Adjuvant radiotherapy for atypical and malignant meningiomas: a systematic review

Metastasis of World Health Organization Grade II and Grade III Meningiomas: Long-Term Survival and Associated Factor Analysis

OBJECTIVE

Metastasis of World Health Organization (WHO) grade II or grade II meningiomas are rare. The aim of this study was to investigate their incidence, associated risk factors, and treatment course.

METHODS

Patients with surgically resected WHO grade II or grade III meningiomas were reviewed based on histopathology with the 2016 WHO criteria. Metastasis was diagnosed through whole body image scan followed by surgical resection or biopsy. Clinical factors were analyzed for their association with metastasis.

RESULTS

Among the 131 enrolled patients, metastasis was diagnosed after tumor relapse in 7 (incidence rate 3.6%) at a mean 30.9 months after the initial surgery. The metastasis after tumor relapse group had the worst overall survival, followed by tumor relapse without metastasis and nonrelapse groups (P < 0.001). The independent factors associated with metastasis were major vessel compromise by primary tumors (hazard ratio [HR] = 9.9, P = 0.035), tumor relapse time less than 24 months (HR = 7.0, P = 0.036), and subtotal resection without adjuvant radiotherapy to the primary tumor (HR = 3.5, P = 0.047). Neither grading nor histochemical staining was significantly associated with metastasis, whereas higher vascularity seemed to be more common in metastatic lesions than primary tumors.

CONCLUSIONS

The presence of metastasis contributed to poor outcomes and was related to earlier tumor relapse and major vessel compromise. Subtotal resection should be followed by adjuvant radiotherapy to reduce the risk of metastasis. Further research is warranted to identify circulating or pathologic biomarkers for the early detection of metastasis.

The role of adjuvant radiotherapy for intracranial malignant meningiomas: analysis of a nationwide database

PURPOSE

This study aimed to examine the effect of postoperative radiotherapy on survival outcomes in patients with malignant meningiomas.

METHODS

We identified patients with malignant meningioma diagnosed between 2007 and 2018 using the Taiwan Cancer Registry and followed them up using the death registry. Survival was compared between patients with and without adjuvant radiotherapy. The potential confounding factors evaluated in this study included age, sex, comorbidities, and the Charlson Comorbidity Index (CCI).

RESULTS

The analysis included 204 patients; 94 (46%) received adjuvant radiotherapy. The two groups had similar sex distributions (p = 0.53), mean age (p = 0.33), histologic subtype (p = 0.13), and CCI (p = 0.62). The prognosis of malignant meningioma was poor, with a median overall survival (OS) of 2.4 years. The median OS was 3.0 years (interquartile range (IQR) [1.4-6.1], and 2.0 years (IQR [0.5-3.9]) in the radiotherapy and non-radiotherapy groups, respectively (p = 0.001). However, Kaplan-Meier curves with the log-rank test showed no significant difference in OS between the two groups (p = 0.999). Controlling for age group, sex, histologic subtype, treatment, comorbidities, and CCI, adjuvant radiotherapy did not impart a survival benefit (hazard ratio [HR] = 0.87; 95% confidence interval [CI]: 0.6‒1.26); however, only factor of higher comorbidity score (HR = 2.03, 95%CI: 1.04‒3.94) was associated with unfavorable survival.

CONCLUSION

This population-based retrospective analysis suggests that the role of radiotherapy remains unclear and underscores the need for randomized clinical trials to assess the usefulness of adjuvant radiotherapy in malignant meningioma.

Proton therapy for intracranial meningioma: a single-institution retrospective analysis of efficacy, survival and toxicity outcomes

PURPOSE

To report the outcomes of a large series of intracranial meningiomas (IMs) submitted to proton therapy (PT) with curative intent.

METHODS

We conducted a retrospective analysis on all consecutive IM patients treated between 2014 and 2021. The median PT prescription dose was 55.8 Gy relative biological effectiveness (RBE) and 66 GyRBE for benign/radiologically diagnosed and atypical/anaplastic IMs, respectively. Local recurrence-free survival (LRFS), distant recurrence-free survival (DRFS), overall survival (OS), and radionecrosis-free survival (RNFS) were evaluated with the Kaplan-Meier method. Univariable analysis was performed to identify potential prognostic factors for clinical outcomes. Toxicity was reported according to the latest Common Terminology Criteria for Adverse Events (CTCAE) version 5.0.

RESULTS

Overall, 167 patients were included. With a median follow-up of 41 months (range, 6-99), twelve patients (7%) developed tumor local recurrence after a median time of 39 months. The 5-year LRFS was 88% for the entire cohort, with a significant difference between benign/radiologically diagnosed and atypical/anaplastic IMs (98% vs. 47%, p < 0.001); this significant difference was maintained also for the 5-year OS and the 5-year DRFS rates. Patients aged ≤ 56 years reported significantly better outcomes, whereas lower prescription doses and skull base location were associated with better RNFS rates. Two patients experienced G3 acute toxicities (1.2%), and three patients G3 late toxicities (1.8%). There were no G4-G5 adverse events.

CONCLUSION

PT proved to be effective with an acceptable toxicity profile. To the best of our knowledge this is one of the largest series including IM patients submitted to PT.

A nomogram to predict cancer-specific mortality in adult patients with malignant meningioma: a competing risk analysis

BACKGROUND

Comprehensive investigations of the prognosis factors and treatment strategies with adjustment of competing causes of death for patients with malignant meningioma (MM) is still lacking.

PATIENT AND METHOD

The surveillance, Epidemiology, and End Results (SEER) database were used to include adult patients with this rare disease between 2004 and 2018. The probability of MM-caused mortality (MMCM) and non-MM-caused mortality (non-MMCM) were presented by cumulative incidence function curves. Then, the association between variates with non-MMCM was evaluated by the cox proportional hazard model, and the prognostic factors of MMCM were identified by Fine-Gray competing risk regression model. Furthermore, a nomogram was developed to predict the 1-year, 2-year, and 5-year MMCM and the performance was tested by a time-dependent area under the receiver operating characteristic (ROC) curve and calibration.

RESULT

577 patients were included, with a median age of 62 (18-100) years old and a median overall survival time of 36 (0-176) months. The percentage of non-MMCM was 15.4% (n = 89) in the entire population and 21.7% (n = 54) in elderly patients. The multivariable Cox proportional hazard regression model revealed that older age and other tumor(s) before or after MM had an independently significant association with higher non-MMCM. After adjustment of competing causes of death, the multivariable Fine-gray regression model identified age group ≥ 65 year, tumor size > 5.3 cm, recurrent MM, and histologic type 9530/3 (Meningioma, malignant) had an independently significant association with higher MMCM. Compared with gross total (GTR) of tumor, subtotal resection of tumor (HR 1.66, 95%CI 1.08-2.56, P = 0.02), partial resection of lobe (HR 2.26, 95%CI 1.32-3.87, P = 0.003), and gross total resection of lobe (HR 1.69, 95%CI 1.12-2.51, P = 0.01) had an independently significant association with higher MMCM.

CONCLUSION

The competing risk nomogram including age group, tumor size, initial status, histologic type, and extent of resection is discriminative and clinically useful. This study emphasized the importance of the GTR of tumor in the treatment of MM patients, which had a significantly lower incidence of MMCM compared with biopsy, STR of tumor, partial resection of lobe, and GTR of lobe.

Gross Tumor and Intracranial Control Benefits with Fractionated Radiotherapy Compared with Stereotactic Radiosurgery for Patients with WHO Grade 2 Meningioma

OBJECTIVE

Surgical resection is the mainstay of treatment for WHO grade 2 meningioma. Fractionated radiation therapy (RT) is frequently used after surgery, though many centers utilize stereotactic radiosurgery (SRS) for recurrence or progression. Herein, we report disease control outcomes from an institutional cohort with adjuvant fractionated RT versus salvage SRS.

METHODS

We identified 32 patients from an institutional database with WHO grade 2 meningioma and residual/recurrent tumor treated with either SRS or fractionated RT. Patients were treated between 2007 and 2021 and had at least 1 year of follow-up. Kaplan-Meier estimators were used to determine gross tumor control (GTC) and intracranial control (IC). Univariate Cox proportional hazards models using biologically effective dose (BED) as a continuous parameter were used to assess for dose responses.

RESULTS

With a median follow-up of 5.5 years, 13 patients (41%) received SRS to a recurrent or progressive nodule, 2 (6%) fractionated RT to a recurrent or progressive nodule, and 17 (53%) adjuvant fractionated RT following subtotal resection. Five-year GTC was higher with fractionated RT versus SRS (82% vs. 38%, P = 0.03). Five-year IC was also better with fractionated RT versus SRS (82% vs. 11%, P < 0.001). On univariate analysis, increasing BED10 was significantly associated with better GTC (P = 0.039); increasing BED3 was not (P = 0.82).

CONCLUSIONS

In this patient cohort, GTC and IC were significantly higher in patients treated with adjuvant fractionated RT compared with salvage SRS. Increasing BED10 was associated with better GTC. Fractionated RT may provide a better therapeutic ratio than SRS for grade 2 meningiomas.

Inhibition of BMP signaling pathway induced senescence and calcification in anaplastic meningioma

PURPOSE

Meningiomas are the most common type of brain tumors and are generally benign, but malignant atypical meningiomas and anaplastic meningiomas frequently recur with poor prognosis. The metabolism of meningiomas is little known, so few effective treatment options other than surgery and radiation are available, and the targets for treatment of recurrence are not well defined. The Aim of this paper is to find the therapeutic target.

METHODS

The effects of bone morphogenetic protein (BMP) signal inhibitor (K02288) and upstream regulator Gremlin2 (GREM2) on meningioma's growth and senescence were examined. In brief, we examined as follows: 1) Proliferation assay by inhibiting BMP signaling. 2) Comprehensive analysis of forced expression GREM2.3) Correlation between GREM2 mRNA expression and proliferation marker in 87 of our clinical samples. 4) Enrichment analysis between GREM2 high/low expressed groups using RNA-seq data (42 cases) from the public database GREIN. 5) Changes in metabolites and senescence markers associated with BMP signal suppression.

RESULTS

Inhibitors of BMP receptor (BMPR1A) and forced expression of GREM2 shifted tryptophan metabolism from kynurenine/quinolinic acid production to serotonin production in malignant meningiomas, reduced NAD + /NADH production, decreased gene cluster expression involved in oxidative phosphorylation, and caused decrease in ATP. Finally, malignant meningiomas underwent cellular senescence, decreased proliferation, and eventually formed psammoma bodies. Reanalyzed RNA-seq data of clinical samples obtained from GREIN showed that increased expression of GREM2 decreased the expression of genes involved in oxidative phosphorylation, similar to our experimental results.

CONCLUSIONS

The GREM2-BMPR1A-tryptophan metabolic pathway in meningiomas is a potential new therapeutic target.

Efficacy and toxicity of bimodal radiotherapy in WHO grade 2 meningiomas following subtotal resection with carbon ion boost: Prospective phase 2 MARCIE trial

BACKGROUND

Novel radiotherapeutic modalities using carbon ions provide an increased relative biological effectiveness (RBE) compared to photons, delivering a higher biological dose while reducing radiation exposure for adjacent organs. This prospective phase 2 trial investigated bimodal radiotherapy using photons with carbon-ion (C12)-boost in patients with WHO grade 2 meningiomas following subtotal resection (Simpson grade 4 or 5).

METHODS

A total of 33 patients were enrolled from July 2012 until July 2020. The study treatment comprised a C12-boost (18 Gy [RBE] in 6 fractions) applied to the macroscopic tumor in combination with photon radiotherapy (50 Gy in 25 fractions). The primary endpoint was the 3-year progression-free survival (PFS), and the secondary endpoints included overall survival, safety and treatment toxicities.

RESULTS

With a median follow-up of 42 months, the 3-year estimates of PFS, local PFS and overall survival were 80.3%, 86.7%, and 89.8%, respectively. Radiation-induced contrast enhancement (RICE) was encountered in 45%, particularly in patients with periventricularly located meningiomas. Patients exhibiting RICE were mostly either asymptomatic (40%) or presented immediate neurological and radiological improvement (47%) after the administration of corticosteroids or bevacizumab in case of radiation necrosis (3/33). Treatment-associated complications occurred in 1 patient with radiation necrosis who died due to postoperative complications after resection of radiation necrosis. The study was prematurely terminated after recruiting 33 of the planned 40 patients.

CONCLUSIONS

Our study demonstrates a bimodal approach utilizing photons with C12-boost may achieve a superior local PFS to conventional photon RT, but must be balanced against the potential risks of toxicities.

Multi-parametric MRI-based machine learning model for prediction of WHO grading in patients with meningiomas

OBJECTIVE

The purpose of this study was to develop and validate a nomogram combined multiparametric MRI and clinical indicators for identifying the WHO grade of meningioma.

MATERIALS AND METHODS

Five hundred and sixty-eight patients were included in this study, who were diagnosed pathologically as having meningiomas. Firstly, radiomics features were extracted from CE-T1, T2, and 1-cm-thick tumor-to-brain interface (BTI) images. Then, difference analysis and the least absolute shrinkage and selection operator were orderly used to select the most representative features. Next, the support vector machine algorithm was conducted to predict the WHO grade of meningioma. Furthermore, a nomogram incorporated radiomics features and valuable clinical indicators was constructed by logistic regression. The performance of the nomogram was assessed by calibration and clinical effectiveness, as well as internal validation.

RESULTS

Peritumoral edema volume and gender are independent risk factors for predicting meningioma grade. The multiparametric MRI features incorporating CE-T1, T2, and BTI features showed the higher performance for prediction of meningioma grade with a pooled AUC = 0.885 (95% CI, 0.821-0.946) and 0.860 (95% CI, 0.788-0.923) in the training and test groups, respectively. Then, a nomogram with a pooled AUC = 0.912 (95% CI, 0.876-0.961), combined radiomics score, peritumoral edema volume, and gender improved diagnostic performance compared to radiomics model or clinical model and showed good calibration as the true results. Moreover, decision curve analysis demonstrated satisfactory clinical effectiveness of the proposed nomogram.

CONCLUSIONS

A novel nomogram is simple yet effective in differentiating WHO grades of meningioma and thus can be used in patients with meningiomas.

CLINICAL RELEVANCE STATEMENT

We proposed a nomogram that included clinical indicators and multi-parameter radiomics features, which can accurately, objectively, and non-invasively differentiate WHO grading of meningioma and thus can be used in clinical work.

KEY POINTS

• The study combined radiomics features and clinical indicators for objectively predicting the meningioma grade. • The model with CE-T1 + T2 + brain-to-tumor interface features demonstrated the best predictive performance by investigating seven different radiomics models. • The nomogram potentially has clinical applications in distinguishing high-grade and low-grade meningiomas.

Fractionated radiotherapy for surgically resected intracranial meningiomas: A multicentre retrospective cohort study

BACKGROUND

Aside from surgical resection, the only standard of care treatment modality for meningiomas is radiotherapy (RT). Despite this, few studies have focused on identifying clinical covariates associated with failure of fractionated RT following surgical resection (fRT), and the timing of fRT following surgery still remains controversial (adjuvant versus salvage fRT). We assessed the outcomes of the largest, multi-institutional cohort of surgically resected meningiomas treated with subsequent adjuvant and salvage fRT to identify factors associated with local freedom from recurrence (LFFR) over 3-10 years post-fRT and to determine the optimal timing of fRT.

METHODS

Patients with intracranial meningiomas who underwent surgery and fRT between 1997 and 2018 were included. Primary endpoints were radiographic recurrence/progression and time to progression from the completion of fRT.

RESULTS

404 meningiomas were included for analysis. Of these, 167 (41.3%) recurred post-fRT. Clinical covariates independently associated with worse PFS post-fRT included receipt of previous RT to the meningioma, having a WHO grade 3 meningioma or recurrent meningioma, the meningioma having a higher MIB1-index or brain invasion on pathology, and older patient age at diagnosis. Subgroup analysis identified higher MIB1-index as a histological factor associated with poorer LFFR in WHO grade 2 meningiomas. 179 patients underwent adjuvant RT shortly after surgery whereas 225 patients had delayed, salvage fRT after recurrence/progression. Following propensity score matching, patients that underwent adjuvant fRT had improved LFFR post-fRT compared to those that received salvage fRT.

CONCLUSION

There is a paucity of clinical factors that can predict a meningioma's response to fRT following surgery. Adjuvant fRT may be associated with improved PFS post-fRT compared to salvage fRT. Molecular biomarkers of RT-responsiveness are needed to better inform fRT treatment decisions.

Combined helical tomotherapy and Gamma Knife stereotactic radiosurgery for high-grade recurrent orbital meningioma: a case report

Orbital meningioma is a rare type of orbital tumor with high invasiveness and recurrence rates, making it extremely challenging to treat. Due to the special location of the disease, surgery often cannot completely remove the tumor, requiring postoperative radiation therapy. Here, we report a case of an elderly male patient with right-sided proptosis, visual impairment, and diplopia. Imaging diagnosis revealed a space-occupying lesion in the extraconal space of the right orbit. Pathological and immunohistochemical examination of the resected tumor confirmed it as a grade 3 anaplastic meningioma. Two months after surgery, the patient complained of right eye swelling and a magnetic resonance imaging (MRI) scan showed a recurrence of the tumor. The patient received helical tomotherapy (TOMO) in the postoperative tumor bed and high-risk areas within the orbit with a total dose of 48Gy. However, there was no significant improvement in the patient's right eye swelling, and the size of the recurrent lesion showed no significant change on imaging. Gamma knife multifractionated stereotactic radiosurgery (MF-SRS) was then given to the recurrent lesion with 50% prescription dose 13.5Gy/3f, once every other day. An imaging diagnosis performed 45 days later showed that the tumor had disappeared completely. The patient's vision remained unchanged, but diplopia was significantly relieved after MF-SRS. We propose a new hybrid treatment model for recurrent orbital meningioma, where conventional radiation therapy ensures local control of high-risk areas around the postoperative cavity, and MF-SRS maximizes the radiation dose to recurrent lesion areas while protecting surrounding tissues and organs.

Meningioma involving the superior sagittal sinus: long-term outcome after robotic radiosurgery in primary and recurrent situation

Objective

Treatment for meningiomas involving the superior sagittal sinus (SSS) is challenging and proved to be associated with higher risks compared to other brain locations. Therapeutical strategies may be either microsurgical (sub-)total resection or adjuvant radiation, or a combination of both. Thrombosis or SSS occlusion following resection or radiosurgery needs to be further elucidated to assess whether single or combined treatment is superior. We here present tumor control and side effect data of robotic radiosurgery (RRS) in combination with or without microsurgery.

Methods

From our prospective database, we identified 137 patients with WHO grade I meningioma involving the SSS consecutively treated between 2005 and 2020. Treatment decisions were interdisciplinary. Patients underwent RRS as initial/solitary treatment (group 1), as adjuvant treatment after subtotal resection (group 2), or due to recurrent tumor growth after preceding microsurgery (group 3). Positive tumor response was assessed by MRI and defined as reduction of more than 50% of volume. Study endpoints were time to recurrence (TTR), time to RRS, risk factors for decreased survival, and side effects. Overall and specific recurrence rates for treatment groups were analyzed. Side effect data included therapy-related morbidity during follow-up (FU).

Results

A total of 137 patients (median age, 58.3 years) with SSS meningiomas WHO grade I were analyzed: 51 patients (37.2%) in group 1, 15 patients (11.0%) in group 2, and 71 patients (51.8%) in group 3. Positive MR (morphological response) to therapy was achieved in 50 patients (36.4%), no response was observed in 25 patients (18.2%), and radiological tumor progression was detected in 8 patients (5.8%). Overall 5-year probability of tumor recurrence was 15.8% (median TTR, 41.6 months). Five-year probabilities of recurrence were 0%, 8.3.%, and 21.5% for groups 1-3 (p = 0.06). In multivariate analysis, tumor volume was significantly associated with extent of SSS occlusion (p = 0.026) and sex (p = 0.011). Tumor volume significantly correlated with TTR (p = 0.0046). Acute sinus venous thrombosis or venous congestion-associated bleedings did not occur in any of the groups.

Conclusion

RRS for grade I meningiomas with SSS involvement represents a good option as first-line treatment, occasionally also in recurrent and adjuvant scenarios as part of a multimodal treatment strategy.

Multidisciplinary approach to anaplastic and metastatic meningioma: A case report and review of the literature

BACKGROUND

Meningiomas are slow-growing neoplasms, accounting for 20% of all primary intracranial neoplasms and 25% of all intraspinal tumors. Atypical and anaplastic meningiomas are infrequent, representing fewer than 5% of all meningiomas. Unusually, they can show aggressive behavior, and extracranial metastases are extremely rare, representing approximately 0.1% of all reported cases.

CASE DESCRIPTION

Fifty-six-year-old male patient diagnosed with atypical basal frontal meningioma with multiple resections, both endoscopic endonasal and transcranial. After hypofractionated radiosurgery, the patient showed new tumor recurrence associated to right cervical level II ganglionic metastasis. We opted for complete resection of the meningioma and reconstruction with anterior rectus abdominis muscle flap, as well as selective cervical ganglionectomy. Anatomical pathology showed neoplastic proliferation of meningothelial cells in syncytial cytoplasm, oval or spherical nuclei with slight anisocariosis and hyperchromasia, and intranuclear vacuoles, all compatible with anaplastic meningioma.

CONCLUSION

Due to a lack of consensus on how to treat a metastatic malignant meningioma, this pathology requires a multidisciplinary approach, and treatment needs to be adapted to each particular case. Complete resection of the lesion is the primary goal, and this requires complex procedures involving endocranial as well as extracranial surgeries, which result in composite defects difficult to resolve. Microvascular free flaps are considered the gold standard in reconstructions of large skull base defects, with high success rates and few complications.

Predictor factors for recurrence in atypical meningiomas

BACKGROUND AND OBJECTIVES

Atypical meningiomas (AMs), World Health Organization (WHO) grade 2, are a group of tumors with uneven and unpredictable clinical behavior. Our aim was to analyze possible tumor recurrence predictors, and to identify factors that improve progression-free survival (PFS).

PATIENTS, MATERIALS AND METHODS

Our retrospective study included 81 patients followed up in the Prof. Dr. Nicolae Oblu Emergency Clinical Hospital, Iaşi, Romania, between 1 January 2010 and 31 December 2020. The histopathological specimens were reviewed according to the WHO 2021 criteria. Analyses included clinical, imaging, pathological and surgical factors.

RESULTS

The tumor recurred in 53.1% of the 81 cases within 60 months of surgery. Tumor location (p<0.000), tumor volume (p<0.010), extent of surgical resection (p<0.000) and dural sinus invasion (p<0.001) were predictive factors of recurrence. Gross total resection (Simpson grade I and II) was achieved in 59.2% of patients. Patients with the tumors located in the brain convexity and volume <26.4 cm³ had better survival rates up to recurrence. PFS showed a significant relationship between Simpson grade I-III and biopsy (p<0.000) and was statistically influenced by tumor volume and location, and dural sinus invasion.

CONCLUSIONS

AMs are a heterogeneous group of tumors, and we identified posterior fossa location, volume ≥26.4 cm³, Simpson grade III and IV resection and dural sinus invasion as predictive factors for relapse and a shorter PFS. Whereas certain characteristics provide some prognostic value, future molecular characterizations of AMs are necessary, which will support the clinical decision-making process.

Advances in the systemic therapy for recurrent meningiomas and the challenges ahead

INTRODUCTION

Meningiomas represent the most common primary neoplasms of the central nervous system (CNS). 20% present with atypical (WHO grade II) or malignant (grade III) meningiomas, which show aggressive biologic behavior and high recurrence. Although surgical resection and radiation therapy are the primary treatment options for these tumors, there is a subgroup of patients who do not respond well to or are poor candidates for these approaches, leading to the exploration of systemic therapies as an alternative.

AREAS COVERED

The literature on different therapeutic groups of systemic drugs for recurrent meningiomas is reviewed, with a focus on the different molecular targets. Past and current ongoing clinical trials are also discussed.

EXPERT OPINION

To date, there is no recognized treatment that has demonstrated a substantial increase in progression-free or overall survival rates. Nonetheless, therapies targeting anti-VEGF have exhibited more encouraging results in general. The examination of genomic and epigenomic traits of meningiomas, along with the integration of molecular markers into the latest WHO tumor grading system, has provided valuable insights. This has opened avenues for exploring numerous intracellular and extracellular pathways, as well as mutations, that have been targeted in ongoing clinical trials.

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.

The role of particle radiotherapy in the treatment of skull base tumors

The skull base is an anatomically and functionally critical area surrounded by vital structures such as the brainstem, the spinal cord, blood vessels, and cranial nerves. Due to this complexity, management of skull base tumors requires a multidisciplinary approach involving a team of specialists such as neurosurgeons, otorhinolaryngologists, radiation oncologists, endocrinologists, and medical oncologists. In the case of pediatric patients, cancer management should be performed by a team of pediatric-trained specialists. Radiation therapy may be used alone or in combination with surgery to treat skull base tumors. There are two main types of radiation therapy: photon therapy and particle therapy. Particle radiotherapy uses charged particles (protons or carbon ions) that, due to their peculiar physical properties, permit precise targeting of the tumor with minimal healthy tissue exposure. These characteristics allow for minimizing the potential long-term effects of radiation exposure in terms of neurocognitive impairments, preserving quality of life, and reducing the risk of radio-induced cancer. For these reasons, in children, adolescents, and young adults, proton therapy should be an elective option when available. In radioresistant tumors such as chordomas and sarcomas and previously irradiated recurrent tumors, particle therapy permits the delivery of high biologically effective doses with low, or however acceptable, toxicity. Carbon ion therapy has peculiar and favorable radiobiological characteristics to overcome radioresistance features. In low-grade tumors, proton therapy should be considered in challenging cases due to tumor volume and involvement of critical neural structures. However, particle radiotherapy is still relatively new, and more research is needed to fully understand its effects. Additionally, the availability of particle therapy is limited as it requires specialized equipment and expertise. The purpose of this manuscript is to review the available literature regarding the role of particle radiotherapy in the treatment of skull base tumors.

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.

Favorable Long-Term Outcomes of Chordoid Meningioma Compared With the Other WHO Grade 2 Meningioma Subtypes

BACKGROUND

WHO grade 2 meningiomas, including atypical, chordoid, and clear cell subtypes, form a heterogenous group of meningiomas with varying aggressiveness and clinical behavior.

OBJECTIVE

To demonstrate the differences of clinical-histopathological characteristics and long-term outcomes among these 3 subtypes.

METHODS

A total of 609 consecutive patients diagnosed with WHO grade 2 meningiomas (543 atypical meningiomas [AMs], 36 chordoid meningiomas [CMs], and 30 clear cell meningiomas [CCMs]) from 2010 to 2018 were enrolled in this study. We compared the clinical-histopathological characteristics and long-term outcomes in these 3 subtypes and assessed survival differences among the subtypes. Targeted panel sequencing of meningioma-relevant genes was performed in the cases of CM.

RESULTS

The patients with CCM were significantly younger than those with AM ( P < .001) and CM ( P = .016). CMs were more likely to receive gross total resection than AMs and CCMs ( P = .033). The Ki-67 index was lower ( P < .001) while the progesterone receptors-positive rate was higher ( P = .034) in CM than in AM and CCM. Importantly, survival analysis demonstrated that CM had better progression-free survival ( P = .022) and overall survival ( P = .0056) than non-CM tumors. However, the PFS of CM was still worse than WHO grade 1 meningiomas ( P < .001). Alterations in NF2 (20.6%) and KMT2C (26.5%) were associated with poorer PFS in CM ( P = .013 for NF2 ; P = .021 for KMT2C ).

CONCLUSION

Patients with CM had better long-term postoperative outcomes than the other WHO grade 2 subtypes. A lower Ki-67 index, higher PR status, higher extent of resection, and lower frequency of NF2 alteration might contribute to favorable clinical outcomes of CM.

Meningioma and Other Meningeal Tumors

Meningiomas develop from meningothelial cells and approximately account for more than 30 percent of central nervous system (CNS) tumors. They can occur anywhere in the dura, most often intracranially and at dural reflection sites. Half of the cases are usually at parasagittal/falcine and convexity locations; other common sites are sphenoid ridge, suprasellar, posterior fossa, and olfactory groove. The female-to-male ratio is approximately 2 or 3-1, and the median age at diagnosis is 65 years. Meningiomas are generally extremely slow-growing tumors; many are asymptomatic or paucisymptomatic at diagnosis and are discovered incidentally. Clinical manifestations, when present, are influenced by the tumor site and by the time course over which it develops. Meningiomas are divided into three grades. Grade I represents the vast majority of cases; they are considered typical or benign, although their CNS location can still lead to severe morbidity or mortality, resulting in a reported ten-year net survival of over 80%. Atypical (WHO grade II) meningiomas are considered "intermediate grade" malignancies and represent 5-7% of cases. They show a tendency for recurrence and malignant degeneration with a relevant increase in tumor cell migration and surrounding tissue infiltration; ten-year net survival is reported over 60%. The anaplastic subtype (WHO III) represents only 1-3% of cases, and it is characterized by a poor prognosis (ten-year net survival of 15%). The treatment of choice for these tumors stands on complete microsurgical resection in case the subsequent morbidities are assumed minimal. On the other hand, and in case the tumor is located in critical regions such as the skull base, or the patient may have accompanied comorbidities, or it is aimed to avoid intensive treatment, some other approaches, including stereotactic radiosurgery and radiotherapy, were recommended as safe and effective choices to be considered as a primary treatment option or complementary to surgery. Adjuvant radiosurgery/radiotherapy should be considered in the case of atypical and anaplastic histology, especially when a residual tumor is identifiable in postoperative imaging. A "watchful waiting" strategy appears reasonable for extremely old individuals and those with substantial comorbidities or low-performance status, while there is a reduced threshold for therapeutic intervention for relatively healthy younger individuals due to the expectation that tumor progression will inevitably necessitate proactive treatment. To treat and manage meningioma efficiently, the assessments of both neurosurgeons and radiation oncologists are essential. The possibility of other rarer tumors, including hemangiopericytomas, solitary fibrous tumors, lymphomas, metastases, melanocytic tumors, and fibrous histiocytoma, must be considered when a meningeal lesion is diagnosed, especially because the ideal diagnostic and therapeutic approaches might differ significantly in every tumor type.

Radiotherapy for Meningioma

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

Health-related quality of life and clinical outcome after radiotherapy of patients with intracranial meningioma

This retrospective, single-institutional study investigated long-term outcome, toxicity and health-related quality of life (HRQoL) in meningioma patients after radiotherapy. We analyzed the data of 119 patients who received radiotherapy at our department from 1997 to 2014 for intracranial WHO grade I-III meningioma. Fractionated stereotactic radiotherapy (FSRT), intensity modulated radiotherapy (IMRT) or radiosurgery radiation was applied. The EORTC QLQ-C30 and QLQ-BN20 questionnaires were completed for assessment of HRQoL. Overall survival (OS) for the entire study group was 89.6% at 5 years and 75.9% at 10 years. Local control (LC) at 5 and 10 years was 82.4% and 73.4%, respectively. Local recurrence was observed in 22 patients (18.5%). Higher grade acute and chronic toxicities were observed in seven patients (5.9%) and five patients (4.2%), respectively. Global health status was rated with a mean of 59.9 points (SD 22.3) on QLQ-C30. In conclusion, radiotherapy resulted in very good long-term survival and tumor control rates with low rates of severe toxicities but with a deterioration of long-term HRQoL.

Radiotherapy for meningiomas

Meningiomas are the most common primary central nervous system neoplasm. Despite promising recent progress in elucidating the genomic landscape and underlying biology of these histologically, molecularly, and clinically diverse tumors, the mainstays of meningioma treatment remain maximal safe resection and radiation therapy. The aim of this review of meningioma radiotherapy is to provide a concise summary of the history, current evidence, and future for application of radiotherapy in meningioma treatment.

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.

Long-Term Follow-Up, Treatment Strategies, Functional Outcome, and Health-Related Quality of Life after Surgery for WHO Grade 2 and 3 Intracranial Meningiomas

Simple Summary

Meningiomas are the most common group of primary intracranial tumors. While the majority are classified as WHO grade 1, WHO grade 2 and 3 meningiomas have poorer outcomes, even after gross total resection, and often require supplementary treatment. Long-term follow-up data regarding the progression-free survival (PFS) and overall survival (OS) for grade 2 and 3 tumors are scarce, and data evaluating the routine use of supplementary radiotherapy and radiosurgery have been inconclusive. Furthermore, few studies have reported data on the health-related quality of life (HRQoL), anxiety, and depression for these patients. In this population-based cohort study, we reviewed 51 cases of WHO grade 2 and 3 meningiomas. We found that the median OS was 13 years for grade 2 and 1.4 years for grade 3 meningiomas. Meningioma was the cause of death in 93% of the patients who passed away. The surviving patients showed HRQoL measures comparable to that of the general population, with the exception of significantly more anxiety and depression. All patients who worked preoperatively returned to work after their treatment.

Abstract

Progression-free survival (PFS) and overall survival (OS) for WHO grade 2 and 3 intracranial meningiomas are poorly described, and long-term results and data evaluating the routine use of supplementary fractionated radiotherapy (RT) or stereotactic radiosurgery (SRS) has been inconclusive. The aim of this study was to determine the long-term PFS and OS at a center that does not employ routine adjuvant RT. For this purpose, a retrospective population-based cohort study was conducted of all WHO grade 2 and 3 meningiomas surgically treated between 2005 and 2013. The cohort was uniformly defined according to the WHO 2007 criteria to allow comparisons to previously published reports. Patient records were reviewed, and patients were then prospectively contacted for structured quality-of-life assessments. In total, 51 consecutive patients were included, of whom 43 were WHO grade 2 and 8 were grade 3. A Simpson grade 1–2 resection was achieved in 62%. The median PFS was 31 months for grade 2 tumors, and 3.4 months for grade 3. The median OS was 13 years for grade 2, and 1.4 years for grade 3. The MIB-1-index was significantly associated with an increased risk for recurrence (p = 0.018, OR 1.12). The median PFS was significantly shorter for high-risk tumors compared to the low-risk group (10 vs. 46 months; p = 0.018). The surviving meningioma patients showed HRQoL measures comparable to that of the general population, with the exception of significantly more anxiety and depression. All patients who worked before surgery returned to work after their treatment. In conclusion, we confirm dismal prognoses in patients with grade 2 and 3 meningiomas, with tumor-related deaths resulting in severely reduced OS. However, the cohort was heterogenous, and a large subgroup of both grade 2 and 3 meningiomas was alive at 10 years follow-up, suggesting that a cure is possible. In addition, fractionated radiotherapy and chemotherapy had little benefit when introduced for recurrent and progressive diseases.

Survival Benefit of Prognostic Factors and Treatment in Adult Patients with Recurrent Anaplastic Meningioma: A Retrospective Case Series and Systematic Literature Review

BACKGROUND

Recurrence rates of anaplastic meningioma (AM) are high even after a complete resection with postoperative radiotherapy.

OBJECTIVE

This study aimed to evaluate predictors and treatment affecting survival of recurrent AM based on our series and a systematic literature review (SLR).

METHODS

Our single-institute (SI) data enrolled patients with first recurrent AM, treated in our hospital from 2012 to 2018. We retrieved eligible cases from SLR from 1966 to 2020. Our SI data and pooled data, integrating SI and SLR data, were subject to Cox proportional hazard regression analysis.

RESULTS

Analysis from SI data (n = 38) showed that second recurrence-free survival (RFS) was associated with intervals (HR [hazard ratio], 0.263; P = 0.002), preoperative Karnofsky Performance Status (KPS) (HR, 0.450; P = 0.043), radiotherapy (HR, 0.395; P = 0.047), whereas overall survival (OS) was related to preoperative KPS (HR, 0.411; P = 0.037) and tumor size (HR, 3.429; P = 0.007). The pooled data (n = 60) indicated that short intervals (HR, 0.370; P = 0.002) and the use of radiotherapy (HR, 0.318; P = 0.003) improved second RFS and number of resections ≥3 (HR, 0.210; P = 0.002) and radiotherapy (HR, 0.209; P = 0.002) prolonged OS. Furthermore, the overall second RFS (P = 0.024) and OS (P = 0.031) stratified by 4 treatment protocols differed significantly.

CONCLUSIONS

Early managements of patients with AM, before presence of poor preoperative KPS and large tumor size, are critical for survival. For patients with recurrent AM, survival benefits could be obtained from radiotherapy and multiple resections.

Landscape of genetic variants in sporadic meningiomas captured with clinical genomics

BACKGROUND

Meningiomas are the most common primary central nervous system tumor. Previous studies have characterized recurrent genetic alterations that can predict patient prognosis and potentially provide new avenues for therapeutic intervention. Continued efforts to characterize the genomic changes in meningioma samples can aid in the discovery of therapeutic targets and appropriate patient stratification.

METHODS

We performed targeted genomic sequencing on 25 primary and 2 recurrent meningiomas using a 500-gene panel, including canonical meningioma drivers. We further detail the genomic profiles and relevant clinical findings in three cases of angiomatous meningiomas and two recurrent atypical meningiomas.

RESULTS

Our approach uncovers a diverse landscape of genomic variants in meningioma samples including mutations in established meningioma-related genes NF2, AKT1, PIK3CA, and TRAF7. In addition to known meningioma drivers, we uncover variants in genes encoding other PI3K subunits, Notch/hedgehog/Wnt signaling pathway components, and chromatin regulators. We additionally identify 22 genes mutated across multiple samples. Three patients included in the study were diagnosed with angiomatous WHO grade I meningiomas, all three of which contained variants in the PI3K-AKT signaling pathway previously described to regulate tumor angiogenesis. Analysis of patient-matched primary and recurrent atypical meningiomas revealed clonal enrichment for mutations in the SWI/SNF complex subunits ARID1A and SMARCA4.

CONCLUSIONS

Targeted genomics implemented in neuro-oncology care can enhance our understanding of the genetic underpinnings of central nervous system tumors, including meningiomas. These molecular signatures may be clinically useful in dictating treatment strategies and patient follow-up.

Incidence trends and survival analysis of atypical meningiomas: a population-based study from 2004 to 2018

PURPOSE

Atypical meningiomas have histologic and clinical features that fall between those for benign and malignant meningiomas. The incidence of atypical meningiomas has not been well studied with respect to changes in the World Health Organization (WHO) classification scheme over time.

METHODS

The National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database was queried to obtain data from 2004 to 2018 for patients with all meningiomas, including atypical. Age-adjusted incidence rates were generated and annual percent change (APC) in the incidence rates was calculated with joinpoint regression. Survival was analyzed using the Kaplan-Meier method and Cox proportional hazards models.

RESULTS

A total of 4476 patients diagnosed with meningioma were identified from the SEER 18 registries. The incidence of atypical meningioma increased at an APC of 5.6% [95% confidence interval [CI], 3.4-7.8]; significantly faster than all meningiomas, which rose at an APC of 2.5% (95%CI 1.8-3.1;p = 0.008). For atypical meningiomas, the 1, 3, 5, and 10-year survival rates were 91.9%, 81.3%, 68.8%, and 34.3%, respectively. Male sex, older age (≥ 60 years), and large tumor size (> 5 cm) were independent risk factors for an unfavorable prognosis.

CONCLUSIONS

The incidence of atypical meningioma was observed to be increasing relative to all meningiomas. It is important to diligently monitor atypical meningioma incidence and mortality rates over time to see whether observed uptrends persist. Continued effort toward improving outcomes in patients with atypical meningiomas is warranted, especially in light of an apparent rise in incidence.

Survival and Recurrence Outcomes Following Adjuvant Radiotherapy for Grade 2 Intracranial Meningiomas: 13-Year Experience in a Tertiary-Care Center

OBJECTIVE

We sought to evaluate overall survival (OS) and local recurrence (LR) in patients with grade 2 meningiomas treated with adjuvant radiotherapy compared to surgery alone at time of diagnosis.

METHODS

All patients at the authors' institution between 2007 and 2020 were retrospectively reviewed. OS, LR, and treatment toxicities were assessed. Sensitivity analyses were performed for patients with initial gross total resection (GTR) and subtotal resection (STR). Kaplan-Meier analyses and log-rank test for significance were used to compare surgery alone and adjuvant radiotherapy groups.

RESULTS

We included 189 patients with mean age 57.4 ± 14.6 years. Patients were 64% female, and median follow-up was 64 (interquartile range: 20-96) months. At initial treatment, 21 patients received adjuvant radiotherapy and 168 received surgery alone. There was no significant difference for OS (hazard ratio = 1.3 [95% confidence interval 0.4-4.5], P = 0.92) overall or when limited to GTR (P = 0.38) or STR (P = 0.85). There was no significant difference in LR overall (P = 0.75) or when restricted to GTR (P = 0.77) or STR (P = 0.20). No patient had radiotherapy stopped or altered because of side effects; however, 71.4% reported tolerable side effects during the treatment period and 14.3% reported chronic side effects persisting longer than 12 months post treatment.

CONCLUSIONS

In a large retrospective cohort, we found no survival or local recurrence benefit to adjuvant radiotherapy in treatment of grade 2 meningiomas. Sensitivity analysis limited to initial GTR and STR also failed to demonstrate any OS or LR benefit with adjuvant radiotherapy. In our experience, there is limited utility to upfront adjuvant radiotherapy following initial surgical resection in the treatment of grade 2 meningiomas.

Ki67 index is the most powerful factor for predicting the recurrence in atypical meningioma: Retrospective analysis of 99 patients in two institutes

Objective

The primary objective of this study was to identify predicting factors for local control (LC) of atypical meningioma, and we validated them with comparing the predicting factors for recurrence-free survival (RFS). We also examined the rate of LC after surgical resection with or without adjuvant treatment and RFS.

Methods

Clinical and radiological records of patients with atypical meningiomas diagnosed at two institutes from January 2000 to December 2018 were reviewed retrospectively. Histopathological features were also reviewed using formalin-fixed paraffin embedded samples from pathological archives.

Results

Of the 99 atypical meningiomas eligible for analysis, 36 (36.4%) recurred during the follow-up period (mean, 83.3 months; range, 12–232 months). The rate of 3-year LC and 5-year LC was 80.8% and 74.7%, respectively. The mean time-to-recurrence was 49.4 months (range, 12–150). The mean RFS was 149.3 months (95% confidence interval, 128.8–169.8 months) during the mean follow-up duration of 83.3 months (range, 12–232 months). Multivariate analysis using Cox proportional-hazard regression model showed that the extent of resection (hazard ratio [HR], 4.761; p=0.013), Ki67 index (HR, 8.541; p=0.004), mitotic index (HR, 3.275; p=0.044), and tumor size (HR, 3.228; p=0.041) were independently associated with LC. These factors were also statistically associated with RFS. In terms of radiotherapy after surgical resection, the recurrence was not prevented by immediate radiotherapy because of the strong effect of proliferative index on recurrence.

Conclusion

The present study suggests that the extent of resection, proliferative index (according to Ki67 expression) and mitotic index, and tumor size are associated with recurrence of atypical meningiomas. However, our results should be further validated through prospective and randomized clinical trials to overcome the inborn bias of retrospective nature of the study design.

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.

Machine Learning for Prediction of Recurrence in Parasagittal and Parafalcine Meningiomas: Combined Clinical and MRI Texture Features

A subset of parasagittal and parafalcine (PSPF) meningiomas may show early progression/recurrence (P/R) after surgery. This study applied machine learning using combined clinical and texture features to predict P/R in PSPF meningiomas. A total of 57 consecutive patients with pathologically confirmed (WHO grade I) PSPF meningiomas treated in our institution between January 2007 to January 2019 were included. All included patients had complete preoperative magnetic resonance imaging (MRI) and more than one year MRI follow-up after surgery. Preoperative contrast-enhanced T1WI, T2WI, T1WI, and T2 fluid-attenuated inversion recovery (FLAIR) were analyzed retrospectively. The most significant 12 clinical features (extracted by LightGBM) and 73 texture features (extracted by SVM) were combined in random forest to predict P/R, and personalized radiomic scores were calculated. Thirteen patients (13/57, 22.8%) had P/R after surgery. The radiomic score was a high-risk factor for P/R with hazard ratio of 15.73 (p < 0.05) in multivariate hazards analysis. In receiver operating characteristic (ROC) analysis, an AUC of 0.91 with cut-off value of 0.269 was observed in radiomic scores for predicting P/R. Subtotal resection, low apparent diffusion coefficient (ADC) values, and high radiomic scores were associated with shorter progression-free survival (p < 0.05). Among different data input, machine learning using combined clinical and texture features showed the best predictive performance, with an accuracy of 91%, precision of 85%, and AUC of 0.88. Machine learning using combined clinical and texture features may have the potential to predict recurrence in PSPF meningiomas.

Preoperative Apparent Diffusion Coefficient Values for Differentiation between Low and High Grade Meningiomas: An Updated Systematic Review and Meta-Analysis

The meta-analysis aimed to compare the preoperative apparent diffusion coefficient (ADC) values between low-grade meningiomas (LGMs) and high-grade meningiomas (HGMs). Medline, Cochrane, Scopus, and Embase databases were screened up to January 2022 for studies investigating the ADC values of meningiomas. The study endpoint was the reported ADC values for LGMs and HGMs. Further subgroup analyses between 1.5T and 3T MRI scanners, ADC threshold values, ADC in different histological LGMs, and correlation coefficients (r) between ADC and Ki-67 were also performed. The quality of studies was evaluated by the quality assessment of diagnostic accuracy studies (QUADAS-2). A χ2-based test of homogeneity was performed using Cochran’s Q statistic and inconsistency index (I2). Twenty-five studies with a total of 1552 meningiomas (1102 LGMs and 450 HGMs) were included. The mean ADC values (×10−3 mm2/s) were 0.92 and 0.79 for LGMs and HGMs, respectively. Compared with LGMs, significantly lower mean ADC values for HGMs were observed with a pooled difference of 0.13 (p < 0.00001). The results were consistent in both 1.5T and 3T MRI scanners. For ADC threshold values, pooled sensitivity of 69%, specificity of 82%, and AUC of 0.84 are obtained for differentiation between LGMs and HGMs. The mean ADC (×10−3 mm2/s) in different histological LGMs ranged from 0.87 to 1.22. Correlation coefficients (r) of mean ADC and Ki-67 ranged from −0.29 to −0.61. Preoperative ADC values are a useful tool for differentiating between LGMs and HGMs. Results of this study provide valuable information for planning treatments in meningiomas.

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.

Outcome After Protontherapy for Progression or Recurrence of Surgically Treated Meningioma

Background

To assess the outcome after meningioma surgery and protontherapy (PT).

Methods

We processed the French Système National des Données de Santé database to retrieve appropriate cases of meningiomas operated and irradiated between 2008 and 2017. Survival methods were implemented.

Results

One hundred ninety-three patients who received PT after meningioma surgery over a 10-year period were identified. Of the 193 patients, 75.6% were female. Median age at surgery was 50 years (interquartile range [IQR] 41–62). The median number of PT fractions was 31 (IQR 30–39) given over a median duration of 52 days (IQR 44–69). Fourteen patients (7.3%) also received photon radiotherapy and six patients (3.1%) stereotactic radiosurgery. Median follow-up was 4.4 years (IQR 3.86–4.71). Five-year progression-free survival (PFS) rate was 69% (95% confidence interval [CI] 62.1–76.6). For benign, atypical, and malignant meningioma, 5-year PFS rates were 71.5% (95% CI 64.4–79.4), 55.6% (95% CI 32.5–95), and 35.6% (95% CI 12.8–98.9), respectively (p<0.01). In the adjusted regression, tumour location (hazard ratio [HR]=0.1, 95% CI 0.05–0.22, p<0.001), aggressive meningioma (HR=2.26, 95% CI 1.1–4.66, p=0.027), and the need of cerebrospinal fluid (CSF) insertion for hydrocephalus (HR=3.51, 95% CI 1.32–9.31, p=0.012) remained significantly associated to the PFS. All grades considered, 5-year overall survival (OS) rates was 89.7% (95% CI 84.6–95.1). For benign, atypical, and malignant meningioma, 5-year OS rates were 93% (95% CI 88.7–97.4), 76.4% (95% CI 51.4–100), and 44.4% (95% CI 16.7–100), respectively (p<0.01). In the multivariable regression, an older age above 70 years (HR=5.95, 95% CI 2.09–16.89, p<0.001) associated to a high level of comorbidities (HR=5.31, 95% CI 1.43–19.78, p=0.013) and a malignant meningioma (HR=5.68, 95% CI 1.54–20.94, p=0.009) remained significantly associated to a reduced OS.

Conclusion

Five-year PFS and OS after meningioma surgery and PT is favourable but impaired for older patients with high level of morbidities, tumour of the convexity, malignant histopathology and for those requiring CSF shunting. Further inclusion and prolonged follow-up is required to assess other predictors such as sex, tumour volume, or given dose.

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.

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.

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.

Stereotactic Radiosurgery for Atypical (World Health Organization II) and Anaplastic (World Health Organization III) Meningiomas: Results From a Multicenter, International Cohort Study

BACKGROUND

Atypical and anaplastic meningiomas have reduced progression-free/overall survival (PFS/OS) compared to benign meningiomas. Stereotactic radiosurgery (SRS) for atypical meningiomas (AMs) and anaplastic meningiomas (malignant meningiomas, MMs) has not been adequately described.

OBJECTIVE

To define clinical/radiographic outcomes for patients undergoing SRS for AM/MMs.

METHODS

An international, multicenter, retrospective cohort study was performed to define clinical/imaging outcomes for patients receiving SRS for AM/MMs. Tumor progression was assessed with response assessment in neuro-oncology (RANO) criteria. Factors associated with PFS/OS were assessed using Kaplan-Meier analysis and a Cox proportional hazards model.

RESULTS

A total of 271 patients received SRS for AMs (n = 233, 85.9%) or MMs (n = 38, 14.0%). Single-fraction SRS was most commonly employed (n = 264, 97.4%) with a mean target dose of 14.8 Gy. SRS was used as adjuvant treatment (n = 85, 31.4%), salvage therapy (n = 182, 67.2%), or primary therapy (1.5%). The 5-yr PFS/OS rate was 33.6% and 77.0%, respectively. Increasing age (hazard ratio (HR) = 1.01, P < .05) and a Ki-67 index > 15% (HR = 1.66, P < .03) negatively correlated with PFS. MMs (HR = 3.21, P < .05), increased age (HR = 1.04, P = .04), and reduced KPS (HR = 0.95, P = .04) were associated with shortened OS. Adjuvant versus salvage SRS did not impact PFS/OS. A shortened interval between surgery and SRS improved PFS for AMs (HR = 0.99, P = .02) on subgroup analysis. Radiation necrosis occurred in 34 (12.5%) patients. Five-year rates of repeat surgery/radiation were 33.8% and 60.4%, respectively.

CONCLUSION

AM/MMs remain challenging tumors to treat. Elevated proliferative indices are associated with tumor recurrence, while MMs have worse survival. SRS can control AM/MMs in the short term, but the 5-yr PFS rates are low, underscoring the need for improved treatment options for these patients.

Treatment of WHO Grade 2 Meningiomas With Stereotactic Radiosurgery: Identification of an Optimal Group for SRS Using RPA

PURPOSE

This study assesses a large multi-institutional database to present the outcomes of World Health Organization grade 2 meningiomas treated with stereotactic radiosurgery (SRS). We also compare the 3-year progression-free survival (PFS) to that reported in the Radiation Therapy Oncology Group 0539 phase 2 cooperative group meningioma trial.

METHODS AND MATERIALS

From an international, multicenter group, data were collected for grade 2 meningioma patients treated with SRS for demonstrable tumor from 1994 to 2019. Statistical methods used included the Kaplan-Meier method, Cox proportional hazards analysis, and recursive partitioning analysis.

RESULTS

Two hundred thirty-three patients treated at 12 institutions were included. Patients presented at a median age of 60 years (range, 13-90), and many had at least 2 prior resections (30%) or radiation therapy (22%). Forty-eight percent of patients had prior gross total resection. At SRS, the median treatment volume was 6.1 cm3 (0.1-97.6). A median 15 Gy (10-30) was delivered to a median percent isodose of 50 (30-80), most commonly in 1 fraction (95%). A model was developed using recursive partitioning analysis, with one point attributed to age >50 years, treatment volume >11.5 cm3, and prior radiation therapy or multiple surgeries. The good-prognostic group (score, 0-1) had improved PFS (P < .005) and time to local failure (P < .005) relative to the poor-prognostic group (score, 2-3). Age >50 years (hazard ratio = 1.85 [95% confidence interval, 1.09-3.14]) and multiple prior surgeries (hazard ratio = 1.80 [1.09-2.99]) also portended reduced PFS in patients without prior radiation therapy. Two hundred eighteen of 233 patients in this study qualified for the high-risk group of Radiation Therapy Oncology Group 0539, and they demonstrated similar outcomes (3-year PFS: 53.9% vs 58.8%). The good-prognostic group of SRS patients demonstrated slightly improved outcomes (3-year PFS: 63.1% vs 58.8%).

CONCLUSIONS

SRS should be considered in carefully selected patients with atypical meningiomas. We suggest the use of our good-prognostic group to optimize patient selection, and we strongly encourage the initiation of a clinical trial to prospectively validate these outcomes.

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.

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.

Atypical Meningioma of the Sinonasal Tract

This case report describes a patient with intellectual disability who presented with a neglected midline nasal mass eroding the anterior skull base, which was found to be a Grade II meningioma likely of the olfactory bulb. Points of interest include differential diagnosis of this atypical mass of the sinonasal tract, as well as decision-making in balancing appropriate management and quality of life in a patient with developmental delay who could not make decisions for herself. Literature review regarding the role of adjuvant radiation based on final diagnosis and extent of disease suggests that radiation can improve locoregional control and overall survival with atypical meningioma. Lack of clear information in the literature on these rare conditions can lead to poor understanding on the part of the treatment team and the healthcare proxies who are making decisions, making goals of care discussions and medical decision-making challenging. This case report seeks to add to the available data on management of atypical meningiomas of the sinonasal tract and olfactory bulb.