The Ki-67 Proliferation Index as a Marker of Time to Recurrence in Intracranial Meningioma

Ki-67 index as a predictive marker of meningioma recurrence following surgical resection

BACKGROUND

Meningiomas are the most common primary intracranial tumors in adults. Although benign in a majority of cases, they have a variable clinical course and may recur even after a thorough surgical resection. Ki-67, a nuclear protein involved in cell cycle regulation, has been widely studied as a marker of cellular proliferation in various cancers. However, the prognostic significance of Ki-67 in meningiomas remains controversial. Here, we investigate the Ki-67 index, as a predictive marker of meningioma recurrence following surgical resection and compare it to established prognostic markers such as WHO grade and degree of resection.

METHODS

The medical records of 451 patients with previously untreated cranial meningiomas who underwent resections from January 2011 to January 2021 at North Shore University Hospital (NSUH) were reviewed. Collected data included WHO grade, Ki-67 proliferative index, degree of resection - gross (GTR) vs subtotal (STR) - as judged by the surgeon, tumor location, and meningioma recurrence. This study was approved by the NSUH Institutional Review Board IRB 21-1107.

RESULTS

There were 290 patients with grade I, 154 with grade II, and 7 with grade III meningiomas. The average post-resection follow-up period was 4 years, and 82 tumors (18 %) recurred. Higher WHO grades were associated with higher rates of recurrence, with rates of 11.4 %, 27.9 %, and 71.4 % for grades 1, 2, and 3, respectively, and subtotal resection corresponded to a higher rate of recurrence than total resection (34.3 % and 13.4 %, respectively). Higher WHO grades also correlated with higher Ki-67 scores (2.59, 10.01, and 20.71) for grades 1, 2, and 3, respectively. A multivariate logistic regression model identified Ki-67 and degree of resection as independent predictive variables for meningioma recurrence, with Ki-67 specifically predicting recurrence in the WHO grade II subset when analyzed separately for WHO grades I and II.

CONCLUSION

Our 10-year retrospective study suggests that the Ki-67 index is an important predictive marker for recurrence of intracranial meningiomas following surgical resection, particularly among patients with WHO grade II tumors. Our findings add to a growing body of data that support inclusion of Ki-67 index in the WHO grading criteria for patients with meningiomas.

A comprehensive correlation of the KI-67 proliferation index to patient´s, imaging and tumor features and its value in predicting long-term course of patients with newly diagnosed intracranial meningiomas

To analyze the correlation of KI-67-Proliferation Index (KI-67-PI) with preoperative patients and MRI characteristics, WHO grading, histological subtype and long-term-course of patients with newly diagnosed intracranial meningiomas (IM). In this single-center retrospective study, all consecutive patients with IM were analyzed from January 2007 to August 2019. Patient´s demographics (age, sex), imaging parameters (location, volume, edema, necrosis), and tumor features (WHO grade, histology) were assessed and correlated with KI-67-PI. Long-term data were retrieved from patient's last follow-up visits. This study included 463 IM in 457 surgically treated patients. Males exhibited a higher KI-67-PI than females (7.31 ± 0.22 vs. 5.37 ± 0.53; p < 0.01, Mann-Whitney U Test). Age positively correlated with KI-67-PI in both sexes (p < 0.01, Spearman), with older patients having a higher KI-67-PI. KI-67-PI was significantly higher in convexity IM compared to frontobasal IM (7.15 ± 5.56 vs. 4.66 ± 2.94; p < 0.05, ANOVA, Tukey´s HSD), while no difference in KI-67-PI expression was found when other locations were compared to each other (Tukey´s HSD). Higher KI-67-PI was significantly correlated with larger tumor volume (p < 0.01, Spearman), larger tumor necrosis and larger peritumoral edema (p < 0.01, Kruskal-Wallis). Patients with recurrent IM had a significantly higher KI-67-PI than patients without recurrence (8.24 ± 5.88 vs. 5.14 ± 3.53; p < 0.01, ANOVA, Tukey´s HSD) during a mean follow-up period of 80.92 ± 38.1 months. Atypical and anaplastic IM exhibited significantly higher KI-67-PI compared to all other WHO grade 1 histological subtypes (12.09 ± 0.73 vs. 4.51 ± 0.13; p < 0.01, Kruskal-Wallis test) and KI-67-PI was significantly higher in anaplastic IM compared to atypical meningioma (19.67 ± 1.41 vs. 11.01 ± 0.38; p < 0.01, ANOVA). Higher KI-67-PI is not only associated with atypical and anaplastic subtypes of IM, but is also significantly higher in males, positively correlates with patients age, larger tumor volume, lager peritumoral edema and necrosis on preoperative MRI and predicts tumor recurrence. Therefore, KI-67-PI may serve as a decision indicator for adjuvant treatment in patients with IM.

Biomarkers for prognosis of meningioma patients: A systematic review and meta-analysis

Meningioma is the most common primary brain tumor and many studies have evaluated numerous biomarkers for their prognostic value, often with inconsistent results. Currently, no reliable biomarkers are available to predict the survival, recurrence, and progression of meningioma patients in clinical practice. This study aims to evaluate the prognostic value of immunohistochemistry-based (IHC) biomarkers of meningioma patients. A systematic literature search was conducted up to November 2023 on PubMed, CENTRAL, CINAHL Plus, and Scopus databases. Two authors independently reviewed the identified relevant studies, extracted data, and assessed the risk of bias of the studies included. Meta-analyses were performed with the hazard ratio (HR) and 95% confidence interval (CI) of overall survival (OS), recurrence-free survival (RFS), and progression-free survival (PFS). The risk of bias in the included studies was evaluated using the Quality in Prognosis Studies (QUIPS) tool. A total of 100 studies with 16,745 patients were included in this review. As the promising markers to predict OS of meningioma patients, Ki-67/MIB-1 (HR = 1.03, 95%CI 1.02 to 1.05) was identified to associate with poor prognosis of the patients. Overexpression of cyclin A (HR = 4.91, 95%CI 1.38 to 17.44), topoisomerase II α (TOP2A) (HR = 4.90, 95%CI 2.96 to 8.12), p53 (HR = 2.40, 95%CI 1.73 to 3.34), vascular endothelial growth factor (VEGF) (HR = 1.61, 95%CI 1.36 to 1.90), and Ki-67 (HR = 1.33, 95%CI 1.21 to 1.46), were identified also as unfavorable prognostic biomarkers for poor RFS of meningioma patients. Conversely, positive progesterone receptor (PR) and p21 staining were associated with longer RFS and are considered biomarkers of favorable prognosis of meningioma patients (HR = 0.60, 95% CI 0.41 to 0.88 and HR = 1.89, 95%CI 1.11 to 3.20). Additionally, high expression of Ki-67 was identified as a prognosis biomarker for poor PFS of meningioma patients (HR = 1.02, 95%CI 1.00 to 1.04). Although only in single studies, KPNA2, CDK6, Cox-2, MCM7 and PCNA are proposed as additional markers with high expression that are related with poor prognosis of meningioma patients. In conclusion, the results of the meta-analysis demonstrated that PR, cyclin A, TOP2A, p21, p53, VEGF and Ki-67 are either positively or negatively associated with survival of meningioma patients and might be useful biomarkers to assess the prognosis.

Meningioma recurrence: Time for an online prediction tool?

Background

Meningioma, the most common brain tumor, traditionally considered benign, has a relatively high risk of recurrence over a patient's lifespan. In addition, with the emergence of several clinical, radiological, and molecular variables, it is becoming evident that existing grading criteria, including Simpson's and World Health Organization classification, may not be sufficient or accurate. As web-based tools for widespread accessibility and usage become commonplace, such as those for gene identification or other cancers, it is timely for meningioma care to take advantage of evolving new markers to help advance patient care.

Methods

A scoping review of the meningioma literature was undertaken using the MEDLINE and Embase databases. We reviewed original studies and review articles from September 2022 to December 2023 that provided the most updated information on the demographic, clinical, radiographic, histopathological, molecular genetics, and management of meningiomas in the adult population.

Results

Our scoping review reveals a large body of meningioma literature that has evaluated the determinants for recurrence and aggressive tumor biology, including older age, female sex, genetic abnormalities such as telomerase reverse transcriptase promoter mutation, CDKN2A deletion, subtotal resection, and higher grade. Despite a large body of evidence on meningiomas, however, we noted a lack of tools to aid the clinician in decision-making. We identified the need for an online, self-updating, and machine-learning-based dynamic model that can incorporate demographic, clinical, radiographic, histopathological, and genetic variables to predict the recurrence risk of meningiomas.

Conclusion

Although a challenging endeavor, a recurrence prediction tool for meningioma would provide critical information for the meningioma patient and the clinician making decisions on long-term surveillance and management of meningiomas.

Time to Recurrence of Intracranial Meningiomas from a Monoinstitutional Surgical Series

BACKGROUND

Meningiomas show variable tendency to recur. While risk factors of recurrence have been largely investigated in literature, a paucity of data is available on the time to recurrence. Our purpose was to identify main factors affecting the time to recurrence to assist preoperative treatment decision-making strategy and to define a tailored clinical and neuroradiological follow-up.

METHODS

Data of 35 patients with intracranial meningioma recurrences have been retrospectively reviewed. Demographic (patient age at initial diagnosis and sex), radiologic (meningioma location, pattern of regrowth and topography of recurrences at first reoperation), pathologic (WHO grade and Ki67-MIB1 at initial surgery and at first reoperation, progesterone receptor [PR] expression), and surgical (extent of resection at initial surgery according to Simpsons grading system, number of reoperations) factors were analyzed.

RESULTS

Time to recurrence ranged from 20 to 120 months. Extent of resection at initial surgery was Simpson grade I in 7 patients (20%), grade II in 10 (28.5%), grade III in 14 (40%), and grade IV in 4 (11.5%). Longer median time to recurrence was observed for skull base localization (P < 0.01), Simpson grades I and II versus grades III (P = 0.01) and IV (P = 0.02), values of Ki67-MIB1 ≤ 4% (P = 0.001), and PR > 60% (P = 0.03); conversely, sex, age, number of reoperations, unchanged/progression of Ki67, and/or World Health Organization grade between first surgery and reoperation did not correlate in statistically significant way with time to recurrence.

CONCLUSIONS

The extent of resection and the Ki67-MIB1 represent the most important factors predicting shorter recurrence time of intracranial meningiomas. Patients with incomplete (Simpson grades III and IV) resection and high Ki67-MIB1 values, especially at non-skull base localization and with low PR values, require a closer short-term clinical and radiologic follow-up in the first years after surgery.

Single versus multiple reoperations for recurrent intracranial meningiomas

PURPOSE

To identify the risk factors and management of the multiple recurrences and reoperations for intracranial meningiomas.

METHODS

Data of a neurosurgical series of 35 patients reoperated on for recurrent intracranial meningiomas were reviewed. Analyzed factors include patient age and sex, tumor location, extent of resection, WHO grade, Ki67-MIB1 and PR expression at initial diagnosis, time to recurrence; pattern of regrowth, extent of resection, WHO grade and Ki67-MIB1 at first recurrence were also analyzed. All these factors were stratified into two groups based on single (Group A) and multiple reoperations (Group B).

RESULTS

Twenty-four patients (69%) belonged to group A and 11 (31%) to group B. The age < 65 years, male sex, incomplete resection at both initial surgery and first reoperation, and multicentric-diffuse pattern of regrowth at first recurrence are risk factors for multiple recurrences and reoperations. In group B, the WHO grade and Ki67-MIB1 increased in further recurrences in 54% and 64%, respectively. The time to recurrence was short in 7 cases (64%), whereas 4 patients (36%) further recurred after many years. Eight patients (73%) are still alive after 7 to 22 years and 2 to 4 reoperations.

CONCLUSION

The extent of resection and the multicentric-diffuse pattern of regrowth at first recurrence are the main risk factors for multiple recurrences and reoperations. Repeated reoperations might be considered even in patients with extensive recurrent tumors before the anaplastic transformation occurs. In such cases, even partial tumor resections followed by radiation therapy may allow long survival in good clinical conditions.

An MRI-Based Deep Transfer Learning Radiomics Nomogram to Predict Ki-67 Proliferation Index of Meningioma

The objective of this study was to predict Ki-67 proliferation index of meningioma by using a nomogram based on clinical, radiomics, and deep transfer learning (DTL) features. A total of 318 cases were enrolled in the study. The clinical, radiomics, and DTL features were selected to construct models. The calculation of radiomics and DTL score was completed by using selected features and correlation coefficient. The deep transfer learning radiomics (DTLR) nomogram was constructed by selected clinical features, radiomics score, and DTL score. The area under the receiver operator characteristic curve (AUC) was calculated. The models were compared by Delong test of AUCs and decision curve analysis (DCA). The features of sex, size, and peritumoral edema were selected to construct clinical model. Seven radiomics features and 15 DTL features were selected. The AUCs of clinical, radiomics, DTL model, and DTLR nomogram were 0.746, 0.75, 0.717, and 0.779 respectively. DTLR nomogram had the highest AUC of 0.779 (95% CI 0.6643-0.8943) with an accuracy rate of 0.734, a sensitivity value of 0.719, and a specificity value of 0.75 in test set. There was no significant difference in AUCs among four models in Delong test. The DTLR nomogram had a larger net benefit than other models across all the threshold probability. The DTLR nomogram had a satisfactory performance in Ki-67 prediction and could be a new evaluation method of meningioma which would be useful in the clinical decision-making.

Progression/Recurrence of Meningioma: An Imaging Review Based on Magnetic Resonance Imaging

Meningiomas are the most common primary central nervous system tumors. The preferred treatment is maximum safe resection, and the heterogeneity of meningiomas results in a variable prognosis. Progression/recurrence (P/R) can occur at any grade of meningioma and is a common adverse outcome after surgical treatment and a major cause of postoperative rehospitalization, secondary surgery, and mortality. Early prediction of P/R plays an important role in postoperative management, further adjuvant therapy, and follow-up of patients. Therefore, it is essential to thoroughly analyze the heterogeneity of meningiomas and predict postoperative P/R with the aid of noninvasive preoperative imaging. In recent years, the development of advanced magnetic resonance imaging technology and machine learning has provided new insights into noninvasive preoperative prediction of meningioma P/R, which helps to achieve accurate prediction of meningioma P/R. This narrative review summarizes the current research on conventional magnetic resonance imaging, functional magnetic resonance imaging, and machine learning in predicting meningioma P/R. We further explore the significance of tumor microenvironment in meningioma P/R, linking imaging features with tumor microenvironment to comprehensively reveal tumor heterogeneity and provide new ideas for future research.

Ki-67 labeling index predicts tumor progression patterns and survival in patients with atypical meningiomas following stereotactic radiosurgery

PURPOSE

This study investigated whether Ki-67 labeling index (LI) correlated with clinical outcomes after SRS for atypical meningiomas.

METHODS

This retrospective study examined 39 patients with atypical meningiomas who underwent SRS over a 10-year study period. Ki-67 LI was categorized into 3 groups: low (< 5%), intermediate (5%-10%), and high (> 10%). Local tumor control rates (LCRs), progression-free rates (PFRs), disease-specific survival (DSS) rates, and adverse radiation-induced events (AREs) were evaluated.

RESULTS

The median follow-up periods were 26 months. SRS was performed at a median prescription dose of 18 Gy for tumors with a median Ki-67 LI of 9.6%. The 3-year LCRs were 100%, 74%, and 25% in the low, intermediate, and high LI groups, respectively (p = 0.011). The 3-year PFRs were 100%, 40%, and 0% in the low, intermediate, and high LI groups (p = 0.003). The 5-year DSS rates were 100%, 89%, and 50% in the low, intermediate, and high LI groups (p = 0.019). Multivariable Cox proportional hazard analysis showed a significant correlation of high LI with lower LCR (hazard ratio [HR], 3.92; 95% confidence interval [CI] 1.18-13.04, p = 0.026), lower PFR (HR 3.80; 95% CI 1.46-9.88, p = 0.006), and shorter DSS (HR 6.55; 95% CI 1.19-35.95, p = 0.031) compared with intermediate LI. The ARE rates were minimal (8%) in the entire group.

CONCLUSION

Patients with high Ki-67 LI showed significantly more tumor progression and tumor-related death. Ki-67 LI might offer valuable predictive insights for the post-SRS management of atypical meningiomas.

Long-Term Outcomes of Stereotactic Radiosurgery for Postoperative World Health Organization Grade I Skull Base Meningioma: Utility of Ki-67 Labeling Index as a Prognostic Indicator

BACKGROUND

Gross total resection, without causing neurological deficits, is challenging in skull base meningioma (SBM). Therefore, stereotactic radiosurgery (SRS) is an important approach for SBMs; however, it is difficult to predict the long-term prognosis.

OBJECTIVE

To identify the predictive factors for tumor progression after SRS for World Health Organization (WHO) grade I SBMs, focusing on the Ki-67 labeling index (LI).

METHODS

In this single-center retrospective study, factors affecting progression-free survival rates (PFSs) and neurological outcomes in patients undergoing SRS for postoperative SBMs were evaluated. Based on the Ki-67 LI, patients were classified into 3 groups: low (<4%), intermediate (4%-6%), and high LI (>6%).

RESULTS

In the 112 patients enrolled, the cumulative 5- and 10-year PFSs were 93% and 83%, respectively. The PFSs were significantly higher in the low LI group (95% at 10 years) compared with the other groups (intermediate LI, 60% at 10 years, P = .007; high LI, 20% at 10 years, P = .001). Multivariable Cox proportional hazard analysis demonstrated that the Ki-67 LI was significantly associated with the PFSs (low vs intermediate LI; hazard ratio, 6.00; 95% CI, 1.41-25.54; P = .015; low vs high LI; hazard ratio, 31.90; 95% CI, 5.59-181.77; P = .001).

CONCLUSION

Ki-67 LI may be a useful predictor of long-term prognosis in SRS for postoperative WHO grade I SBM. SRS provides excellent long- and mid-term PFSs in SBMs with Ki-67 LIs <4% or 4% to 6%, with a low risk of radiation-induced adverse events.

Novel Postoperative Serum Biomarkers in Atypical Meningiomas: A Multicenter Study

BACKGROUND

There has been no known serum biomarker to predict the prognosis of atypical meningioma.

OBJECTIVE

To investigate the prognostic impact of serum biomarkers in patients newly diagnosed with resected intracranial atypical meningiomas.

METHODS

This study enrolled 523 patients with atypical meningioma who underwent surgical resection between 1998 and 2018 from 5 Asian institutions. Serum laboratory data within 1 week after surgery were obtained for analysis. Optimal cutoffs were calculated for each serum marker using the maxstat package of R.

RESULTS

Of 523 patients, 19.5% underwent subtotal resection and 29.8% were treated with adjuvant radiation therapy (ART). Among the 523 patients, 454 were included in the multivariate analysis for the progression/recurrence (P/R) rate excluding patients with incomplete histopathologic or laboratory data. On multivariate analysis, tumor size >5 cm, subtotal resection, and postoperative aspartate aminotransferase/alanine transaminase (De Ritis) ratio >2 were associated with higher P/R rates, whereas ART and postoperative platelet count >137 × 10 3 /μL were associated with lower P/R rates. In the subgroup of patients treated with ART, tumor size >5 cm and postoperative neutrophil-to-lymphocyte ratio >21 were associated with higher P/R rates. By contrast, postoperative De Ritis ratio >2 remained an adverse prognosticator in patients not treated with ART.

CONCLUSION

Postoperative De Ritis ratio, platelet count, and neutrophil-to-lymphocyte ratio were revealed as a novel serum prognosticator in newly diagnosed atypical meningiomas. Additional studies are warranted to validate its clinical significance and biological background.

A Nomogram Model for Stratifying the Risk of Recurrence in Patients with Meningioma After Surgery

BACKGROUND

Here, we aimed to investigate the clinical parameters affecting the recurrence of meningiomas, and to construct a predictive nomogram model, so as to predict the recurrence-free survival (RFS) of meningiomas more accurately.

METHODS

The Clinical, imaging, and pathological data of 155 primary meningioma patients treated surgically from January 2014 to March 2021 were retrospectively analyzed. Independent prognostic factors affecting postoperative recurrence of meningioma were identified by univariate and multivariate Cox regression analyses. A predictive nomogram was established based on independent influence parameters. Subsequently, time-dependent receiver operating characteristic curve, calibration curve, and Kaplan-Meier method were utilized to evaluate the predictive ability of the model.

RESULTS

The multivariate Cox regression analysis showed that tumor size, Ki-67 index, and resection extent had independent prognostic significance, and these parameters were subsequently used to construct a predictive nomogram. Receiver operating characteristic curves indicated that the model was more accurate in predicting RFS than independent factors. Calibration curves suggested that the predicted RFS were similar to the actual observed RFS. In the Kaplan-Meier analysis, the RFS of high-risk cases was obviously shorter than that of low-risk cases.

CONCLUSIONS

The tumor size, Ki-67 index, and extent of resection were independent factors affecting the RFS of meningioma. The predictive nomogram based on these factors can be used as an effective method to stratify the recurrence risk of meningioma and provide a reference for patients to choose personalized treatment.

Immunohistochemical Expression of Ki-67, Dopamine D1 and Dopamine D2 Receptors in Meningiomas in a Tertiary Institution in Mexico

Objectives Meningiomas (MNGs) are the most common intracranial tumors found in the adult population. While most intracranial MNGs may be surgically removed, a subset of patients remains ineligible for conventional treatment. This is either because of a lack of surgical access or due to atypical, anaplastic or invasive characteristics of the tumors. These patients may benefit from targeted therapies that focus on cell receptor expression. The aim of this study was to assess dopamine receptor (DR) and Ki-67 expression in the MGNs of patients treated with surgery in the Instituto Nacional de Neurología y Neurocirugía, Mexico. Materials and methods This study analyzed 23 patients with confirmed MNG diagnoses (10 female and 13 male (mean age: 44.5 years)) who had undergone surgical resection between 2010 and 2014 at our institution. In the collected samples, we performed analyses for Ki-67, Dopamine 1 and Dopamine 2 receptors' expression. Results For the markers Ki-67, DR-D1 and DR-D2, the mean percentual expressions were 18.9%, 23.02% and 8.33%. No significant correlation was found between the expressions of these receptors and the studied MNG characteristics. The expression index of Ki-67 showed a significant relation with mean age (p = 0.03) and prolactin levels (p = 0.02). Conclusions Samples showed varied expressions of the studied receptors. Despite the difference in expressions between the markers, more studies are needed to confirm the findings. In contrast to previous studies, we could not find any relationship between D2-R and tumor characteristics.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Volumetric Growth and Growth Curve Analysis of Residual Intracranial Meningioma

BACKGROUND

After meningioma surgery, approximately 1 in 3 patients will have residual tumor that requires ongoing imaging surveillance. The precise volumetric growth rates of these tumors are unknown.

OBJECTIVE

To identify the volumetric growth rates of residual meningioma, growth trajectory, and factors associated with progression.

METHODS

Patients with residual meningioma identified at a tertiary neurosurgery center between 2004 and 2020 were retrospectively reviewed. Tumor volume was measured using manual segmentation, after surgery and at every follow-up MRI scan. Growth rates were ascertained using a linear mixed-effects model and nonlinear regression analysis of growth trajectories. Progression was defined according to the Response Assessment in Neuro-Oncology (RANO) criteria (40% volume increase).

RESULTS

There were 236 patients with residual meningioma. One hundred and thirty-two patients (56.0%) progressed according to the RANO criteria, with 86 patients being conservatively managed (65.2%) after progression. Thirteen patients (5.5%) developed clinical progression. Over a median follow-up of 5.3 years (interquartile range, 3.5-8.6 years), the absolute growth rate was 0.11 cm 3 per year and the relative growth rate 4.3% per year. Factors associated with residual meningioma progression in multivariable Cox regression analysis were skull base location (hazard ratio [HR] 1.60, 95% CI 1.02-2.50) and increasing Ki-67 index (HR 3.43, 95% CI 1.19-9.90). Most meningioma exhibited exponential and logistic growth patterns (median R 2 value 0.84, 95% CI 0.60-0.90).

CONCLUSION

Absolute and relative growth rates of residual meningioma are low, but most meet the RANO criteria for progression. Location and Ki-67 index can be used to stratify adjuvant treatment and surveillance paradigms.

Predictive Value of K i -67 Index in Evaluating Sporadic Vestibular Schwannoma Recurrence: Systematic Review and Meta-analysis

Introduction  K _i -67 is often used as a proliferation index to evaluate how aggressive a tumor is and its likelihood of recurrence. Vestibular schwannomas (VS) are a unique benign pathology that lends itself well to evaluation with K _i -67 as a potential marker for disease recurrence or progression following surgical resection. Methods  All English language studies of VSs and K _i -67 indices were screened. Studies were considered eligible for inclusion if they reported series of VSs undergoing primary resection without prior irradiation, with outcomes including both recurrence/progression and K _i -67 for individual patients. For published studies reporting pooled K _i -67 index data without detailed by-patient values, we contacted the authors to request data sharing for the current meta-analysis. Studies reporting a relationship between K _i -67 index and clinical outcomes in VS for which detailed patients' outcomes or K _i -67 indices could not be obtained were incorporated into the descriptive analysis, but excluded from the formal (i.e., quantitative) meta-analysis. Results  A systematic review identified 104 candidate citations of which 12 met inclusion criteria. Six of these studies had accessible patient-specific data. Individual patient data were collected from these studies for calculation of discrete study effect sizes, pooling via random-effects modeling with restricted maximum likelihood, and meta-analysis. The standardized mean difference in K _i -67 indices between those with and without recurrence was calculated as 0.79% (95% confidence interval [CI]: 0.28-1.30; p  = 0.0026). Conclusion  K _i -67 index may be higher in VSs that demonstrate recurrence/progression following surgical resection. This may represent a promising means of evaluating tumor recurrence and potential need for early adjuvant therapy for VSs.

Association between preoperative hematologic markers and aggressive behavior in meningiomas

INTRODUCTION

Meningiomas have varying degrees of aggressive behavior. Some systemic hematologic makers are associated with malignancy, but their value in predicting aggressive meningioma behavior is not fully understood.

OBJECTIVE

To evaluate the association between preoperative markers such as neutrophil-lymphocyte ratio (NLR), neutrophil-monocyte ratio (NMR), monocyte-lymphocyte ratio (MLR), platelet-lymphocyte ratio (PLR), and prognostic nutritional index (PNI), and diagnostic and prognostic factors including WHO grade, proliferation index, presence of edema on preoperative MRI, and tumor recurrence.

METHODS

A retrospective review of patients treated between 2000 and 2019 with a preoperative complete blood count (CBC) differential lab draw before intracranial meningioma resection was conducted. All preoperative steroid dosages were converted to dexamethasone equivalents. Primary outcomes included presence/absence of perilesional edema, WHO grade, Ki-67/MIB-index, and recurrence. Univariate and multivariable regression analyses were conducted.

RESULTS

A total of 209 meningioma patients were included. Of these, 143 (68 %) were WHO grade I, 61 (29 %) grade II and 5 (2 %) were grade III. Recurrence was reported in 19 (9.1 %) tumors. No hematologic markers were associated with recurrence. In separate multivariable logistic analyses, no biomarkers were associated with perilesional edema or WHO grade. MLR was associated with higher MIB-index (p = 0.018, OR 6.57, 95 % CI 1.37-30.91).

CONCLUSION

Most hematologic markers were not associated with meningioma invasiveness, grade, proliferative index, or aggressiveness. Preoperative MLR was associated with high proliferation index in patients undergoing surgery for intracranial meningioma. Higher MLR could be a surrogate for meningioma proliferation and has potential to be used as an adjunct for risk-stratifying meningiomas.

An integrative non-invasive malignant brain tumors classification and Ki-67 labeling index prediction pipeline with radiomics approach

BACKGROUND

The histological sub-classes of brain tumors and the Ki-67 labeling index (LI) of tumor cells are major factors in the diagnosis, prognosis, and treatment management of patients. Many existing studies primarily focused on the classification of two classes of brain tumors and the Ki-67LI of gliomas. This study aimed to develop a preoperative non-invasive radiomics pipeline based on multiparametric-MRI to classify-three types of brain tumors, glioblastoma (GBM), metastasis (MET) and primary central nervous system lymphoma (PCNSL), and to predict their corresponding Ki-67LI.

METHODS

In this retrospective study, 153 patients with malignant brain tumors were involved. The radiomics features were extracted from three types of MRI (T1-weighted imaging (T1WI), fluid-attenuated inversion recovery (FLAIR), and contrast-enhanced T1-weighted imaging (CE-T1WI)) with three masks (tumor core, edema, and whole tumor masks) and selected by a combination of Pearson correlation coefficient (CORR), LASSO, and Max-Relevance and Min-Redundancy (mRMR) filters. The performance of six classifiers was compared and the top three performing classifiers were used to construct the ensemble learning model (ELM). The proposed ELM was evaluated in the training dataset (108 patients) by 5-fold cross-validation and in the test dataset (45 patients) by hold-out. The accuracy (ACC), sensitivity (SEN), specificity (SPE), F1-Score, and the area under the receiver operating characteristic curve (AUC) indicators evaluated the performance of the models.

RESULTS

The best feature sets and ELM with the optimal performance were selected to construct the tri-categorized brain tumor aided diagnosis model (training dataset AUC: 0.96 (95% CI: 0.93, 0.99); test dataset AUC: 0.93) and Ki-67LI prediction model (training dataset AUC: 0.96 (95% CI: 0.94, 0.98); test dataset AUC: 0.91). The CE-T1WI was the best single modality for all classifiers. Meanwhile, the whole tumor was the most vital mask for the tumor classification and the tumor core was the most vital mask for the Ki-67LI prediction.

CONCLUSION

The developed radiomics models led to the precise preoperative classification of GBM, MET, and PCNSL and the prediction of Ki-67LI, which could be utilized in clinical practice for the treatment planning for brain tumors.

MKI67 an potential oncogene of oral squamous cell carcinoma via the high throughput technology

Oral squamous cell carcinoma is a malignant tumor that occurs in the oral cavity, with poor prognosis and easy recurrence. However, the relationship between MKI67 and oral squamous cell carcinoma remains unclear. The oral squamous cell carcinoma datasets GSE138206, GSE146483 and GSE184616 were downloaded from the gene expression omnibus database, and the differentially expressed genes (DEGs) were screened. The protein-protein interaction network was constructed and analyzed by search tool for the retrieval of interacting genes database and Cytoscape software. Gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) were used for functional enrichment analysis. GO and KEGG analyses were performed on the whole genome, as formulated by gene set enrichment analysis. comparative toxicogenomics database was used to identify the diseases most associated with the core genes. TargetScan was used to screen miRNA regulating central DEGs. A total of 1472 DEGs were identified. GO analysis showed that the differentially expressed genes were mainly enriched in the tissues of extracellular matrix, type i interferon signaling pathway, human papillomavirus infection, adhesion spot, hepatitis C and ECM-receptor interaction. Enrichment items were similar to GO and KEGG enrichment items of differentially expressed genes. 10 core genes were obtained, and their expression was different between oral squamous cell carcinoma and normal tissue samples. MKI67 is highly expressed in oral squamous cell carcinoma and may be an oncogene in oral squamous cell carcinoma.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Predictive Power of MIB-1 vs. Mitotic Count on Progression-Free Survival in Skull-Base Meningioma

Simple Summary

Meningiomas are mainly benign intracranial tumors. Nevertheless, risk of recurrence exists in long-term follow-up, so new prognostic markers are still need to be identified. MIB-1 is no diagnostic criterion in WHO classification of meningiomas by now. This retrospective study shows that MIB-1 as well as mitotic count are good predictors for progression-free survival in skull-base meningiomas. The implantation of MIB-1 may enable an improved classification of meningiomas regarding progression-free survival. Moreover, this analysis of skull-base meningiomas shows that current cut-offs may have to be adjusted for meningioma location.

Abstract

Although meningiomas are mainly non-aggressive and slow-growing tumors, there is a remarkable recurrence rate in a long-term follow-up. Proliferative activity and progression-free survival (PFS) differs significantly among the anatomic location of meningiomas. The aim of the present study was to investigate the predictive power of MIB-1 labeling index and mitotic count (MC) regarding the probability of PFS in the subgroup of skull-base meningiomas. A total of 145 patients were included in this retrospective study. Histopathological examinations and follow-up data were collected. Ideal cut-off values for MIB-1 and MC were ≥4.75 and ≥6.5, respectively. MIB-1 as well as MC were good predictors for PFS in skull-base meningiomas. Time-dependent analysis of MIB-1 and MC in prediction of recurrence of skull-base meningioma showed that their prognostic values were comparable, but different cut-offs for MC should be considered regarding the meningioma’s location. As the achievement of a gross total resection can be more challenging in skull-base meningiomas and second surgery implies a higher risk profile, the recurrence risk could be stratified according to these findings and guide decision-making for follow-ups vs. adjuvant therapies.

Gene expression analysis during progression of malignant meningioma compared to benign meningioma

OBJECTIVE

Meningioma is the most common primary intracranial neoplasm. Only 1%-3% of meningiomas are malignant according to the 2016 WHO criteria (WHO grade III). High-grade meningiomas present specific gene expression signatures indicating aggressive growth or recurrence. However, changes in gene expression and in neuroinflammatory gene expression signatures in WHO grade III meningiomas and during progression from WHO grade I or II to grade III are unknown.

METHODS

The authors used a NanoString targeted gene expression panel with focus on 787 genes relevant in meningioma pathology and neuroinflammatory pathways to investigate patients with grade III meningiomas treated at Rigshospitalet from 2000 to 2020 (n = 51). A temporal dimension was added to the investigation by including samples from patients' earlier grade I and II meningiomas and grade III recurrences (n = 139 meningiomas). The authors investigated changes in neuroinflammatory gene expression signatures in 1) grade I meningiomas that later transformed into grade III meningiomas, and 2) grade III meningiomas compared with nonrecurrent grade I meningiomas.

RESULTS

The authors' data indicate that FOXM1, TOP2A, BIRC5, and MYBL2 were enriched and the HOTAIR regulatory pathway was enriched in grade III meningiomas compared with nonrecurrent grade I meningiomas. They discovered a separation of malignant and benign meningiomas based only on genes involved in microglia regulation with enrichment of P2RY12 in grade I compared with grade III meningiomas. Interestingly, FOXM1 was upregulated in premalignant grade I meningioma years before the grade III transformation.

CONCLUSIONS

The authors found gene expression changes in low-grade meningiomas that predated histological transformation to grade III meningiomas. Neuroinflammation genes distinguished grade III from grade I meningiomas.

MAC-spinal meningioma score: A proposal for a quick-to-use scoring sheet of the MIB-1 index in sporadic spinal meningiomas

Objective

MIB-1 index is an important predictor of meningioma progression. However, MIB-1 index is not available in the preoperative tailored medical decision-making process. A preoperative scoring sheet independently estimating MIB-1 indices in spinal meningioma (SM) patients has not been investigated so far.

Methods

Between 2000 and 2020, 128 patients with clinical data, tumor imaging data, inflammatory laboratory (plasma fibrinogen, serum C-reactive protein) data, and neuropathological reports (MIB-1, mitotic count, CD68 staining) underwent surgery for spinal WHO grade 1 and 2 meningioma.

Results

An optimal MIB-1 index cut-off value (≥5/<5) predicting recurrence was calculated by ROC curve analysis (AUC: 0.83; 95%CI: 0.71-0.96). An increased MIB-1 index (≥5%) was observed in 55 patients (43.0%) and multivariable analysis revealed significant associations with baseline Modified McCormick Scale ≥2, age ≥65, and absence of calcification. A four-point scoring sheet (MAC-Spinal Meningioma) based on Modified McCormick, Age, and Calcification facilitates prediction of the MIB-1 index (sensitivity 71.1%, specificity 60.0%). Among those patients with a preoperative MAC-Meningioma Score ≥3, the probability of a MIB-1 index ≥5% was 81.3%.

Conclusion

This novel score (MAC-Spinal Meningioma) supports the preoperative estimation of an increased MIB-1 index, which might support preoperative patient-surgeon consultation, surgical decision making and enable a tailored follow-up schedule or an individual watch-and-wait strategy.

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

Objectives

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

Methods

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

Results

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

Conclusions

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

Supplementary Information

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

Somatostatin analogues in treatment-refractory meningioma: a systematic review with meta-analysis of individual patient data

Treatment-refractory meningiomas have a dismal prognosis and limited treatment options. Meningiomas express high-densities of somatostatin receptors (SSTR), thus potentially susceptible to antitumorigenic effects of somatostatin analogues (SSA). Evidence for SSA in meningiomas is scarce, and it is unclear if published literature would either (1) support wider use of SSA, if (2) more evidence is desirable, or if (3) available evidence is sufficient to discard SSA. We addressed the need for more evidence with a systematic review and meta-analysis. We performed an individual patient data (IPD) meta-analysis. Main outcomes were toxicity, best radiological response, progression-free survival, and overall survival. We applied multivariable logistic regression models to estimate the effect of SSA on the probability of obtaining radiological disease control. The predictive performance was evaluated using area under the curve and Brier scores. We included 16 studies and compiled IPD from 8/9 of all previous cohorts. Quality of evidence was overall ranked "very low." Stable disease was reported in 58% of patients as best radiological response. Per 100 mg increase in total SSA dosage, the odds ratios for obtaining radiological disease control was 1.42 (1.11 to 1.81, P = 0.005) and 1.44 (1.00 to 2.08, P = 0.05) for patients treated with SSA as monodrug therapy vs SSA in combination with everolimus, respectively. Low quality of evidence impeded exact quantification of treatment efficacy, and the association between response and treatment may represent reverse causality. Yet, the SSA treatment was well tolerated, and beneficial effect cannot be disqualified. A prospective trial without bias from inconsistent study designs is warranted to assess SSA therapy for well-defined meningioma subgroups.

Increased MIB-1 Labeling Index Is Associated with Abducens Nerve Morbidity in Primary Sporadic Petroclival Meningioma Surgery: Beyond Location and Approach

Abducens nerve palsy is a severe dysfunction after petroclival meningioma (PC MNG) surgery. The objective of this investigation was to analyze abducens nerve outcomes in patients who underwent the retrosigmoid approach in relation to the MIB-1 index. Thirty-two patients with primary sporadic PC MNG were retrospectively analyzed. Mean follow-up was 28.0 months. Analysis of the MIB-1 index was performed to evaluate the abducens nerve outcome. An optimal MIB-1 index cut-off value (<4/≥4) in the association with postoperative CN VI palsy was determined by ROC analysis (AUC: 0.74, 95% CI: 0.57−0.92). A new-onset CN VI palsy was present in 7 cases (21.88%) and was significantly associated with an increased MIB-1 index (≥4%, p = 0.025) and a peritumoral edema in the brachium pontis (p = 0.047) which might be caused by the increased growth rate. Tumor volume, cavernous sinus infiltration, auditory canal invasion, and Simpson grading were not associated with new CN VI deficits. Six (85.7%) of the 7 patients with both an increased MIB-1 index (≥4%) and new abducens nerve palsy still had a CN VI deficit at the 12-month follow-up. A peritumoral edema caused by a highly proliferative PC MNG with an elevated MIB-1 index (≥4%) is associated with postoperative abducens nerve deficits.

Clinical significance of NF2 alteration in grade I meningiomas revisited; prognostic impact integrated with extent of resection, tumour location, and Ki-67 index

NF2 alteration is the most commonly-found genetic abnormality in meningiomas and is known to initiate events for aggressive-type meningiomas. Whereas the prognosis of meningiomas differs depending on their epigenomic/transcriptomic profile, the effect of NF2 alteration on the prognosis of benign meningiomas is not fully elucidated. This study aimed to probe the importance of NF2 alteration in prognosis of WHO grade I meningiomas. A long-term retrospective follow-up (5.3 ± 4.5 years) study involving 281 consecutive WHO grade I meningioma patients was performed. We assessed tumour recurrence in correlation with extent of resection (EOR), histopathological findings, tumour location, and NF2 alteration. "NF2 meningioma" was defined as meningiomas with presence of NF2 mutation and/or 22q loss. Overall, NF2 meningioma per se was not a predictor of prognosis in the whole cohort; however, it was a predictor of recurrence in supratentorial meningiomas, together with EOR and Ki-67. In a striking contrast, NF2 meningioma showed a better prognosis than non-NF2 meningioma in infratentorial lesion. Supratentorial NF2 meningiomas had higher Ki-67 and forkhead box protein M1 expression than those of others, possibly explaining the worse prognosis in this subtype. The combination of NF2 alteration, high Ki-67 and supratentorial location defines subgroup with the worst prognosis among WHO grade I meningiomas. Clinical connotation of NF2 alteration in terms of prognosis of WHO grade I meningioma differs in an opposite way between supratentorial and infratentorial tumors. Integrated anatomical, histopathological, and genomic classifications will provide the best follow-up schedule and proactive measures.

Adjuvant radiotherapy and stereotactic radiosurgery in grade 3 meningiomas - a systematic review and meta-analysis

Malignant meningioma is a rare, aggressive form of meningioma. Radiation is commonly included in treatment guidelines either as adjuvant radiotherapy (RT) or stereotactic radiosurgery (SRS). Nevertheless, the treatment recommendations are not supported by prospective comparative trials and systematical, critical evaluation of supportive evidence is lacking. For this systematic review, studies analyzing the effectiveness of adjuvant RT and SRS in grade 3 (gr. 3) meningioma were reviewed. Thirty studies met the inclusion criteria for qualitative synthesis, and 6 studies were assessed in quantitative analysis. In quantitative analysis, the weighted average of hazard ratios for adjuvant RT in univariate analyses of overall survival (OS) was 0.55 (CI: 0.41; 0.69). The median 5-year OS after adjuvant RT in gr. 3 meningiomas was 56.3%, and the median OS ranged from 24 to 80 months for patients treated with adjuvant RT versus 13 to 41.2 months in patients not treated. For SRS, the 3-year progression free survival was 0% in one study and 57% in another. The 2-year OS ranged from 25 to 75% in 2 studies. The quality of evidence was rated as "very low" in 14 studies analyzed, and considerable allocation bias was detected. Treatment toxicity was reported in 47% of the studies. The severity, according to the CTCAE, ranged from grades I-V and 5.3 to 100% of patients experienced complications. Adjuvant RT is usually considered standard of care for WHO grade 3 meningiomas, although supporting evidence was of low quality. Better evidence from registries and prospective trials can improve the evidence base for adjuvant fractionated RT in malignant meningiomas.

Regrowth factors of WHO grade I skull base meningiomas following incomplete resection

OBJECTIVE

The role of adjuvant radiation therapy following incomplete resection of WHO grade I skull base meningiomas (SBMs) is controversial, and little is known regarding the behavior of residual tumors. The authors investigated the factors that influence regrowth of residual WHO grade I SBMs following incomplete resection.

METHODS

From 2005 to 2019, a total of 710 patients underwent surgery for newly diagnosed WHO grade I SBMs. The data of 115 patients (16.2%) with incomplete resection and without any adjuvant radiotherapy were retrospectively assessed during a mean follow-up of 78 months (range 27-198 months). Pre-, intra-, and postoperative clinical and molecular factors were analyzed for relevance to regrowth-free survival (RFS).

RESULTS

Eighty patients were eligible for analysis, excluding those who were lost to follow-up (n = 10) or had adjuvant radiotherapy (n = 25). Regrowth occurred in 39 patients (48.7%), with a mean RFS of 50 months (range 3-191 months). Significant predictors of regrowth were Ki-67 proliferative index (PI) ≥ 4% (p = 0.017), Simpson resection grades IV and V (p = 0.005), and invasion of the cavernous sinus (p = 0.027) and Meckel's cave (p = 0.027). After Cox regression analysis, only Ki-67 PI ≥ 4% (hazard ratio [HR] 9.39, p = 0.003) and Simpson grades IV and V (HR 8.65, p = 0.001) showed significant deterioration of RFS. When stratified into 4 scoring groups, the mean RFSs were 110, 70, 38, and 9 months for scores 1 (Ki-67 PI < 4% and Simpson grade III), 2 (Ki-67 PI < 4% and Simpson grades IV and V), 3 (Ki-67 PI ≥ 4% and Simpson grade III), and 4 (Ki-67 PI ≥ 4% and Simpson grades IV and V), respectively. RFS was significantly longer for score 1 versus scores 2-4 (p < 0.01). Tumor consistency, histology, location, peritumoral edema, vascular encasement, and telomerase reverse transcriptase promoter mutation had no impact on regrowth.

CONCLUSIONS

Ki-67 PI and Simpson resection grade showed significant associations with RFS for WHO grade I SBMs following incomplete resection. Ki-67 PI and Simpson resection grade could be utilized to stratify the level of risk for regrowth.

The Simpson Grading: Is It Still Valid?

The Simpson Grade was introduced in the era of limited resources, outdated techniques, and rudimentary surgical and imaging technologies. With the advent of modern techniques including pre- and post-operative imaging, microsurgical and endoscopic techniques, advanced histopathology and molecular analysis and adjuvant radiotherapy, the utility of the Simpson Grade scale for prognostication of recurrence after meningioma resection has become less useful. While the extent of resection remains an important factor in reducing recurrence, a subjective naked-eye criteria to Grade extent of resection cannot be generalized to all meningiomas regardless of their location or biology. Achieving the highest Simpson Grade resection should not always be the goal of surgery. It is prudent to take advantage of all the tools in the neurosurgeons’ armamentarium to aim for maximal safe resection of meningiomas. The primary goal of this study was to review the literature highlighting the Simpson Grade and its association with recurrence in modern meningioma practice. A PubMed search was conducted using terms “Simpson”, “Grade”, “meningioma”, “recurrence”, “gross total resection”, “extent of resection” “human”. A separate search using the terms “intraoperative imaging”, “intraoperative MRI” and “meningioma” were conducted. All studies reporting prognostic value of Simpson Grades were retrospective in nature. Simpson Grade I, II and III can be defined as gross total resection and were associated with lower recurrence compared to Simpson Grade IV or subtotal resection. The volume of residual tumor, a factor not considered in the Simpson Grade, is also a useful predictor of recurrence. Subtotal resection followed by stereotactic radiosurgery has similar recurrence-free survival as gross total resection. In current modern meningioma surgery, the Simpson Grade is no longer relevant and should be replaced with a grading scale that relies on post-operative MRI imaging that assess GTR versus STR and then divides STR into > or <4−5 cm3, in combination with modern molecular-based techniques for recurrence risk stratification.

Inflammatory Tumor Microenvironment in Cranial Meningiomas: Clinical Implications and Intraindividual Reproducibility

The MIB-1 index was demonstrated to be significantly correlated to meningioma recurrence. However, to date, the relationship of the intraindividual course of the MIB-1 index and the growth fraction, respectively, to clinical tumor recurrence has not been demonstrated in cranial WHO grade 1 and 2 meningiomas. In the present paper, we compare the MIB-1 indices of 16 solely surgically treated primary meningiomas and their recurrent tumors regarding the course of the MIB-1 indices, time to recurrence, reproducibility and factors influencing the intraindividual MIB-1 indices. Regression analyses revealed (1) a strong intra-lab reproducibility (r = 0.88) of the MIB-1 index at the second versus the first operation, corresponding to a constant intrinsic growth activity of an individual meningioma, (2) a significant inverse correlation of both primary (r = −0.51) and secondary (r = −0.70) MIB-1 indices to time to recurrence, and (3) male sex, low plasma fibrinogen and diffuse CD68⁺ macrophage infiltrates contribute to an increase in the MIB-1 index. A strong intraindividual reproducibility of the MIB-1 index and a direct relationship of the MIB-1 index to the time to recurrence were observed. Individual MIB-1 indices might be used for tailored follow-up imaging intervals. Further research on the role of macrophages and inflammatory burden in the regrowth potential of meningiomas are needed.

Risk Stratification to Define the Role of Radiotherapy for Benign and Atypical Meningioma: A Recursive Partitioning Analysis

BACKGROUND

The role of adjuvant radiotherapy (RT) for benign or atypical meningioma is controversial.

OBJECTIVE

To identify prognostic factors and a subgroup that could be potentially indicated for adjuvant RT.

METHODS

A total of 336 patients with benign and 157 patients with atypical meningioma underwent surgical resection between January 2015 and December 2019. We retrospectively analyzed 407 patients who did not receive adjuvant RT to stratify risk groups for recurrence. A recursive partitioning analysis (RPA) with the prognostic factors for their failure-free survival (FFS) divided the patients into risk groups.

RESULTS

The 3-year FFS with surgical resection only was 76.5%. Identified prognostic factors for FFS were skull base location, tumor size, brain invasion, a Ki-67 proliferation index of ≥5%, and subtotal resection. The RPA-classified patients were divided into 4 risk groups: very low, low, intermediate, and high, and their 3-year FFS were 98.9%, 78.5%, 59.8%, and 34.2%, respectively. Intermediate-risk and high-risk groups comprise the patients with meningioma of sizes ≥2 cm after subtotal resection or meningioma of sizes >3 cm, located in the skull base or with brain invasion, respectively. After combining with patients treated with adjuvant RT, no FFS benefit was found in the very low-risk and low-risk groups after adjuvant RT, whereas significantly improved FFS was found in the intermediate-risk and high-risk groups (P < .05).

CONCLUSION

The RPA classification revealed a subgroup of patients who could be potentially indicated for adjuvant RT even after gross total resection or for whom adjuvant RT could be deferred.

Proliferative Potential, and Inflammatory Tumor Microenvironment in Meningioma Correlate with Neurological Function at Presentation and Anatomical Location-From Convexity to Skull Base and Spine

Simple Summary

The World Health Organization (WHO) classification grades meningiomas exclusively due to their histopathological features. Meningiomas are predominantly benign intracranial entities, and surgical resection represents the therapy of choice. However, risk of progression and tailored scheduling of follow-up appointments are significantly influenced by various items, such as immunohistochemistry (e.g., MIB-1 index). Emerging evidence focuses attention on the anatomic location of meningiomas, especially regarding the differentiation between skull base and non-skull base meningiomas. In the present study, we therefore investigated demographic, histopathological, and laboratory variables regarding their association with the anatomic location. We found that spinal meningiomas have a significantly lower proliferative activity, less density of macrophage infiltrates, and a longer time to tumor progression. Moreover, increased MIB-1 indices are significantly associated with location-specific baseline symptoms (e.g., convexity: seizure burden, medial skull base: decreased vision, spinal: ambulatory ability). Therefore, anatomic location might be considered as a future subclassification in the grading of the prognosis of meningiomas.

Abstract

Emerging evidence emphasizes the prognostic importance of meningioma location. The present investigation evaluates whether progression-free survival (PFS), proliferative potential, World Health Organization (WHO) grades, and inflammatory burden differ between anatomical locations (skull base, non-skull base, and spinal) meningiomas. Five-hundred-forty-one patients underwent Simpson grade I or II resection for WHO grade 1 or 2 meningiomas. Univariable analysis revealed that spinal meningioma patients are significantly older, had a worse baseline Karnofsky Performance Status (KPS), higher acute-phase protein levels, lower incidence of WHO grade 2, lower mitotic counts, lower MIB-1 index, and less CD68⁺ macrophage infiltrates. Multivariable analysis identified WHO grade 2 (OR: 2.1, 95% CI: 1.1–3.7, p = 0.02) and cranial location (OR: 3.0, 95% CI: 1.8–4.9, p = 0.001) as independent predictors of diffuse CD68⁺ macrophage infiltrates. The mean PFS in cranial meningiomas was 115.9 months (95% CI: 107.5–124.3), compared to 162.2 months (95% CI: 150.5–174.0; log-rank test: p = 0.02) in spinal meningiomas. Multivariable Cox regression analysis revealed cranial location as an independent predictor (HR: 4.7, 95% CI: 1.0–21.3, p = 0.04) of shortened PFS. Increased MIB-1 indices ≥5% were significantly associated with location-specific deficits at presentation, such as decreased vision and seizure burden. Spinal meningiomas have a significantly longer PFS time and differ from the cranial meningiomas regarding MIB-1 index and density of tumor-associated macrophages.

Proposal of a new grading system for meningioma resection: the Copenhagen Protocol

INTRODUCTION

The extent of meningioma resection is the most fundamental risk factor for recurrence, and exact knowledge of extent of resection is necessary for prognostication and for planning of adjuvant treatment. Currently used classifications are the EANO-grading and the Simpson grading. The former comprises radiological imaging with contrast-enhanced MRI and differentiation between "gross total removal" and "subtotal removal," while the latter comprises a five-tiered differentiation of the surgeon's impression of the extent of resection. The extent of resection of tumors is usually defined via analyses of resection margins but has until now not been implemented for meningiomas. PET/MRI imaging with ⁶⁸Ga-DOTATOC allows more sensitive and specific imaging than MRI following surgery of meningiomas.

OBJECTIVE

To develop an objective grading system based on microscopic analyses of resection margins and sensitive radiological analyses to improve management of follow-up, adjuvant therapy, and prognostication of meningiomas. Based on the rationale of resection-margin analyses as gold standard and superior imaging performance of ⁶⁸Ga DOTATOC PET, we propose "Copenhagen Grading" for meningiomas.

RESULTS

Copenhagen Grading was described for six pilot patients with examples of positive and negative findings on histopathology and DOTATOC PET scanning. The grading could be traceably implemented and parameters of grading appeared complementary. Copenhagen Grading is prospectively implemented as a clinical standard at Rigshospitalet, Copenhagen.

CONCLUSION

Copenhagen Grading provided a comprehensive, logical, and reproducible definition of the extent of resection. It offers promise to be the most sensitive and specific imaging modality available for meningiomas. Clinical and cost-efficacy remain to be established during prospective implementation.

The role of systemic inflammatory cells in meningiomas

The aim of this review is to describe the inflammatory systemic cell infiltrate and its role in pathophysiology and prognostic implications of meningiomas. Articles from PubMed describing inflammation and immune cells in meningioma were systematically selected and reviewed. Infiltrating inflammatory cells are common in meningiomas and correlate with tumor behavior and peritumoral edema. The immune cell infiltrate mainly comprised macrophages, CD4 + T cells of the Th1 and Th2 subtype, CD8 + cytotoxic T cells, mast cells, and to a lesser degree B cells. The polarization of macrophages to M1 or M2 states, as well as the differentiation of T-helper cells to Th1 or Th2 subsets, is of prognostic value, but whether or not the presence of macrophages is associated with the degree of malignancy of the tumor is controversial. The best documented immunosuppressive and tumor-promoting mechanism is the expression of programmed cell death protein 1 (PD-1/PD-1L) which is found on both tumor cells and tumor-infiltrating immune cells. The immune cell infiltration varies between different meningiomas. It contributes to a microenvironment with potential contradictory effects on tumor growth and edema. The immune mechanisms are potential therapeutic targets provided that their effects can be comprehensively understood.

A Clinical Prognostic Model Based on Preoperative Hematological and Clinical Parameters Predicts the Progression of Primary WHO Grade II Meningioma

Purpose

The purpose was to explore the correlation between hematological parameters and the progression of WHO grade II meningioma, and establish a clinical prognostic model based on hematological parameters and clinical prognostic factors to predict the progression-free survival (PFS) of patients.

Methods

A total of 274 patients with WHO grade II meningiomas were included. Patients were randomly divided into a training cohort (192, 70%) and a test cohort (82, 30%). In the training cohort, the least absolute shrinkage and selection operator Cox regression analysis were used to screen for hematological parameters with prognostic value, and the hematological risk model (HRM) was constructed based on these parameters; univariate and multivariate Cox regression analyses were utilized to screen for clinical prognostic factors, and a clinical prognostic model was constructed based on clinical prognostic factors and HRM. The prognostic stability and accuracy of the HRM and clinical prognostic model were verified in the test cohort. Subgroup analysis was performed according to the patients' different clinical characteristics.

Results

Preoperative neutrophil-to-lymphocyte ratio, lymphocyte-to-monocyte ratio, platelet-to-lymphocyte ratio, albumin-to-globulin ratio, D-dimer, fibrinogen, and lactate dehydrogenase were associated with the PFS of patients. The areas under curve of the HRM were 0.773 (95% confidence interval [CI] 0.707-0.839) and 0.745 (95% CI 0.637-0.852) in the training cohort and test cohort, respectively. The progression risk was higher in the high-risk group than that in the low-risk group categorized by the optimal cutoff value (2.05) of hematological risk scores. The HRM, age, tumor location, tumor size, peritumoral edema, extent of resection, Ki-67 index, and postoperative radiotherapy were the prognostic factors for the progression of meningiomas. The corrected C-index of the clinical prognosis model was 0.79 in the training cohort. Clinical decision analysis showed that the clinical prognostic model could be used to obtain favorable clinical benefits. In the subgroup analysis, the HRM displayed excellent prognostic stability and general applicability in different subgroups.

Conclusions

Preoperative hematological parameters are associated with the postoperative progression of WHO grade II meningiomas. The clinical prognosis model constructed based on hematological parameters and clinical prognostic factors has favorable predictive accuracy and clinical benefits.

Machine Learning Using Multiparametric Magnetic Resonance Imaging Radiomic Feature Analysis to Predict Ki-67 in World Health Organization Grade I Meningiomas

BACKGROUND

Although World Health Organization (WHO) grade I meningiomas are considered "benign" tumors, an elevated Ki-67 is one crucial factor that has been shown to influence tumor behavior and clinical outcomes. The ability to preoperatively discern Ki-67 would confer the ability to guide surgical strategy.

OBJECTIVE

In this study, we develop a machine learning (ML) algorithm using radiomic feature analysis to predict Ki-67 in WHO grade I meningiomas.

METHODS

A retrospective analysis was performed for a cohort of 306 patients who underwent surgical resection of WHO grade I meningiomas. Preoperative magnetic resonance imaging was used to perform radiomic feature extraction followed by ML modeling using least absolute shrinkage and selection operator wrapped with support vector machine through nested cross-validation on a discovery cohort (n = 230), to stratify tumors based on Ki-67 <5% and ≥5%. The final model was independently tested on a replication cohort (n = 76).

RESULTS

An area under the receiver operating curve (AUC) of 0.84 (95% CI: 0.78-0.90) with a sensitivity of 84.1% and specificity of 73.3% was achieved in the discovery cohort. When this model was applied to the replication cohort, a similar high performance was achieved, with an AUC of 0.83 (95% CI: 0.73-0.94), sensitivity and specificity of 82.6% and 85.5%, respectively. The model demonstrated similar efficacy when applied to skull base and nonskull base tumors.

CONCLUSION

Our proposed radiomic feature analysis can be used to stratify WHO grade I meningiomas based on Ki-67 with excellent accuracy and can be applied to skull base and nonskull base tumors with similar performance achieved.

Clinical Outcomes Following Re-Operations for Intracranial Meningioma

Simple Summary

This study investigated patients who underwent more than one operation for a meningioma, a type of brain tumor. Currently, there is little evidence available for this specific patient group. The purpose of this study was to determine if patients had an improvement or deterioration following a second operation for a recurrent meningioma, and to identify any factors that may influence this change. The results demonstrated that following a second operation for meningioma, patients have poorer outcomes. The findings of this study provide supporting information for surgeons and patients, thereby informing decisions related to patient care and re-operation.

Abstract

The outcomes following re-operation for meningioma are poorly described. The aim of this study was to identify risk factors for a performance status outcome following a second operation for a recurrent meningioma. A retrospective, comparative cohort study was conducted. The primary outcome measure was World Health Organization performance. Secondary outcomes were complications, and overall and progression free survival (OS and PFS respectively). Baseline clinical characteristics, tumor details, and operation details were collected. Multivariable binary logistic regression was used to identify risk factors for performance status outcome following a second operation. Between 1988 and 2018, 712 patients had surgery for intracranial meningiomas, 56 (7.9%) of which underwent a second operation for recurrence. Fifteen patients (26.8%) had worsened performance status after the second operation compared to three (5.4%) after the primary procedure (p = 0.002). An increased number of post-operative complications following the second operation was associated with a poorer performance status following that procedure (odds ratio 2.2 [95% CI 1.1–4.6]). The second operation complication rates were higher than after the first surgery (46.4%, n = 26 versus 32.1%, n = 18, p = 0.069). The median OS was 312.0 months (95% CI 257.8–366.2). The median PFS following the first operation was 35.0 months (95% CI 28.9–41.1). Following the second operation, the median PFS was 68.0 months (95% CI 49.1–86.9). The patients undergoing a second operation for meningioma had higher rates of post-operative complications, which is associated with poorer clinical outcomes. The decisions surrounding second operations must be balanced against the surgical risks and should take patient goals into consideration.

FORGE: A Novel Scoring System to Predict the MIB-1 Labeling Index in Intracranial Meningiomas

Simple Summary

Meningiomas are predominantly benign intracranial tumors, and surgical therapy represents the treatment of choice. However, the risk of recurrence and scheduling of follow-up intervals are significantly influenced by immunohistochemical items such as the MIB-1 labeling index. To date, it is not possible to integrate this essential information into the pre- or intraoperative surgical decision making. In the present study, we therefore analyzed baseline variables associated with the MIB-1 labeling index. We found four easily identifiable and routinely recorded risk factors for an increased MIB-1 index and developed a simple and quick-to-use score that allows us to estimate the risk of an elevated MIB-1 index prior to the surgical resection. Furthermore, this score seems to predict the progression-free survival in intracranial meningiomas. We believe that this score might us to more reliably guide patients in preoperative surgical strategy planning and postoperative follow-up scheduling.

Abstract

The MIB-1 index is an essential predictor of progression-free-survival (PFS) in meningioma. To date, the MIB-1 index is not available in preoperative treatment planning. A preoperative score estimating the MIB-1 index in patients with intracranial meningiomas has not been investigated so far. Between 2013 and 2019, 208 patients with tumor morphology data, MIB-1 index data, and plasma fibrinogen and serum C-reactive protein (CRP) data underwent surgery for intracranial WHO grade I and II meningioma. An optimal MIB-1 index cut-off value (≥6/<6) in the prediction of recurrence was determined by ROC curve analysis (AUC: 0.71; 95% CI: 0.55–0.87). A high MIB-1 index (≥6%) was present in 50 cases (24.0%) and was significantly associated with male sex, peritumoral edema, low baseline CRP, and low fibrinogen level in the multivariate analysis. A scoring system (“FORGE”) based on sex, peritumoral edema, preoperative CRP value, and plasma fibrinogen level supports prediction of the MIB-1 index (sensitivity 62%, specificity 79%). The MIB-1 labeling index and the FORGE score are significantly associated with an increased risk of poor PFS time. We suggest a novel score (“FORGE”) to preoperatively estimate the risk of an increased MIB-1 index (≥6%), which might help in surgical decision making and follow-up interval determination and inform future trials investigating inflammatory burden and proliferative activity.

Long-Term Follow-Up and Predictors of Functional Outcome after Surgery for Spinal Meningiomas: A Population-Based Cohort Study

Simple Summary

Spinal meningiomas are the most common adult primary intradural spinal tumors. While mostly benign, they may give rise to spinal cord compression with acute or chronic neurologic dysfunction. The primary treatment is surgical resection. Previous studies, limited by small sample sizes and short follow-up times, report that histopathological grade, tumor localization and size affect outcomes following surgery. In this population-based cohort study, we retrospectively reviewed 129 cases of surgically treated spinal meningiomas to assess postoperative complications, long-term clinical and radiological outcomes, predictors of neurological improvement and potential differences between elderly and non-elderly patients. Our median follow-up time was 8.2 years. We found that surgery was associated with significant neurological improvement. There was no significant difference in postoperative complications, tumor control or neurological improvement between elderly and non-elderly. Shorter time from diagnosis to surgery, larger tumor size and spinal cord compression predicted postoperative outcomes.

Abstract

Spinal meningiomas are the most common adult primary spinal tumor, constituting 24–45% of spinal intradural tumors and 2% of all meningiomas. The aim of this study was to assess postoperative complications, long-term outcomes, predictors of functional improvement and differences between elderly (≥70 years) and non-elderly (18–69 years) patients surgically treated for spinal meningiomas. Variables were retrospectively collected from patient charts and magnetic resonance images. Baseline comparisons, paired testing and regression analyses were used. In conclusion, 129 patients were included, with a median follow-up time of 8.2 years. Motor deficit was the most common presenting symptom (66%). The median time between diagnosis and surgery was 1.3 months. A postoperative complication occurred in 10 (7.8%) and tumor growth or recurrence in 6 (4.7%) patients. Surgery was associated with significant improvement of motor and sensory deficit, gait disturbance, bladder dysfunction and pain. Time to surgery, tumor area and the degree of spinal cord compression significantly predicted postoperative improvement in a modified McCormick scale (mMCs) in the univariable regression analysis, and spinal cord compression showed independent risk association in multivariable analysis. There was no difference in improvement, complications or tumor control between elderly and non-elderly patients. We concluded that surgery of spinal meningiomas was associated with significant long-term neurological improvement, which could be predicted by time to surgery, tumor size and spinal cord compression.

Somatostatin Receptor-Targeted Radiopeptide Therapy in Treatment-Refractory Meningioma: Individual Patient Data Meta-analysis

Somatostatin receptor (SSTR)-targeted peptide receptor radionuclide therapy (PRRT) represents a promising approach for treatment-refractory meningiomas. Methods: We performed an individual patient data meta-analysis, including all published data on meningioma patients treated with SSTR-targeted PRRT. The main outcomes were toxicity, response to treatment, progression-free survival (PFS), and overall survival (OS). We applied the Kaplan-Meier method to estimate survival probabilities and report incidence rates per 100 person-years. We applied Cox proportional hazards models to determine the effect of covariates. Results: We screened 537 papers and identified 6 eligible cohort studies. We included a total of 111 patients who had treatment-refractory meningioma and received SSTR-targeted PRRT. Disease control was achieved in 63% of patients. The 6-mo PFS rates were 94%, 48%, and 0% for World Health Organization grades I, II, and III, respectively. The risk of disease progression decreased by 13% per 1,000-MBq increase in the total applied activity. The 1-y OS rates were 88%, 71%, and 52% for World Health Organization grades I, II, and III, respectively. The risk of death decreased by 17% per 1,000-MBq increase in the total applied activity. The main side effects comprised transient hematotoxicity, such as anemia in 22% of patients, leukopenia in 13%, lymphocytopenia in 24%, and thrombocytopenia in 17%. Conclusion: To our knowledge, this individual patient data meta-analysis represents the most comprehensive analysis of the benefits of and adverse events associated with SSTR-targeted PRRT for treatment-refractory meningioma. The treatment was well tolerated, achieved disease control in most cases, and showed promising results regarding PFS and OS.

J, Eriksson F, Ugleholdt H, Broholm H, Mathiesen T. Mitotic and Proliferative Indices in WHO Grade III Meningioma

Simple Summary

Malignant meningiomas are rare primary intracranial tumors associated with considerable morbidity and mortality. The diagnosis is based on the number of mitotic figures (mitotic index, MI). Consequently, the quantification of mitotic figures is prone to inter- and intraobserver variability. The mitotic marker, phosphohistone-H3 (PHH3), has been shown to be a more robust mitotic marker. Despite the prognostic value of MI across all meningioma grades, little is known of the prognostic value of the MI within malignant meningioma. Therefore, this study investigates the MI in a series of malignant meningiomas to analyze the association to progression-free survival and mitotic and proliferative indices. Furthermore, we investigated the precision (repeatability) of mitotic counts and the agreement between MI and PHH3 MI.

Abstract

Meningiomas with inherently high mitotic indices and poor prognosis, such as WHO grade III meningiomas, have not been investigated separately to establish interchangeability between conventional mitotic index counted on H&E stained slides (MI) and mitotic index counted on phosphohistone-H3 stained slides (PHH3 MI). This study investigates the agreement of MI and PHH3 MI and to analyze the association of progression-free survival (PFS) and MI, PHH3 MI, and the proliferative index (PI, Ki-67) in WHO grade III meningioma. Tumor specimens from 24 consecutive patients were analyzed for expression of Ki-67, PHH3 MI, and MI. Quantification was performed independently by two observers who made replicate counts in hot spots and overall tumor staining. Repeatability in replicate counts from MI and PHH3 MI was low in both observers. Consequently, we could not report the agreement. MI, PHH3 MI and hot spot counts of Ki-67 were associated with PFS (MI hot spot HR = 1.61, 95% CI 1.12–2.31, p = 0.010; PHH3 MI hot spot HR = 1.59, 95% CI 1.15–2.21, p = 0.006; Ki-67 hot spot HR = 1.06, 95% CI 1.02–1.11. p = 0.004). We found markedly low repeatability of manually counted MI and PHH3 MI in WHO grade III meningioma, and we could not conclude that the two methods agreed. Subsequently, quantification with better repeatability should be sought. All three biomarkers were associated with PFS.

TERT promoter mutations in primary and secondary WHO grade III meningioma

Purpose:TERT promoter mutation (TERTp^Mut) has a strong association to recurrence and has been suggested to act as a driver mutation for malignant transformation of WHO grade I and II meningiomas. TERTp^Mut has been investigated in selected high‐grade meningioma samples. The existence of TERTp^Mut across recurrent tumors in a population‐based cohort needs to be investigated in order to identify when TERTp^Mut emerges across recurrent samples and to validate prognostic impact among WHO grade III tumors. Methods: We gathered material from a consecutive single‐center cohort of 40 patients with malignant meningioma (WHO grade III) treated between 2000 and 2018, including specimens from primary and secondary malignant meningiomas with the corresponding earlier benign specimens and later malignant recurrences. In total 107 tumor samples were studied by Sanger sequencing for TERT promoter mutational status. Results: Seven of 40 patients (17.5%) harbored TERTp^Mut thus validating the incidence of TERTp^Mut in previous non‐population‐based cohorts. In 6/7 patients, the TERTp^Mut was present at initial surgery (WHO grade I–III) while in one patient the TERTp^Mut was found de novo when the meningioma became malignant. The incidences were 2/1.000.000/year for TERTp^Mut WHO grade III meningioma and 8/1.000.000/year for TERTp^wt WHO grade III meningioma in our catchment area. We found a 1.7 times higher recurrence rate (CI 95% 0.65–4.44) and a 2.5 higher mortality rate per 10 person‐years (CI 95% 1.01–6.19) for TERTp^Mut compared to TERTp^wt. Conclusion:TERTp^Mut can occur independently of malignant progression in meningioma and was most often present from the first tumor sample across recurring tumors. TERTp^Mut in WHO grade III may represent a marker of an aggressive subset of tumors.