Multimodal management of surgery- and radiation-refractory meningiomas: an analysis of the French national tumor board meeting on meningiomas cohort

Application of bevacizumab in the management of meningiomas: a systematic review and meta-analysis

Meningiomas are the most common intracranial lesions and constitute one-third of diagnoses. Surgical resection is the gold-standard treatment option. In case of treatment failure, therapeutic options are limited. Bevacizumab is a vascular endothelial growth factor ligand-binding monoclonal antibody that prevents angiogenesis. This study aims to investigate the efficacy and feasibility of bevacizumab in meningiomas On December 30, 2023, a systematic search was conducted according to PRISMA guidelines using the PubMed, Scopus, Web of Science, and Embase databases. This study is conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flowchart. Our study included 12 studies, comprising 243 individuals and 310 tumors. Most of the studies were retrospective (80%). Most of the patients were male (47.9%). The bevacizumab was mostly administered intravenously at 10 mg/kg every two weeks (77.8%). The mean progression-free survival (PFS) and overall survival (OS) were 19.1 ± 4.7 and 23.9 ± 8.4 months, respectively. The response rate was 0.33 (95%CI: 0.14-0.60). The PFS-6, PFS-12, and PFS-24 were 0.80 (95% CI: 0.64-0.89), 0.66 (95%CI: 0.46-0.82), and 25% (95%CI: 0.16-0.37), respectively. The OS-6, OS-12, and OS-24 were 0.89 (95% CI: 0.80-0.96), 0.86 (95%CI: 0.65-0.95), and 0.48 (95%CI: 0.16-0.82), respectively. The meta-regression identified the total number of individuals, number of tumors, gender, WHO II/III, and prior resection as a possible source of heterogeneity for outcomes. This study highlights the effectiveness of bevacizumab in meningiomas, especially in refractory, high-grade, or neurofibromatosis patients.

Evaluation of the SSTR2-targeted Radiopharmaceutical 177Lu-DOTATATE and SSTR2-specific 68Ga-DOTATATE PET as Imaging Biomarker in Patients with Intracranial Meningioma

PURPOSE

There are no effective medical therapies for patients with meningioma who progress beyond surgical and radiotherapeutic interventions. Somatostatin receptor type 2 (SSTR2) represents a promising treatment target in meningiomas. In this multicenter, single-arm phase II clinical study (NCT03971461), the SSTR2-targeting radiopharmaceutical 177Lu-DOTATATE is evaluated for its feasibility, safety, and therapeutic efficacy in these patients.

PATIENTS AND METHODS

Adult patients with progressive intracranial meningiomas received 177Lu-DOTATATE at a dose of 7.4 GBq (200 mCi) every eight weeks for four cycles. 68Ga-DOTATATE PET-MRI was performed before and six months after the start of the treatment. The primary endpoint was progression-free survival (PFS) at 6 months (PFS-6). Secondary endpoints were safety and tolerability, overall survival (OS) at 12 months (OS-12), median PFS, and median OS.

RESULTS

Fourteen patients (female = 11, male = 3) with progressive meningiomas (WHO 1 = 3, 2 = 10, 3 = 1) were enrolled. Median age was 63.1 (range 49.7-78) years. All patients previously underwent tumor resection and at least one course of radiation. Treatment with 177Lu-DOTATATE was well tolerated. Seven patients (50%) achieved PFS-6. Best radiographic response by modified Macdonald criteria was stable disease (SD) in all seven patients. A >25% reduction in 68Ga-DOTATATE uptake (PET) was observed in five meningiomas and two patients. In one lesion, this corresponded to >50% reduction in bidirectional tumor measurements (MRI).

CONCLUSIONS

Treatment with 177Lu-DOTATATE was well tolerated. The predefined PFS-6 threshold was met in this interim analysis, thereby allowing this multicenter clinical trial to continue enrollment. 68Ga-DOTATATE PET may be a useful imaging biomarker to assess therapeutic outcome in patients with meningioma.

Semi-automated segmentation methods of SSTR PET for dosimetry prediction in refractory meningioma patients treated by SSTR-targeted peptide receptor radionuclide therapy

OBJECTIVES

Tumor dosimetry with somatostatin receptor-targeted peptide receptor radionuclide therapy (SSTR-targeted PRRT) by 177Lu-DOTATATE may contribute to improved treatment monitoring of refractory meningioma. Accurate dosimetry requires reliable and reproducible pretherapeutic PET tumor segmentation which is not currently available. This study aims to propose semi-automated segmentation methods to determine metabolic tumor volume with pretherapeutic 68Ga-DOTATOC PET and evaluate SUVmean-derived values as predictive factors for tumor-absorbed dose.

METHODS

Thirty-nine meningioma lesions from twenty patients were analyzed. The ground truth PET and SPECT volumes (VolGT-PET and VolGT-SPECT) were computed from manual segmentations by five experienced nuclear physicians. SUV-related indexes were extracted from VolGT-PET and the semi-automated PET volumes providing the best Dice index with VolGT-PET (Volopt) across several methods: SUV absolute-value (2.3)-threshold, adaptative methods (Jentzen, Otsu, Contrast-based method), advanced gradient-based technique, and multiple relative thresholds (% of tumor SUVmax, hypophysis SUVmean, and meninges SUVpeak) with optimal threshold optimized. Tumor-absorbed doses were obtained from the VolGT-SPECT, corrected for partial volume effect, performed on a 360° whole-body CZT-camera at 24, 96, and 168 h after administration of 177Lu-DOTATATE.

RESULTS

Volopt was obtained from 1.7-fold meninges SUVpeak (Dice index 0.85 ± 0.07). SUVmean and total lesion uptake (SUVmeanxlesion volume) showed better correlations with tumor-absorbed doses than SUVmax when determined with the VolGT (respective Pearson correlation coefficients of 0.78, 0.67, and 0.56) or Volopt (0.64, 0.66, and 0.56).

CONCLUSION

Accurate definition of pretherapeutic PET volumes is justified since SUVmean-derived values provide the best tumor-absorbed dose predictions in refractory meningioma patients treated by 177Lu-DOTATATE. This study provides a semi-automated segmentation method of pretherapeutic 68Ga-DOTATOC PET volumes to achieve good reproducibility between physicians.

CLINICAL RELEVANCE STATEMENT

SUVmean-derived values from pretherapeutic 68Ga-DOTATOC PET are predictive of tumor-absorbed doses in refractory meningiomas treated by 177Lu-DOTATATE, justifying to accurately define pretherapeutic PET volumes. This study provides a semi-automated segmentation of 68Ga-DOTATOC PET images easily applicable in routine.

KEY POINTS

• SUVmean-derived values from pretherapeutic 68Ga-DOTATOC PET images provide the best predictive factors of tumor-absorbed doses related to 177Lu-DOTATATE PRRT in refractory meningioma. • A 1.7-fold meninges SUVpeak segmentation method used to determine metabolic tumor volume on pretherapeutic 68Ga-DOTATOC PET images of refractory meningioma treated by 177Lu-DOTATATE is as efficient as the currently routine manual segmentation method and limits inter- and intra-observer variabilities. • This semi-automated method for segmentation of refractory meningioma is easily applicable to routine practice and transferrable across PET centers.

Innovative treatments for meningiomas

Multi-recurrent high-grade meningiomas remain an unmet medical need in neuro-oncology when iterative surgeries and radiation therapy sessions fail to control tumor growth. Nevertheless, the last 10years have been marked by multiple advances in the comprehension of meningioma tumorigenesis via the discovery of new driver mutations, the identification of activated intracellular signaling pathways, and DNA methylation analyses, providing multiple potential therapeutic targets. Today, Anti-VEGF and mTOR inhibitors are the most used and probably the most active drugs in aggressive meningiomas. Peptide radioactive radiation therapy aims to target SSTR2A receptors, which are strongly expressed in meningiomas, but have an insufficient effect in most aggressive meningiomas, requiring the development of new techniques to increase the dose applied to the tumor. Based on the multiple potential intracellular targets, multiple targeted therapy clinical trials targeting Pi3K-Akt-mTOR and MAP kinase pathways as well as cell cycle and particularly, cyclin D4-6 are ongoing. Recently discovered driver mutations, SMO, Akt, and PI3KCA, offer new targets but are mostly observed in benign meningiomas, limiting their clinical relevance mainly to rare aggressive skull base meningiomas. Therefore, NF2 mutation remains the most frequent mutation and main challenging target in high-grade meningioma. Recently, inhibitors of focal adhesion kinase (FAK), which is involved in tumor cell adhesion, were tested in a phase 2 clinical trial with interesting but insufficient activity. The Hippo pathway was demonstrated to interact with NF2/Merlin and could be a promising target in NF2-mutated meningiomas with ongoing multiple preclinical studies and a phase 1 clinical trial. Recent advances in immune landscape comprehension led to the proposal of the use of immunotherapy in meningiomas. Except in rare cases of MSH2/6 mutation or high tumor mass burden, the activity of PD-1 inhibitors remains limited; however, its combination with various radiation therapy modalities is particularly promising. On the whole, therapeutic management of high-grade meningiomas is still challenging even with multiple promising therapeutic targets and innovations.

Meningiomas and Somatostatin Analogs: A Systematic Scoping Review on Current Insights and Future Perspectives

Meningioma is the most frequent brain tumor, and the incidence is ever-increasing. Though often benign and slow growth, recurrence rates are substantial and today's surgical and radiation-based treatment are not without complications. No drugs specific for meningiomas are hitherto approved and patients with inoperable or recurrent meningioma are left with few treatment options. Somatostatin receptors are previously detected in meningiomas and may inhibit growth when stimulated by somatostatin. Hence, somatostatin analogs could provide a targeted drug therapy. The aim of this study was to compile the current insights of somatostatin analogs for patients with meningioma. This paper adheres to the PRISMA extension for Scoping Reviews. A systematic search was conducted in the search databases PubMed, Embase via Ovid, and Web of Science. Seventeen papers adhered to the inclusion and exclusion criteria, and critical appraisal was conducted. The overall quality of evidence is low, as none of the studies were randomized or controlled. Various efficacy of somatostatin analogs is reported, and adverse effects are sparse. Due to the beneficial effects reported by some studies, somatostatin analogs may offer a novel last-option treatment for severely ill-patients. Nonetheless, only a controlled study, preferably a randomized clinical trial, could clarify the efficacy of somatostatin analogs.

Co-Targeting MAP Kinase and Pi3K-Akt-mTOR Pathways in Meningioma: Preclinical Study of Alpelisib and Trametinib

Simple Summary

Multi recurrent or high-grade meningiomas remain an unmet medical need in neuro-oncology. Several studies have highlighted the potential therapeutic efficacy of mTor inhibitors to control tumoral growth of meningiomas. However, a positive feedback on AKT oncogenic pathway from these drugs may explain the modest success. Our aim was to target Pi3kinase upstream mTor, and MAP kinase pathway, overactivated in meningiomas, alone or in combined targeting in comparison to mTor targeting. Our in vitro results obtained on three meningioma cell lines and on a large series of fresh human meningiomas, including 35 WHO grade 1, 23 grade 2, and five grade 3, showed that co-targeting Pi3kinase and MAP kinase seemed promising, opening new therapeutic strategies in these tumors.

Abstract

Recurrent or high-grade meningiomas are an unmet medical need. Recently, we demonstrated that targeting mTOR by everolimus was relevant both in vitro and in humans. However, everolimus induces an AKT activation that may impact the anti-proliferative effect of the drug. Moreover, the MAP kinase pathway was shown to be involved in meningioma tumorigenesis. We therefore targeted both the Pi3k-AKT-mTOR and MAP kinase pathways by using combinations of the Pi3k inhibitor alpelisib and the MEK inhibitor trametinib. Our study was performed in vitro on the human meningioma cell lines and on a large series of primary cultures providing from 63 freshly operated meningiomas including 35 WHO grade 1, 23 grade 2, and five grade 3, half of which presented a NF2 genomic alteration. Alpelisib induced a higher inhibitory effect on cell viability and proliferation than everolimus in all cell lines and 32 randomly selected tumors no matter the genomic status, the histological subtype or grade. Trametinib also strongly inhibited cell proliferation and induced AKT activation. Combined treatment with alpelisib plus trametinib reversed the AKT activation induced by trametinib and induced an additive inhibitory effect irrespective of the cell lines or tumor features. Co-targeting pathways seems promising and may be considered particularly for aggressive meningioma.

Identification and Management of Aggressive Meningiomas

Meningiomas are common primary central nervous system tumors derived from the meninges, with management most frequently entailing serial monitoring or a combination of surgery and/or radiation therapy. Although often considered benign lesions, meningiomas can not only be surgically inaccessible but also exhibit aggressive growth and recurrence. In such cases, adjuvant radiation and systemic therapy may be required for tumor control. In this review, we briefly describe the current WHO grading scale for meningioma and provide demonstrative cases of treatment-resistant meningiomas. We also summarize frequently observed molecular abnormalities and their correlation with intracranial location and recurrence rate. We then describe how genetic and epigenetic features might supplement or even replace histopathologic features for improved identification of aggressive lesions. Finally, we describe the role of surgery, radiotherapy, and ongoing systemic therapy as well as precision medicine clinical trials for the treatment of recurrent meningioma.

Preliminary experience with a new institutional tumor board dedicated to patients with neuroendocrine neoplasms

PURPOSE

To determine the decision patterns of a neuroendocrine neoplasm (NEN) tumor board (TB) and the factors behind those.

METHODS

We retrospectively reviewed all NEN-TB recommendations from 07/2018 to 12/2021 and recorded patient characteristics, TB outcomes and associations between them.

RESULTS

A total of 652 patient entries were identified. Median age of participants was 61 years and an equal number of men and women were presented. Most patients (33.4%) had tumors originating in the small bowel with 16.8% of high grade and 25.9% of pancreatic origin. Imaging was reviewed 97.2% of the time, with most frequently reviewed modalities being PET (55.3%) and CT (44.3%). Imaging review determined that there was no disease progression 20.8% of the time and significant treatment changes were recommended in 36.1% of patients. Major pathology amendments occurred in 3.7% of cases and a clinical trial was identified in 2.6%. There was no association between patient or disease presentation with the tumor board outcomes. There was a slight decrease in number of patients discussed per session, from 10.0 to 8.2 (p < 0.001) when the TB transitioned to a virtual format during the COVID-19 pandemic but all other factors remained unchanged.

CONCLUSION

NEN-TB relies heavily on image review, can impact significant treatment changes in patients with rare tumors like NENs, and was not affected by the switch to a virtual format. Finally, none of the examined factors were predictive of the tumor board recommendations.

[Meningiomas: A review of current knowledge]

Meningiomas are the most frequent among intracranial tumors, and represent more than 30% of primitive central nervous system neoplasms. Arising from the meninges, they are generally benign lesions and can be treated by either radio-clinical follow-up or surgical resection with excellent outcome. However, more than 20% of meningiomas harbor atypical or malignant features and represent challenges for both prognostic evaluation and therapeutic strategy. The discovery of the genetic and epigenetic landscapes of meningiomas enabled the identification of new prognostic markers and potential therapeutic targets for refractory meningiomas. This review summarizes current epidemiology, histological and molecular characteristics, diagnosis and treatments for meningiomas, and highlights the close relationship between the development of meningiomas and hormonal intake, as illustrated by recent recommendations of the "Agence Nationale de Securité du Medicament", the French national drug safety agency.