to boost long-term tumor response. Staged multimodality intervention led to extended survival in these patients with otherwise unresectable meningiomas.

LESSONS

Multimodality management with radiosurgery and fractionated radiation therapy was associated with long-term survival of two patients with otherwise surgically incurable and invasive meningiomas of the dural venous sinuses.

Relationship between Pathological Characteristics and Radiological Findings on Perfusion MR Imaging of Meningioma

Few studies have reviewed the roles of perfusion magnetic resonance (MR) imaging in the histopathological examination of meningiomas. We analyzed the relationships between radiological findings on perfusion MR imaging and pathological characteristics such as origin of the tumor, mitotic activity, pathological subtype, and perifocal edema formation. The subjects were 21 surgical cases of meningioma preoperatively evaluated by perfusion MR imaging. A region of interest (ROI) was set inside of the tumor, and perifocal edema of the same size, cerebral blood volume (CBV), and cerebral blood flow (CBF) on perfusion MR and diffusion-weighted (DW) imaging were analyzed. These radiological data were evaluated in comparison with histopathological characteristics. On perfusion MR imaging, the average ratio of CBV against the contralateral side was 6.43 (1.13–20.0) and that of CBF was 7.73 (1.34–11.3). There was no significant relationship with perfusion MR imaging data, tumor volume, or perifocal edema volume. However, the large peritumoral edema group often had a higher CBV and CBF than the non-large peritumoral edema group. The skull base group had a significantly higher CBV and lower signal intensity on DW images than the non-skull base group. Signal intensity on DW images was higher in grade II or III than in grade I. Perfusion MR imaging data revealed that the higher ratio of peritumoral edema against tumor size was associated with higher blood flow and blood volume under intratumoral circulatory conditions, and that skull base meningioma had a higher blood volume than non-skull base meningioma.

Stereotactic radiosurgery for treatment of radiation-induced meningiomas: a multiinstitutional study

OBJECTIVE

Radiation-induced meningiomas (RIMs) are associated with aggressive clinical behavior. Stereotactic radiosurgery (SRS) is sometimes considered for selected RIMs. The authors investigated the effectiveness and safety of SRS for the management of RIMs.

METHODS

From 12 institutions participating in the International Radiosurgery Research Foundation, the authors pooled patients who had prior cranial irradiation and were subsequently clinically diagnosed with WHO grade I meningiomas that were managed with SRS.

RESULTS

Fifty-two patients underwent 60 SRS procedures for histologically confirmed or radiologically suspected WHO grade I RIMs. The median ages at initial cranial radiation therapy and SRS for RIM were 5.5 years and 39 years, respectively. The most common reasons for cranial radiation therapy were leukemia (21%) and medulloblastoma (17%). There were 39 multiple RIMs (35%), the mean target volume was 8.61 ± 7.80 cm3, and the median prescription dose was 14 Gy. The median imaging follow-up duration was 48 months (range 4-195 months). RIM progressed in 9 patients (17%) at a median duration of 30 months (range 3-45 months) after SRS. Progression-free survival at 5 years post-SRS was 83%. Treatment volume ≥ 5 cm3 predicted progression (HR 8.226, 95% CI 1.028-65.857, p = 0.047). Seven patients (14%) developed new neurological symptoms or experienced SRS-related complications or T2 signal change from 1 to 72 months after SRS.

CONCLUSIONS

SRS is associated with durable local control of RIMs in the majority of patients and has an acceptable safety profile. SRS can be considered for patients and tumors that are deemed suboptimal, poor surgical candidates, and those whose tumor again progresses after removal.

Ten-year follow-up after Gamma Knife radiosurgery of meningioma and review of the literature

Objectives

With regard to the generally slow growth of meningioma, it is essential to analyse clinical treatment results in a long-term perspective. The purpose of the present analysis is to provide clinical data after Gamma Knife radiosurgery of meningioma in a 10-year perspective together with a review of the current literature.

Methods

The current study is a retrospective analysis of 86 consecutive Swedish patients with meningiomas treated using Gamma Knife radiosurgery at the Karolinska Hospital Stockholm between March 1991 and May 2001. A total of 130 tumours were treated in 115 treatment sessions. The median radiological follow-up was 10 years (1.8–16.5 years), and the median clinical follow-up was 9.4 years (2.1–17.4 years).

Results

After a median follow-up period of 10 years, local tumour control was achieved in 87.8% of meningiomas (108/123 tumours). The median latency between initial treatment and local (in-field) recurrence (n = 15) was 5.8 years (1.9–11.5). Recurrences adjacent but outside the initial radiation field occurred in 15.1% of patients (13/86) at a median of 7.5 years (1.3–15.7). New meningiomas were seen in 10.5% after a median of 5.4 years (0.9–10.8). In 72% of patients, no further treatment was required, 17.4% (15/86) underwent a second Gamma Knife treatment, 4.7% (4/86) required later open surgery and 5.8% (5/86) required both secondary treatments. Eighty-six percent of patients were neurologically unchanged or improved. A significantly lower rate of local (in-field) recurrences was seen in meningiomas treated with a prescription dose of > 13.4 Gy (7.1% vs. 24%, p = 0.02).

Conclusions

The current retrospective analysis provides a 10-year follow-up and comprises one of the longest available follow-up studies of radiosurgically treated meningiomas. The current series documents a persistent high local tumour control after Gamma Knife treatment, while providing an estimation of a necessary minimum dose for long-term tumour control in meningiomas. The study confirms the validity of previous short-term data in a long-term perspective.

Endovascular Stenting Following Stereotactic Radiosurgery for Meningioma Involving the Superior Sagittal Sinus

Objective

Surgical removal of meningiomas that have partially invaded the superior sagittal sinus (SSS) is difficult because it requires reconstruction of the SSS, which can lead to SSS occlusion and venous infarction. The present report details the case of an SSS-involved meningioma treated by stereotactic radiosurgery (SRS) and stenting.

Case Presentation

A 60-year-old woman was admitted to the hospital with blurred vision and papilledema. Lumbar puncture showed markedly increased intracranial pressure (ICP; 340 mm H2O). Gadolinium-enhanced T1-weighted imaging revealed a 1-cm meningioma located mainly in the SSS. Digital subtraction angiography revealed severe stenosis, at the posterior part of the SSS, and no collateral flow. The ICP was considered a result of the stenosis caused by the meningioma. A combined therapy comprising transarterial embolization (for tumor growth suppression), endovascular stenting of the SSS (for intracranial hypertension improvement), and SRS (for tumor control) was planned. SRS was performed first to avoid interference by the metal artifacts caused by the stent. After placement of a self-expanding stent, partial recanalization was achieved. Two months after stenting, SSS stenosis improved and MRI results showed shrinkage of the meningioma. Thirty months after the treatment, no tumor recurrence was observed.

Conclusion

The treatment strategy of SRS followed by stenting was successful for a SSS-involved meningioma. ICP and a pressure gradient between the pre- and post-stenotic segments should be considered indications for stenting.

Late recovery of stereotactic radiosurgery induced perilesional edema of an arteriovenous malformation after bevacizumab treatment

MATERIALS AND METHODS

We present a 41-year old male patient who was admitted to our clinic with epileptic seizures, headaches and hemiparesis 14 months after SRS treatment for a left fronto-parietal Spetzler-Martin Grade III arteriovenous malformation (AVM). On his first-year follow-up perilesional edema was observed for which the patient received steroid treatment, but the patient did not show any benefit from it. In the cases of steroid resistant perilesional edemas, bevacizumab can be used for reducing symptoms and even radiological perilesional edema as well.

RESULTS

In our case, we have seen the effect of bevacizumab for symptomatic perilesional edema in a AVM patient after SRS treatment after radiological / neurological recovery. Our patient's headaches decreased rapidly after 2 days after treatment and was able to mobilize himself after 2 months but total resolution of symptoms and radiological findings observed after 1,5 years.

CONCLUSIONS

The duration and optimum dose of bevacizumab therapy needed to further investigation. Our study showed that bevacizumab was a long-term and effective treatment option for the cases with peritumoral edema resistant to glucocorticoid treatment, where the patient had conditions such as severe headache and neurological deficits.

Stereotactic Radiotherapy for Parasagittal and Parafalcine Meningiomas: Patient Selection and Special Considerations

Treatment options for intracranial meningiomas are surgical resection alone, surgery followed by adjuvant radiation therapy (RT), or exclusive RT. Parasagittal and parafalcine meningiomas are a subgroup of meningeal disease located close to the vascular structures. Considering the frequent venous invasion, a complete resection is not possible in the majority of cases, and even if a Simpson Grade I resection can be performed, the risk of recurrence is relevant. To date, few studies are focused on parasagittal and parafalcine meningiomas. Because of their specific related issues, particular considerations on decision-making process, outcome, and toxicity follow-up are mandatory. In fact, parasagittal and parafalcine meningiomas require a clear-cut radiological assessment, as well as a tailored toxicity risk evaluation. Moreover, similarly to other meningioma sites, also for parasagittal and parafalcine ones, a standardization of local control, toxicity, and quality of life evaluation is needed in order to lead to a pooled analysis of the results. In this context, our aim was to review the literature data regarding the role of both single-session and multisession radiosurgery (RS), and stereotactic radiotherapy (SRT) for parasagittal and parafalcine meningioma management, summarizing available data on safety and efficacy. It was also discussed how RS and SRT can be performed in a setting of evolving views concerning the treatment paradigm of the parasagittal and parafalcine meningiomas.

Single-Fractionated Stereotactic Radiosurgery for Intracranial Meningioma in Elderly Patients: 25-Year Experience at a Single Institution

BACKGROUND

Stereotactic radiosurgery (SRS) has been accepted as a therapeutic option for intracranial meningiomas; however, the detailed data on outcomes in elderly patients remain unclear.

OBJECTIVE

To delineate the efficacy of SRS for meningiomas in elderly patients.

METHODS

The outcomes of 67 patients aged ≥65 yr who underwent SRS for benign intracranial meningioma (World Health Organization grade I) between 1990 and 2014 at our institution were retrospectively analyzed. The median age was 71 yr (range, 65-83 yr), and the mean and median follow-up were 62 and 52 mo (range, 7-195 mo), respectively. Tumor margins were irradiated with a median dose of 16 Gy, and the median tumor volume was 4.9 cm3 (range, 0.7-22.9 cm3).

RESULTS

Actuarial local tumor control rates at 3, 5, and 10 yr after SRS were 92%, 86%, and 72%, respectively. Previous surgery and parasagittal/falcine location were statistically significant predictive factors for failed tumor control. Mild or moderate adverse events were noted in 9 patients. No severe adverse event was observed. A higher margin dose was significantly associated with adverse events by univariate analysis.

CONCLUSION

SRS is one of the standard therapies for meningiomas in elderly patients, providing both favorable tumor control and a low risk of adverse events under minimum invasiveness.

Gamma Knife stereotactic radiosurgery for cavernous sinus meningioma: long-term follow-up in 200 patients

OBJECTIVE

The authors of this study evaluate the long-term outcomes of stereotactic radiosurgery (SRS) for cavernous sinus meningioma (CSM).

METHODS

The authors retrospectively assessed treatment outcomes 5-18 years after SRS in 200 patients with CSM. The median patient age was 57 years (range 22-83 years). In total, 120 (60%) patients underwent Gamma Knife SRS as primary management, 46 (23%) for residual tumors, and 34 (17%) for recurrent tumors after one or more surgical procedures. The median tumor target volume was 7.5 cm3 (range 0.1-37.3 cm3), and the median margin dose was 13.0 Gy (range 10-20 Gy).

RESULTS

Tumor volume regressed in 121 (61%) patients, was unchanged in 49 (25%), and increased over time in 30 (15%) during a median imaging follow-up of 101 months. Actuarial tumor control rates at the 5-, 10-, and 15-year follow-ups were 92%, 84%, and 75%, respectively. Of the 120 patients who had undergone SRS as a primary treatment (primary SRS), tumor progression was observed in 14 (11.7%) patients at a median of 48.9 months (range 4.8-120.0 months) after SRS, and actuarial tumor control rates were 98%, 93%, 85%, and 85% at the 1-, 5-, 10-, and 15-year follow-ups post-SRS. A history of tumor progression after microsurgery was an independent predictor of an unfavorable response to radiosurgery (p = 0.009, HR = 4.161, 95% CI 1.438-12.045). Forty-four (26%) of 170 patients who had presented with at least one cranial nerve (CN) deficit improved after SRS. Development of new CN deficits after initial microsurgical resection was an unfavorable factor for improvement after SRS (p = 0.014, HR = 0.169, 95% CI 0.041-0.702). Fifteen (7.5%) patients experienced permanent CN deficits without evidence of tumor progression at a median onset of 9 months (range 2.3-85 months) after SRS. Patients with larger tumor volumes (≥ 10 cm3) were more likely to develop permanent CN complications (p = 0.046, HR = 3.629, 95% CI 1.026-12.838). Three patients (1.5%) developed delayed pituitary dysfunction after SRS.

CONCLUSIONS

This long-term study showed that Gamma Knife radiosurgery provided long-term tumor control for most patients with CSM. Patients who underwent SRS for progressive tumors after prior microsurgery had a greater chance of tumor growth than the patients without prior surgery or those with residual tumor treated after microsurgery.

Analysis of MRI Volumetric Changes After Hypofractionated Stereotactic Radiation Therapy for Benign Intracranial Neoplasms

Purpose

To quantitatively assess volumetric changes after hypofractionated stereotactic radiation therapy (HFSRT) in patients treated for vestibular schwannomas and meningiomas.

Methods and materials

We retrospectively reviewed records of patients treated with HFSRT at our institution from 2002 to 2014. Patients received a median dose of 25 Gy in 5 fractions. After treatment, they underwent clinical and radiologic follow-up with magnetic resonance imaging (MRI) at 3- to 12-month intervals. Gross tumor volume was outlined on each thin slice of contrast-enhanced T1 series before and on each scan after HFSRT. Volumetric changes were calculated and compared with neuroradiologist interpretations.

Results

Forty-three patients underwent 182 MRI scans. Tumor types included vestibular schwannoma (n = 34) and meningioma (n = 9). Median follow-up time was 29 months. Median gross tumor volume was 3.1 cm³. Local control was 81.4% for the entire cohort at the time of last follow-up. Transient volume expansion was noted in 17 patients (50%) with vestibular schwannoma and 2 (22%) with meningioma. For all patients, transient volume expansion and subsequent regression occurred at a median time of 5.5 and 12 months, respectively. Neuroradiologist agreement with regard to tumor regression, progression, or stability occurred in 155 of 182 total reports (85%). The largest discordance identified was a stable finding on the MRI interpretation when the measured volumetric change exceeded 20% (n = 24 [13%]).

Conclusions

HFSRT is associated with excellent local control and a low incidence of toxicity. With volumetric MRI measurement, transient volume expansion was a common finding and was associated with temporary adverse effects. Although the neuroradiologist’s interpretation generally agreed with the volumetric MRI measurement, the overall 15% discordance rate emphasizes the potential benefit of considering volumetric measurements, which may help clinicians correlate posttreatment symptoms with MRI findings.

Microsurgical treatment of parafalcine meningiomas: a retrospective study of 126 cases

Objective

To discuss the diagnosis, operation methods, and clinical effects of parafalcine meningiomas.

Methods

The clinical and preoperative imaging characteristics, operative methods, and effects of operations of 126 cases of parafalcine meningiomas were respectively discussed.

Results

G1 resection was achieved in 13 cases, G2 in 105 cases, G3 in four cases, and G4 in four cases, with no deaths. Among these, there were 16 patients with dyskinesia of the contralateral extremities after surgery, but they recovered after several months.

Conclusion

In order to avoid postoperative complications, we consider it vital to analyze the patients’ condition, the anatomy of venous drainage in by digital subtractional angiography, the relationship between tumor location and brain tissue according to MRI, and to remove the tumor in an adequately exposed surgical field.

Radiation-Induced Edema After Single-Fraction or Multifraction Stereotactic Radiosurgery for Meningioma: A Critical Review

PURPOSE

Potential dosimetric and clinicopathologic predictors of radiation-induced brain edema after single-fraction or multifraction stereotactic radiosurgery (SRS) for non-base of skull (non-BOS) meningiomas are summarized based on a systematic review of the published literature.

METHODS AND MATERIALS

Reviewed studies (PubMed indexed from 1998 through 2017) included all or some non-BOS meningioma patients, reported risks of edema after SRS, and correlated dosimetric and/or nondosimetric measures with the magnitude of risk.

RESULTS

Twenty-six studies reporting risks of edema after SRS for meningioma are reviewed. The treatment techniques as well as distribution of tumor locations, target dosing, and target volume varied across studies. Among 13 studies that included only non-BOS tumors or separately grouped non-BOS tumors, symptomatic edema occurred in 5% to 43% of patients and any edema occurred in 28% to 50%. The reported average time to onset of edema ranged from approximately 3 to 9 months in most studies. Factors reported to significantly correlate with increased risks of edema and/or symptomatic edema after SRS for meningioma include the following: greater tumor margin and/or maximum dose, greater tumor size and/or volume, non-BOS (particularly parasagittal) location, no prior resection for meningioma, and presence of pretreatment edema. Nevertheless, the extent and significance of these factors were inconsistent across studies. Potentially important dosimetric factors, such as volume of brain or tissue receiving single-fraction doses > 10 to 12 Gy, are not well studied.

CONCLUSIONS

The variability in risks of edema and in factors impacting those risks is likely a result of differences across studies in the clinicopathologic characteristics of the patient populations, as well as differences in treatment modalities and SRS planning and delivery parameters. More studies on pooled populations, grouped by potential prognostic factors such as tumor location and prior therapy, are needed to better understand dosimetric and nondosimetric factors predictive of edema risk after SRS for meningioma.

Post-Treatment Edema after Meningioma Radiosurgery is a Predictable Complication

Symptomatic post-treatment edema (PTE) causing seizures, focal deficits, and intracranial hypertension is a rather common complication of meningioma radiosurgery. Factors associated to the occurrence of PTE still needs to be clarified. We retrospectively analyzed our patients’ data to identify factors associated with the development of symptomatic PTE. Supposed risk factors were systematically analyzed.

Between July 2007 and March 2014, 245 meningiomas in 229 patients were treated by a single fraction or multisession radiosurgery (2-5 fractions) or hypofractionated stereotactic radiotherapy (6-15 fractions) using the CyberKnife system (Accuray Inc., Sunnyvale, CA) at the University Hospital of Messina, Italy.

Local tumor control was achieved in 200 of 212 patients with World Health Organization (WHO) Grade I meningiomas (94%) at a mean follow-up of 62 months. Symptomatic PTE on MRI was diagnosed in 19 patients (8.3%) causing seizure (n=17, 89%), aggravating headache (n=12, 63%), or focal deficits (n=13, 68%). Four variables were found to be associated with the likelihood of edema development, including tumor volume > 4.5 mL, non-basal tumor location, tight brain/tumor interface, and atypical histology. Nonetheless, when multivariate logistic regression analysis was performed, only tumor volume and brain-tumor interface turned out to be independent predictors of PTE development.

Our results suggest that the factor associated with the risk of developing PTE is associated to characteristics of meningioma rather than to the treatment modality used. Accordingly, an appropriate patient selection is the way to achieve safe treatment and long-term disease control.

Peritumoral Brain Edema after Stereotactic Radiosurgery for Asymptomatic Intracranial Meningiomas: Risks and Pattern of Evolution

Objective

To investigate the risks and pattern of evolution of peritumoral brain edema (PTE) after stereotactic radiosurgery (SRS) for asymptomatic intracranial meningiomas.

Methods

A retrospective study was conducted on 320 patients (median age 56 years, range 24-87 years) who underwent primary Gamma Knife radiosurgery for asymptomatic meningiomas between 1998 and 2012. The median tumor volume was 2.7 cc (range 0.2-10.5 cc) and the median follow-up was 48 months (range 24-168 months). Volumetric data sets for tumors and PTE on serial MRIs were analyzed. The edema index (EI) was defined as the ratio of the volume of PTE including tumor to the tumor volume, and the relative edema indices (rEIs) were calculated from serial EIs normalized against the baseline EI. Risk factors for PTE were analyzed using logistic regression.

Results

Newly developed or increased PTE was noted in 49 patients (15.3%), among whom it was symptomatic in 28 patients (8.8%). Tumor volume larger than 4.2 cc (p<0.001), hemispheric tumor location (p=0.005), and pre-treatment PTE (p<0.001) were associated with an increased risk of PTE. rEI reached its maximum value at 11 months after SRS and decreased thereafter, and symptoms resolved within 24 months in most patients (85.7%).

Conclusion

Caution should be exercised in decision-making on SRS for asymptomatic meningiomas of large volume (>4.2 cc), of hemispheric location, or with pre-treatment PTE. PTE usually develops within months, reaches its maximum degree until a year, and resolves within 2 years after SRS.

Long-Term Results of Stereotactic Radiosurgery for Skull Base Meningiomas

BACKGROUND:

Gamma knife radiosurgery (GKRS) is well established in the management of inaccessible, recurrent, or residual benign skull base meningiomas. Most series report clinical outcome parameters and complications in the short intermediate period after radiosurgery. Reports of long-term tumor control and neurological status are still lacking.

OBJECTIVE:

To report the presentation, treatment, and long-term outcome of skull base meningiomas after GKRS.

METHODS:

From a prospectively collected institutional review board-approved database, we selected patients with a World Health Organization grade I skull base meningioma treated with a single-session GKRS and a minimum of 60 months follow-up. One hundred thirty-five patients, 54.1% males (n = 73), form the cohort. Median age was 54 years (19–80). Median tumor volume was 4.7 cm3 (0.5–23). Median margin dose was 15 Gy (7.5–36). Median follow-up was 102.5 months (60.1–235.4). Patient and tumor characteristics were assessed to determine the predictors of neurological function and tumor progression.

RESULTS:

At last follow-up, tumor volume control was achieved in 88.1% (n = 119). Post-GKRS clinical improvement or stability was reported in 61.5%. The 5-, 10-, and 15-year actuarial progression-free survival rates were 100%, 95.4%, and 68.8%, respectively. Favorable outcome (both tumor control and clinical preservation/improvement) was attained in 60.8% (n = 79). Pre-GKRS performance status (Karnofsky Performance Scale) was shown to influence tumor progression (P = .001) and post-GKRS clinical improvement/preservation (P = .003).

CONCLUSION:

GKRS offers a highly durable rate of tumor control for World Health Organization grade I skull base meningiomas, with an acceptably low incidence of neurological deficits. The Karnofsky Performance Scale at the time of radiosurgery serves as a reliable long-term predictor of overall outcome.