Combined proton and photon conformal radiotherapy for intracranial atypical and malignant meningioma

The Evolving Classification of Meningiomas: Integration of Molecular Discoveries to Inform Patient Care

Meningioma classification and treatment have evolved over the past eight decades. Since Bailey, Cushing, and Eisenhart's description of meningiomas in the 1920s and 1930s, there have been continual advances in clinical stratification by histopathology, radiography and, most recently, molecular profiling, to improve prognostication and predict response to therapy. Precise and accurate classification is essential to optimizing management for patients with meningioma, which involves surveillance imaging, surgery, primary or adjuvant radiotherapy, and consideration for clinical trials. Currently, the World Health Organization (WHO) grade, extent of resection (EOR), and patient characteristics are used to guide management. While these have demonstrated reliability, a substantial number of seemingly benign lesions recur, suggesting opportunities for improvement of risk stratification. Furthermore, the role of adjuvant radiotherapy for grade 1 and 2 meningioma remains controversial. Over the last decade, numerous studies investigating the molecular drivers of clinical aggressiveness have been reported, with the identification of molecular markers that carry clinical implications as well as biomarkers of radiotherapy response. Here, we review the historical context of current practices, highlight recent molecular discoveries, and discuss the challenges of translating these findings into clinical practice.

Staged Resection of Difficult-to-Treat Intracranial Meningiomas: A Systematic Review of the Indications, Surgical Approaches, and Postoperative Outcomes

Introduction  Meningiomas-the most common extra-axial tumors-are benign, slow-growing dural-based lesions that can involve multiple cranial fossae and can progress insidiously for years until coming to clinical attention secondary to compression of adjacent neurovascular structures. For complex, multicompartmental lesions, multistaged surgeries have been increasingly shown to enhance maximal safe resection while minimizing adverse sequela. Here, we systematically review the extant literature to highlight the merits of staged resection. Methods  PubMed, Scopus, and Web of Science databases were queried to identify articles reporting resections of intracranial meningiomas using a multistaged approach, and articles were screened for possible inclusion in a systematic process performed by two authors. Results  Of 118 identified studies, 36 describing 169 patients (mean age 42.6 ± 21.3 years) met inclusion/exclusion criteria. Petroclival lesions comprised 57% of cases, with the most common indications for a multistaged approach being large size, close approximation of critical neurovascular structures, minimization of brain retraction, identification and ligation of deep vessels feeding the tumor, and resection of residual tumor found on postoperative imaging. Most second-stage surgeries occurred within 3 months of the index surgery. Few complications were reported and multistaged resections appeared to be well tolerated overall. Conclusions  Current literature suggests multistaged approaches for meningioma resection are well-tolerated. However, there is insufficient comparative evidence to draw definitive conclusions about its advantages over an unstaged approach. There are similarly insufficient data to generate an evidence-based decision-making framework for when a staged approach should be employed. This highlights the need for collaborative efforts among skull base surgeons to establish an evidentiary to support the use of staged approaches and to outline those indications that merit such an approach.

Radiotherapy intensification for atypical and malignant meningiomas: A systematic review

Background

The outcomes of nonbenign (WHO Grades 2 and 3 [G2, G3]) meningiomas are suboptimal and radiotherapy (RT) dose intensification strategies have been investigated. The purpose of this review is to report on clinical practice and outcomes with particular attention to RT doses and techniques.

Methods

The PICO criteria (Population, Intervention, Comparison, and Outcomes) were used to frame the research question, directed at outlining the clinical outcomes in patients with G2-3 meningiomas treated with RT. The same search strategy was run in Embase and MEDLINE and, after deduplication, returned 1 807 records. These were manually screened for relevance and 25 were included.

Results

Tumor outcomes and toxicities are not uniformly reported in the selected studies since different endpoints and time points have been used by different authors. Many risk factors for worse outcomes are described, the most common being suboptimal RT. This includes no or delayed RT, low doses, and older techniques. A positive association between RT dose and progression-free survival (PFS) has been highlighted by analyzing the studies in this review (10/25) that report the same endpoint (5y-PFS).

Conclusions

This literature review has shown that standard practice RT leads to suboptimal tumor control rates in G2-3 meningiomas, with a significant proportion of disease recurring after a relatively short follow-up. Randomized controlled trials are needed in this setting to define the optimal RT approach. Given the increasing data to suggest a benefit of higher RT doses for high-risk meningiomas, novel RT technologies with highly conformal dose distributions are preferential to achieve optimal target coverage and organs at risk sparing.

A Prospective Registry Study of 68Ga-DOTATATE PET/CT Incorporation Into Treatment Planning of Intracranial Meningiomas

PURPOSE

The current standard for meningioma treatment planning involves magnetic resonance imaging-based guidance. Somatostatin receptor ligands such as 68Ga-DOTATATE are being explored for meningioma treatment planning due to near-universal expression of somatostatin receptors 1 and 2 in meningioma tissue. We hypothesized that 68Ga-DOTATATE positron emission tomography (PET)-guided treatment management for patients with meningiomas is safe and effective and can identify which patients benefit most from adjuvant radiation therapy.

METHODS AND MATERIALS

A single-institution prospective registry study was created for inclusion of patients with intracranial meningiomas who received a 68Ga-DOTATATE PET/CT to assist with radiation oncologist decision making. Patients who received a PET scan from January 1, 2018, to February 25, 2022, were eligible for inclusion.

RESULTS

Of the 60 patients included, 40%, 47%, and 5% had World Health Organization grades 1, 2, and 3 meningiomas, respectively, and 8% (5 patients) had no grade assigned. According to Radiation Therapy Oncology Group 0539 criteria, 22%, 72%, and 7% were categorized as high, intermediate, and low risk, respectively. After completing their PET scans, 48 patients, 11 patients, and 1 patient proceeded with radiation therapy, observation, and redo craniotomy, respectively. The median follow-up for the entire cohort was 19.5 months. Of the 3 patients (5%) who experienced local failure between 9.2 and 28.5 months after diagnosis, 2 had PET-avid disease in their postoperative cavity and elected for observation before recurrence, and 1 high-risk patient with multifocal disease experienced local failure 2 years after a second radiation course and multiple previous recurrences. Notably, 5 patients did not have any local PET uptake and were observed; none of these patients experienced recurrence. Only 1 grade 3 toxicity was attributed to PET-guided radiation.

CONCLUSIONS

This study examined one of the largest known populations of patients with intracranial meningiomas followed by physicians who used 68Ga-DOTATATE PET-guided therapy. Incorporating 68Ga-DOTATATE PET into future trials may assist with clinician decision making and improve patient outcomes.

How proton therapy fits into the management of adult intracranial tumors

Intracranial tumors include a challenging array of primary and secondary parenchymal and extra-axial tumors which cause neurologic morbidity consequential to location, disease extent, and proximity to critical neurologic structures. Radiotherapy can be used in the definitive, adjuvant, or salvage setting either with curative or palliative intent. Proton therapy (PT) is a promising advance due to dosimetric advantages compared to conventional photon radiotherapy with regards to normal tissue sparing, as well as distinct physical properties, which yield radiobiologic benefits. In this review, the principles of efficacy and safety of PT for a variety of intracranial tumors are discussed, drawing upon case series, retrospective and prospective cohort studies, and randomized clinical trials. This manuscript explores the potential advantages of PT, including reduced acute and late treatment-related side effects and improved quality of life. The objective is to provide a comprehensive review of the current evidence and clinical outcomes of PT. Given the lack of consensus and directives for its utilization in patients with intracranial tumors, we aim to provide a guide for its judicious use in clinical practice.

Dose-Escalated Radiation Therapy Is Associated With Improved Outcomes for High-Grade Meningioma

PURPOSE

The optimal modern radiation therapy (RT) approach after surgery for atypical and malignant meningioma is unclear. We present results of dose escalation in a single-institution cohort spanning 2000 to 2021.

METHODS AND MATERIALS

Consecutive patients with histopathologic grade 2 or 3 meningioma treated with RT were reviewed. A dose-escalation cohort (≥66 Gy equivalent dose in 2-Gy fractions using an α/β = 10) was compared with a standard-dose cohort (<66 Gy). Outcomes were progression-free survival (PFS), cause-specific survival, overall survival (OS), local failure (LF), and radiation necrosis.

RESULTS

One hundred eighteen patients (111 grade 2, 94.1%) were identified; 54 (45.8%) received dose escalation and 64 (54.2%) standard dose. Median follow-up was 45.4 months (IQR, 24.0-80.0 months) and median OS was 9.7 years (Q1: 4.6 years, Q3: not reached). All dose-escalated patients had residual disease versus 65.6% in the standard-dose cohort (P < .001). PFS at 3, 4, and 5 years in the dose-escalated versus standard-dose cohort was 78.9%, 72.2%, and 64.6% versus 57.2%, 49.1%, and 40.8%, respectively, (P = .030). On multivariable analysis, dose escalation (hazard ratio [HR], 0.544; P = .042) was associated with improved PFS, whereas ≥2 surgeries (HR, 1.989; P = .035) and older age (HR, 1.035; P < .001) were associated with worse PFS. The cumulative risk of LF was reduced with dose escalation (P = .016). Multivariable analysis confirmed that dose escalation was protective for LF (HR, 0.483; P = .019), whereas ≥2 surgeries before RT predicted for LF (HR, 2.145; P = .008). A trend was observed for improved cause-specific survival and OS in the dose-escalation cohort (P < .1). Seven patients (5.9%) developed symptomatic radiation necrosis with no significant difference between the 2 cohorts.

CONCLUSIONS

Dose-escalated RT with ≥66 Gy for high-grade meningioma is associated with improved local control and PFS with an acceptable risk of radiation necrosis.

Particle beam radiotherapy in the treatment of WHO grade 2 and 3 meningiomas: an early experience from Shanghai Proton and Heavy Ion Center

PURPOSE

To investigate the efficacy and safety of particle beam radiotherapy (PBRT) in the management of patients with WHO grade 2 and 3 meningiomas.

METHODS

Thirty-six consecutive and non-selected patients with WHO grade 2 (n = 28) and grade 3 (n = 8) meningiomas were treated at the Shanghai Proton and Heavy Ion Center, from May 2015 to March 2022. The median age of the cohort at PBRT was 48 years. There were 25 and 11 patients treated with PBRT in the setting of newly diagnosed diseases and progressive/recurrent diseases, respectively. PBRT was utilized as re-irradiation in 5 patients. Proton radiotherapy (PRT) and carbon-ion radiotherapy (CIRT), with a median dose of 60 Gy-Equivalent (GyE), were provided to 30 and 6 patients, respectively.

RESULTS

With a median follow-up of 23.3 months, the local control rates were 92.0%, 82.0%, and 82.0% at 1, 2, and 3 years for the entire cohort, respectively. Patients with WHO grade 2 meningiomas (100%, 94.1%, 94,1% at 1,2,3 years) had a much better local control than those with WHO grade 3 meningiomas (50%, 25%, 25% at 1,2,3 years; P < 0.001). Three patients, all with WHO grade 3 meningiomas, had deceased at the time of this analysis. Multivariate analyses revealed that WHO grade (grade 2 vs. 3) (p = 0.016) was a significant prognosticator for local control. No severe toxicities (G3 or above) were observed.

CONCLUSIONS

Treatment-induced efficacy and toxicities to PBRT in WHO grade 2 and 3 meningiomas were both highly acceptable. Longer follow-up is needed to evaluate the long-term outcome in terms of disease control, survival, as well as potential late effects.

Frontiers of Cranial Base Surgery: Integrating Technique, Technology, and Teamwork for the Future of Neurosurgery

The landscape of cranial base surgery has undergone monumental transformations over the past several decades. This article serves as a comprehensive survey, detailing both the historical and current techniques and technologies that have propelled this field into an era of unprecedented capabilities and sophistication. In the prologue, we traverse the historical evolution from rudimentary interventions to the state-of-the-art neurosurgical methodologies that define today's practice. Subsequent sections delve into the anatomical complexities of the anterior, middle, and posterior cranial fossa, shedding light on the intricacies that dictate surgical approaches. In a section dedicated to advanced techniques and modalities, we explore cutting-edge evolutions in minimally invasive procedures, pituitary surgery, and cranial base reconstruction. Here, we highlight the seamless integration of endocrinology, biomaterial science, and engineering into neurosurgical craftsmanship. The article emphasizes the paradigm shift towards "Functionally" Guided Surgery facilitated by intraoperative neuromonitoring. We explore its historical origins, current technologies, and its invaluable role in tailoring surgical interventions across diverse pathologies. Additionally, the digital era's contributions to cranial base surgery are examined. This includes breakthroughs in endoscopic technology, robotics, augmented reality, and the potential of machine learning and AI-assisted diagnostic and surgical planning. The discussion extends to radiosurgery and radiotherapy, focusing on the harmonization of precision and efficacy through advanced modalities such as Gamma Knife and CyberKnife. The article also evaluates newer protocols that optimize tumor control while preserving neural structures. In acknowledging the holistic nature of cranial base surgery, we advocate for an interdisciplinary approach. The ecosystem of this surgical field is presented as an amalgamation of various medical disciplines, including neurology, radiology, oncology, and rehabilitation, and is further enriched by insights from patient narratives and quality-of-life metrics. The epilogue contemplates future challenges and opportunities, pinpointing potential breakthroughs in stem cell research, regenerative medicine, and genomic tailoring. Ultimately, the article reaffirms the ethos of continuous learning, global collaboration, and patient-first principles, projecting an optimistic trajectory for the field of cranial base surgery in the coming decade.

Interdisciplinary Therapeutic Approaches to Atypical and Malignant Meningiomas

Meningiomas have the highest incidence among brain tumors. In contrast to benign tumors that constitute the majority of this tumor entity, the treatment of aggressive meningiomas (WHO Grade 2 and 3) is more challenging, requiring gross total removal of the tumor and the affected dura and adjuvant radiotherapy. Sometimes the location and/or the configuration of the tumor do not favor radical surgical resection without endangering the patient's clinical condition after surgery and pharmacological therapy has, until now, not been proven to be a reliable alternative. Discussion: In this narrative review, we discuss the current literature with respect to the management of meningiomas, discussing the importance of the grade of resection in the overall prognosis of the patient and in the planning of adjuvant therapy. Conclusions: According to the location and size of the tumor, radical resection should be taken into consideration. In patients with aggressive meningiomas, adjuvant radiotherapy should be performed after surgery. In cases of skull base meningiomas, a maximal, though safe, resection should take place before adjuvant therapy. An interdisciplinary approach is beneficial for patients with primary or recurrent meningioma.

Intracranial meningiomas: an update of the 2021 World Health Organization classifications and review of management with a focus on radiation therapy

Meningiomas account for approximately one third of all primary intracranial tumors. Arising from the cells of the arachnoid mater, these neoplasms are found along meningeal surfaces within the calvarium and spinal canal. Many are discovered incidentally, and most are idiopathic, although risk factors associated with meningioma development include age, sex, prior radiation exposure, and familial genetic diseases. The World Health Organization grading system is based on histologic criteria, and are as follows: grade 1 meningiomas, a benign subtype; grade 2 meningiomas, which are of intermediately aggressive behavior and usually manifest histologic atypia; and grade 3, which demonstrate aggressive malignant behavior. Management is heavily dependent on tumor location, grade, and symptomatology. While many imaging-defined low grade appearing meningiomas are suitable for observation with serial imaging, others require aggressive management with surgery and adjuvant radiotherapy. For patients needing intervention, surgery is the optimal definitive approach with adjuvant radiation therapy guided by extent of resection, tumor grade, and location in addition to patient specific factors such as life expectancy. For grade 1 lesions, radiation can also be used as a monotherapy in the form of stereotactic radiosurgery or standard fractionated radiation therapy depending on tumor size, anatomic location, and proximity to dose-limiting organs at risk. Optimal management is paramount because of the generally long life-expectancy of patients with meningioma and the morbidity that can arise from tumor growth and recurrence as well as therapy itself.

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.

Case of a WHO Grade II Atypical Meningioma in a 16-Year-Old Female

Meningiomas have a high frequency of occurrence as primary intracranial tumors. We report the case of a 16-year-old female who presented with a three-week history of persistent headache, vomiting, and photophobia. Imaging studies revealed the presence of a meningioma in the right occipital lobe of the brain. The patient underwent surgical resection, and histopathological analysis confirmed the diagnosis of an atypical WHO grade 2 meningioma. The patient experienced a significant improvement in her symptoms postoperatively and had no evidence of recurrence on follow-up imaging. This case highlights the importance of considering meningioma in the differential diagnosis of relatively young patients presenting with chronic headaches, and the favorable prognosis associated with atypical WHO grade 2 meningiomas following complete surgical resection.

Efficacy of radiotherapy and stereotactic radiosurgery as adjuvant or salvage treatment in atypical and anaplastic (WHO grade II and III) meningiomas: a systematic review and meta-analysis

The role of radiotherapy (RT) and stereotactic radiosurgery (SRS) as adjuvant or salvage treatment in high-grade meningiomas (HGM) is still debated. Despite advances in modern neuro-oncology, HGM (WHO grade II and III) remains refractory to multimodal therapies. Published reports present aggregated data and are extremely varied in population size, exclusion criteria, selection bias, and inclusion of mixed histologic grades, making it extremely difficult to draw conclusions when taken individually. This current work aims to gather the existing evidence on RT and SRS as adjuvants following surgery or salvage treatment at recurrence after multimodality therapy failure and to conduct a systematic comparison between these two modalities. An extensive systematic literature review and meta-analysis were performed. A total of 42 papers were eligible for final analysis (RT n = 27; SRS n = 15) after searching MEDLINE via PubMed, Web-of-science, Cochrane Wiley, and Embase databases. Adjuvant regimens were addressed in 37 papers (RT n = 26; SRS n = 11); salvage regimens were described in 5 articles (RT n = 1; SRS n = 4). The primary outcomes of the study were the overall recurrence rate and mortality. Other actuarial rates (local and distant control, OS, PFS, and complications) were retrieved and analyzed as secondary outcomes. A total of 2853 patients harboring 3077 HGM were included. The majority were grade II (87%) with a mean pre-radiation volume of 8.7 cc. Adjuvant regimen: 2742 patients (76.4% RT; 23.6% SRS) with an overall grade II/III rate of 6.6/1. Lesions treated adjSRS were more frequently grade III (17 vs 12%, p < 0.001), and received subtotal resection (57 vs 27%, p = 0.001) compared to the RT cohort. AdjSRS cohort had a significantly shorter mean follow-up than adjRT (36.7 vs 50.3 months, p = 0.01). The overall recurrence rate was 38% in adjRT vs 25% in adjSRS (p = 0.01), while mortality did not differ between the groups (20% vs 23%, respectively; p = 0.80). The median time to recurrence was 1.5 times longer in the RT group (p = 0.30). Five-year local control was 55% in adjRT and 26% in adjSRS (p = 0.01), while 5-year OS was 73% and 78% (p = 0.62), and 5-year PFS was 62% and 40% in adjRT and adjSRS (p = 0.008). No difference in the incidence of complications (24% vs 14%, p = 0.53). Salvage regimen: 110 patients (37.3% RT; 62.7% SRS) with a grade II/III rate of 8.6/1. The recurrence rate was 46% in salRT vs 24% in salSRS (p = 0.39), time to recurrence was 1.8 times longer in the salRT group (35 vs 18.5 months, p = 0.74). Mortality was slightly yet not significantly higher in salRT (34% vs 12%, p = 0.54). Data on local and distant control were only available for salSRS. The 5-year OS was 49% and 83% (p = 0.90), and the 5-year PFS was 39% and 50% in salRT and salSRS (p = 0.66), respectively. High-grade meningiomas (WHO grade II and III) receiving adjuvant RT showed a higher overall recurrence rate than meningiomas receiving adjuvant SRS. The adjRT cohort, however, achieved higher 5-year LC and PFS rates, thus suggesting a potentially longer time to recurrence compared to adjSRS patients, who, meanwhile, experienced a significantly shorter follow-up. This result must also consider the higher number of grade III lesions and the smaller extent of resection achieved in the adjSRS group. Overall mortality did not differ between the two groups. No differences in outcome measures were observed in salvage regimens.

The "Combo" radiotherapy treatment for high-risk grade 2 meningiomas: dose escalation and initial safety and efficacy analysis

PURPOSE

The subgroup "high-risk" WHO grade 2 (hRG2) meningiomas may benefit from adjuvant radiation therapy (RT), but results are still suboptimal with high rates of local progression. A dose escalation using high-conformal RT techniques needs to be evaluated in terms of efficacy and safety. We report the results of a dose-escalation study, named "Combo-RT", combining Intensity Modulated Radiotherapy (IMRT) or Volumetric Arc Therapy (VMAT) with Hypofractionated Stereotactic Radiotherapy (hSRT) boost.

PATIENTS AND METHODS

From November 2015 to January 2019, we prospectively enrolled 16 patients with hRG2. Seven patients had subtotal resection (STR) and 9 patients had a recurrent tumor. All patients received Combo-RT: LINAC-IMRT/ VMAT on the surgical bed and CyberKnife-hSRT boost on residual/recurrent meningioma Toxicity and initial efficacy were evaluated.

RESULTS

The median age was 62 years (range, 31-80 years). The median cumulative dose delivered was 46 Gy For IMRT or VMAT and 15 Gy in 3 fractions at a median isodose line of 77% for hSRT. The median cumulative BED and EQD2 were 108.75 Gy and 72.5 Gy respectively. 3-year-PFS was 75% for the whole cohort,100% for patients with STR, and 55.5% for recurrent patients. Negligible toxicities, and stable or improved symptoms during long-term follow-up were observed. Salvage treatment for recurrence was an independent predictor of treatment failure (P = 0.025).

CONCLUSIONS

With the limitation of a small series of patients, our results suggest that a dose escalation for hRG2 meningiomas, using a Combo-RT approach, is safe and particularly effective in the subgroup of patients with STR. Further studies are warranted.

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.

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.

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.

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.

Combined proton-photon therapy for non-small cell lung cancer

PURPOSE

Advanced non-small cell lung cancer (NSCLC) is still a challenging indication for conventional photon radiotherapy. Proton therapy has the potential to improve outcomes, but proton treatment slots remain a limited resource despite an increasing number of proton therapy facilities. This work investigates the potential benefits of optimally combined proton-photon therapy delivered using a fixed horizontal proton beam line in combination with a photon Linac, which could increase accessibility to proton therapy for such a patient cohort.

MATERIALS AND METHODS

A treatment planning study has been conducted on a patient cohort of seven advanced NSCLC patients. Each patient had a planning CT and multiple repeated CTs from three different days and for different breath-holds on each day. Treatment plans for combined proton-photon therapy (CPPT) were calculated for individual patients by optimizing the combined cumulative dose on the initial planning CT only (non-adapted) as well as on each daily CT respectively (adapted). The impact of inter-fractional changes and/or breath-hold variability was then assessed on the repeat breath-hold CTs. Results were compared to plans for IMRT or IMPT alone, as well as against combined treatments assuming a proton gantry. Plan quality was assessed in terms of dosimetric, robustness and NTCP metrics.

RESULTS

Combined treatment plans improved plan quality compared to IMRT treatments, especially in regard to reductions of low and medium doses to organs at risk (OARs), which translated into lower NTCP estimates for three side effects. For most patients, combined treatments achieved results close to IMPT-only plans. Inter-fractional changes impact mainly the target coverage of combined and IMPT treatments, while OARs doses were less affected by these changes. With plan adaptation however, target coverage of combined treatments remained high even when taking variability between breath-holds into account.

CONCLUSIONS

Optimally combined proton-photon plans improve treatment plan quality compared to IMRT only, potentially reducing the risk of toxicity while also allowing to potentially increase accessibility to proton therapy for NSCLC patients. This article is protected by copyright. All rights reserved.

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.

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.

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.

The Efficacy and Safety of Carbon Ion Radiotherapy for Meningiomas: A Systematic Review and Meta-Analysis

Objective

The purpose of this systematic review and meta-analysis is to evaluate the efficacy and safety of carbon ion radiotherapy (CI-RT) in improving meningioma by comparing photon and protons radiotherapy.

Methods

A comprehensive search for relevant studies published until March 17, 2021, was conducted in PubMed, the Cochrane Library, Chinese Biomedical Literature Database and EMBASE. Statistical analyses were performed with R 4.0.3.

Results

We identified 396 studies, of which 18 studies involving 985 participants were included. Except for one low quality study, the quality of the included studies was found to be either moderate or high quality. The analyses conducted according random effects model indicated that the 1-year overall survival rate (OS) of benign and non-benign meningiomas after the CI-RT treatment was 99% (95%CL=.91-1.00, I² = 0%). The overall average 5-year OS for meningiomas was 72% (95%CL=0.52-0.86, I² = 35%), not as effective as proton radiotherapy (PR-RT) 85% (95%CL=.72-.93, I² = 73, Q=4.17, df=2, p=.12). Additionally, 5-year OS of atypical meningiomas (81%) was found to be significantly higher than anaplastic meningiomas (52%). The 10-year OS after CI-RT of patients with mixed grade meningioma was 91% (95%CL=.75-.97, I² = 73%). The 15-year OS after CI-RT 87% (95%CL=.11-1.00) or PR-RT 87% (95%CL=.23-.99, I² = 79%) were the same (Q=0, df=1, p=.99). After undergoing CI-RT for 3 and 5 years, the LC for benign meningioma was 100% and 88%, respectively, while the 2-year LC of non-benign meningiomas (atypical/anaplastic) was 33%. Headache, sensory impairment, cognitive impairment, and hearing impairment were found to be the most common adverse reactions, with individual incidences of 19.4%, 23.7%, 9.1%, and 9.1%, respectively.

Conclusion

CI-RT is a rapidly developing technique that has been proven to be an effective treatment against meningioma. The efficacy and safety of CI-RT for meningiomas were similar to those of PR-RT, better than photon radiotherapy (PH-RT). However, there is a need for more prospective trials in the future that can help provide more supportive evidence.

Proton Therapy for Intracranial Meningioma for the Treatment of Primary/Recurrent Disease Including Re-Irradiation

Meningeal tumors represent approximately 10-25% of primary brain tumors and occur usually in elderly female patients. Most meningiomas are benign (80-85%) and for symptomatic and/or large tumors, surgery, with or without radiation therapy (RT), has been long established as an effective means of local tumor control. RT can be delivered to inoperable lesions or to those with non-benign histology and for Simpson I-III and IV-V resection. RT can be delivered with photons or particles (protons or carbon ions) in stereotactic or non-stereotactic conditions. Particle therapy delivered for these tumors uses the physical properties of charged carbon ions or protons to spare normal brain tissue (i.e. Bragg peak), with or without or a dose-escalation paradigm for non-benign lesions. PT can substantially decrease the dose delivered to the non-target brain tissues, including but not limited to the hippocampi, optic apparatus or cochlea. Only a limited number of meningioma patients have been treated with PT in the adjuvant or recurrent setting, as well as for inoperable lesions with pencil beam scanning and with protons only. Approximately 500 patients with image-defined or WHO grade I meningioma have been treated with protons. The reported outcome, usually 5-year local tumor control, ranges from 85 to 99% (median, 96%). For WHO grade II or III patients, the outcome of only 97 patients has been published, reporting a median tumor local control rate of 52% (range, 38-71.1). Only 24 recurring patients treated previously with photon radiotherapy and re-treated with PT were reported. The clinical outcome of these challenging patients seems interesting, provided that they presented initially with benign tumors, are not in the elderly category and have been treated previously with conventional radiation dose of photons. Overall, the number of meningioma patients treated or-re-irradiated with this treatment modality is small and the clinical evidence level is somewhat low (i.e. 3b-5). In this review, we detail the results of upfront PT delivered to patients with meningioma in the adjuvant setting and for inoperable tumors. The outcome of meningioma patients treated with this radiation modality for recurrent tumors, with or without previous RT, will also be reviewed.

Prognostic Model That Predicts Benefits of Adjuvant Radiotherapy in Patients With High Grade Meningioma

Objective

Adjuvant radiotherapy is the main treatment modality for high grade meningioma after surgical resection; however, recurrence and survival outcomes vary. The aim of this study was to create a new “prognostic score” that allows personalized recommendations for post-operative adjuvant radiotherapy in patients with high grade meningioma.

Methods

Clinical data were collected from 115 patients with high grade meningioma treated with surgical resection and adjuvant radiotherapy. A prognostic model was built based on the hazards ratios of independent prognostic factors yielded by multivariate cox proportional analysis. Calibration and discrimination of the prognostic score was evaluated using good of fit test and Harrel’s C index, respectively.

Results

A total of 115 high grade meningioma patients (72 atypical and 43 anaplastic meningiomas) were enrolled. Three factors were independently associated with progression-free survival (PFS): extent of resection (GTR vs. STR), recurrent status (de novo vs. recurrent), and Ki-67 labeling index (<5% vs. ≥ 5%). The respective β-coefficients were used to generate the “prognostic score”. The cohort was divided into low-risk and high-risk groups based on the median prognostic score. Good of fit test showed strong calibration (P = 0.7133) and Harrel’s C index 0.766 indicated a strong discrimination capability of the prognostic score. The Harrel’s C index for OS was 0.60.

Conclusions

Our prognostic model using three basic clinical parameters robustly separated high grade meningioma patients who benefit vs. do not benefit from adjuvant radiotherapy. External validation of our model is warranted to help improve patient selection suitable for adjuvant radiotherapy.

Efficacy and toxicity of particle radiotherapy in WHO grade II and grade III meningiomas: a systematic review

OBJECTIVEAdjuvant radiotherapy has become a common addition to the management of high-grade meningiomas, as immediate treatment with radiation following resection has been associated with significantly improved outcomes. Recent investigations into particle therapy have expanded into the management of high-risk meningiomas. Here, the authors systematically review studies on the efficacy and utility of particle-based radiotherapy in the management of high-grade meningioma.METHODSA literature search was developed by first defining the population, intervention, comparison, outcomes, and study design (PICOS). A search strategy was designed for each of three electronic databases: PubMed, Embase, and Scopus. Data extraction was conducted in accordance with the PRISMA guidelines. Outcomes of interest included local disease control, overall survival, and toxicity, which were compared with historical data on photon-based therapies.RESULTSEleven retrospective studies including 240 patients with atypical (WHO grade II) and anaplastic (WHO grade III) meningioma undergoing particle radiation therapy were identified. Five of the 11 studies included in this systematic review focused specifically on WHO grade II and III meningiomas; the others also included WHO grade I meningioma. Across all of the studies, the median follow-up ranged from 6 to 145 months. Local control rates for high-grade meningiomas ranged from 46.7% to 86% by the last follow-up or at 5 years. Overall survival rates ranged from 0% to 100% with better prognoses for atypical than for malignant meningiomas. Radiation necrosis was the most common adverse effect of treatment, occurring in 3.9% of specified cases.CONCLUSIONSDespite the lack of randomized prospective trials, this review of existing retrospective studies suggests that particle therapy, whether an adjuvant or a stand-alone treatment, confers survival benefit with a relatively low risk for severe treatment-derived toxicity compared to standard photon-based therapy. However, additional controlled studies are needed.

Management trends for anaplastic meningioma with adjuvant radiotherapy and predictors of long-term survival

OBJECTIVEThe purpose of this study was to describe effects of adjuvant radiotherapy (RT) for anaplastic meningiomas (AMs) on long-term survival, and to analyze patient and RT characteristics associated with long-term survival.METHODSThe authors queried a retrospective cohort of patients with AM from the National Cancer Database (NCDB) diagnosed between 2004 and 2015 to describe treatment trends. For outcome analysis, patients with at least 10 years of follow-up were included, and they were stratified based on adjuvant RT status and propensity matched to controls for covariates. Survival curves were compared. A data-driven approach was used to find a biologically effective dose (BED) of RT with the largest difference between survival curves. Factors associated with long-term survival were quantified.RESULTSThe authors identified 2170 cases of AM in the NCDB between 2004 and 2015. They observed increased use of adjuvant RT in patients treated with higher doses. A total of 178 cases met the inclusion criteria for outcome analysis. Forty-five percent (n = 80) received adjuvant RT. Patients received a BED of 80.23 ± 16.6 Gy (mean ± IQR). The median survival time was not significantly different (32.8 months for adjuvant RT vs 38.5 months for no RT; p = 0.57, log-rank test). Dichotomizing the patients at a BED of 81 Gy showed maximal difference in survival distribution with a decrease in median survival in favor of no adjuvant RT (31.2 months for adjuvant RT vs 49.7 months for no RT; p = 0.03, log-rank test), but this difference was not significant after false discovery rate correction. Age was a significant predictor for long-term survival.CONCLUSIONSAMs are aggressive tumors that carry a poor prognosis. Conventional adjuvant RT improves local control. However, the effect of adjuvant radiation on overall survival is unclear. Further investigation into this area is warranted.

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.

An Aggressive Extension of Dumbbell-Type Pediatric Skull Base Meningioma: A Case Report with Review of the Literature

BACKGROUND

Pediatric meningiomas account for less than 2% of pediatric brain tumors. Pediatric clear cell meningiomas (CCMs) occurring in the posterior fossa are particularly rare. Therapeutic strategies differ among the previous pediatric CCM case reports. Therefore, to clarify the clinical features of pediatric CCMs, we report a rare case of dumbbell-type pediatric CCM and a corresponding literature review.

CASE DESCRIPTION

A 7-year-old boy with complaints of headache, left facial palsy, dysarthria, and left-sided ataxic gait was emergently admitted to our hospital. His consciousness level was slight stupor, with Glasgow Coma Scale score 3-5-6, and he showed left ptosis, dysarthria, and ataxias of the left trunk and extremities. Magnetic resonance imaging (MRI) scan showed acute obstructive hydrocephalus because of the tumor's compression of the brainstem. The dumbbell-shaped tumor extended from the lateral wall of the cavernous sinus, through the left Meckel's cave, to the cerebellopontine angle. Physical examination and perioperative MRI scan showed no evidence regarding neurofibromatosis type I or II. The tumor was removed in a 2-staged operation. Postoperative proton therapy was done to treat some residual tumors. One year after postoperative proton therapy, there is no recurrence, and apart from left corneal and facial hypesthesia, he is healthy.

CONCLUSIONS

We reported a rare case of pediatric skull base-type CCM with huge extension originating from the anteromedial wall of Meckel's cave firmly adhered to the cavernous sinus wall to the posterior fossa that was successfully treated with surgery and postoperative proton therapy. CCM has a high recurrence rate; therefore, careful prolonged follow-up is needed.

Accounting for Range Uncertainties in the Optimization of Combined Proton-Photon Treatments Via Stochastic Optimization

PURPOSE

Proton treatment slots are a limited resource. Combined proton-photon treatments, in which most fractions are delivered with photons and only a few with protons, may represent a practical solution to optimize the allocation of proton resources over the patient population. We demonstrate how a limited number of proton fractions can be optimally used in multimodality treatments and address the issue of the robustness of combined treatments against proton range uncertainties.

METHODS AND MATERIALS

Combined proton-photon treatments are planned by simultaneously optimizing intensity modulated radiation therapy and proton therapy plans while accounting for the fractionation effect through the biologically effective dose model. The method was investigated for different tumor sites (a spinal metastasis, a sacral chordoma, and an atypical meningioma) in which organs at risk (OARs) were located within or near the tumor. Stochastic optimization was applied to mitigate range uncertainties.

RESULTS

In optimal combinations, proton and photon fractions deliver similar doses to OARs overlaying the target volume to protect these dose-limiting normal tissues through fractionation. Meanwhile, parts of the tumor are hypofractionated with protons. Thus, the total dose delivered with photons is reduced compared with simple combinations in which each modality delivers the prescribed dose per fraction to the target volume. The benefit of optimal combinations persists when range errors are accounted for via stochastic optimization.

CONCLUSIONS

Limited proton resources are optimally used in combined treatments if parts of the tumor are hypofractionated with protons and near-uniform fractionation is maintained in serial OARs. Proton range uncertainties can be efficiently accounted for through stochastic optimization and are not an obstacle for clinical application.

Long-term outcomes of multimodality management for parasagittal meningiomas

PURPOSE

The aim of this study was to systematically analyze the clinical characteristics of a large cohort of parasagittal meningioma (PM) and to evaluate the patients' outcomes and best treatment strategies based on tumor features.

METHODS

To minimize selection bias we performed a single-institutional review of PM with restricted criteria. One hundred and ninety-two consecutive patients who met criteria for inclusion were reviewed from 2003 to 2011 in our general hospital.

RESULTS

A total of 131 cases (68.2%) were with WHO grade I, while grade II and grade III PMs constituted 40 (20.8%) and 21 cases (10.9%). Higher histological grade was associated with loss of trimethylation of H3K27 (P = 0.000). For WHO grade I PMs, GTR was significantly associated with a better PFS (P = 0.023); however, adjuvant radiotherapy did not benefit patients with STR (P = 0.215). For de novo high-grade (WHO grade II and III) PMs (n = 37), adjuvant radiotherapy was associated with a significantly longer OS (P = 0.013), while no difference was observed between GTR and STR (P = 0.654). In recurrent high-grade PM patients (n = 24), GTR combined with adjuvant radiotherapy increased PFS (P = 0.005).

CONCLUSIONS

This study demonstrated that PMs were a heterogeneous group of tumors with a high proportion of high-grade tumors that often displayed aggressive clinical behaviors. Low-grade PM benefited from radical resection, whereas high-grade de novo PM did not. Adjuvant radiotherapy significantly prolonged OS for high-grade primary PM, but did not impact survival of patients with subtotally resected low-grade tumors. Long-term outcome of high-grade recurrent PMs was dismal. We thus show that extent of tumor resection, tumor grade and tumor recurrent status inform therapeutic decisions for PMs.

Impact of postoperative radiotherapy on recurrence of primary intracranial atypical meningiomas

BACKGROUND

Atypical meningiomas (WHO grade II) have high recurrence rate. However, data on the effect of radiotherapy (RT) is still conflicting. The aim of this study was to evaluate the influence of postoperative RT on the recurrence of primary atypical intracranial meningiomas.

METHODS

The medical records of all patients who underwent surgery (2007-2017 in 4 neurosurgical departments) for a histologically diagnosed primary atypical meningioma were reviewed to assess progression-free survival (PFS) and prognostic factors.

RESULTS

This analysis included 258 patients with a median age of 60 years (54.7% female). The predominant tumor locations were convexity and falx (60.9%) followed by the skull base (37.2%). Simpson grade I-II resection was achieved in 194 (75.2%) patients, Simpson grade III-IV in 53 patients (20.5%). Tumor progressed in 54 cases (20.9%). Postoperative RT was performed in 46 cases (17.8%). RT was more often applied after incomplete resection (37.7% vs. 13.4% Simpson III-IV vs. I-II). A multivariate analysis showed a significantly shorter PFS associated with Simpson III-IV [HR 1.19, (95% CI) 1.09-1.29, p < 0.001] and age > 65 years [HR 2.89, (95% CI) 1.56-5.33, p = 0.001]. A subgroup analysis with a minimal follow-up of 36 months revealed that Simpson III-IV [HR 3.01, 95% CI 1.31-6.931.03-1.24, p = 0.009] and age > 65 years [HR 2.48, 95% CI 1.20-5.13, p = 0.014] reduced PFS. The impact of postoperative RT on PFS remained statistically insignificant, even in a propensity-score matched survival analysis [n = 46; p = 0.438; OR 0.710 (0.299-1.687)].

CONCLUSIONS

In the present study, postoperative RT did not improve PFS. The most important prognostic factors remain the extent of resection and age.

Relationship between tumor location, size, and WHO grade in meningioma

OBJECTIVE Prior studies have investigated preoperative risk factors for meningioma; however, no association has been shown between meningioma tumor size and tumor grade. The objective of this study was to investigate the relationship between tumor size and grade in a large single-center study of patients undergoing meningioma resection. METHODS A retrospective chart review of patients undergoing meningioma resection at the University of California, San Francisco, between 1985 and 2015 was performed. Patients with incomplete information, spinal meningiomas, multiple meningiomas, or WHO grade III meningiomas were excluded. The largest tumor dimension was used as a surrogate for tumor size. Univariate and multivariate logistic regression models were used to investigate the relationship between tumor grade and tumor size. A recursive partitioning analysis was performed to identify groups at higher risk for atypical (WHO grade II) meningioma. RESULTS Of the 1113 patients identified, 905 (81%) had a WHO grade I tumor and in 208 (19%) the tumors were WHO grade II. The median largest tumor dimension was 3.6 cm (range 0.2-13 cm). Tumors were distributed as follows: skull base (n = 573, 51%), convexity/falx/parasagittal (n = 431, 39%), and other (n = 109, 10%). On univariate regression, larger tumor size (p < 0.001), convexity/falx/parasagittal location (p < 0.001), and male sex (p < 0.001) were significant predictors of WHO grade II pathology. After controlling for interactions, multivariate regression found male sex (OR 1.74, 95% CI 1.25-2.43), size 3-6 cm (OR 1.69, 95% CI 1.08-2.66), size > 6 cm (OR 3.01, 95% CI 1.53-5.94), and convexity/falx/parasagittal location (OR 1.83, 95% CI 1.19-2.82) to be significantly associated with WHO grade II. Recursive partitioning analysis identified male patients with tumors > 3 cm as a high-risk group (32%) for WHO grade II meningioma. CONCLUSIONS Larger tumor size is associated with a greater likelihood of a meningioma being WHO grade II, independent of tumor location and male sex, which are known risk factors.

A Systematic Review of Ion Radiotherapy in Maintaining Local Control Regarding Atypical and Anaplastic Meningiomas

OBJECTIVE

Atypical and anaplastic meningiomas, unlike their benign counterparts, are highly aggressive, locally destructive, and likely to recur after treatment. These diseases are difficult to definitively treat with traditional radiotherapy without injuring adjacent brain parenchyma. The physical properties of ion radiotherapy allows for treatment plans that avoid damaging critical neural structures. The objectives of this systematic review were to evaluate the use and efficacy of ion radiotherapy in the treatment of atypical and anaplastic meningiomas.

METHODS

We performed a systematic review of the literature by querying the PubMed and Ovid databases to identify and examine literature addressing the efficacy of ion radiotherapy in maintaining long-term local tumor control for patients with atypical or anaplastic meningiomas. The outcome of interest was rate of local tumor control at 5 years after ion radiotherapy.

RESULTS

Across the included studies, proton therapy delivered a mean local control rate of 59.62% after 5 years. Carbon ion radiotherapy studies showed local control rates of 95% and 63% at 2 years for grade II and III meningiomas, respectively. In contrast, carbon ion radiotherapy studies that failed to differentiate between atypical and anaplastic meningiomas produced a local control rate of 33% at 2 years.

CONCLUSIONS

Proton and carbon ion radiotherapy maintain comparable rates of local control to conventional photon therapy and allow for more targeted treatment plans that may limit excess radiation damage. Although additional prospective trials are needed, ion therapy represents a burgeoning field in the treatment of atypical and anaplastic meningiomas.

Multimodal Management of Metastatic Malignant Meningiomas: The Role of Radiosurgery in Long-Term Local Control

BACKGROUND

Metastatic meningiomas (MMs) are rare (0.1 of 100 cases). Their treatment requires a multimodal approach, with surgery, radiotherapy, chemotherapy, and radiosurgery, which allows a long-term local control (LC) and an extension of free survival. In this study, the authors performed a review of the literature and reported 2 cases of patients affected by extracranial MMs, with long-term follow-up.

CASE DESCRIPTION

Case 1: A 48-year-old woman was admitted for resection of an extra-axial falx lesion (meningioma G1). After 2 years, the lesion got a local recurrence, resected with a histologic diagnosis of meningioma G3. During the next 9 years, the patient underwent 5 Gamma Knife radiosurgery (GKRS) procedures for local recurrence. At 56 years, she was readmitted for a surgical local recurrence (histologic definition: anaplastic meningioma G3). At the age of 62, the patient underwent a right lobectomy for a lung mass (histologic diagnosis: anaplastic meningioma G3). After that, multiple lesions at soma L5 and adrenal gland were discovered and then monitored. Case 2: A 48-year-old woman was operated for a lesion involving torcular herophili (meningioma G2). After 3 years, a local recurrence requires GKRS combined with tamoxifen. In the next 7 years, she underwent 5 GKRS procedures for local recurrence. The patient also underwent chemotherapy with octreotide. At the age of 61, she discovered multiple lesions in both lungs, liver, and kidney. A hepatic biopsy showed anaplastic meningioma G3. Also this patient does not suffer from any neurologic or clinical deficits.

CONCLUSIONS

LC in malignant meningioma is achievable through a multimodal approach; GKRS makes possible LC, but a novel aspect of these lesions is opened to discussion: the metastases. These reports show that multimodal treatment for MMs is an effective approach with good LC and improvement of overall survival. However, a long survival may allow systemic diffusion of the disease, in particular, when sagittal sinus is involved.

The Role of Particle Therapy for the Treatment of Skull Base Tumors and Tumors of the Central Nervous System (CNS)

Radiation therapy (RT) is a mainstay in the interdisciplinary treatment of brain tumors of the skull base and brain. Technical innovations during the past 2 decades have allowed for increasingly precise treatment with better sparing of adjacent healthy tissues to prevent treatment-related side effects that influence patients' quality of life. Particle therapy with protons and charged ions offer favorable kinetics with sharp dose deposition in a well-defined depth (Bragg-Peak) and a steep radiation fall-off beyond that maximum. This review highlights the role of particle therapy in the management of primary brain tumors and tumors of the skull base.

Grade III meningioma with gastro-intestinal tract and brain metastases: case report and review of the literature

Background

Meningioma is the most common adult primary intracranial tumor. Malignant meningioma is a rare variant of meningioma. The prognosis for the patients with these tumors is poor, due to the tumor’s capacity for relapse and to develop distant metastases. These tumors can present the same evolutionary course as aggressive carcinoma.

Case description

We report the case of distant brain and gastro-intestinal tract (GIT) metastases. A 78-year-old patient developed malignant meningioma with a Ki-67 proliferative index of 40%. According to guidelines, surgery followed by postoperative radiotherapy (RT) was performed. Three months after the end of RT, he presented histologically proven meningioma distant brain and GIT metastases.

Conclusions

To our knowledge, this is the first case of meningioma GIT metastases. Also, we report the difficulty to confirm the diagnosis of meningioma metastases. Indeed, malignant meningioma has the same histopathological features as melanoma or carcinoma. The standard of care for the management of malignant meningioma is gross total surgery followed by postoperative radiotherapy. Metastatic meningioma is uncommon and no guidelines for the management of recurrent or metastatic meningioma have yet been published. However, several studies reported systemic therapeutic options such as antibody against VEGF, somatostatin analogs, PDGF-R, and VEGF-R tyrosine kinase inhibitors, in the case of recurrent or metastatic meningioma. We also made a review of the actual literature of systemic treatment options for metastatic meningioma.

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.

Surgery and protontherapy in Grade I and II skull base chondrosarcoma: A comparative retrospective study

Objective

Skull base chondrosarcoma is a rare tumour usually treated by surgery and proton therapy. However, as mortality rate is very low and treatment complications are frequent, a less aggressive therapeutic strategy could be considered. The objective of this study was to compare the results of surgery only vs surgery and adjuvant proton therapy, in terms of survival and treatment adverse effects, based on a retrospective series.

Methods

Monocentric retrospective study at a tertiary care centre. All patients treated for a skull base grade I and II chondrosarcoma were included. We collected data concerning surgical and proton therapy treatment and up-to-date follow-up, including Common Terminology Criteria for Adverse Events (CTCAE) scores.

Results

47 patients (23M/24F) were operated on between 2002 and 2015; mean age at diagnosis was 47 years-old (10–85). Petroclival and anterior skull base locations were found in 34 and 13 patients, respectively. Gross total resection was achieved in 17 cases (36%) and partial in 30 (64%). Adjuvant proton therapy (mean total dose 70 GyRBE,1.8 GyRBE/day) was administered in 23 cases. Overall mean follow-up was 91 months (7–182). Of the patients treated by surgery only, 8 (34%) experienced residual tumour progression (mean delay 51 months) and 5 received second-line proton therapy. Adjuvant proton therapy was associated with a significantly lower rate of relapse (11%; p = 0.01). There was no significant difference in 10-year disease specific survival between patients initially treated with or without adjuvant proton therapy (100% vs 89.8%, p = 0.14). Difference in high-grade toxicity was not statistically significant between patients in both groups (25% (7) vs 11% (5), p = 0.10). The most frequent adverse effect of proton therapy was sensorineural hearing loss (39%).

Conclusion

Long-term disease specific survival was not significantly lower in patients without adjuvant proton therapy, but they experienced less adverse effects. We believe a surgery only strategy could be discussed, delaying as much as possible proton therapy in cases of relapse. Further prospective studies are needed to validate this more conservative strategy in skull base chondrosarcoma.

Protons vs Photons for Brain and Skull Base Tumors

The physical characteristics of proton therapy result in steeper dose gradients and superior dose conformality compared to photon therapy. These properties render proton therapy ideal for skull base tumors requiring dose escalation for optimal tumor control, and may also be beneficial for brain tumors as a means of mitigating radiation-related adverse effects. This review summarizes the literature regarding the role of proton therapy compared to photon therapy in the treatment of adult brain and skull base tumors.

Boron Neutron Capture Therapy for High-Grade Skull-Base Meningioma

Objectives  Boron neutron capture therapy (BNCT) is a nuclear reaction-based tumor cell-selective particle irradiation that occurs when nonradioactive Boron-10 is irradiated with low-energy neutrons to produce high-energy α particles (10B [ n , α] 7Li). Possible complications associated with extended surgical resection render high-grade meningioma (HGM) a challenging pathology and skull-base meningiomas (SBMs) even more challenging. Lately, we have been trying to control HGMs using BNCT. This study aims to elucidate whether the recurrence and outcome of HGMs and SBMs differ based on their location. Design  Retrospective review. Setting  Osaka Medical College Hospital and Kyoto University Research Reactor Institute. Participants  Between 2005 and 2014, 31 patients with recurrent HGM (7 SBMs) were treated with BNCT. Main Outcome Measures  Overall survival and the subgroup analysis by the anatomical tumor location. Results  Positron emission tomography revealed that HGMs exhibited 3.8 times higher boron accumulation than the normal brain. Although tumors displayed transient increases in size in several cases, all lesions were found to decrease during observation. Furthermore, the median survival time of patients with SBMs post-BNCT and after being diagnosed as high-grade were 24.6 and 67.5 months, respectively (vs non-SBMs: 40.4 and 47.5 months). Conclusions  BNCT could be a robust and beneficial therapeutic modality for patients with high-grade SBMs.

Intermediate-risk meningioma: initial outcomes from NRG Oncology RTOG 0539

OBJECTIVE This is the first clinical outcomes report of NRG Oncology RTOG 0539, detailing the primary endpoint, 3-year progression-free survival (PFS), compared with a predefined historical control for intermediate-risk meningioma, and secondarily evaluating overall survival (OS), local failure, and prospectively scored adverse events (AEs). METHODS NRG Oncology RTOG 0539 was a Phase II clinical trial allocating meningioma patients to 1 of 3 prognostic groups and management strategies according to WHO grade, recurrence status, and resection extent. For the intermediate-risk group (Group 2), eligible patients had either newly diagnosed WHO Grade II meningioma that had been treated with gross-total resection (GTR; Simpson Grades I-III) or recurrent WHO Grade I meningioma with any resection extent. Pathology and imaging were centrally reviewed. Patients were treated with radiation therapy (RT), either intensity modulated (IMRT) or 3D conformal (3DCRT), 54 Gy in 30 fractions. The RT target volume was defined as the tumor bed and any nodular enhancement (e.g., in patients with recurrent WHO Grade I tumors) with a minimum 8-mm and maximum 15-mm margin, depending on tumor location and setup reproducibility of the RT method. The primary endpoint was 3-year PFS. Results were compared with historical controls (3-year PFS: 70% following GTR alone and 90% with GTR + RT). AEs were scored using NCI Common Toxicity Criteria. RESULTS Fifty-six patients enrolled in the intermediate-risk group, of whom 3 were ineligible and 1 did not receive RT. Of the 52 patients who received protocol therapy, 4 withdrew without a recurrence before 3 years leaving 48 patients evaluable for the primary endpoint, 3-year PFS, which was actuarially 93.8% (p = 0.0003). Within 3 years, 3 patients experienced events affecting PFS: 1 patient with a WHO Grade II tumor died of the disease, 1 patient with a WHO Grade II tumor had disease progression but remained alive, and 1 patient with recurrent WHO Grade I meningioma died of undetermined cause without tumor progression. The 3-year actuarial local failure rate was 4.1%, and the 3-year OS rate was 96%. After 3 years, progression occurred in 2 additional patients: 1 patient with recurrent WHO Grade I meningioma and 1 patient with WHO Grade II disease; both remain alive. Among 52 evaluable patients who received protocol treatment, 36 (69.2%) had WHO Grade II tumors and underwent GTR, and 16 (30.8%) had recurrent WHO Grade I tumors. There was no significant difference in PFS between these subgroups (p = 0.52, HR 0.56, 95% CI 0.09-3.35), validating their consolidation. Of the 52 evaluable patients, 44 (84.6%) received IMRT, and 50 (96.2%) were treated per protocol or with acceptable variation. AEs (definitely, probably, or possibly related to protocol treatment) were limited to Grade 1 or 2, with no reported Grade 3 events. CONCLUSIONS This is the first clinical outcomes report from NRG Oncology RTOG 0539. Patients with intermediate-risk meningioma treated with RT had excellent 3-year PFS, with a low rate of local failure and a low risk of AEs. These results support the use of postoperative RT for newly diagnosed gross-totally resected WHO Grade II or recurrent WHO Grade I meningioma irrespective of resection extent. They also document minimal toxicity and high rates of tumor control with IMRT. Clinical trial registration no.: NCT00895622 (clinicaltrials.gov).