Adjuvant radiotherapy for atypical meningiomas

Multiparameter MRI-based radiomics nomogram for preoperative prediction of brain invasion in atypical meningioma:a multicentre study

OBJECTIVE

To develop a nomogram based on tumor and peritumoral edema (PE) radiomics features extracted from preoperative multiparameter MRI for predicting brain invasion (BI) in atypical meningioma (AM).

METHODS

In this retrospective study, according to the 2021 WHO classification criteria, a total of 469 patients with pathologically confirmed AM from three medical centres were enrolled and divided into training (n = 273), internal validation (n = 117) and external validation (n = 79) cohorts. BI was diagnosed based on the histopathological examination. Preoperative contrast-enhanced T1-weighted MR images (T1C) and T2-weighted MR images (T2) for extracting meningioma features and T2-fluid attenuated inversion recovery (FLAIR) sequences for extracting meningioma and PE features were obtained. The multiple logistic regression was applied to develop separate multiparameter radiomics models for comparison. A nomogram was developed by combining radiomics features and clinical risk factors, and the clinical usefulness of the nomogram was verified using decision curve analysis.

RESULTS

Among the clinical factors, PE volume and PE/tumor volume ratio are the risk of BI in AM. The combined nomogram based on multiparameter MRI radiomics features of meningioma and PE and clinical indicators achieved the best performance in predicting BI in AM, with area under the curve values of 0.862 (95% CI, 0.819-0.905) in the training cohort, 0.834 (95% CI, 0.780-0.908) in the internal validation cohort and 0.867 (95% CI, 0.785-0.950) in the external validation cohort, respectively.

CONCLUSIONS

The nomogram based on tumor and PE radiomics features extracted from preoperative multiparameter MRI and clinical factors can predict the risk of BI in patients with AM.

Overall Survival of Primary Single Intracranial Atypical Meningioma with Different Surgical and Postoperative Treatment Options: Evidence from the SEER Database

Objective

The aim of this study is to evaluate the impact of different surgical and postoperative treatment options on the long-term overall survival (OS) in patients with primary single intracranial atypical meningioma.

Methods

In this retrospective study, participants were drawn from the Surveillance, Epidemiology, and End Results (SEER) database. Inclusion criteria comprised patients who underwent either gross total resection (GTR) or subtotal resection (STR). The inverse probability weighting (IPW) method using generalized boosted models was used to achieve balance in variables across various treatment groups. Subsequent to IPW, multivariate Cox analysis and Kaplan-Meier analysis were conducted, with OS as the endpoint.

Results

GTR was conducted on 1650 patients, while STR was conducted on 1109 patients. Among these, 432 patients who underwent GTR and 401 patients who underwent STR received postoperative radiotherapy (PORT). In the case of patients who were under 60 years old, PORT emerged as a significant protective factor for OS in those who underwent STR (HR 0.44; 95% CI 0.23-0.84; p = 0.013). Survival curves demonstrated that patients who underwent STR with PORT exhibited comparable OS to those who underwent GTR without PORT (p = 0.546). Conversely, for patients aged 60 years or older, PORT emerged as an independent risk factor for both GTR (HR 1.42; 95% CI 1.00-2.00; p = 0.048) and STR (HR 1.81; 95% CI 1.26-2.60; p = 0.001).

Conclusion

PORT may contribute to improving OS in primary single atypical meningioma patients under 60 years old who receive STR. However, in older patients who underwent either GTR or STR, the administration of PORT may be associated with a potential risk of OS. Therefore, age should be taken into account in applying PORT therapy, and the optimal treatment strategy for PORT in patients with atypical meningiomas needs to be further explored and validated.

Radiolabeled Somatostatin Receptor Antagonist Versus Agonist for Peptide Receptor Radionuclide Therapy in Patients with Therapy-Resistant Meningioma: PROMENADE Phase 0 Study

Our primary aim was to compare the therapeutic index (tumor-to-bone marrow and tumor-to-kidney absorbed-dose ratios) of the new radiolabeled somatostatin receptor antagonist [177Lu]Lu-DOTA-JR11 with the established radiolabeled somatostatin receptor agonist [177Lu]Lu-DOTATOC in the same patients with progressive, standard therapy-refractory meningioma. Methods: In this prospective, single-center, open-label phase 0 study (NCT04997317), 6 consecutive patients were included: 3 men and 3 women (mean age, 63.5 y). Patients received 6.9-7.3 GBq (standard injected radioactivity) of [177Lu]Lu-DOTATOC followed by 3.3-4.9 GBq (2 GBq/m2 × body surface area) of [177Lu]Lu-DOTA-JR11 at an interval of 10 ± 1 wk. In total, 1 [177Lu]Lu-DOTATOC and 2-3 [177Lu]Lu-DOTA-JR11 treatment cycles were performed. Quantitative SPECT/CT was done at approximately 24, 48, and 168 h after injection of both radiopharmaceuticals to calculate meningioma and organ absorbed doses as well as tumor-to-organ absorbed-dose ratios (3-dimensional segmentation approach for meningioma, kidneys, liver, bone marrow, and spleen). Results: The median of the meningioma absorbed dose of 1 treatment cycle was 3.4 Gy (range, 0.8-10.2 Gy) for [177Lu]Lu-DOTATOC and 11.5 Gy (range, 4.7-22.7 Gy) for [177Lu]Lu-DOTA-JR11. The median bone marrow and kidney absorbed doses after 1 treatment cycle were 0.11 Gy (range, 0.05-0.17 Gy) and 2.7 Gy (range, 1.3-5.3 Gy) for [177Lu]Lu-DOTATOC and 0.29 Gy (range, 0.16-0.39 Gy) and 3.3 Gy (range, 1.6-5.9 Gy) for [177Lu]Lu-DOTA-JR11, resulting in a 1.4 (range, 0.9-1.9) times higher median tumor-to-bone marrow absorbed-dose ratio and a 2.9 (range, 2.0-4.8) times higher median tumor-to-kidney absorbed-dose ratio with [177Lu]Lu-DOTA-JR11. According to the Common Terminology Criteria for Adverse Events version 5.0, 2 patients developed reversible grade 2 lymphopenia after 1 cycle of [177Lu]Lu-DOTATOC. Afterward, 2 patients developed reversible grade 3 lymphopenia and 1 patient developed reversible grade 3 lymphopenia and neutropenia after 2-3 cycles of [177Lu]Lu-DOTA-JR11. No grade 4 or 5 adverse events were observed at 15 mo or more after the start of therapy. The disease control rate was 83% (95% CI, 53%-100%) at 12 mo or more after inclusion. Conclusion: Treatment with 1 cycle of [177Lu]Lu-DOTA-JR11 showed 2.2-5.7 times higher meningioma absorbed doses and a favorable therapeutic index compared with [177Lu]Lu-DOTATOC after injection of 1.4-2.1 times lower activities. The first efficacy results demonstrated a high disease control rate with an acceptable safety profile in the standard therapy for refractory meningioma patients. Therefore, larger studies with [177Lu]Lu-DOTA-JR11 are warranted in meningioma patients.

Epidemiology of adult meningioma: Report from the Dutch Brain Tumour Registry (2000-2019)

BACKGROUND AND PURPOSE

Meningiomas are the most common primary tumours of the central nervous system. This study aimed to provide comprehensive nationwide estimates on the incidence, prevalence and prognostic impact of meningioma diagnosis in the Netherlands.

METHODS

Adult patients diagnosed with meningioma in 2000-2019 were selected from the Dutch Brain Tumour Registry (DBTR), part of the Netherlands Cancer Registry (NCR). Time trends in age-adjusted incidence and prevalence rates were evaluated using the estimated annual percentage change (EAPC). Relative survival rates were calculated using the Pohar Perme estimator. Case completeness of the DBTR/NCR was estimated through record linkage with one of the Dutch neuro-oncology centres.

RESULTS

From a total of 23,454 cases of meningioma, 11,306 (48.2%) were histologically confirmed and 12,148 (51.8%) were radiological diagnoses. Over time, the incidence of diagnosis increased from 46.9 per 1,000,000 inhabitants (European Standardized Rate [ESR]) to 107.3 (EAPC 4.7%, p < 0.01), with an increase in the incidence of radiological diagnoses from 14.0 to 70.2 per 1,000,000 ESR (EAPC 9.1%, p < 0.01). The prevalence of meningioma was estimated at 1012/1,000,000 on 1 January 2020, with almost 17,800 individuals having had a diagnosis of meningioma. Relative survival rate at 10 years for grade 1 meningiomas was 91.0% (95% confidence interval [CI] 89.4%-92.3%), 71.3% (95% CI 66.8%-75.2%) for grade 2 meningiomas and 36.4% (95% CI 27.3%-45.6%) for grade 3 meningiomas. Local case completeness was estimated at 97.6% for histologically confirmed meningiomas and 84.5% for radiological diagnoses.

CONCLUSION

With a near-complete registry, meningioma prevalence was estimated at over 1000 per 1,000,000 inhabitants.

Long Term Outcome and Quality of Life of Intracranial Meningioma Patients Treated with Pencil Beam Scanning Proton Therapy

The aim of this study was to assess the clinical outcome, including QoL, of patients with intracranial meningiomas WHO grade 1-3 who were treated with Pencil Beam Scanning Proton Therapy (PBS PT) between 1997 and 2022. Two hundred patients (median age 50.4 years, 70% WHO grade 1) were analyzed. Acute and late side effects were classified according to CTCAE version 5.0. Time to event data were calculated. QoL was assessed descriptively by the EORTC-QLQ-C30 and BN20 questionnaires. With a median follow-up of 65 months (range: 3.8-260.8 months) the 5 year OS was 95.7% and 81.8% for WHO grade 1 and grade 2/3, respectively (p < 0.001). Twenty (10%) local failures were observed. Failures occurred significantly (p < 0.001) more frequent in WHO grade 2 or 3 meningioma (WHO grade 1: n = 7, WHO grade 2/3: n = 13), in patients with multiple meningiomas (p = 0.005), in male patients (p = 0.005), and when PT was initiated not as upfront therapy (p = 0.011). There were no high-grade toxicities in the majority (n = 176; 88%) of patients. QoL was assessed for 83 (41.5%) patients and for those patients PT did not impacted QoL negatively during the follow-up. In summary, we observed very few local recurrences of meningiomas after PBS PT, a stable QoL, and a low rate of high-grade toxicity.

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.

Dose-response relationship in patients with newly diagnosed atypical meningioma treated with adjuvant radiotherapy

PURPOSE

This study aimed to identify the radiation dose-response relationship in patients with newly diagnosed atypical meningioma (AM) treated with adjuvant radiotherapy (ART) using conventional fractionation.

METHODS

In total, 158 patients who underwent surgery and ART between 1998 and 2018 were reviewed. Among these patients, 135 with complete information on radiotherapy (RT) dose/fractionation and pathological reports were analyzed. We entered RT dose as a continuous variable into the Cox regression model using penalized spline to allow for a nonlinear relationship between RT dose and events. Local control (LC), progression-free survival (PFS), and overall survival (OS) were evaluated. The corresponding biological equivalent dose in 2 Gy fractions (EQD2) was calculated using an α/β ratio of 4 Gy.

RESULTS

The median follow-up duration was 56.0 months. The median ART dose delivered was 61.2 Gy in 24-34 daily fractions, corresponding to a median EQD2 of 59.16 Gy. In multivariate analysis, larger size and higher mitotic count were associated with significantly reduced LC (P < 0.001 and P = 0.002, respectively), PFS (P < 0.001 and P = 0.006, respectively), and OS (P = 0.006 and P = 0.001, respectively). Meanwhile, a higher RT dose was significantly associated with improved LC, PFS, and OS. Moreover, RT showed a dose-dependent effect on LC, PFS, and OS; local failure, tumor progression, and death were reduced by 12%, 12%, and 16%, respectively, per 1 Gy increase in the dose (EQD2).

CONCLUSION

The dose of ART in AM has a dose-response relationship with LC and survival outcomes.

Progesterone receptor expression and prediction of benefits of adjuvant radiotherapy in de novo atypical meningiomas after gross-total resection

OBJECTIVE

Benefits of adjuvant radiotherapy (ART) after gross-total resection (GTR) of de novo atypical meningiomas (AMs) are controversial, and factors predictive of radiotherapy benefits in patients with de novo AMs after GTR are unknown. The authors aimed to evaluate the benefits of ART and explore potential factors sensitizing AMs to ART.

METHODS

A total of 231 consecutive patients who were pathologically diagnosed with de novo AMs and treated with GTR (Simpson class I–III resections) from 2010 to 2018 were enrolled in the study. Clinicopathological and prognostic information was collected and analyzed. Univariate and multivariate Cox analyses were used to evaluate prognostic predictors and compare the response to radiotherapy. Propensity score matching (PSM) was used to balance the confounding bias in subgroups.

RESULTS

A total of 138 patients (59.74%) received ART. Progesterone receptor (PR) expression was positive in 157 patients (67.97%). During the mean follow-up period of 76.25 months, 65 patients (28.14%) experienced recurrence and 38 (16.45%) died of tumor progression. For disease-specific survival (DSS), ART was a better prognostic factor via univariate (p = 0.003) and multivariate (p = 0.025) analyses. For progression-free survival (PFS), univariate Cox analysis showed that ART improved PFS (p = 0.013), but multivariate analysis did not (p = 0.068). Positive PR expression (p = 0.019), age 53.5 years or younger (p = 0.012), and Ki-67 7.5% or lower (p = 0.025) were independent prognostic predictors for better PFS. In the subcohort analysis, the beneficial impact of ART was observed in the PR-negative cohort (p = 0.002) but not in the PR-positive cohort (p = 0.86). The heterogeneity analysis demonstrated that the PR-negative cohort was more sensitive to ART than the PR-positive cohort (p = 0.036). ART was not found to be associated with better PFS in younger patients (≤ 53.5 years, p = 0.14), older patients (> 53.5 years, p = 0.085), those with a Ki-67 index ≤ 7.5% (p = 0.068), or those with a Ki-67 > 7.5% (p = 0.13). The contrasting effects of ART in the PR-negative versus PR-positive cohorts remained true even after PSM, confirming that PR-negative, but not PR-positive, de novo AMs benefited from ART after GTR.

CONCLUSIONS

ART was an independent prognostic factor for DSS of patients with de novo AMs treated with GTR (p = 0.025), but not for PFS (p = 0.068). Negative PR expression was a radiosensitive biomarker on PFS for de novo AM patients after GTR.

An interpretable radiomics model to select patients for radiotherapy after surgery for WHO grade 2 meningiomas

Objectives

This study investigated whether radiomic features can improve the prediction accuracy for tumor recurrence over clinicopathological features and if these features can be used to identify high-risk patients requiring adjuvant radiotherapy (ART) in WHO grade 2 meningiomas.

Methods

Preoperative magnetic resonance imaging (MRI) of 155 grade 2 meningioma patients with a median follow-up of 63.8 months were included and allocated to training (n = 92) and test sets (n = 63). After radiomic feature extraction (n = 200), least absolute shrinkage and selection operator feature selection with logistic regression classifier was performed to develop two models: (1) a clinicopathological model and (2) a combined clinicopathological and radiomic model. The probability of recurrence using the combined model was analyzed to identify candidates for ART.

Results

The combined clinicopathological and radiomics model exhibited superior performance for the prediction of recurrence compared with the clinicopathological model in the training set (area under the curve [AUC] 0.78 vs. 0.67, P = 0.042), which was also validated in the test set (AUC 0.77 vs. 0.61, P = 0.192). In patients with a high probability of recurrence by the combined model, the 5-year progression-free survival was significantly improved with ART (92% vs. 57%, P = 0.024), and the median time to recurrence was longer (54 vs. 17 months after surgery).

Conclusions

Radiomics significantly contributes added value in predicting recurrence when integrated with the clinicopathological features in patients with grade 2 meningiomas. Furthermore, the combined model can be applied to identify high-risk patients who require ART.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13014-022-02090-7.

Adjuvant Radiotherapy Versus Surveillance for Grade 2 Intracranial Meningiomas: A Multi-Institutional Propensity Score-Matched Study

Purpose

We aimed to compare the outcomes of adjuvant radiotherapy (ART) and surveillance in patients with grade 2 meningiomas (MNG2) who underwent surgical resection.

Materials and Methods

Data from four hospitals, in which patients aged ≥18 years underwent Simpson grade 1−4 surgical resection for newly diagnosed MNG2 between 1998 and 2018, were examined in this multicenter retrospective cohort study. Patients receiving ART with conventional fractionation were compared with those undergoing surveillance. Progression-free survival (PFS), progression/recurrence (P/R) were evaluated.

Results

This study included 518 patients, 158 of whom received ART. The median follow-up duration was 64.9 months. In the total cohort, ART was independently associated with significantly improved PFS (HR, 0.35; 95% CI, 0.23–0.55; P<0.001) and P/R (HR, 0.30; 95% CI, 0.18–0.48; P<0.001). In the propensity score-matched cohort (n=143 in each group), the 5-year PFS rates were 80.8% and 57.7% (P=0.004), and the 5-year P/R rates were 16.5% and 40.0% (P=0.002) in the ART and surveillance groups, respectively. After gross total resection, the 5-year PFS (85.0% vs. 64.7%; P=0.020) and P/R rates (15.2% vs. 32.0%; P=0.035) were significantly better in the ART group than in the surveillance group. A model for P/R was developed using recursive partitioning analysis with surgical extent, tumor size, and Ki-67 index. ART reduced the risk of P/R in the low- (P=0.069), intermediate- (P=0.044), and high-risk groups (P<0.001). Local control was also significantly enhanced by ART among all the risk groups (all P<0.05).

Conclusions

ART significantly improved PFS and P/R in patients with MNG2, irrespective of the surgical extent, and can be recommended after gross total resection. A prognostic model may guide decision-making for the use of ART.

Long-Term Outcomes for Patients With Atypical or Malignant Meningiomas Treated With or Without Radiation Therapy: A 25-Year Retrospective Analysis of a Single-Institution Experience

Purpose

Atypical (World Health Organization [WHO] grade 2) and malignant (WHO grade 3) meningiomas have high rates of local recurrence, and questions remain about the role of adjuvant radiation therapy (RT) for patients with WHO grade 2 disease. These patients frequently require salvage therapy, and optimal management is uncertain given limited prospective data. We report on the long-term outcomes for patients with atypical and malignant meningiomas treated with surgery and/or RT at our institution.

Methods and Materials

Data were collected through a retrospective chart review for all patients with WHO grade 2 or 3 meningiomas treated with surgery and/or RT at our institution between January 1992 and March 2017. Progression-free survival (PFS) and overall survival (OS) were described using the KaplanMeier estimator. The outcomes in the subgroups were compared with a log-rank test. A Cox proportional hazards model was used for the univariable and multivariable analyses of predictors of PFS.

Results

A total of 66 patients were included in this analysis. The median follow-up was 12.4 years overall and 8.6 years among surviving patients. Fifty-two patients (78.8%) had WHO grade 2 meningiomas, and 14 patients (21.2%) had WHO grade 3 disease. Thirty-six patients (54.5%) were treated with surgery alone, 28 patients (42.4%) with surgery and adjuvant RT, and 2 patients (3%) with RT alone. Median PFS and OS were 3.2 years and 8.8 years, respectively. PFS was significantly improved with adjuvant RT compared with surgery alone (hazard ratio, 0.36; 95% confidence interval, 0.18-0.70). Patients with Ki-67 index >10% showed a trend toward worse PFS compared with patients with Ki-67 ≤10% (hazard ratio, 0.51; 95% confidence interval, 0.25-1.04). No significant differences in PFS or OS were observed with respect to Simpson or WHO grade.

Conclusions

For patients with atypical or malignant meningiomas, adjuvant RT was associated with significantly improved PFS, and Ki-67 index >10% was associated with a trend toward worse PFS. Given the long-term survival, high recurrence rates, and efficacy of salvage therapy, patients with atypical and malignant meningiomas should be monitored systematically long after initial treatment.

Multisession radiosurgery for grade 2 (WHO), high risk meningiomas. A phase II clinical trial

Purpose

Patients suffering from recurrent and residual grade 2 (WHO) meningiomas after subtotal excision should be considered as high-risk groups with an uncertain prognosis. Adjuvant radiotherapy seems to be the best approach to reduce disease progression. The primary aim of this phase II explorative, monocentric, single arm study was to evaluate the safety of adjuvant multisession radiosurgery (mRS) in this group of patients; the efficacy in terms of tumour local control was the secondary endpoint.

Methods

Patients recruited from April 2017 to May 2019 were over 18 years old, had a histologically-documented intracranial recurrent or residual Grade 2 meningioma (WHO 2016) and a KPS > 70. Patients with NF2, concomitant neoplasm or pregnancy were excluded. Descriptive statistics were provided for categorical variables. Progression free survival (PFS) was modelled using the Kaplan–Meier method.

Results

Twenty-four patients were enrolled. All 24 patients underwent mRS: twenty-two patients received 28 Gy in 4 fractions, 2 patients received 24 Gy in 4 Treatment related adverse events (CTCAE 4.3) were limited to grade 2 in 1 patient (4.1%). At a median follow-up of 28 months, 8 patients (33.3%) had disease progression, either out-of-field or infield, compared with the planning target volume. Considering both infield and out-of-field progressions, 3-year PFS was 47% (95% confidence interval, CI, 22–69%); considering only the infield ones, 3-year PFS was 86% (95% CI 55–96%), and local control at last follow-up was 92%.

Conclusion

mRS provides good local control of the tumour volume (TV) and is associated with a low rate of toxicity. These results call for further investigation to confirm favourable outcomes in patients with high-risk meningioma.

Trial information

NCT05081908, October 18, 2021, retrospectively registered.

Radiation therapy for atypical and anaplastic meningiomas: an overview of current results and controversial issues

Meningiomas are the most common intracranial tumors. Most meningiomas are WHO grade 1 tumors whereas less than one-quarter of all meningiomas are classified as atypical (WHO grade 2) and anaplastic (WHO grade 3) tumors, based on local invasiveness and cellular features of atypia. Surgical resection remains the cornerstone of meningioma therapy and represents the definitive treatment for the majority of patients; however, grade 2 and grade 3 meningiomas display more aggressive behavior and are difficult to treat. Several retrospective series have shown the efficacy and safety of postoperative adjuvant external beam radiation therapy (RT) for patients with atypical and anaplastic meningiomas. More recently, two phase II prospective trials by the Radiation Therapy Oncology Group (RTOG 0539) and the European Organisation for Research and Treatment of Cancer (EORTC 2042) have confirmed the potential benefits of fractionated RT for patients with intermediate and high-risk meningiomas; however, several issues remain a matter of debate. Controversial topics include the timing of radiation treatment in patients with totally resected atypical meningiomas, the optimal radiation technique, dose and fractionation, and treatment planning/target delineation. Ongoing randomized trials are evaluating the efficacy of early adjuvant RT over observation in patients undergoing gross total resection.

Postoperative Adjuvant Radiotherapy in Atypical Meningioma Patients: A Meta-Analysis Study

Background and Purpose

Consensus regarding the need for adjuvant radiotherapy (RT) in patients with atypical meningiomas (AMs) is lacking. We compared the effects of adjuvant RT after surgery, gross total resection (GTR), and subtotal resection (STR) on progression-free survival (PFS) and overall survival (OS) in patients with AMs, respectively.

Methods

We performed a systematic review and meta-analysis of the literature published in PubMed, Embase, and the Cochrane Library from inception to February 1, 2021, to identify articles comparing the PFS and OS of patients receiving postoperative RT after surgery, GTR and STR.

Results

We identified 2307 unique studies; 24 articles including 3078 patients met the inclusion criteria. The sensitivity analysis results showed that for patients undergoing undifferentiated surgical resection, adjuvant RT reduced tumor recurrence (HR=0.70, p<0.0001) with no significant effect on survival (HR=0.89, p=0.49). Postoperative RT significantly increased PFS (HR=0.69, p=0.01) and OS (HR=0.55, p=0.007) in patients undergoing GTR. The same improvement was observed in patients undergoing STR plus RT (PFS: HR=0.41, p<0.00001; OS: HR=0.47, p=0.01). A subgroup analysis of RT in patients undergoing GTR showed no change in PFS in patients undergoing Simpson grade I and II resection (HR=1.82, p=0.22) but significant improvement in patients undergoing Simpson grade III resection (HR=0.64, p=0.02).

Conclusion

Regardless of whether GTR or STR was performed, postoperative RT improved PFS and OS to varying degrees. Especially for patients undergoing Simpson grade III or IV resection, postoperative RT confers the benefits for recurrence and survival.

Adjuvant radiotherapy in grossly total resected grade II atypical meningiomas. A protective effect on recurrence? A systematic review and meta-analysis

INTRODUCTION

Management of grade II Atypical Meningiomas (AM) remains controversial. Conflicting evidences exist on the possible protective effect of adjuvant radiotherapy (ART) on recurrence in grossly resected AMs. The aim of this meta-analysis is to evaluate the role of ART in grossly resected (Simpson grades 1-3) AMs on the recurrence and survival.

EVIDENCE ACQUISITION

Data were retrieved from comparative studies of AMs undergone surgical resection alone vs. surgery+ART. Only grossly total resected AMs (Simpson grade 1,2,3) were included. The individual and pooled odds ratio (OR) for the crude recurrence, progression free survival (PFS) at 1, 3 and 5-years, as well as for the overall survival (OS) at 5-years were calculated by using the Mantel-Haenszel model in surgery alone vs. surgery+ART.

EVIDENCE SYNTHESIS

11 studies were considered eligible. 8 were included for the outcome "crude recurrence"; 6 for PFS at 1-3 years, 7 for PFS at 5-years; 6 for the OS at 5-years. Results suggest that surgery+ART might have a protective role on recurrence in gross-totally resected AMs (OR:1.66). Specifically, surgery+ART slightly improved PFS at 1-year (OR:0.92) and more consistently at 3- and 5-years (OR:0.31 and 0.35 respectively) hence favoring a combined approach.

CONCLUSIONS

Current literature on the impact of ART after gross total resection of AM are still heterogeneous and not systematically reported. The present meta-analysis suggests a possible protective role of postoperative RT against long-term recurrence as compared to surgical resection alone.

The role of single-fraction stereotactic radiosurgery for atypical meningiomas (WHO grade II): treatment results based on a 25-year experience

PURPOSE

To clarify the role of stereotactic radiosurgery (SRS) for atypical meningiomas (AM).

METHODS

A retrospective analysis of 68 patients with AM having SRS from 1995 until 2019.

RESULTS

Nineteen patients (28%) had undergone prior external beam radiation therapy (EBRT) (median dose, 54 Gy). The median follow-up period was 52 months. Eighteen (26%), 17 (25%), and 33 (49%) patients received SRS as an upfront adjuvant (≤ 6 months), early salvage (7-18 months), or late salvage treatment (> 18 months), respectively. The 3-, 5-, and 10-year progression-free survivals (PFSs) were 52%, 35%, and 25%, respectively. The 3-, 5-, and 10-year disease-specific survivals were 85%, 78%, and 61%, respectively. Adverse radiation events (AREs) were observed in 12 patients (18%), with increased or new seizures being the most frequent complication (n = 7). Prior EBRT was associated with reduced PFS (HR 5.92, P < 0.01), reduced DSS (HR 5.84, P < 0.01), and an increased risk of ARE (HR 3.31, P = 0.04). Timing of SRS was correlated with reduced PFS for patients having early salvage treatment compared to upfront adjuvant (HR 3.17, P = 0.01) or late salvage treatment (HR 4.39, P < 0.01).

CONCLUSION

PFS for patients with residual/recurrent AM remains poor despite SRS. Prior EBRT was associated with worse tumor control, higher tumor-related mortality, and an increased risk of ARE. Further study on the timing of SRS is needed to determine if upfront adjunctive SRS improves tumor control compared to salvage SRS.

Adjuvant radiation versus observation with salvage radiation after gross-total resection of WHO grade II meningiomas: a propensity score-adjusted analysis

OBJECTIVE

After gross-total resection (GTR) of a newly diagnosed WHO grade II meningioma, the decision to treat with radiation upfront or at initial recurrence remains controversial. A comparison of progression-free survival (PFS) between observation and adjuvant radiation fails to account for the potential success of salvage radiation, and a direct comparison of PFS between adjuvant and salvage radiation is hampered by strong selection bias against salvage radiation cohorts in which only more aggressive, recurrent tumors are included. To account for the limitations of traditional PFS measures, the authors evaluated radiation failure-free survival (RFFS) between two treatment strategies after GTR: adjuvant radiation versus observation with salvage radiation, if necessary.

METHODS

The authors performed a retrospective review of patients who underwent GTR of newly diagnosed WHO grade II meningiomas at their institution between 1996 and 2019. They assessed traditional PFS in patients who underwent adjuvant radiation, postoperative observation, and salvage radiation. For RFFS, treatment failure was defined as time from initial surgery to failure of first radiation. To assess the association between treatment strategy and RFFS while accounting for potential confounders, a multivariable Cox regression analysis adjusted for the propensity score (PS) and inverse probability of treatment weighted (IPTW) Cox regression analysis were performed.

RESULTS

A total of 160 patients underwent GTR and were included in this study. Of the 121 patients who underwent observation, 32 (26.4%) developed recurrence and required salvage radiation. PFS at 3, 5, and 10 years after observation was 75.1%, 65.6%, and 45.5%, respectively. PFS at 3 and 5 years after salvage radiation was 81.7% and 61.3%, respectively. Of 160 patients, 39 received adjuvant radiation, and 3- and 5-year PFS/RFFS rates were 86.1% and 59.2%, respectively. In patients who underwent observation with salvage radiation, if necessary, the 3-, 5-, and 10-year RFFS rates were 97.7%, 90.3%, and 87.9%, respectively. Both PS and IPTW Cox regression models demonstrated that patients who underwent observation with salvage radiation treatment, if necessary, had significantly longer RFFS (PS model: hazard ratio [HR] 0.21, p < 0.01; IPTW model: HR 0.21, p < 0.01).

CONCLUSIONS

In this retrospective, nonrandomized study, adjuvant radiation after GTR of a WHO II meningioma did not add significant benefit over a strategy of observation and salvage radiation at initial recurrence, if necessary, but results must be considered in the context of the limitations of the study design.

Adjuvant Radiotherapy in Grade II, Atypical Meningioma of the Skull Base

Introduction Atypical meningiomas (AM) are meningiomas that are more aggressive than their grade-I counterparts and have a higher rate of recurrence. The effect of adjuvant radiotherapy (ART) on AM of the skull base is not defined.

Methods A retrospective review of all AM's of the skull base primarily resected at our institution from 1996 to 2018 was completed. ART was defined as radiotherapy (RT) that occurred within 6 months of initial resection, regardless of Simpson's grade. Minimum time length of follow-up after resection was 2 years. Statistical analysis was performed using SAS.

Results There were a total of 59 skull base–located (SBL) AMs resected at our institution from 1996 to 2018. The average age of our cohort was 53.2 years. Gross total resection, defined as Simpson's grades I to III resection, was achieved in 36 (61%) of cases. Thirty-five of 59 (59%) patients received ART. Recurrence was observed in 14 patients (24%), and mean time to recurrence was 63.8 months. Patients who received ART had a lower observed rate of recurrence (8 vs. 46%); however, time to recurrence was not significantly different between the two populations.

Conclusion We observe that AM in the skull base location have higher recurrence rates than we would expect from grade-I meningioma. These data suggest that ART may offer benefit to the overall observed frequency of recurrence of SBL AM; however, the time to recurrence between patients who received ART and those who did not was not statistically significant in survival analysis.

Lateral Ventricular Meningiomas: Clinical Features, Radiological Findings and Long-Term Outcomes

Purpose

Lateral ventricle meningioma (LVM) is a rare type of intracranial meningioma, which has been rarely studied. It has different clinical features, imaging features, and long-term results from other locations. This study investigated the epidemiology, clinical characteristics and prognosis of LVM and comprehensively describes its characteristics.

Methods

This article analyzes the LVMs that were diagnosed pathologically in West China hospital between January 1, 2009 and July 1 2020. Demographic information, imaging characteristics and prognostic factors are discussed. Data analysis was performed using SPSS 23.0 and R version 3.5.3.

Results

We collected 7202 meningiomas and 195 LVMs (136 females; median age, 46 years; range, 5–81 years) were included in this study. Gross total resection was completed in 189 patients. The OS rate was 93.8%, and the recurrence rate was 5.2%. Multivariate regression analysis showed that sex (P = 0.01) and tumor size (P = 0.018) were related to WHO grade. Postoperative KPS (P = 0.003) was associated with OS. WHO grade (P = 0.025), extent of tumor resection (P < 0.001), and hospital day (P=0.028) were associated with recurrence.

Conclusion

LVMs require long-term follow-up, individualized treatment, and follow-up strategies to be formulated according to the relevant risk factors.

Treatment and follow-up results of WHO grade II meningiomas

Meningiomas are the most common primary intracranial tumors. They have three pathologic grades. Surgical resection aiming Simpson I resection is the standard treatment for meningiomas. Radiotherapy and Gamma Knife radiosurgery are the main adjuvant and salvage treatments. Chemotherapy has limited use. Grade II, and III meningiomas have a higher recurrence rate, and adjuvant radiotherapy is usually the standard treatment for grade III meningiomas but there is not a consensus regarding grade II meningiomas. In this paper, we analyzed our meningioma series of 1401 patients and presented the treatment and follow-up results of 170 grade II meningioma cases. The median follow-up of grade II meningiomas was 61 (range = 1-231) months. The mean age of patients was 52.5 ± 15.0 years, 102 of them were female and 68 were male (female/male ratio = 1.5). The median progression-free survival (PFS) of them was 109 months, and the cumulative overall survival (OS) rate was 85% at 10 years. Meningiomas with gross total resection, non-skull base meningiomas, and primary grade II meningiomas had longer PFS with statistical significance, while non-skull base meningiomas, younger group of patients, and primary grade II meningiomas had longer OS with a statistical significance.

Adjuvant radiotherapy for atypical meningiomas is associated with improved progression free survival

PURPOSE

To assess the progression-free survival benefits of adjuvant radiotherapy (ART) following surgical resection compared to surgery alone in high-grade meningioma patients.

METHODS

We retrospectively identified 43 patients with atypical meningiomas, who underwent either radiotherapy post-surgical resection (Surgery+ART) or surgery alone (Surgery alone) at our institution between February 2007 to March 2019. GTR was achieved in 28 patients, and STR, in 11. Patient, meningioma, and treatment data were extracted from records and compared using Kaplan-Meier methodology, log-rank tests, and Cox proportional hazard models. Radiation complications were also evaluated.

RESULTS

Overall 32.6% (n = 14) of patients, 6 patients in the Surgery+ART group and 8 in the Surgery alone group, experienced recurrence. In the Surgery+ART group, the median PFS time was 46.5 months (CI: [35.8-50.6]), compared to 24.5 months (CI: [18.3-32.9]) in the Surgery alone group. 2-year PFS for Surgery+ART was 100% vs. 69.0% for Surgery alone, and the 5-year PFS rate was 70.6% and 39.2%, respectively (log-rank p-value = .004).

CONCLUSIONS

Our data revealed a significant PFS increase for those treated with adjuvant radiotherapy following surgery compared to surgery alone. Future prospective studies evaluating differing radiation modalities and dosages should be conducted.

Neurosurgical follow-up and treatment of a series of 26 WHO grade III meningiomas

Meningiomas are the most common primary intracranial tumors. They have three pathologic grades. Surgical resection aiming Simpson I resection is the standard treatment for meningiomas. Radiotherapy and Gamma Knife radiosurgery are the main adjuvant and salvage treatments. Chemotherapy has limited use. Grade II, and III meningiomas have a higher recurrence rate, and adjuvant radiotherapy is usually the standard treatment for grade III meningiomas. In this paper, we analyzed our meningioma series of 1401 patients and presented the treatment and follow-up results of 26 grade III meningioma cases. Median follow-up of grade III meningiomas was 40.5 (range, 1-154) months. The mean age of patients was 51.7 ± 15.7 years; 12 of them were female and 14 were male (female/male ratio = 0.9). The median progression-free survival (PFS) of them was 22 months, and overall survival (OS) was 62 months. Meningiomas with gross total resection (GTR), non-skull base meningiomas, and primary grade III meningiomas had longer PFS, while meningiomas with GTR, non-skull base meningiomas, and primary meningiomas had longer OS with a statistical significance.

Adjuvant Radiotherapy Versus Watchful Waiting for World Health Organization Grade II Atypical Meningioma: A Single-Institution Experience

BACKGROUND

Atypical meningiomas (AMs) are meningiomas that have a higher rate of recurrence than grade I meningioma. Due to the higher risk of recurrence, adjuvant radiotherapy (RT) after resection of AM has been employed. At our institution, some neurosurgeons employ adjuvant RT on all primarily resected AMs, while others employ watchful waiting with serial imaging.

OBJECTIVE

To study the effect of adjuvant RT on newly resected AMs.

METHODS

A retrospective review of all AMs primarily resected at our institution from 1996 to 2018 was completed. Data on patient demographics, radiographic findings, use of adjuvant RT, time of follow-up, and recurrences were collected. Adjuvant RT was defined as RT that occurred within 6 mo of initial resection.

RESULTS

A total of 162 patients met the inclusion criteria. Gross total resection was achieved in 73% of cases. Average time until recurrence in the cohort was 37 mo. A total of 108 patients had adjuvant RT, while 54 patients did not. On multivariate survival analysis, sex, Simpson grade resection, and use of adjuvant RT were independent predictors of recurrence. Mean time to recurrence in patients who received adjuvant RT was 43.7 mo versus 34.7 mo for those who did not receive adjuvant RT.

CONCLUSION

This study includes the largest retrospective cohort of patients who have received adjuvant RT after primary resection of AM. Our results suggest that the use of adjuvant RT is independently associated with a lower chance of recurrence. These data suggest that practitioners can consider the use of adjuvant RT for newly resected AMs, regardless of Simpson grade resection.

Atypical meningioma: patterns of postradiotherapy recurrences

PURPOSE

There is no consensus on a target definition and optimal dose in radiotherapy for atypical meningioma (AM). Insight into the postradiotherapy recurrence pattern is needed for optimal target definition and local control. The objective was to describe the patterns of recurrence after postoperative or salvage radiotherapy in patients with AM.

MATERIALS AND METHODS

A retrospective analysis was conducted of patients treated for intracranial AM with (fractionated) stereotactic radiotherapy (FSRT). The relationships between postradiotherapy recurrences, the dura and irradiated volume were established. Moreover, the dose prescriptions and fractionation schedules were converted to a reference to determine the relationship between dose and local control.

RESULTS

The included patients received 57 (F)SRT treatments and 73 surgeries. Recurrent disease was found in 21 of 29 patients (72%) and after 39 of 57 (F)SRTs (68%). The median interval to first recurrence was 39.7 months. Of these recurrences, 25 were in-field, 11 were marginal, and 3 were out of field. In-field recurrence rates after biological equivalent doses < 60 Gy or ≥ 60 Gy were 50% and 21%. All recurrences were connected to the dura. Of the marginal recurrences, 64% were within 2 cm and 91% were within 3 cm of the volume receiving the prescribed dose.

CONCLUSIONS

AM frequently recurs after radiotherapy. All postradiotherapy recurrences were connected to the dura. Most marginal recurrences occurred within 3 cm of the irradiated abnormal dura. The lowest rate of in-field recurrences occurred after equivalent doses of least 60 Gy in 2 Gy fractions suggesting a dose-effect relationship.

Clinical Factors and Outcomes of Atypical Meningioma: A Population-Based Study

Objective

Atypical meningioma is a non-benign tumor, and its prognostic factors and treatment strategies are unclear.

Methods

Patients with atypical meningioma, between 2004 and 2016, were collected from the Surveillance, Epidemiology, and End Results database. Then, we randomly divided patients into a training set and a validation set at a ratio of 8:2. The nomogram was constructed based on the multivariate Cox regression analyses. And the concordance index, calibration curves, and receiver operating character were used to assess the predictive ability of the nomogram. We divided the patient scores into three groups and constructed a survival curve using Kaplan–Meier analysis.

Results

After our inclusion and exclusion criteria, 2358 patients were histologically diagnosed of atypical meningioma. The prognostic nomogram comprised factors of overall survival, including age, tumor size and surgery. The concordance index was 0.715 (95%CI=0.688-0.742) for overall survival in the training set and 0.688 (95%CI=0.629-0.747) for overall survival in the validation set. The calibration curves and receiver operating character also indicated the good predictability of the nomogram. Risk stratification revealed a statistically significant difference among the three groups of patients according to quartiles of risk score.

Conclusion

Gross total resection is an independent factor for survival, and radiation after non-gross total resection potentially confers a survival advantage for patients with atypical meningioma.

Effect of adjuvant radiotherapy after subtotal resection for WHO grade I meningioma: a propensity score matching analysis of the Brain Tumor Registry of Japan

PURPOSE

This study aimed to improve the understanding of the role of adjuvant radiotherapy (AR) after subtotal resection (STR) of World Health Organization (WHO) grade I meningiomas.

METHODS

We retrospectively reviewed the Brain Tumor Registry of Japan database. Among 7341 patients diagnosed with intracranial meningioma during 2001-2008, we identified 406 patients with WHO grade I meningioma treated with STR as initial treatment. Data on progression-free survival (PFS) were assessed for their relevance to clinical factors including age, sex, tumor location and size, presence of preoperative symptoms, and AR.

RESULTS

AR was administered for 73 patients (18.0%). Regrowth occurred in 90 cases (22.2%) during the median follow-up period of 6.0 years (interquartile range, 2.7-7.7 years). Multivariate Cox regression analysis of the entire cohort showed that no AR was associated with significantly shorter PFS (hazard ratio [HR] 2.52, 95% confidence interval [CI] 1.33-5.42, p = 0.004). The therapeutic effect of AR was confirmed for skull base, but not non-skull base, meningiomas (p = 0.003 and 0.69, respectively). Propensity score matching analysis balanced the influence of confounding factors to generate AR+ and AR- cohorts of 73 patients each. PFS was significantly longer in the AR+ cohort than in the AR- cohort (HR 3.46, 95% CI 1.53-8.59, p = 0.003). Subgroup analysis demonstrated the favorable effect of AR only for skull base meningiomas.

CONCLUSIONS

Our study revealed that AR improves tumor control after STR in WHO grade I meningiomas. However, this beneficial effect might be limited to skull base meningiomas.

Meta-analysis of adjuvant radiotherapy for intracranial atypical and malignant meningiomas

INTRODUCTION

Meningiomas comprise 33% of all CNS tumors. The World Health Organization (WHO) describes meningiomas as benign (BM), atypical (AM), and malignant/anaplastic (MM). High-grade meningiomas such as AMs and MMs are more aggressive, recur more frequently, and portend a worse prognosis than BMs. Currently, the standard treatment for high-grade meningiomas, especially AMs, is ill-defined. In particular, the benefit to survival outcomes of adjuvant radiotherapy post-surgical resection remains unclear. In this study, we investigated the effect of adjuvant radiotherapy (ART) post-surgery on survival outcomes compared to surgery alone for high-grade meningiomas.

METHODS

PRISMA guidelines were a foundation for our literature review. We screened the PubMed database for studies reporting overall survival (OS), progression free survival (PFS), and tumor recurrence for intracranial, primary AM and MMs treated with surgery+ART or surgery alone. Fixed and random effect models compared tumor control rate for AM aforementioned groups.

RESULTS

Mean 5-year PFS was 76.9% for AM (surgery+ART) and 55.9% for AM (surgery alone) patients. Mean 5-year OS was 81.3% and 74% for AM (surgery+ART) and AM (surgery alone) groups, respectively. Overall, the mean 5-year PFS for aggregated high-grade meningiomas AM+MM (surgery+ART) was 67.6%. Fixed effect models revealed tumor control rate as 76% for AM (surgery+ART) and 69% for AM (surgery alone) groups. ART induced toxicity incidence ranged from 12.0% to 35.5% for AM and MM patients.

CONCLUSIONS

Our analysis suggests that (surgery+ART) may increase PFS, OS, and tumor control rates in high-grade meningiomas. However, further studies involving surgery+ ART should be conducted to fully evaluate the ideal radiosurgical candidate, modality, and dosage.

Adjuvant radiotherapy versus observation following gross total resection for atypical meningioma: a systematic review and meta-analysis

Background

The impact of adjuvant radiotherapy (RT) on atypical meningioma (AM) underwent a gross total resection (GTR) remains unclear, showing conflicting results from various studies. The objective of this study was to perform an updated meta-analysis for observational studies to determine the effect of adjuvant RT after GTR on local recurrence and survival outcomes compared to observation after GTR.

Methods

PubMed, Embase, and Web of Science were searched to identify comparative studies that reported outcomes of adjuvant RT versus observation for AM patients after GTR. Local recurrence rate, progression-free survival (PFS), overall survival (OS), and toxicities related to RT were considered as outcomes of interest. Differences between two cohorts were estimated by calculating odds ratios (OR) for LR rate and hazard ratios (HR) for survival outcomes with 95% confidence intervals (CIs) for meta-analysis, using R version 4.0.3 software. Included studies were appraised with the Risk of Bias Assessment tool for Non-Randomized Studies. Outcome ratios were combined with the Mantel–Haenszel method and the inverse variance-weighted method, appropriately.

Results

Data from 30 studies involving 2904 patients (adjuvant RT: n = 737; observation: n = 2167) were eventually included. Significant reduction of local recurrence rate was seen in the adjuvant RT cohort compare to that in the observation cohort (OR 0.50; 95% CI 0.36–0.68; p < 0.0001). Pooled HRs of PFS at 1-year, 3-year, 5-year, and > 5-year revealed that adjuvant RT was superior to observation. There was no significant difference in OS between the two cohorts during any period. Most toxicities were tolerable with grade 1 or 2. There was no documented grade 5 toxicity.

Conclusions

For AM patients who underwent GTR, evidence suggested that adjuvant RT could potentially decrease local recurrence and improve PFS better than observation.

Outcomes of salvage radiation for recurrent world health organization grade II meningiomas: a retrospective cohort study

PURPOSE

The optimal modality of radiation-intensity-modulated radiation therapy (IMRT) or stereotactic radiosurgery (SRS)-in patients with recurrent WHO grade II meningiomas is not well-established. The purpose of this study was to compare progression-free survival (PFS) in patients undergoing salvage IMRT vs SRS. We compared PFS in those with and without history of prior radiation.

METHODS

Forty-two patients with 71 tumor recurrences treated with IMRT or SRS were retrospectively reviewed. Thirty-two salvage treatments were performed on recurrent tumors never treated with prior radiation ('radiation-naïve' cohort), whereas 39 salvage treatments were performed on recurrent tumors previously treated with radiation ('re-treatment cohort').

RESULTS

In the 'radiation-naïve' cohort, 3-year PFS for IMRT and SRS was 68.8% and 60.7%, respectively (p = 0.61). The median tumor volume for patients treated with IMRT was significantly larger than for patients treated with SRS (5.7 vs 2.2 cm³; p = 0.04). The 3-year PFS for salvage IMRT or SRS in the 're-treatment' cohort was 45.4% vs 65.8% in the 'radiation-naïve' cohort (p = 0.008). When analyzing the outcome of multiple re-treatments, median PFS was 47 months for 1^st or 2nd salvage radiation (IMRT or SRS) compared to 16 months for the 3rd or greater salvage radiation treatment (p = 0.003).

CONCLUSION

For salvage radiation of recurrent grade II tumors that are 'radiation-naïve', comparable 3-year PFS rates were found between IMRT and SRS, despite the IMRT group having significantly larger tumors. Salvage radiation overall was less successful in the 're-treatment' cohort compared with the 'radiation-naïve' cohort. Additionally, the effectiveness of radiation significantly declines with successive salvage radiation treatments.

Effectiveness of Postoperative Adjuvant Radiotherapy in Atypical Meningioma Patients After Gross Total Resection: A Meta-Analysis Study

Background

It still remains unclear whether patients with atypical meningioma (AM) could benefit from postoperative adjuvant radiotherapy (PORT) after gross-total resection (GTR).

Objective

Exploring the effectiveness of PORT on AM patients after GTR.

Methods

Literatures on PubMed, Embase, Web of science, and Scopus databases published between January 2000 and January 2019 were searched. After the selection based on the certain exclusion criteria, the Newcastle-Ottawa evaluation scale was used to evaluate the quality of the included literatures. Finally, a meta-analysis was conducted to analyze the effectiveness of PORT on local control (LC), progression-free survival (PFS) and overall survival (OS) in atypical meningioma patients after GTR.

Results

A total of 17 articles with 2,008 AM patients were included in the meta-analysis. The 5-year LC, 5-year PFS, and 5-year OS rates were 82.2, 84.1, and 79.0%, respectively, for AM patients receiving PORT after GTR, and they were 71.0, 71.9, and 81.5%, respectively, for those not receiving PORT after GTR. PORT could significantly improve 5-year LC rate (OR [95% Cl] = 2.59 [1.40–4.81], P = 0.002) and 5-year PFS rate (OR [95% Cl] = 1.99 [1.35–2.95], P = 0.001), but did not significantly improve 5-year OS rate (OR [95% Cl] = 1.07 [0.60–1.91], P = 0.828).

Conclusion

PORT could improve the 5-year LC rate and 5-year PFS rate in AM patients after GTR. AM patients might benefit from PORT after GTR.

The Role of the Transorbital Superior Eyelid Approach in the Management of Selected Spheno-orbital Meningiomas: In-Depth Analysis of Indications, Technique, and Outcomes from the Study of a Cohort of 35 Patients

Objective Primary goal in spheno-orbital meningioma (SOM) surgery still remains complete resection. Nevertheless, given their highly infiltrative nature, a growing body of literature suggests to shift toward function-sparing surgeries. We here present our experience in the management of SOMs through the endoscopic superior eyelid approach (SEA).

Methods Surgical database from our multidisciplinary work group was retrospectively reviewed to identify patients treated for SOMs in the last 10 years by our senior authors, analyzing and correlating clinical, radiological, and outcome variables among the different approaches used.

Results There were 35 patients (mean age of 57.3 ± 12.86 years), with a mean follow-up of 31.5 months (range: 6–84 months). The most common preoperative complaint was proptosis (62.9%) followed by diplopia and visual deficit. Greater and lesser sphenoid wings were the areas mainly involved by the pathology (91.4% and 88.6%, respectively), whereas orbital invasion was evidenced in one-third of cases. Patients were operated on through craniotomic (48.6%), endoscopic superior eyelid (37.1%), and combined cranioendoscopic (14.3%) approaches. Simpson grades 0 to II were accomplished in 46.2% of SEA and 76.5% of craniotomies. All patients with a preoperative visual deficit improved in the postoperative period, independently from the approach used. On patients who underwent endoscopic SEA, there was improved their short-/long-term postoperative Karnofsky Performance Status.

Conclusions Endoscopic SEA is a safe and effective alternative to transcranial approaches in very selected cases of SOMs, where the planned primary objective was to obtain a maximally safe resection, aimed at symptom relief, rather than a gross total resection at any cost.

A Prognostic Gene-Expression Signature and Risk Score for Meningioma Recurrence After Resection

BACKGROUND

Prognostic markers for meningioma are needed to risk-stratify patients and guide postoperative surveillance and adjuvant therapy.

OBJECTIVE

To identify a prognostic gene signature for meningioma recurrence and mortality after resection using targeted gene-expression analysis.

METHODS

Targeted gene-expression analysis was used to interrogate a discovery cohort of 96 meningiomas and an independent validation cohort of 56 meningiomas with comprehensive clinical follow-up data from separate institutions. Bioinformatic analysis was used to identify prognostic genes and generate a gene-signature risk score between 0 and 1 for local recurrence.

RESULTS

We identified a 36-gene signature of meningioma recurrence after resection that achieved an area under the curve of 0.86 in identifying tumors at risk for adverse clinical outcomes. The gene-signature risk score compared favorably to World Health Organization (WHO) grade in stratifying cases by local freedom from recurrence (LFFR, P < .001 vs .09, log-rank test), shorter time to failure (TTF, F-test, P < .0001), and overall survival (OS, P < .0001 vs .07) and was independently associated with worse LFFR (relative risk [RR] 1.56, 95% CI 1.30-1.90) and OS (RR 1.32, 95% CI 1.07-1.64), after adjusting for clinical covariates. When tested on an independent validation cohort, the gene-signature risk score remained associated with shorter TTF (F-test, P = .002), compared favorably to WHO grade in stratifying cases by OS (P = .003 vs P = .10), and was significantly associated with worse OS (RR 1.86, 95% CI 1.19-2.88) on multivariate analysis.

CONCLUSION

The prognostic meningioma gene-expression signature and risk score presented may be useful for identifying patients at risk for recurrence.

A Practical Overview on the Molecular Biology of Meningioma

PURPOSE OF REVIEW

Meningioma is a common intracranial neoplasm currently classified in 15 histologic subtypes across 3 grades of malignancy. First-choice therapy for meningioma is maximum safe resection for grade I tumors, and surgery plus optional and mandatory adjuvant radiotherapy for grade II and III, respectively, given the increased rate of recurrence even in the event of complete resection. The WHO 2016 histopathologic grading of meningioma has been questioned due to subjectivity and its controversial predictive power for recurrence.

RECENT FINDINGS

Novel DNA methylation profiling has simplified classification into six classes that seem to improve prognostic accuracy. We review five main topics of molecular biology research regarding tumorigenesis and natural history of meningioma from the clinician's perspective: the histopathologic diagnostic features and pitfalls of the current tumor classification; the molecular integrated diagnosis supported by identification of genetic alterations and DNA methylation profiling; the general landscape of the various signaling pathways involved in meningioma formation; the pathogenic theories of the peri-tumoral edema present in meningioma and its therapy implications; and a summarized review on the current treatments and plausible targeted therapies directed to meningioma. It seems likely that molecular assessment will be introduced within the next update of the WHO classification of meningiomas, acknowledging the promising value of DNA methylation profiling. This integrated diagnostic protocol will simplify tumor subtype categorization and provide improved accuracy in predicting recurrence and outcome. Although much effort is being done in identifying key gene mutations, and elucidating specific intracellular signaling pathways involved in meningioma tumorigenesis, effective targeted therapies for recurrent meningiomas are still lacking.

Adjuvant radiation for WHO grade II and III intracranial meningiomas: insights on survival and practice patterns from a National Cancer Registry

INTRODUCTION

WHO grades II (atypical) and III (malignant) meningiomas are associated with significant morbidity and mortality. The role of adjuvant radiotherapy (RT) in management remains controversial. The goal of this study was to evaluate the impact of adjuvant RT on 5-year survival in patients with atypical and malignant meningiomas. We secondarily aimed to assess contemporary practice patterns and the impact of sociodemographic factors on outcome.

METHODS

We queried the National Cancer Database for patients ≥ 18 years of age with cranial atypical or malignant meningiomas from 2010 through 2015 who underwent surgical resection with or without adjuvant radiotherapy. Subjects with unknown WHO grade or radiation status and those not receiving any surgical procedure were excluded from analysis.

RESULTS

The study includes 7486 patients, 6788 with atypical and 698 with malignant meningiomas. Overall 5-year survival was 76.9% (95% CI 75.5-78.3%) and 43.3% (95% CI 38.8-48.2%) among patients with WHO grades II and III meningiomas, respectively. Adjuvant RT correlated with improved survival in a multivariable model in patients with grade II tumors (HR 0.78; p = 0.029) regardless of the extent of resection. Age (HR 2.33; p < 0.001), male sex (HR 1.27; p < 0.001), Black race (HR 1.27; p = 0.011) and Charlson-Deyo Score ≥ 2 (1.35; p = 0.001) correlated with poorer survival whereas private insurance (HR 0.71; p < 0.001) correlated with improved survival. Adjuvant RT was also associated with improved 5-year survival among those with grade III tumors on univariate analysis (log-rank p = 0.006) but was underpowered for multivariable modeling. Utilization of adjuvant radiotherapy was only 28.4% and correlated with private insurance status. Academic institutions (25.3%) and comprehensive community cancer programs (21.4%) had lower radiotherapy utilization rates compared with integrated network cancer programs (30.5%) and community cancer programs (29.7%).

CONCLUSIONS

Adjuvant RT may correlate with improved overall survival in patients with grades II and III intracranial meningiomas regardless of the extent of resection. There is poor utilization of adjuvant RT for patients with grades II and III meningiomas likely due to a paucity of quality data on the subject. These findings will be strengthened with prospective data evaluating the role of adjuvant RT.

Major complications from radiotherapy following treatment for atypical meningiomas

OBJECTIVEComplications from radiotherapy (RT), in a primary or adjuvant setting, have overall been described as uncommon, with few detailed descriptions of major complications. The authors present two cases involving significant complications and their management in their review of patients undergoing RT for treatment of atypical meningioma.METHODSThe authors conducted a retrospective review of all patients with pathologically confirmed atypical meningioma (WHO grade II) treated with primary or adjuvant RT from February 2011 through February 2019. They identified two patients with long-term, grade 3 toxicity. The cases of these patients are described in detail.RESULTSTwo patients had major complications associated with postoperative RT. Patients 1 and 2 both were treated with postoperative RT for pathologically confirmed atypical meningioma. Patient 1 experienced worsening behavioral changes, cognitive decline, and hydrocephalus following treatment. This required cerebrospinal fluid diversion. Patient 2 developed radiation necrosis with mass effect and cognitive decline. Neither patient returned to his/her initial post-RT status after steroid therapy, and each remained in need of supportive care. Both patients remained free of tumor progression at 52 and 38 months following treatment.CONCLUSIONSThe postoperative management of patients with atypical meningioma continues to be defined, with questions remaining regarding timing of RT, dose, target delineation, and fractionation. Both of the patients in this study received fractionated RT, which included a greater volume of normal brain than more focal treatment options such as would be required by stereotactic radiosurgery (SRS). Further research is needed to compare SRS and fractionated RT for the management of patients with grade II meningiomas. The more focused nature of SRS may make this a preferred option in certain cases of focal recurrence.

Adjuvant Radiation Therapy Versus Surveillance After Surgical Resection of Atypical Meningiomas

PURPOSE

The optimal timing of adjuvant radiation therapy (RT) in the management of atypical meningiomas remains controversial. We compared the outcomes of atypical meningiomas managed with upfront adjuvant RT versus postoperative surveillance.

METHODS AND MATERIALS

Patients with intracranial atypical meningiomas who underwent resection between 2000 and 2015 at a single institution were identified. Patients receiving adjuvant RT (n = 51), defined as RT within the first year of surgery before tumor progression/recurrence (P/R), were compared with those undergoing initial surveillance (n = 179). The primary endpoints were radiographic evidence of P/R and time to P/R from surgery.

RESULTS

A total of 230 patients were identified. Fifty-one (22%) patients received upfront adjuvant RT, and 179 (78%) underwent surveillance. Compared with the surveillance group, patients who received adjuvant RT had larger tumors (5.2 cm vs 4.6 cm; P = .04), were more likely to have undergone subtotal resection (65% vs 26%; P < . 01), and more often had bone invasion (18% vs 7%; P = .02). On multivariable analysis, receipt of adjuvant RT was associated with a lower risk of P/R compared with surveillance (hazard ratio, 0.21; 95% confidence interval, 0.11-0.41; P < .01). Patients who initially underwent surveillance and then received salvage RT at time of P/R had a shorter median time to local progression after RT compared with patients who developed local P/R after upfront adjuvant RT (19 vs 64 months, respectively; P < . 01).

CONCLUSION

Upfront adjuvant RT was associated with improved local control in atypical meningiomas irrespective of extent of initial resection compared with surveillance. Early adjuvant RT should be strongly considered after gross total resection of atypical meningiomas.

WHO grade II meningioma: Epidemiology, survival and contribution of postoperative radiotherapy in a multicenter cohort of 88 patients

BACKGROUND

Meningioma is the most common primary intracranial tumor, representing 13-36.6% of all primary central nervous system tumors. Meningiomas are benign in about 90% of cases. World Health Organization (WHO) grade II meningioma is associated with a high rate of recurrence and poorer survival than in grade I. The reference treatment is surgery, which should be as complete as possible. Currently, in grade II, there are no recommendations for systematic adjuvant treatment such as radiotherapy. We studied a homogeneous series of grade II meningiomas treated by surgery in two university hospital centers to analyze use of radiotherapy and its efficacy.

METHODS

We retrospectively analyzed patients in our database with WHO grade II meningioma, operated on between 2007 and 2010 in the university hospitals of Montpellier and Bordeaux, France. Clinical and radiological data, treatments and survival were analyzed.

RESULTS

Eighty-eight patients were included. Five-year overall survival was 89.7%. Nineteen patients received radiotherapy during follow-up, without significant impact on survival (P=0.27).

CONCLUSION

In WHO grade II meningioma, it is currently difficult to establish clear recommendations for radiotherapy. The present study is in accordance with the literature that early postoperative radiotherapy is not mandatory in grade II meningioma with macroscopically total resection.

Long-Term Clinical Outcome of First Recurrence Skull Base Meningiomas

Skull base meningiomas (SBMs) are considered to be less aggressive and have a slower growth rate than non-SBMs. However, SBMs often develop local recurrences after surgical resection. Gross total removal is difficult because SBMs are deep-seated tumors and involve critical neurovascular structures. The treatment strategy for recurrent SBMs remains controversial. The present study aimed to evaluate the long-term clinical course and prognostic factors associated with shorter progression-free survival (PFS) of recurrent SBMs. This retrospective study included 85 recurrent SBMs from 65 patients who underwent surgery from January 2005 to September 2018. Overall survival (OS) and PFS were evaluated, and the associations among shorter PFS and age, sex, tumor size, lesions, World Health Organization (WHO) grading, removal rate, and time since prior surgery were analyzed. The median follow-up period for PFS was 68 months. The 2-, 5-, and 10-year PFS rates were 68.0%, 52.8%, and 22.7%, respectively. WHO grade II or III, multiple lesions, and tumor size were significantly associated with shorter PFS (p < 0.0001, p = 0.030, and p = 0.173, respectively). Although, radiotherapy did not improve PFS and OS for overall patients, PFS of the patients with subtotal and partial removal for WHO grade II SBMs was significantly improved by the radiotherapy. Multivariate analysis identified WHO grade II or III and multiple lesions as independent prognostic factors for shorter PFS (p < 0.0001 and p = 0.040, respectively). It is essential to estimate the risks associated with shorter PFS for patients with recurrent SBMs to aid in the development of appropriate postoperative strategies.

High-risk Meningioma: Initial Outcomes From NRG Oncology/RTOG 0539

BACKGROUND

Phase 2 cooperative group meningioma trial assessing the safety and efficacy of risk-adaptive management strategies. This is the initial analysis of the high-risk cohort.

METHODS AND MATERIALS

High-risk patients were those with a new or recurrent World Health Organization (WHO) grade III meningioma of any resection extent, recurrent WHO grade II of any resection extent, or new WHO grade II after subtotal resection. Patients received intensity-modulated radiotherapy (IMRT) using a simultaneous integrated boost technique (60 Gy high dose and 54 Gy low dose in 30 fractions). Three-year progression-free survival (PFS) was the primary endpoint. Adverse events (AEs) were scored per NCI Common Terminology Criteria for Adverse Events version 3.

RESULTS

Of 57 enrolled patients, 53 received protocol treatment. Median follow-up was 4.0 years (4.8 years for living patients). Two patients withdrew without progression before year 3; for the remaining 51 patients, 3-year PFS was 58.8%. Among all 53 protocol-treated patients, 3-year PFS was 59.2%. Three-year local control was 68.9%, and overall survival was 78.6%. Of 51 patients, 1 patient (1.9%) experienced a late grade-5 necrosis-related AE. All other acute (23 of 53 patients) and late (21 of 51 patients) AEs were grades 1 to 3.

CONCLUSIONS

Patients with high-risk meningioma treated with IMRT (60 Gy/30) experienced 3-year PFS of 58.8%. Combined acute and late AEs were limited to grades 1 to 3, except for a single necrosis-related grade 5 event. These results support postoperative IMRT for high-risk meningioma and invite ongoing investigations to improve outcomes further.

Pharmacotherapeutic options for atypical meningiomas

Introduction: Atypical meningiomas are aggressive tumors associated with high rates of recurrence and mortality. Current therapy is surgical resection followed by radiotherapy which has reasonable success rates. However, there are cases where surgical resection is not possible, and radiotherapy is not advisable. Areas covered: In this short review, the authors have searched the current literature for explorations of adjuvant treatments such as chemotherapy and pharmaceutical agents. Most current chemotherapeutic agents have been unsuccessful in producing radiographic reduction or disease stabilization, although drugs like somatostatin analogs and plant-derived chemotherapeutics have shown some promise. The authors note that most of the studies in this field have been case series with a few randomized trials present. This makes it hard to ascertain the effectiveness of the drugs and so further research is required in the field. Expert opinion: Finding pharmacotherapies to combat atypical meningiomas needs Big data genomic analysis. This will assist in generating drug candidates and a multidrug approach to therapy that will exploit several of the pathological pathways of atypical meningiomas. Using multidrug therapy that affects several pathways also addresses the issue of meningioma heterogeneity and adaptability.

Analysis of patterns of failure and appraisal of postoperative radiation field for grade II-III meningioma

PURPOSE

To analyze patterns of failure according to treatment modalities and evaluate the adequacy of an institution's current volume of postoperative radiotherapy (PORT) for World Health Organization (WHO) grade II or III meningiomas.

PATIENTS AND METHODS

Data of 98 patients treated by either surgery and PORT (PORT group, n = 53) or surgery alone (surgery group, n = 45) between March 2000 and December 2013 were reviewed. Clinical target volume of PORT was delineated as a 1.5-2-cm expansion from the tumor bed. Local failure (LF) was defined as recurrence within a 2-cm margin from the tumor bed. Failures other than LF were defined as out-field failure (OFF). Median total dose of PORT was 59.4 (range 45.0-69.0) Gy.

RESULTS

The PORT group had larger proportions of grade III meningiomas (18/53, 34.0%) than the surgery group (8/46, 15.6%) (p = 0.037). After a median 73.4-month follow-up, 29 patients experienced LF and 5 developed OFF. The actuarial 5-year local control (LC) rates were 86.7% and 59.3% in the PORT and surgery groups, respectively (p = 0.002). PORT was a significant factor of LC in the univariate (p = 0.003, hazard ratio [HR] 3.449, 95% confidence interval [CI] 1.516-7.846) and multivariate analyses (p < 0.001, HR 5.486, 95% CI 2.178-13.820).

CONCLUSIONS

Despite the larger proportion of grade III meningiomas in the PORT group, PORT reduced LF in patients with WHO grade II or III meningiomas compared with the surgery group. The current PORT field seems reasonable because LF was the dominant pattern of failure in patients treated by surgery alone.

The Sovereignty of Primary Cranial Tumors-Meningiomas: Vetting the Cardinal Epidemiological Features

Introduction:

Cranial meningiomas considered one of most frequently encountered primary intracranial tumors in our daily neurosurgical practice, represent about 36% of brain neoplasms.

Aim:

In this cohort analysis, we investigated epidemiological features of brain meningiomas diagnosed at a single institution. Special highlighting has been dedicated to demographic features, foretelling radiological signs, and concomitant factors predictive of tumor atypia.

Material and Methods:

This retrospective analysis was conducted by revising all medical registries of patients aged ≥18 years, with a diagnosis of brain meningioma treated at King Hussein Medical Center, patients were retrieved from the electronic hospital database during a 12-year period (2004 to 2015). Preoperative radiology reports were examined to confirm tumor site and size based on largest measured dimension. Level of resection was based on surgical operative reports and post-operative radiological imaging.

Results:

A total of 665-patients operated for intracranial meningiomas were analyzed out of total 2047-patients operated for intracranial neoplasm during the same period. Demographic analysis showed; female to male ratio 2.4:1. Mean age 49.6-years. Average follow-up of 8.7 years. Tumor locations were classified as parasagittal (39.55%), convexity (27.52%), tentorial/ falx (6.17%), intraventricular (2.04%). Mean tumor size was 3,86 cm and tumor size was >4.5cm in (28. 07%) of cases. In this study we achieved gross total resection in (73.1%) of cases, subtotal resection in (22.6%). The majority of patients evolved favorably with respect to their neurological examination post-operatively, though a neurological deficit persisted in 64-cases and 16-cases developed a new neurological deficit. Ninety five cases developed recurrence during the observation period. Surgical mortality was reported in 11-cases in the immediate post-operative period and in 42-cases further cases during the observation period related to other causes.

Conclusion:

Neurosurgery faces a large number of intracranial meningioma patients in daily practice. Because of its “benign” nature; the variability in management strategy, Neurosurgery is more and more challenged with the concern of intracranial meningioma treatment in the daily practice. Because of its “benign” nature; the variability in management strategy, research regarding the meningioma etiology and epidemiology has lagged behind that for more malignant intracranial neoplasms. These risk factors piloted a revitalization in the study of meningiomas.

Effectiveness of Postoperative Radiotherapy on Atypical Meningioma Patients: A Population-Based Study

Purpose: It is controversial whether atypical meningioma patients undergoing gross-total resection (GTR) can benefit from postoperative radiotherapy (PORT). This study aimed to investigate the effectiveness of PORT on atypical meningioma patients.

Methods: Patients diagnosed with atypical meningioma from 2008 to 2015 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. The Kaplan–Meier survival curves were generated, and the log-rank test was used to compare the differences among groups. Univariable and multivariable COX regressions were conducted for survival analyses.

Results: A total of 1,014 patients were enrolled. The 5-years survival rate of the overall patients was 79.0%. PORT was performed in 315 (31.1%) patients. The utilization rates of PORT in patients undergoing GTR and undergoing subtotal resection (STR) were 26.7% and 42.2%, respectively. For patients undergoing STR, log-rank test showed that overall survival (OS) time was significantly longer in patients receiving PORT than those not (p = 0.026). For patients undergoing GTR, OS time did not show significant association with PORT (p = 0.339). In addition, patients undergoing STR with PORT had no significantly different OS time compared with those undergoing GTR with PORT (p = 0.398). Multivariable Cox regression analysis showed that receipt of PORT (p = 0.187) was not an independent predictor of OS after adjustment.

Conclusion: PORT may not prolong the OS in atypical meningioma patients undergoing GTR. However, patients undergoing STR may benefit from PORT and achieve similar OS to those undergoing GTR.

Prognostic factors for progression in atypical meningioma

OBJECTIVE

The optimal adjuvant management for atypical meningiomas remains controversial. The aim of this study was to review long-term outcomes to identify potential prognostic factors for disease progression.

METHODS

From August 1992 to August 2013, 70 patients with atypical meningioma were treated at the authors’ institution. Pathology revision was performed based on WHO 2007 criteria. Patients with multiple tumors, neurofibromatosis Type 2, or inadequate imaging follow-up were not eligible. The authors performed pre- and postoperative serial measurements of tumor volume from MRI. Age, sex, tumor location, bone involvement, brain invasion, mitotic figures, preoperative disease volume, extent of resection, tumor growth rates, use of adjuvant postoperative radiation therapy (PORT), and residual tumor volume at the time of radiation therapy (RT) were assessed by univariate and multivariate analysis to determine their potential impact on disease progression.

RESULTS

Forty patients (57%) underwent gross-total resection (GTR) and 30 (43%) underwent subtotal resection (STR). PORT was delivered to 12 patients (30%) with a GTR and in only 4 (13%) with an STR. The 5-year progression-free survival (PFS) rate for patients in the GTR group with or without PORT was 100% and 54.1%, respectively (p = 0.0058). PFS for patients in the STR group with or without PORT was 75% and 0%, respectively (p = 0.0026). On multivariate analysis, STR and PORT were the only independent significant prognostic factors for disease progression with hazard ratios of 5.4873 (95% CI 2.19–13.72, p = 0.0003) and 0.0464 (95% CI 0.0059–0.364, p = 0.0035), respectively. Based on Youden’s index statistic, a cutoff residual tumor volume of more than 8.76 cm3 at the time of RT was associated with worse PFS (13.6% vs 56%, p = 0.0079). Before receiving RT, the median relative and absolute growth rates and tumor doubling time for patients were 124.2%/year, 4.8 cm3/year, and 1.67 years, respectively. These indices changed after RT to 0.245%/year, −0.09 cm3/year, and −0.005 year, respectively (p < 0.05).

CONCLUSIONS

In atypical meningioma, the use of PORT is associated with improved PFS even in patients who undergo GTR. Patients with residual tumor volume larger than 8.76 cm3 have an increased risk of disease progression and should be considered for early RT.

Pathologic Predictors of Local Recurrence in Atypical Meningiomas Following Gross Total Resection

PURPOSE

To assess the local recurrence rate of gross totally resected atypical meningiomas and evaluate for pathologic predictors of recurrence.

METHODS AND MATERIALS

All patients meeting the 2016 World Health Organization grade 2 meningioma criteria who received gross total resection were included in this retrospective analysis. A neuropathologist re-reviewed all surgical specimens for the following pathologic factors: brain invasion, macronuclei, necrosis, sheeting architecture, hypercellularity, high nuclear to cytoplasmic ratio, Ki67 proliferative index, mitotic number, and choroid or clear cell histology. Local recurrence and salvage therapy were recorded.

RESULTS

Ninety-seven patients met the inclusion criteria and had a median radiographic follow-up of 53 months (range, 3-153). Necrosis was present in 41 specimens (42%), and brain invasion occurred in 30 (31%). Seventy-six patients (78%) had 3 of 5 World Health Organization grade 2 qualifying atypical features. Median mitotic number and Ki67 index were 3 (0-12) and 15 (2%-55%), respectively. Only Ki67 proliferative index and mitotic number predict for local recurrence. The Kaplan-Meier estimate of local recurrence was 30.3% at 3 years.

CONCLUSIONS

In this cohort of gross totally resected atypical meningioma followed with observation, local recurrence occurred in 30.3% at 3 years. Ki67 index and mitotic number predict for local failure and could help stratify patients who would benefit from adjuvant therapy.