Surgical Resectability of Skull Base Meningiomas

Neuroimaging of Brain Tumor Surgery and Epilepsy

To make the best clinical judgements, surgeons need to integrate information acquired via multimodal imaging [...].

De Novo Skull Base Atypical Meningioma: Incidence and Outcome

Objective  Atypical meningiomas are uncommon in skull base practice and present a management challenge. We aimed to review all de novo atypical skull base meningioma cases within a single unit to analyze presentation and outcome. Methods  A retrospective review of all patients undergoing surgery for intracranial meningioma identified consecutive cases of de novo atypical skull base meningioma. Electronic case records were analyzed for patient demographics, tumor location and size, extent of resection, and outcome. Tumor grading is based on the 2016 WHO criteria. Results  Eighteen patients with de novo atypical skull base meningiomas were identified. The most common tumor location was the sphenoid wing in 10 patients (56%). Gross total resection (GTR) was achieved in 13 patients (72%) and subtotal resection (STR) in 5 patients (28%). There was no tumor recurrence recorded in patients who had undergone GTR. Patients with tumors >6 cm were more likely to undergo a STR as opposed to a GTR ( p  < 0.01). Patients who had undergone a STR were more likely to have postoperative tumor progression and be referred for radiotherapy ( p  = 0.02 and <0.01, respectively). On multiple regression analysis, tumor size is the only significant factor correlating with overall survival ( p  = 0.048). Conclusion  The incidence of de novo atypical skull base meningioma is higher in our series than currently published data. Tumor size was a significant indicator for patient outcome and extent of resection. Those undergoing a STR were more likely to have tumor recurrence. Multicenter studies of skull base meningiomas with associated molecular genetics are needed to guide management.

Efficacy and Outcome of Embolization of Intracranial Meningiomas With Minimal Resources

BACKGROUND

Preoperative embolization of intracranial meningiomas is an accepted treatment modality and offers many advantages for subsequent surgery. It has also been used as a primary therapy without subsequent surgery in selected cases. In this study, the authors share their experience of this procedure with minimal resources carried out in cases where definitive surgery was not advisable.

METHODS

This is a prospective study of 6 cases of meningiomas treated over a period of 11 months (November 2020 to September 2021). None of the cases were fit for prolonged surgery under general anesthesia and also had certain comorbid conditions. Embolization was done in a setup with limited resources without a fully equipped catheterization lab. Post-procedure magnetic resonance imaging (MRI) was done within 48 hours of the procedure. Follow-up was done in the outpatient department.

RESULTS

There was complete disappearance of tumor blush in all the 6 cases. Immediate post-procedure MRI revealed significant necrosis of the tumor cavity. Three cases succumbed to their primary comorbid conditions and in the other cases follow-up was uneventful. Following embolization, clinical improvement of presenting symptoms was seen in all 6 cases.

CONCLUSIONS

In resource-restricted settings, by introducing such innovative methods it is possible to perform selected endovascular procedures. Embolization can be used as a primary treatment modality avoiding subsequent surgery in selected cases with a good outcome.

Visualization of Resected Area in Endonasal Endoscopic Approach versus Transcranial Approach for Skull Base Meningiomas by Voxel-Based-Lesion Mapping

Background: We aimed to evaluate the resected area of endonasal endoscopic approach (EEA) and transcranial approach (TCA) for skull base meningiomas (SBMs) using voxel-based-lesion mapping and visualized the appropriate tumor location in each approach. Methods: We retrospectively examined 182 patients with SBMs who underwent tumor resection in our hospital between 2014 and 2019. Pre- and post-operative SBMs were manually delineated on MRI to create the voxels-of-interest (VOIpre and VOIpost) and were registered onto the normalized brain (normalized VOIpre and normalized VOIpost). The resected map was created by subtracting normalized VOIpost from the normalized VOIpre divided by the number of cases. The resected maps of TCA and EEA were compared by subtracting them. Results: Twenty patients underwent EEA and 135 patients underwent TCA. The tumor resected map demonstrated that the resected area of EEA frequently accumulated on the central skull base, while that of TCA accumulated near the central skull base. The border of both approaches matched the circle that connects neural foramens at the skull base. Conclusions: The resected area of SBMs by EEA and TCA was well visualized by voxel-based-lesion mapping. The circle connecting the neural foramens was the border of EEA and TCA.

Case Series of Skull Base Meningioma Resection in the Octogenarian Population

Introduction The geriatric population is the fastest growing segment of the American population, and octogenarians are increasingly seen by neurosurgeons for relatively common lesions such as meningiomas. Unfortunately, providers do not have clear data to guide decision-making regarding these lesions, particularly if they involve the skull base. Current research in outcomes among the elderly looks at a wide range of ages, often anyone older than 65. Previous studies in octogenarians report a wide-range of mortality rates and do not focus on skull base lesions. This paper strives to clarify the experiences and outcomes of octogenarians.

Patients and Methods This retrospective series reviews skull base tumor surgeries performed at a single academic institution over the past 15 years in octogenarian patients. Primary endpoint was 30-day mortality; however, potential risk factors, perioperative morbidity, postdischarge disposition, and longer term follow-up were also captured. Multivariate logistic regression was performed to identify relevant perioperative and medical characteristics that increases the risk of adverse events.

Results Fourteen patients underwent craniotomies for skull base procedures with an average age of 84.5, with a 14% 30-day mortality rate. One patient required a tracheostomy on discharge and approximately half were able to either go home or rehabilitation after their procedure. On statistical analysis, there were no noted characteristics that predisposed any of the patients to a poorer outcome.

Conclusion Octogenarian patients were able to tolerate surgery for skull base meningiomas resection. This outcome data may be used to inform surgical decision and guide conversation with patients and their families.

Skull Base Meningiomas in Patients with Neurofibromatosis Type 2: An International Multicenter Study Evaluating Stereotactic Radiosurgery

Objective  Meningiomas are the second most common tumors in neurofibromatosis type 2 (NF-2). Microsurgery is challenging in NF-2 patients presenting with skull base meningiomas due to the intrinsic risks and need for multiple interventions over time. We analyzed treatment outcomes and complications after primary Gamma Knife radiosurgery (GKRS) to delineate its role in the management of these tumors. Methods  An international multicenter retrospective study approved by the International Radiosurgery Research Foundation was performed. NF-2 patients with at least one growing and/or symptomatic skull base meningioma and 6-month follow-up after primary GKRS were included. Clinical and radiosurgical parameters were recorded for analysis. Results  In total, 22 NF-2 patients with 54 skull base meningiomas receiving GKRS as primary treatment met inclusion criteria. Median age at GKRS was 38 years (10-79 years). Most lesions were located in the posterior fossa (55.6%). Actuarial progression free survival (PFS) rates were 98.1% at 2 years and 90.0% at 5 and 10 years. The median follow-up time after initial GKRS was 5.0 years (0.6-25.5 years). Tumor volume at GKRS was a predictor of tumor control. Lesions >5.5 cc presented higher chances to progress after radiosurgery ( p  = 0.043). Three patients (13.64%) developed adverse radiation effects. No malignant transformation or death due to meningioma or radiosurgery was reported. Conclusions  GKRS is effective and safe in the management of skull base meningiomas in NF-2 patients. Tumor volume deserve greater relevance during clinical decision-making regarding the most appropriate time to treat. GKRS offers a minimally invasive approach of particular interest in this specific group of patients.

Advances in Multidisciplinary Management of Skull Base Meningiomas

The surgical management of Skull Base Meningiomas (SBMs) has radically changed over the last two decades. Extensive surgery for patients with SBMs represents the mainstream treatment; however, it is often challenging due to narrow surgical corridors and proximity to critical neurovascular structures. Novel surgical technologies, including three-dimensional (3D) preoperative imaging, neuromonitoring, and surgical instruments, have gradually facilitated the surgical resectability of SBMs, reducing postoperative morbidity. Total removal is not always feasible considering a risky tumor location and invasion of surrounding structures and brain parenchyma. In recent years, the use of primary or adjuvant stereotactic radiosurgery (SRS) has progressively increased due to its safety and efficacy in the control of grade I and II meningiomas, especially for small to moderate size lesions. Patients with WHO grade SBMs receiving subtotal surgery can be monitored over time with surveillance imaging. Postoperative management remains highly controversial for grade II meningiomas, and depends on the presence of residual disease, with optional upfront adjuvant radiation therapy or close surveillance imaging in cases with total resection. Adjuvant radiation is strongly recommended in patients with grade III tumors. Although the currently available chemotherapy or targeted therapies available have a low efficacy, the molecular profiling of SBMs has shown genetic alterations that could be potentially targeted with novel tailored treatments. This multidisciplinary review provides an update on the advances in surgical technology, postoperative management and molecular profile of SBMs.

Pre-operative MRI Radiomics for the Prediction of Progression and Recurrence in Meningiomas

Objectives: A subset of meningiomas may show progression/recurrence (P/R) after surgical resection. This study applied pre-operative MR radiomics based on support vector machine (SVM) to predict P/R in meningiomas.

Methods: From January 2007 to January 2018, 128 patients with pathologically confirmed WHO grade I meningiomas were included. Only patients who had undergone pre-operative MRIs and post-operative follow-up MRIs for more than 1 year were studied. Pre-operative T2WI and contrast-enhanced T1WI were analyzed. On each set of images, 32 first-order features and 75 textural features were extracted. The SVM classifier was utilized to evaluate the significance of extracted features, and the most significant four features were selected to calculate SVM score for each patient.

Results: Gross total resection (Simpson grades I–III) was performed in 93 (93/128, 72.7%) patients, and 19 (19/128, 14.8%) patients had P/R after surgery. Subtotal tumor resection, bone invasion, low apparent diffusion coefficient (ADC) value, and high SVM score were more frequently encountered in the P/R group (p < 0.05). In multivariate Cox hazards analysis, bone invasion, ADC value, and SVM score were high-risk factors for P/R (p < 0.05) with hazard ratios of 7.31, 4.67, and 8.13, respectively. Using the SVM score, an AUC of 0.80 with optimal cutoff value of 0.224 was obtained for predicting P/R. Patients with higher SVM scores were associated with shorter progression-free survival (p = 0.003).

Conclusions: Our preliminary results showed that pre-operative MR radiomic features may have the potential to offer valuable information in treatment planning for meningiomas.

Knowledge-based planning in robotic intracranial stereotactic radiosurgery treatments

Purpose

To develop a knowledge‐based planning (KBP) model that predicts dosimetric indices and facilitates planning in CyberKnife intracranial stereotactic radiosurgery/radiotherapy (SRS/SRT).

Methods

Forty CyberKnife SRS/SRT plans were retrospectively used to build a linear KBP model which correlated the equivalent radius of the PTV (r_{eq_PTV}) and the equivalent radius of volume that receives a set of prescription dose (r_{eq_Vi}, where V_i = V_10%, V_20% … V_120%). To evaluate the model’s predictability, a fourfold cross‐validation was performed for dosimetric indices such as gradient measure (GM) and brain V_50%. The accuracy of the prediction was quantified by the mean and the standard deviation of the difference between planned and predicted values, (i.e., ΔGM = GM_pred − GM_clin and fractional ΔV_50% = (V_50%pred − V_50%clin)/V_50%clin) and a coefficient of determination, R². Then, the KBP model was incorporated into the planning for another 22 clinical cases. The training plans and the KBP test plans were compared in terms of the new conformity index (nCI) as well as the planning efficiency.

Results

Our KBP model showed desirable predictability. For the 40 training plans, the average prediction error from cross‐validation was only 0.36 ± 0.06 mm for ΔGM, and 0.12 ± 0.08 for ΔV_50%. The R² for the linear fit between r_{eq_PTV} and r_{eq_vi} was 0.985 ± 0.019 for isodose volumes ranging from V_10% to V_120%; particularly, R² = 0.995 for V_50% and R² = 0.997 for V_100%. Compared to the training plans, our KBP test plan nCI was improved from 1.31 ± 0.15 to 1.15 ± 0.08 (P < 0.0001). The efficient automatic generation of the optimization constraints by using our model requested no or little planner’s intervention.

Conclusion

We demonstrated a linear KBP based on PTV volumes that accurately predicts CyberKnife SRS/SRT planning dosimetric indices and greatly helps achieve superior plan quality and planning efficiency.

Surgical Strategies and Clinical Outcome of Large to Giant Sphenoid Wing Meningiomas: A Case Series Study

Large to giant sphenoid wing meningiomas (SWMs) remain surgically challenging due to frequent vascular encasement and a tendency for tumoral invasion of the cavernous sinus and optic canal. We aimed to study the quality of resection, postoperative clinical evolution, and recurrence rate of large SWMs. This retrospective study enrolled 21 patients who underwent surgery between January 2014 and December 2019 for SWMs > 5 cm in diameter (average 6.3 cm). Tumor association with cerebral edema, extension into the cavernous sinus or optic canal, degree of encasement of the major intracranial arteries, and tumor resection grade were recorded. Cognitive decline was the most common symptom (65% of patients), followed by visual decline (52%). Infiltration of the cavernous sinus and optical canal were identified in five and six patients, respectively. Varying degrees of arterial encasement were seen. Gross total resection was achieved in 67% of patients. Long-term follow-up revealed improvement in 17 patients (81%), deterioration in two patients (9.5%), and one death (4.7%) directly related to the surgical procedure. Seven patients displayed postoperative tumor progression and two required reintervention 3 years post initial surgery. Tumor size, vascular encasement, and skull base invasion mean that, despite technological advancements, surgical results are dependent on surgical strategy and skill. Appropriate microsurgical techniques can adequately solve arterial encasement but tumor progression remains an issue.

Hypofractionated stereotactic radiosurgery for large-sized skull base meningiomas

PURPOSE

Although stereotactic radiosurgery (SRS) has been proven to be effective and safe for treating intracranial meningiomas, concerns have been raised about the use of SRS for large-sized tumors involving the skull base that frequently encroach onto adjacent critical neural structures. The purpose of this study was to investigate the role of hypofractionated SRS as a therapeutic option for large-sized skull base meningiomas.

METHODS

Thirty-one consecutive patients (median age: 55 years, 9 men and 22 women) who had been treated with hypofractionated SRS using CyberKnife for large-sized skull base meningiomas (> 10 cm³ in volume, median of 18.9 cm³, range 11.6-58.2 cm³) were enrolled. All patients harbored middle or posterior skull base tumors, most frequently of cavernous sinus (n = 7, 22.6%), petroclival (n = 6, 19.4%), or tentorial edge (n = 6, 19.4%) locations. SRS was delivered in five daily fractions (range 3-5 fractions) with a median cumulative dose of 27.8 Gy (range 22.6-27.8 Gy).

RESULTS

With a median follow-up of 57 months (range 9-98 months), tumor control was achieved for 28 (90.3%) of 31 patients. Treatment response on MRI included partial response (volume decrease > 20%) in 17 (54.8%) patients, stable in 11 (35.5%), and progression (volume increase > 20%) in 3 (9.7%). Of 21 patients with cranial neuropathy, 20 (95.2%) showed improved neurological status.

CONCLUSIONS

Our current results suggest a promising role of hypofractionated SRS for large-sized skull base megningiomas in terms of tumor control and neurological outcomes. It is a reasonable therapeutic option for select patients.

Surgery for posterior fossa meningioma: elevated postoperative cranial nerve morbidity discards aggressive tumor resection policy

Radical excision of meningioma is suggested to provide for the best tumor control rates. However, aggressive surgery for meningiomas located at the posterior cranial fossa may lead to elevated postoperative morbidity of adjacent cranial nerves which in turn worsens patients' postoperative quality of life. Therefore, we analyzed our institutional database with regard to new cranial nerve dysfunction as well as postoperative cerebrospinal fluid (CSF) leakage depending on the extent of tumor resection. Between 2009 and 2017, 89 patients were surgically treated for posterior fossa meningioma at the authors' institution. Postoperative new cranial nerve dysfunction as well as CSF leakage were stratified into Simpson grade I resections with excision of the adjacent dura as an aggressive resection regime versus Simpson grade II-IV tumor removal. Simpson grade I resections revealed a significantly higher percentage of new cranial nerve dysfunction immediately after surgery (39%) compared with Simpson grade II (11%, p = 0.01) and Simpson grade II-IV resections (14%, p = 0.02). These observed differences were also present for the 12-month follow-up (27% Simpson grade I, 3% Simpson grade II (p = 0.004), 7% Simpson grades II-IV (p = 0.01)). Postoperative CSF leakage was present in 21% of Simpson grade I and 3% of Simpson grade II resections (p = 0.04). Retreatment rates did not significantly differ between these two groups (6% versus 8% (p = 1.0)). Elevated levels of postoperative new cranial nerve deficits as well as CSF leakage following radical tumor removal strongly suggest a less aggressive resection policy to constitute the surgical modality of choice for posterior cranial fossa meningiomas.

The Role of Surgery in Meningiomas

PURPOSE OF REVIEW

This review presents the most recent evidences and recommendations in the pre-, intra-, and post-surgical management of patients harboring meningiomas. Due to the increasing relevance of multimodal approaches, in order to preserve patients' neurological function and quality of life (QoL), the role of observation and radiation treatments (as either primary or adjuvant therapy) has also been discussed.

RECENT FINDINGS

Multiple advances in neurosurgery, including the use of the microscope and endoscope, improved preoperative neuroimaging, intraoperative image-guided approaches, and intraoperative neurophysiological monitoring, have extended the neurosurgeon's ability to remove lesions that were previously considered only partially resectable or unresectable, while minimizing morbidity. On the other hand, the preservation of patients' neurological integrity and QoL are increasingly important issues, more than complete tumor resection, for both patients and neurosurgeons. In this setting, stereotactic radiosurgery (SRS) and radiotherapy (RT) may be considered safe and effective alternatives for asymptomatic small- to moderate-sized tumors that demonstrate growth on serial imaging, or in combination with planned subtotal resection (STR) for tumors in critical locations. Data supporting the use of pharmacotherapy in meningiomas are, to date, weak, but the strength of the evidence might improve in the next future with the identification of targetable mutations. Complete microsurgical resection remains the standard of care if it can be achieved with minimal or no morbidity. However, many studies have reported SRS/RT as safe and effective treatments, either as primary approach or as complementary to surgery, especially when dealing with critically located meningiomas (e.g., cranial base) or in patients with comorbidity or wishing to avoid invasive treatments. The management of meningiomas is a field of complementary disciplines: neurosurgeon needs to work closely with radiation oncologists while tailoring the optimal treatment for these patients in order to achieve the best results.

Radiomics approach for prediction of recurrence in skull base meningiomas

PURPOSE

A subset of skull base meningiomas (SBM) may show early progression/recurrence (P/R) as a result of incomplete resection. The purpose of this study is the implementation of MR radiomics to predict P/R in SBM.

METHODS

From October 2006 to December 2017, 60 patients diagnosed with pathologically confirmed SBM (WHO grade I, 56; grade II, 3; grade III, 1) were included in this study. Preoperative MRI including T2WI, diffusion-weighted imaging (DWI), and contrast-enhanced T1WI were analyzed. On each imaging modality, 13 histogram parameters and 20 textural gray level co-occurrence matrix (GLCM) features were extracted. Random forest algorithms were utilized to evaluate the importance of these parameters, and the most significant three parameters were selected to build a decision tree for prediction of P/R in SBM. Furthermore, ADC values obtained from manually placed ROI in tumor were also used to predict P/R in SBM for comparison.

RESULTS

Gross-total resection (Simpson Grades I-III) was performed in 33 (33/60, 55%) patients, and 27 patients received subtotal resection. Twenty-one patients had P/R (21/60, 35%) after a postoperative follow-up period of at least 12 months. The three most significant parameters included in the final radiomics model were T1 max probability, T1 cluster shade, and ADC correlation. In the radiomics model, the accuracy for prediction of P/R was 90%; by comparison, the accuracy was 83% using ADC values measured from manually placed tumor ROI.

CONCLUSIONS

The results show that the radiomics approach in preoperative MRI offer objective and valuable clinical information for treatment planning in SBM.

Incidence, Clinico-Radiological Features and Outcome of Skull Base versus Non-Skull Base Meningiomas Treated in Kuala Lumpur General Hospital: A Five-Year Experience

Background

Meningiomas are the most common intracranial tumours; they account for 13%-26% of all the primary intracranial tumours. Skull base meningiomas make up 25% of all meningiomas and are one of the most difficult intracranial tumours to be managed surgically. This is due to the fact that it is difficult to approach the lesions which are also close to vital structures such as cranial nerves and major blood vessels. Despite the abundance of these cases in Malaysia, local data on meningiomas is scarce.

Methods

This is a retrospective study consisting of 199 patients with meningiomas who have been operated at the Kuala Lumpur General Hospital from January 2010-December 2014. They were categorised into skull base and non-skull base groups. Demography, tumour characteristics, and patient outcomes were analysed. Kaplan-Meier survival curves as well as Cox hazard univariable and multivariable regressions for the possible predictors of survival were analysed.

Results

97.5% of the patients (n = 194) had WHO grade I meningioma and only five patients had WHO grade II meningioma. There was a female predominance (n = 134; 67.3%), with a male-to-female ratio of 1:2. Some 27.1 % patients had skull base meningiomas. Patients with skull base meningiomas had poorer outcomes and discharge conditions (n = 23; 42.6% P < 0.01), in addition to higher risk of incomplete resections (n = 34; 63% P < 0.01). Multivariate cox hazard regressions showed that the skull base meningioma group had four times the risk of death of the non-skull base group.

Conclusions

Symptomatic meningiomas can be curative if the tumour is completely removed. Our study has revealed that skull base meningiomas which were operated locally had higher rates of incomplete resection and poorer surgical outcomes as compared to the non-skull base group. Patients with skull base meningiomas had four times the risk of death vis-à-vis non-skull base ones. More local studies are needed to look into skull base meningiomas for the improvement of its surgical outcomes.

The evolution of cranial meningioma surgery-a single-center 25-year experience

BACKGROUND

There have been major developments in diagnostic and surgical and non-surgical techniques used in the management of meningiomas over last three decades. We set out to describe these changes in a systematic manner.

METHOD

Clinical and radiological data, surgical procedures, complications, and outcome of 817 patients who underwent surgery for primarily diagnosed meningioma between 1991 and 2015 were investigated.

RESULTS

Median age at diagnosis increased significantly from 56 to 59 years (p = .042), while tumor location and preoperative Karnofsky performance status did not change during the observation period. Availability of preoperative MRI increased, and rates of angiography and tumor embolization decreased (p < .001, each). Median duration of total, pre-, and postoperative stay was 13, 2, and 9 days, respectively, and decreased between 1991 and 2015 (p < .001, each). Median incision-suture time varied annually (p < .001) but without becoming clearly longer or shorter during the entire observation period. The use of intraoperative neuronavigation and neuromonitoring increased, while the rates of Simpson grade I and III surgeries decreased (p < .001). Rates of postoperative hemorrhage (p = .997), hydrocephalus (p = .632), and wound infection (p = .126) did not change, while the frequency of early postoperative neurological deficits decreased from 21% between 1991 and 1995 to 13% between 2011 and 2015 (p = .003). During the same time, the rate of surgeries for postoperative cerebrospinal fluid leakage slightly increased from 2 to 3% (p = .049). Within a median follow-up of 62 months, progression was observed in 114 individuals (14%). Progression-free interval did not significantly change during observation period (p > .05). Multivariate analyses confirmed the lack of correlation between year of surgery and tumor relapse (HR: 1.1, p > .05).

CONCLUSIONS

Preoperative diagnosis and surgery of meningiomas have been substantially evolved. Although early neurological outcome has improved, long-term prognosis remains unchanged.

CyberKnife Stereotactic Radiosurgery and Hypofractionated Stereotactic Radiotherapy As First-line Treatments for Imaging-diagnosed Intracranial Meningiomas

Definitive radiotherapy is an important alternative treatment for meningioma patients who are inoperable or refuse surgery. We evaluated the efficacy and toxicity of CyberKnife-based stereotactic radiosurgery (SRS) and hypofractionated stereotactic radiotherapy (hSRT) as first-line treatments for intracranial meningiomas that were diagnosed using magnetic resonance imaging (MRI) and/or computed tomography (CT). Between February 2005 and September 2015, 41 patients with intracranial meningiomas were treated with CyberKnife-based SRS or hSRT. Eleven of those tumors were located in the skull base. The median tumor volume was 10.4 ml (range, 1.4–56.9 ml). The median prescribed radiation dose was 17 Gy (range, 13–20 Gy to the 61–88% isodose line) for SRS (n = 9) and 25 Gy (range, 14–38 Gy to the 44–83% isodose line) for hSRT (n = 32). The hSRT doses were delivered in 2 to 10 daily fractions. The median follow-up period was 49 months (range, 7–138). The 5-year progression-free survival rate (PFS) for all 41 patients was 86%. The 3-year PFS was 69% for the 14 patients with tumor volumes of ≥13.5 ml (30 mm in diameter) and 100% for the 27 patients with tumor volumes of <13.5 ml (P = 0.031). Grade >2 toxicities were observed in 5 patients (all of them had tumor volumes of ≥13.5 ml). SRS and hSRT are safe and effective against relatively small (<13.5 ml) meningiomas.

High-precision radiotherapy for meningiomas : Long-term results and patient-reported outcome (PRO)

OBJECTIVE

To evaluate long-term outcome after high-precision radiotherapy (RT) of meningioma patients in terms of survival and side effects.

METHODS

We analyzed 275 meningioma cases: 147 low-grade and 43 high-grade meningiomas (WHO II: n = 40, III: n = 3). In all, 85 patients had no pathologically confirmed histology but were determined as low-grade based on multimodal imaging. Surgery was performed in 183 cases. RT was delivered as either radiosurgery (RS, n = 16), fractionated stereotactic radiotherapy (FSRT, n = 241), or intensity-modulated radiation therapy (IMRT, n = 18). Of 218 patients contacted for patient-reported-outcome (PRO), 207 responded (95%).

RESULTS

Median follow-up was 7.2 years. For low-grade meningioma the survival rate (OS) was 97% at 3 years, 85% at 10 years, and 64% at 15 years, for atypical meningioma 91% at 3 years, 62% at 10 years, and 50% at 15 years. Local control rate (PFS) for low-grade meningioma was 91% at 3 years, 87% at 5 years, and 86% at 10 years, for atypical cases 67% at 3 years and 55% at 5 years. Of all, 3.0% of patients reported worsened or new symptoms grade ≥3 during RT and the first 6 months thereafter; 17.5% reported a deterioration after more than 2 years. We found the prognostic factors tumor volume and age significantly influencing OS and PFS.

CONCLUSION

Complemented by PRO, we found long-term low toxicity rates in addition to excellent local control. Thus, due to the beneficial risk-benefit profile of benign and high-risk meningiomas, RT should be performed as adjuvant treatment and should not be postponed until tumor progression.