Radical surgical resection with molecular margins is associated with improved survival in IDH wildtype GBM

BACKGROUND

Survival is variable in patients with glioblastoma IDH wild-type (GBM), even after comparable surgical resection of radiographically-detectable disease, highlighting the limitations of radiographic assessment of infiltrative tumor anatomy. The majority of post-surgical progressive events are failures within 2cm of the resection margin, motivating supramaximal resection strategies to improve local control. However, which patients benefit from such radical resections remains unknown.

METHODS

We developed a predictive model to identify which IDH wild-type GBM are amenable to radiographic gross total resection (GTR). We then investigated whether GBM survival heterogeneity following GTR is correlated with microscopic tumor burden a by analyzing tumor cell content at the surgical margin with a rapid qPCR-based method for detection of TERT promoter mutation.

RESULTS

Our predictive model for achievable GTR, developed on retrospective radiographic and molecular data of GBM patients undergoing resection, had an AUC of 0.83, sensitivity of 62%, and specificity of 90%. Prospective analysis of this model in 44 patients found 89% of patients were correctly predicted to achieve a RV<4.9cc. Of the 44 prospective patients undergoing rapid qPCR TERT promoter mutation analysis at the surgical margin, 7 had undetectable TERT mutation, of which 5 also had a gross total resection (RV<1cc). In these 5 patients at 30 months follow up, 75% showed no progression, compared to 0% in the group with TERT mutations detected at the surgical margin (p=0.02).

CONCLUSIONS

These findings identify a subset of patients with GBM that may derive local control benefit from radical resection to undetectable molecular margins.

County-level disparities in care for patients with glioblastoma

OBJECTIVE

Racial and socioeconomic disparities in neuro-oncological care for patients with brain tumors remain underexplored. This study aimed to analyze county-level disparities in glioblastoma (GBM) care in the United States, focusing on access to surgery and the use of adjuvant temozolomide chemotherapy and radiation therapy.

METHODS

Using repeated cross-sectional data from the Surveillance, Epidemiology, and End Results 17 database; the Area Health Resources File; and the American Community Survey, from 2010 to 2019, the authors performed multivariate regression analyses to understand the associations between county-level racial and socioeconomic characteristics, as well as the rates of surgery performed, delays in surgery, and use of adjuvant chemotherapy and radiation therapy for newly diagnosed GBM.

RESULTS

In total, 29,609 GBM patients from 602 different US counties over a decade were included in this study. Counties with lower rates of surgery for GBM were associated with a higher percentage of Black residents (coefficient [CE] -0.001, 95% CI -0.002 to 0; p < 0.05) and being located in the Midwest (CE -0.132, 95% CI -0.195 to -0.069; p < 0.001) or West (CE -0.127, 95% CI -0.189 to -0.065; p < 0.001) relative to the Northeast. Counties with delayed surgical treatment were more likely to lack neurosurgeons (adjusted OR [aOR] 2.52, 95% CI 1.77-3.60; p < 0.001), have a higher percentage of Black residents (aOR 1.011, 95% CI 1.00-1.02; p < 0.05), and be located in the Midwest (aOR 3.042, 95% CI 1.12-8.24; p < 0.05) or West (aOR 3.175, 95% CI 1.12-8.97 p < 0.05). Counties with high rates of adjuvant radiation therapy were less likely to have higher percentages of Black residents (aOR 0.987, 95% CI 0.980-0.995; p < 0.01) and uninsured individuals (aOR 0.962, 95% CI 0.937-0.987; p < 0.01).

CONCLUSIONS

Counties without neurosurgeons and those with a higher percentage of Black patients have delays in surgical care and demonstrate lower overall rates of surgery and adjuvant therapy for GBM. This study underscores the need for targeted interventions and policies that address structural barriers in healthcare access, improve equitable distribution of the neurosurgery workforce, and ensure timely and comprehensive GBM care to all populations.

BRAF-MEK Inhibition in Newly Diagnosed Papillary Craniopharyngiomas

BACKGROUND

Craniopharyngiomas, primary brain tumors of the pituitary-hypothalamic axis, can cause clinically significant sequelae. Treatment with the use of surgery, radiation, or both is often associated with substantial morbidity related to vision loss, neuroendocrine dysfunction, and memory loss. Genotyping has shown that more than 90% of papillary craniopharyngiomas carry BRAF V600E mutations, but data are lacking with regard to the safety and efficacy of BRAF-MEK inhibition in patients with papillary craniopharyngiomas who have not undergone previous radiation therapy.

METHODS

Eligible patients who had papillary craniopharyngiomas that tested positive for BRAF mutations, had not undergone radiation therapy previously, and had measurable disease received the BRAF-MEK inhibitor combination vemurafenib-cobimetinib in 28-day cycles. The primary end point of this single-group, phase 2 study was objective response at 4 months as determined with the use of centrally determined volumetric data.

RESULTS

Of the 16 patients in the study, 15 (94%; 95% confidence interval [CI], 70 to 100) had a durable objective partial response or better to therapy. The median reduction in the volume of the tumor was 91% (range, 68 to 99). The median follow-up was 22 months (95% CI, 19 to 30) and the median number of treatment cycles was 8. Progression-free survival was 87% (95% CI, 57 to 98) at 12 months and 58% (95% CI, 10 to 89) at 24 months. Three patients had disease progression during follow-up after therapy had been discontinued; none have died. The sole patient who did not have a response stopped treatment after 8 days owing to toxic effects. Grade 3 adverse events that were at least possibly related to treatment occurred in 12 patients, including rash in 6 patients. In 2 patients, grade 4 adverse events (hyperglycemia in 1 patient and increased creatine kinase levels in 1 patient) were reported; 3 patients discontinued treatment owing to adverse events.

CONCLUSIONS

In this small, single-group study involving patients with papillary craniopharyngiomas, 15 of 16 patients had a partial response or better to the BRAF-MEK inhibitor combination vemurafenib-cobimetinib. (Funded by the National Cancer Institute and others; ClinicalTrials.gov number, NCT03224767.).

Prospective phase II trial of the dual mTORC1/2 inhibitor vistusertib for progressive or symptomatic meningiomas in persons with neurofibromatosis 2

Background

Meningiomas occur in 80% of persons with neurofibromatosis 2 (NF2) and cause significant mortality and morbidity, yet there are no effective medical treatments. NF2-deficient tumors have constitutive activation of mammalian/mechanistic target of rapamycin (mTOR), and treatment with mTORC1 inhibitors results in growth arrest in a minority of tumors, with paradoxical activation of the mTORC2/AKT pathway. We studied the effect of vistusertib, a dual mTORC1/mTORC2 inhibitor, in NF2 patients with progressive or symptomatic meningiomas.

Methods

Vistusertib was administered orally at 125 mg twice daily for 2 consecutive days each week. The primary endpoint was the imaging response in the target meningioma, defined as a volume decrease of 20% compared with the baseline. Secondary endpoints included toxicity, imaging response of nontarget tumors, quality of life, and genetic biomarkers.

Results

Eighteen participants (13 female), median age of 41 (range, 18-61) years, were enrolled. In target meningiomas, the best response was partial response (PR) in 1/18 tumors (6%) and stable disease (SD) in 17/18 tumors (94%). For all measured intracranial meningiomas and vestibular schwannomas, the best imaging response was PR in 6/59 tumors (10%) and SD in 53 (90%). Treatment-related grade 3/4 adverse events occurred in 14 (78%) participants, and 9 participants discontinued treatment due to side effects.

Conclusions

Although the study did not meet the primary endpoint, vistusertib treatment was associated with high rates of SD in progressive NF2-related tumors. However, this dosing regimen for vistusertib was poorly tolerated. Future studies of dual mTORC inhibitors for NF2 should focus on optimizing tolerability and evaluating the relevance of tumor stability in participants.

Association of Long-term Outcomes With Stereotactic Radiosurgery vs Whole-Brain Radiotherapy for Resected Brain Metastasis: A Secondary Analysis of The N107C/CEC.3 (Alliance for Clinical Trials in Oncology/Canadian Cancer Trials Group) Randomized Clinical Trial

Importance

Long-term outcomes of radiotherapy are important in understanding the risks and benefits of therapies for patients with brain metastases.

Objective

To determine how the use of postoperative whole-brain radiotherapy (WBRT) or stereotactic radiosurgery (SRS) is associated with quality of life (QOL), cognitive function, and intracranial tumor control in long-term survivors with 1 to 4 brain metastases.

Design, Setting, and Participants

This secondary analysis of a randomized phase 3 clinical trial included 48 institutions in the US and Canada. Adult patients with 1 resected brain metastases but limited to those with 1 to 4 brain metastasis were eligible. Unresected metastases were treated with SRS. Long-term survivors were defined as evaluable patients who lived longer than 1 year from randomization. Patients were recruited between July 2011 and December 2015, and data were first analyzed in February 2017. For the present study, intracranial tumor control, cognitive deterioration, QOL, and cognitive outcomes were measured in evaluable patients who were alive at 12 months from randomization and reanalyzed in June 2017.

Interventions

Stereotactic radiosurgery or WBRT.

Main Outcomes and Measures

Intracranial tumor control, toxic effects, cognitive deterioration, and QOL.

Results

Fifty-four patients (27 SRS arm, 27 WBRT arm; female to male ratio, 65% vs 35%) were included for analysis with a median follow-up of 23.8 months. Cognitive deterioration was less frequent with SRS (37%-60%) compared with WBRT (75%-91%) at all time points. More patients declined by 2 or more standard deviations (SDs) in 1 or more cognitive tests for WBRT compared with SRS at 3, 6, and 9 months (70% vs 22%, 46% vs 19%, and 50% vs 20%, respectively). A 2 SD decline in at least 2 cognitive tests was associated with worse 12-month QOL in emotional well-being, functional well-being, general, additional concerns, and total scores. Overall QOL and functional independence favored SRS alone for categorical change at all time points. Total intracranial control for SRS alone vs WBRT at 12 months was 40.7% vs 81.5% (difference, -40.7; 95% CI, -68.1% to -13.4%), respectively. Data were first analyzed in February 2017.

Conclusions and Relevance

The use of SRS alone compared with WBRT resulted in less cognitive deterioration among long-term survivors. The association of late cognitive deterioration with WBRT was clinically meaningful. A significant decline in cognition (2 SD) was associated with overall QOL. However, intracranial tumor control was improved with WBRT. This study provides detailed insight into cognitive function over time in this patient population.

Trial Registration

ClinicalTrials.gov Identifier: NCT01372774; ALLIANCE/CCTG: N107C/CEC.3 (Alliance for Clinical Trials in Oncology/Canadian Cancer Trials Group).

Neurosurgical Study Design: Past and Future

Clinical trials are performed to determine the safety, efficacy, or effectiveness of a medical or surgical intervention. A clinical trial is, by definition, prospective in nature with a uniform treatment of a defined patient cohort. The outcomes assessment should also be uniform. Often a control group is included. At present, the number of neurosurgical clinical trials is increasing, and the study designs have become more sophisticated. Historically, the standard of neurosurgical care has evolved from the findings from many case series and retrospective comparative studies. However, in the present report, we have focused exclusively on prospective clinical trials. An urgent need exists to understand how clinical trials have been performed in the past and how they can be improved to advance our neurosurgical practice. In the present review, we have discussed the barriers, successes, and failures regarding prospective clinical trials in neurosurgery with an outlook to the future.

Phase 2 study of pembrolizumab in patients with recurrent and residual high-grade meningiomas

High-grade meningiomas are associated with neuro-cognitive morbidity and have limited treatments. High-grade meningiomas harbor an immunosuppressive tumor microenvironment (TME) and programmed death-ligand 1 (PD-L1) expression may contribute to their aggressive phenotype. Here, we present the results of a single-arm, open-label phase 2 trial (NCT03279692) evaluating the efficacy of pembrolizumab, a PD-1 inhibitor, in a cohort of 25 evaluable patients with recurrent and progressive grade 2 and 3 meningiomas. The primary endpoint is the proportion of patients alive and progression-free at 6 months (PFS-6). Secondary endpoints include progression-free and overall survival, best intracranial response, and toxicity. Our study has met its primary endpoint and achieved a PFS-6 rate of 0.48 (90% exact CI: 0.31-0.66) and a median PFS of 7.6 months (90% CI: 3.4-12.9 months). Twenty percent of patients have experienced one (or more) grade-3 or higher treatment-related adverse events. These results suggest that pembrolizumab exerts promising efficacy on a subset of these tumors. Further studies are needed to identify the biological facets within the meningioma TME that may drive response to immune-based therapies.

Craniopharyngiomas, including Recurrent Cases, Lack TERT Promoter Hotspot Mutations

Adamantinomatous craniopharyngiomas (ACP) are characterized by alterations in the CTNNB1 gene while almost all papillary craniopharyngiomas (PCP) harbor a canonical V600E mutation in the BRAF gene. Although other recurrent driver genes have not been described to date in craniopharyngiomas, the heterogeneous clinical course of these tumors might be associated with the acquisition of further genomic alterations. It is well known that telomerase reverse transcriptase (TERT) promoter (TERTp) alterations, including mutations or methylation, upregulate the expression of TERT and increase telomerase activity, promoting tumorigenesis. We investigated whether TERTp mutations or methylation are associated with tumor relapse in a subset of craniopharyngiomas. Samples from 42 patients with histologically confirmed craniopharyngioma were retrieved. We determined TERTp, BRAF, and CTNNB1 hotspot mutations in all samples using targeted sequencing and the TERTp methylation status by methylation-specific polymerase chain reaction (PCR) in 30 samples. While BRAF V600E mutations and CTNNB1 mutations were detected in 12 (28.6%) and 21 patients (50%) in the initial tumors and subsequent recurrences, respectively, none of the patients in our cohort, including those with multiple relapses, harbored a TERTp mutation. Furthermore, TERTp methylation was detected in 14 out of 24 cases (58.3%) with available primary samples; however, no correlation between TERTp methylation with the pathological subtype, genotype, or tumor aggressiveness was detected. These data suggest that elevated telomerase activity via acquisition of TERTp mutations is an infrequent pathway in the tumorigenesis of craniopharyngiomas, regardless of their clinical course.

Effect of Ventral vs Dorsal Spinal Surgery on Patient-Reported Physical Functioning in Patients With Cervical Spondylotic Myelopathy: A Randomized Clinical Trial

IMPORTANCE

Cervical spondylotic myelopathy is the most common cause of spinal cord dysfunction worldwide. It remains unknown whether a ventral or dorsal surgical approach provides the best results.

OBJECTIVE

To determine whether a ventral surgical approach compared with a dorsal surgical approach for treatment of cervical spondylotic myelopathy improves patient-reported physical functioning at 1 year.

DESIGN, SETTING, AND PARTICIPANTS

Randomized clinical trial of patients aged 45 to 80 years with multilevel cervical spondylotic myelopathy enrolled at 15 large North American hospitals from April 1, 2014, to March 30, 2018; final follow-up was April 15, 2020.

INTERVENTIONS

Patients were randomized to undergo ventral surgery (n = 63) or dorsal surgery (n = 100). Ventral surgery involved anterior cervical disk removal and instrumented fusion. Dorsal surgery involved laminectomy with instrumented fusion or open-door laminoplasty. Type of dorsal surgery (fusion or laminoplasty) was at surgeon's discretion.

MAIN OUTCOMES AND MEASURES

The primary outcome was 1-year change in the Short Form 36 physical component summary (SF-36 PCS) score (range, 0 [worst] to 100 [best]; minimum clinically important difference = 5). Secondary outcomes included 1-year change in modified Japanese Orthopaedic Association scale score, complications, work status, sagittal vertical axis, health resource utilization, and 1- and 2-year changes in the Neck Disability Index and the EuroQol 5 Dimensions score.

RESULTS

Among 163 patients who were randomized (mean age, 62 years; 80 [49%] women), 155 (95%) completed the trial at 1 year (80% at 2 years). All patients had surgery, but 5 patients did not receive their allocated surgery (ventral: n = 1; dorsal: n = 4). One-year SF-36 PCS mean improvement was not significantly different between ventral surgery (5.9 points) and dorsal surgery (6.2 points) (estimated mean difference, 0.3; 95% CI, -2.6 to 3.1; P = .86). Of 7 prespecified secondary outcomes, 6 showed no significant difference. Rates of complications in the ventral and dorsal surgery groups, respectively, were 48% vs 24% (difference, 24%; 95% CI, 8.7%-38.5%; P = .002) and included dysphagia (41% vs 0%), new neurological deficit (2% vs 9%), reoperations (6% vs 4%), and readmissions within 30 days (0% vs 7%).

CONCLUSIONS AND RELEVANCE

Among patients with cervical spondylotic myelopathy undergoing cervical spinal surgery, a ventral surgical approach did not significantly improve patient-reported physical functioning at 1 year compared with outcomes after a dorsal surgical approach.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02076113.

Distinct genomic subclasses of high-grade/progressive meningiomas: NF2-associated, NF2-exclusive, and NF2-agnostic

BACKGROUND

Genomic studies of high-grade/progressive meningiomas have reported a heterogeneous mutation spectrum, identifying few recurrently mutated genes. Most studies have been underpowered to detect genomic subclasses of aggressive meningiomas due to relatively small number of available samples. Here, we present a genomic survey of one of the largest multi-institutional cohorts of high-grade/progressive meningiomas to date.

METHODS

850 high-grade/progressive meningiomas, including 441 WHO grade 2 and 176 WHO grade 3 meningiomas and 220 progressive WHO grade 1 meningiomas, were tested as part of a clinical testing program by hybridization capture of 406 cancer-related genes to detect base substitutions, indels, amplifications, deletions, and rearrangements. Information from pathology reports, histopathology review, and patient clinical data was assessed.

RESULTS

Genomic analyses converged to identify at least three distinct patterns of biologically-aggressive meningiomas. The first and most common contained NF2-mutant tumors (n = 426, 50%), was associated with male sex (64.4% %, p = 0.0001) and often harbored additional mutations in CDKN2A/B (24%), and the chromatin regulators ARID1A (9%), and KDM6A (6%). A second group (NF2-agnostic) featured TERT promoter (TERTp; n = 56) or TP53 mutations (n = 25) and were either NF2-mutant or wild-type, and displayed no association with either sex (p = 0.39). The remaining group generally lacked NF2 mutations, and accounted for 40% of the cases-with three subgroups. One consistent primarily of grade 3 lesions harboring alterations in chromatin regulators BAP1 (n = 22) or PBRM1 (n = 16). A second subgroup contained AKT1 (n = 26), PIK3CA (n = 14) and SMO (n = 7) mutant skull-based meningiomas, and a third mixed subgroup included 237 meningiomas with a heterogeneous spectrum of low frequency and non-recurrent alterations.

CONCLUSIONS

Our findings indicate that the patterns of genomic alterations in high-grade/progressive meningiomas commonly group into three different categories. The most common NF2-associated canonical group frequently harbored CDKN2A/B alterations, which is potentially amenable to targeted therapies. An NF2-agnostic group harbored frequent TERTp and TP53 mutations. The final subclass, distinct from the canonical NF2 mutant associated pathway, was partly characterized by BAP1/PBRM1 alterations (rhabdoid/papillary histology) or skull-base disease. Overall, these data increase our understanding of the pathobiology of high-grade/progressive meningiomas and can guide the design of clinical trials.

IRB APPROVAL STATUS

Reviewed and approved by Western IRB; Protocol No. 20152817.

Exome Sequencing Implicates Impaired GABA Signaling and Neuronal Ion Transport in Trigeminal Neuralgia

Trigeminal neuralgia (TN) is a common, debilitating neuropathic face pain syndrome often resistant to therapy. The familial clustering of TN cases suggests that genetic factors play a role in disease pathogenesis. However, no unbiased, large-scale genomic study of TN has been performed to date. Analysis of 290 whole exome-sequenced TN probands, including 20 multiplex kindreds and 70 parent-offspring trios, revealed enrichment of rare, damaging variants in GABA receptor-binding genes in cases. Mice engineered with a TN-associated de novo mutation (p.Cys188Trp) in the GABA_A receptor Cl⁻ channel γ-1 subunit (GABRG1) exhibited trigeminal mechanical allodynia and face pain behavior. Other TN probands harbored rare damaging variants in Na⁺ and Ca⁺ channels, including a significant variant burden in the α-1H subunit of the voltage-gated Ca²⁺ channel Ca_v3.2 (CACNA1H). These results provide exome-level insight into TN and implicate genetically encoded impairment of GABA signaling and neuronal ion transport in TN pathogenesis.

•

Genomic analysis of trigeminal neuralgia (TN) using exome sequencing

•

Rare mutations in GABA signaling and ion transport genes are enriched in TN cases

•

Generation of a genetic TN mouse model engineered with a patient-specific mutation

Isocitrate Dehydrogenase Mutations in Low-Grade Gliomas Correlate With Prolonged Overall Survival in Older Patients

BACKGROUND

Older age has been associated with worse outcomes in low-grade gliomas (LGGs). Given their rarity in the older population, determining optimal treatment plans and patient outcomes remains difficult.

OBJECTIVE

To retrospectively study LGG survival outcomes in an older population stratified by molecular genetic profiles.

METHODS

We included patients age ≥40 yr with pathologically confirmed World Health Organization grade II gliomas treated at a single institution between 1995 and 2015. We collected tumor genomic information when available.

RESULTS

Median overall survival for the entire group (n = 111, median age 51 yr, range 40-77 yr) was 15.75 yr with 5- and 10-yr survival rates of 84.3% and 67.7%, respectively. On univariate analysis, patients with isocitrate dehydrogenase (IDH) mutation had significantly increased survival compared to IDH wildtype (hazard ratio [HR] 0.17 [0.07-0.45], P < .001). Older age, seizure at presentation, larger tumor size, IDH wildtype, biopsy only, chemotherapy, and radiation were significantly associated with shorter survival based on univariate analyses. In patients with known IDH status (n = 73), bivariate analysis of IDH mutation status and age showed only IDH status significantly influenced overall survival (HR 0.22 [0.07-0.68], P = .008). Greater surgical resection was predictive of survival, although extent of resection significantly correlated with IDH mutation status (odds ratio 7.5; P < .001).

CONCLUSION

We show that genomic alterations in LGG patients ≥40 occur at high rates like the younger population and predict a similar survival advantage. Maximizing surgical resection may have survival benefit, although feasibility of resection is often linked to IDH status. Given the importance of molecular genetics, a redefinition of prognostic factors associated with these tumors is likely to emerge.

Receptor tyrosine kinase gene amplification is predictive of intraoperative seizures during glioma resection with functional mapping

OBJECTIVE

Intraoperative seizures during craniotomy with functional mapping is a common complication that impedes optimal tumor resection and results in significant morbidity. The relationship between genetic mutations in gliomas and the incidence of intraoperative seizures has not been well characterized. Here, the authors performed a retrospective study of patients treated at their institution over the last 12 years to determine whether molecular data can be used to predict the incidence of this complication.

METHODS

The authors queried their institutional database for patients with brain tumors who underwent resection with intraoperative functional mapping between 2005 and 2017. Basic clinicopathological characteristics, including the status of the following genes, were recorded: IDH1/2, PIK3CA, BRAF, KRAS, AKT1, EGFR, PDGFRA, MET, MGMT, and 1p/19q. Relationships between gene alterations and intraoperative seizures were evaluated using chi-square and two-sample t-test univariate analysis. When considering multiple predictive factors, a logistic multivariate approach was taken.

RESULTS

Overall, 416 patients met criteria for inclusion; of these patients, 98 (24%) experienced an intraoperative seizure. Patients with a history of preoperative seizure and those treated with antiepileptic drugs prior to surgery were less likely to have intraoperative seizures (history: OR 0.61 [95% CI 0.38-0.96], chi-square = 4.65, p = 0.03; AED load: OR 0.46 [95% CI 0.26-0.80], chi-square = 7.64, p = 0.01). In a univariate analysis of genetic markers, amplification of genes encoding receptor tyrosine kinases (RTKs) was specifically identified as a positive predictor of seizures (OR 5.47 [95% CI 1.22-24.47], chi-square = 5.98, p = 0.01). In multivariate analyses considering RTK status, AED use, and either 2007 WHO tumor grade or modern 2016 WHO tumor groups, the authors found that amplification of the RTK proto-oncogene, MET, was most predictive of intraoperative seizure (p < 0.05).

CONCLUSIONS

This study describes a previously unreported association between genetic alterations in RTKs and the occurrence of intraoperative seizures during glioma resection with functional mapping. Future models estimating intraoperative seizure risk may be enhanced by inclusion of genetic criteria.

A Clinical Rule for Preoperative Prediction of BRAF Mutation Status in Craniopharyngiomas

BACKGROUND

Papillary craniopharyngiomas are characterized by BRAFV600E mutations. Targeted therapy can elicit a dramatic radiographic regression of these tumors. Therefore, prediction of BRAF mutation status before definitive surgery could enable neoadjuvant treatment strategies.

OBJECTIVE

To establish preoperative prediction criteria to identify patients with a BRAF mutant craniopharyngioma.

METHODS

Sixty-four patients with craniopharyngioma were included in this study. We determined BRAF mutation status by targeted sequencing. After scoring interobserver variability between presurgical clinical data and radiographic features, we established a diagnostic rule for BRAF mutation in our discovery cohort. We then validated the rule in an independent cohort.

RESULTS

The BRAFV600E mutation was detected in 12 of 42 patients in the discovery cohort. There were no patients under age 18 with BRAF mutation. Calcification was rare in tumors with BRAF mutation (P < .001), and 92% of them were supradiaphragmatic in location. Combining these 3 features—older than 18 years, absence of calcification, and supradiaphragmatic tumor location—we established a rule for predicting BRAF mutation. In cases where all 3 criteria were fulfilled, the sensitivity and specificity for the presence of BRAF mutation were 83% and 93%, respectively. In the validation cohort (n = 22), the sensitivity was 100% and specificity was 89%.

CONCLUSION

We propose predictive criteria for a BRAF mutation in craniopharyngioma using preoperative clinical and radiographic data. This rule may be useful in identifying patients who could potentially benefit from neoadjuvant BRAFV600E-targeted systemic therapies.

Launching Effectiveness Research to Guide Practice in Neurosurgery: A National Institute Neurological Disorders and Stroke Workshop Report

This workshop addressed challenges of clinical research in neurosurgery. Randomized controlled clinical trials (RCTs) have high internal validity, but often insufficiently generalize to real-world practice. Observational studies are inclusive but often lack sufficient rigor. The workshop considered possible solutions, such as (1) statistical methods for demonstrating causality using observational data; (2) characteristics required of a registry supporting effectiveness research; (3) trial designs combining advantages of observational studies and RCTs; and (4) equipoise, an identified challenge for RCTs. In the future, advances in information technology potentially could lead to creation of a massive database where clinical data from all neurosurgeons are integrated and analyzed, ending the separation of clinical research and practice and leading to a new "science of practice."

Postoperative stereotactic radiosurgery compared with whole brain radiotherapy for resected metastatic brain disease (NCCTG N107C/CEC·3): a multicentre, randomised, controlled, phase 3 trial

BACKGROUND

Whole brain radiotherapy (WBRT) is the standard of care to improve intracranial control following resection of brain metastasis. However, stereotactic radiosurgery (SRS) to the surgical cavity is widely used in an attempt to reduce cognitive toxicity, despite the absence of high-level comparative data substantiating efficacy in the postoperative setting. We aimed to establish the effect of SRS on survival and cognitive outcomes compared with WBRT in patients with resected brain metastasis.

METHODS

In this randomised, controlled, phase 3 trial, adult patients (aged 18 years or older) from 48 institutions in the USA and Canada with one resected brain metastasis and a resection cavity less than 5·0 cm in maximal extent were randomly assigned (1:1) to either postoperative SRS (12-20 Gy single fraction with dose determined by surgical cavity volume) or WBRT (30 Gy in ten daily fractions or 37·5 Gy in 15 daily fractions of 2·5 Gy; fractionation schedule predetermined for all patients at treating centre). We randomised patients using a dynamic allocation strategy with stratification factors of age, duration of extracranial disease control, number of brain metastases, histology, maximal resection cavity diameter, and treatment centre. Patients and investigators were not masked to treatment allocation. The co-primary endpoints were cognitive-deterioration-free survival and overall survival, and analyses were done by intention to treat. We report the final analysis. This trial is registered with ClinicalTrials.gov, number NCT01372774.

FINDINGS

Between Nov 10, 2011, and Nov 16, 2015, 194 patients were enrolled and randomly assigned to SRS (98 patients) or WBRT (96 patients). Median follow-up was 11·1 months (IQR 5·1-18·0). Cognitive-deterioration-free survival was longer in patients assigned to SRS (median 3·7 months [95% CI 3·45-5·06], 93 events) than in patients assigned to WBRT (median 3·0 months [2·86-3·25], 93 events; hazard ratio [HR] 0·47 [95% CI 0·35-0·63]; p<0·0001), and cognitive deterioration at 6 months was less frequent in patients who received SRS than those who received WBRT (28 [52%] of 54 evaluable patients assigned to SRS vs 41 [85%] of 48 evaluable patients assigned to WBRT; difference -33·6% [95% CI -45·3 to -21·8], p<0·00031). Median overall survival was 12·2 months (95% CI 9·7-16·0, 69 deaths) for SRS and 11·6 months (9·9-18·0, 67 deaths) for WBRT (HR 1·07 [95% CI 0·76-1·50]; p=0·70). The most common grade 3 or 4 adverse events reported with a relative frequency greater than 4% were hearing impairment (three [3%] of 93 patients in the SRS group vs eight [9%] of 92 patients in the WBRT group) and cognitive disturbance (three [3%] vs five [5%]). There were no treatment-related deaths.

INTERPRETATION

Decline in cognitive function was more frequent with WBRT than with SRS and there was no difference in overall survival between the treatment groups. After resection of a brain metastasis, SRS radiosurgery should be considered one of the standards of care as a less toxic alternative to WBRT for this patient population.

FUNDING

National Cancer Institute.

Histopathological prognostic factors of recurrence following definitive therapy for atypical and malignant meningiomas

OBJECTIVE Patients with atypical and malignant (WHO Grade II and III) meningiomas have a worse prognosis than patients with benign (WHO Grade I) meningiomas. However, there is limited understanding of the pathological risk factors that affect long-term tumor control following combined treatment with surgery and radiation therapy. Here, the authors identify clinical and histopathological risk factors for the progression and/or recurrence (P/R) of high-grade meningiomas based on the largest series of patients with atypical and malignant meningiomas, as defined by the 2007 WHO classification. METHODS Patients diagnosed with WHO Grade II and III meningiomas between 2007 and 2014 per the WHO 2007 criteria and treated with both surgery and external beam radiation therapy were retrospectively reviewed for clinical and histopathological factors at the time of diagnosis and assessed for P/R outcomes at the last available follow-up. RESULTS A total of 76 patients met the inclusion criteria (66 Grade II meningiomas, 10 Grade III meningiomas). Median follow-up from the time of pathological diagnosis was 52.6 months. Three factors were found to predict P/R: Grade III histology, brain and/or bone invasion, and a Ki-67 proliferation rate at or above 3%. The crude P/R rate was 80% for patients with Grade III histology, 40% for those with brain and/or bone involvement (regardless of WHO tumor grade), and 20% for those with a proliferative index ≥ 3% (regardless of WHO tumor grade). The median proliferation index was significantly different between patients in whom treatment failed and those in whom it did not fail (11% and 1%, respectively). CONCLUSIONS In patients with atypical or malignant meningiomas, the presence of Grade III histology, brain and/or bone involvement, and a high mitotic index significantly predicted an increased risk of treatment failure despite combination therapy. These patients can be stratified into risk groups predicting P/R. Patients with high-risk features may benefit from more treatment and counseling than is typically offered currently.

Diagnosis and management of craniopharyngiomas in the era of genomics and targeted therapy

Craniopharyngiomas are rare intracranial neoplasms that pose clinical challenges due to their location adjacent to vital structures. The authors have previously shown high mutation rates of BRAF V600E in papillary craniopharyngioma and of CTNNB1 in adamantinomatous craniopharyngioma. These activating driver mutations are potential therapeutic targets, and the authors have recently reported a significant response to BRAF/MEK inhibition in a patient with multiply recurrent PCP. As these targetable mutations warrant prospective research, the authors will be conducting a national National Cancer Institute-sponsored multicenter clinical trial to investigate BRAF/MEK inhibition in the treatment of craniopharyngioma. In this new era of genomic discovery, the treatment paradigm of craniopharyngioma is likely to change.

Prophylactic nimodipine treatment and improvement in hearing outcome after vestibular schwannoma surgery: a combined analysis of a randomized, multicenter, Phase III trial and its pilot study

OBJECTIVE In clinical routines, neuroprotective strategies in neurosurgical interventions are still missing. A pilot study (n = 30) and an analogously performed Phase III trial (n = 112) pointed to a beneficial effect of prophylactic nimodipine and hydroxyethyl starch (HES) in vestibular schwannoma (VS) surgery. Considering the small sample size, the data from both studies were pooled. METHODS The patients in both investigator-initiated studies were assigned to 2 groups. The treatment group (n = 70) received parenteral nimodipine (1-2 mg/hour) and HES (hematocrit 30%-35%) from the day before surgery until the 7th postoperative day. The control group (n = 72) was not treated prophylactically. Facial and cochlear nerve functions were documented preoperatively, during the inpatient care, and 1 year after surgery. RESULTS Pooled raw data were analyzed retrospectively. Intent-to-treat analysis revealed a significantly lower risk for hearing loss (Class D) 12 months after surgery in the treatment group compared with the control group (OR 0.46, 95% CI 0.22-0.97; p = 0.04). After exclusion of patients with preoperative Class D hearing, this effect was more pronounced (OR 0.38, 95% CI 0.17-0.83; p = 0.016). Logistic regression analysis adjusted for tumor size showed a 4 times lower risk for hearing loss in the treatment group compared with the control group (OR 0.25, 95% CI 0.09-0.63; p = 0.003). Facial nerve function was not significantly improved with treatment. Apart from dose-dependent hypotension (p < 0.001), the study medication was well tolerated. CONCLUSIONS Prophylactic nimodipine is safe and may be recommended in VS surgery to preserve hearing. Prophylactic neuroprotective treatment in surgeries in which nerves are at risk seems to be a novel and promising concept. Clinical trial registration no.: DRKS 00000328 ( https://drks-neu.uniklinik-freiburg.de/drks_web/ ).

Targeted sequencing of SMO and AKT1 in anterior skull base meningiomas

OBJECTIVE Meningiomas located in the skull base are surgically challenging. Recent genomic research has identified oncogenic SMO and AKT1 mutations in a small subset of meningiomas. METHODS The authors performed targeted sequencing in a large cohort of patients with anterior skull base meningiomas (n = 62) to better define the frequency of SMO and AKT1 mutations in these tumors. RESULTS The authors found SMO mutations in 7 of 62 (11%) and AKT1 mutations in 12 of 62 (19%) of their cohort. Of the 7 meningiomas with SMO mutations, 6 (86%) occurred in the olfactory groove. Meningiomas with an SMO mutation presented with significantly larger tumor volume (70.6 ± 36.3 cm³) compared with AKT1-mutated (18.2 ± 26.8 cm³) and wild-type (22.7 ± 23.9 cm³) meningiomas, respectively. CONCLUSIONS Combined, these data demonstrate clinically actionable mutations in 30% of anterior skull base meningiomas and suggest an association between SMO mutation status and tumor volume. Genotyping of SMO and AKT1 is likely to be high yield in anterior skull base meningiomas with available surgical tissue.

Effect of Radiosurgery Alone vs Radiosurgery With Whole Brain Radiation Therapy on Cognitive Function in Patients With 1 to 3 Brain Metastases: A Randomized Clinical Trial

IMPORTANCE

Whole brain radiotherapy (WBRT) significantly improves tumor control in the brain after stereotactic radiosurgery (SRS), yet because of its association with cognitive decline, its role in the treatment of patients with brain metastases remains controversial.

OBJECTIVE

To determine whether there is less cognitive deterioration at 3 months after SRS alone vs SRS plus WBRT.

DESIGN, SETTING, AND PARTICIPANTS

At 34 institutions in North America, patients with 1 to 3 brain metastases were randomized to receive SRS or SRS plus WBRT between February 2002 and December 2013.

INTERVENTIONS

The WBRT dose schedule was 30 Gy in 12 fractions; the SRS dose was 18 to 22 Gy in the SRS plus WBRT group and 20 to 24 Gy for SRS alone.

MAIN OUTCOMES AND MEASURES

The primary end point was cognitive deterioration (decline >1 SD from baseline on at least 1 cognitive test at 3 months) in participants who completed the baseline and 3-month assessments. Secondary end points included time to intracranial failure, quality of life, functional independence, long-term cognitive status, and overall survival.

RESULTS

There were 213 randomized participants (SRS alone, n = 111; SRS plus WBRT, n = 102) with a mean age of 60.6 years (SD, 10.5 years); 103 (48%) were women. There was less cognitive deterioration at 3 months after SRS alone (40/63 patients [63.5%]) than when combined with WBRT (44/48 patients [91.7%]; difference, -28.2%; 90% CI, -41.9% to -14.4%; P < .001). Quality of life was higher at 3 months with SRS alone, including overall quality of life (mean change from baseline, -0.1 vs -12.0 points; mean difference, 11.9; 95% CI, 4.8-19.0 points; P = .001). Time to intracranial failure was significantly shorter for SRS alone compared with SRS plus WBRT (hazard ratio, 3.6; 95% CI, 2.2-5.9; P < .001). There was no significant difference in functional independence at 3 months between the treatment groups (mean change from baseline, -1.5 points for SRS alone vs -4.2 points for SRS plus WBRT; mean difference, 2.7 points; 95% CI, -2.0 to 7.4 points; P = .26). Median overall survival was 10.4 months for SRS alone and 7.4 months for SRS plus WBRT (hazard ratio, 1.02; 95% CI, 0.75-1.38; P = .92). For long-term survivors, the incidence of cognitive deterioration was less after SRS alone at 3 months (5/11 [45.5%] vs 16/17 [94.1%]; difference, -48.7%; 95% CI, -87.6% to -9.7%; P = .007) and at 12 months (6/10 [60%] vs 17/18 [94.4%]; difference, -34.4%; 95% CI, -74.4% to 5.5%; P = .04).

CONCLUSIONS AND RELEVANCE

Among patients with 1 to 3 brain metastases, the use of SRS alone, compared with SRS combined with WBRT, resulted in less cognitive deterioration at 3 months. In the absence of a difference in overall survival, these findings suggest that for patients with 1 to 3 brain metastases amenable to radiosurgery, SRS alone may be a preferred strategy.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00377156.

Prophylactic antiepileptic drug administration following brain tumor resection: results of a recent AANS/CNS Section on Tumors survey

OBJECTIVE Antiepileptic drugs (AEDs) are often administered prophylactically following brain tumor resection. With conflicting evidence and unestablished guidelines, however, the nature of this practice among tumor surgeons is unknown. METHODS On November 24, 2015, a REDCap (Research Electronic Database Capture) survey was sent to members of the AANS/CNS Section on Tumors to query practice patterns. RESULTS Responses were received from 144 individuals, including 18.8% of board-certified neurosurgeons surveyed (across 86 institutions, 16 countries, and 5 continents). The majority reported practicing in an academic setting (85%) as a tumor specialist (71%). Sixty-three percent reported always or almost always prescribing AED prophylaxis postoperatively in patients with a supratentorial brain tumor without a prior seizure history. Meanwhile, 9% prescribed occasionally and 28% rarely prescribed AED prophylaxis. The most common agent was levetiracetam (85%). The duration of seizure prophylaxis varied widely: 25% of surgeons administered prophylaxis for 7 days, 16% for 2 weeks, 21% for 2 to 6 weeks, and 13% for longer than 6 weeks. Most surgeons (61%) believed that tumor pathology influences epileptogenicity, with high-grade glioma (39%), low-grade glioma (31%), and metastases (24%) carrying the greatest seizure risk. While the majority used prophylaxis, 62% did not believe or were unsure if prophylactic AEDs reduced seizures postoperatively. The vast majority (82%) stated that a well-designed randomized trial would help guide their future clinical decision making. CONCLUSIONS Wide knowledge and practice gaps exist regarding the frequency, duration, and setting of AED prophylaxis for seizure-naive patients undergoing brain tumor resection. Acceptance of universal practice guidelines on this topic is unlikely until higher-level evidence supporting or refuting the value of modern seizure prophylaxis is demonstrated.

Natural history of cavernous malformation: Systematic review and meta-analysis of 25 studies

OBJECTIVE

We pooled the results of studies on natural history of cavernous malformations (CM) to calculate point estimates and investigate main sources of heterogeneity.

METHODS

We searched MEDLINE, EMBASE, and ISI Web of Science for relevant studies published before May 2015. We used fixed or random effects models and meta-regression to pool the data.

RESULTS

Twenty-five studies were entered into the meta-analysis (90-1,295 patients depending on the analysis). Bleeding was defined as symptomatic hemorrhage plus radiologic evidence of hemorrhage. Sources of heterogeneity were identified as mixture of hemorrhage and rehemorrhage, mixture of rehemorrhage before and after 2 years of first bleeding, brainstem vs other locations, and calculation method. The rehemorrhage rate was higher than the hemorrhage rate (incidence rate ratio 16.5, p < 0.001, 95% confidence interval [CI] 9.7-28.0). Rehemorrhage within 2 years of the first hemorrhage was higher than after that (incidence rate ratio 1.8, p = 0.042, 95% CI 1.5-2.0). In two metaregression models, rough estimate of the annual incidence rate of hemorrhage was 0.3% (95% CI 0.1%-0.5%) and 2.8% (2.5%-3.3%) per person year in nonbrainstem and brainstem lesions and rough estimate of annual rehemorrhage rate per person year was 6.3% (3%-13.2%) and 32.3% (19.8%-52.7%) in nonbrainstem and brainstem lesions. Median time to rehemorrhage was 10.5 months. Posthemorrhage full recovery was 38.8%/person-year (28.7%-48.8%). Posthemorrhage full recovery or minimal disability was 79.5%/person-year (74.3%-84.8%). Mortality after bleeding was 2.2%.

CONCLUSIONS

The incidence of symptomatic hemorrhage or rehemorrhage is higher in brainstem lesions. First symptomatic hemorrhage increases the chance of symptomatic rehemorrhage, which decreases after 2 years.

Outcomes following Pediatric Auditory Brainstem Implant Surgery: Early Experiences in a North American Center

There are no approved Food and Drug Administration indications for pediatric auditory brainstem implant (ABI) surgery in the United States. Our prospective case series aims to determine the safety and feasibility of ABI surgery in pediatric patients <5 years old with congenital deafness at a tertiary North American center. The inclusion criterion was pre- or postlinguistic deafness in children not eligible for cochlear implantation. Seventeen candidates were evaluated (mean ± SD: age, 2.52 ± 0.39 years). Four patients underwent ABI surgery (age, 19.2 ± 3.43 months), including 4 primary procedures and 1 revision for device failure. Spontaneous device failure occurred in another subject postoperatively. No major/minor complications occurred, including cerebrospinal fluid leak, facial nerve injury, hematoma, and nonauditory stimulation. All subjects detected sound with environmental awareness, and several demonstrated babbling and mimicry. Poor durability of older implants underscores need for updated technology.

Laminectomy plus Fusion versus Laminectomy Alone for Lumbar Spondylolisthesis

BACKGROUND

The comparative effectiveness of performing instrumented (rigid pedicle screws affixed to titanium alloy rods) lumbar spinal fusion in addition to decompressive laminectomy in patients with symptomatic lumbar grade I degenerative spondylolisthesis with spinal stenosis is unknown.

METHODS

In this randomized, controlled trial, we assigned patients, 50 to 80 years of age, who had stable degenerative spondylolisthesis (degree of spondylolisthesis, 3 to 14 mm) and symptomatic lumbar spinal stenosis to undergo either decompressive laminectomy alone (decompression-alone group) or laminectomy with posterolateral instrumented fusion (fusion group). The primary outcome measure was the change in the physical-component summary score of the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36; range, 0 to 100, with higher scores indicating better quality of life) 2 years after surgery. The secondary outcome measure was the score on the Oswestry Disability Index (range, 0 to 100, with higher scores indicating more disability related to back pain). Patients were followed for 4 years.

RESULTS

A total of 66 patients (mean age, 67 years; 80% women) underwent randomization. The rate of follow-up was 89% at 1 year, 86% at 2 years, and 68% at 4 years. The fusion group had a greater increase in SF-36 physical-component summary scores at 2 years after surgery than did the decompression-alone group (15.2 vs. 9.5, for a difference of 5.7; 95% confidence interval, 0.1 to 11.3; P=0.046). The increases in the SF-36 physical-component summary scores in the fusion group remained greater than those in the decompression-alone group at 3 years and at 4 years (P=0.02 for both years). With respect to reductions in disability related to back pain, the changes in the Oswestry Disability Index scores at 2 years after surgery did not differ significantly between the study groups (-17.9 in the decompression-alone group and -26.3 in the fusion group, P=0.06). More blood loss and longer hospital stays occurred in the fusion group than in the decompression-alone group (P<0.001 for both comparisons). The cumulative rate of reoperation was 14% in the fusion group and 34% in the decompression-alone group (P=0.05).

CONCLUSIONS

Among patients with degenerative grade I spondylolisthesis, the addition of lumbar spinal fusion to laminectomy was associated with slightly greater but clinically meaningful improvement in overall physical health-related quality of life than laminectomy alone. (Funded by the Jean and David Wallace Foundation and others; SLIP ClinicalTrials.gov number, NCT00109213.).

Rapid Intraoperative Molecular Characterization of Glioma

IMPORTANCE

Conclusive intraoperative pathologic confirmation of diffuse infiltrative glioma guides the decision to pursue definitive neurosurgical resection. Establishing the intraoperative diagnosis by histologic analysis can be difficult in low-cellularity infiltrative gliomas. Therefore, we developed a rapid and sensitive genotyping assay to detect somatic single-nucleotide variants in the telomerase reverse transcriptase (TERT) promoter and isocitrate dehydrogenase 1 (IDH1).

OBSERVATIONS

This assay was applied to tissue samples from 190 patients with diffuse gliomas, including archived fixed and frozen specimens and tissue obtained intraoperatively. Results demonstrated 96% sensitivity (95% CI, 90%-99%) and 100% specificity (95% CI, 95%-100%) for World Health Organization grades II and III gliomas. In a series of live cases, glioma-defining mutations could be identified within 60 minutes, which could facilitate the diagnosis in an intraoperative timeframe.

CONCLUSIONS AND RELEVANCE

The genotyping method described herein can establish the diagnosis of low-cellularity tumors like glioma and could be adapted to the point-of-care diagnosis of other lesions that are similarly defined by highly recurrent somatic mutations.

Case-Based Review: meningioma

Meningioma is by far the most common primary intracranial tumor in adults. Treatment of meningioma is complex due to a tremendous amount of variability in tumor behavior. Many patients are incidentally found to have tumors that will remain asymptomatic throughout their lives. It is important to identify these patients so that they can be spared from potentially morbid interventions. On the other end of the spectrum, high-grade meningiomas can behave very aggressively. When treatment is necessary, surgical resection is the cornerstone of meningioma therapy. Studies spanning decades have demonstrated that extent of resection correlates with prognosis. Radiation therapy, either in the form of external beam radiation therapy or stereotactic radiosurgery, represents another important therapeutic tool that can be used in place of or as a supplement to surgery. There are no chemotherapeutic agents of proven efficacy against meningioma, and chemotherapy treatment is generally reserved for patients who have exhausted surgical and radiotherapy options. Ongoing and future studies will help to answer unresolved questions such as the optimum use of radiation in resected WHO grade II meningiomas and the efficacy of additional chemotherapy agents.

Benign meningiomas (WHO Grade I) with atypical histological features: correlation of histopathological features with clinical outcomes

OBJECT

World Health Organization (WHO) Grade I (benign) meningiomas with atypical features may behave more aggressively than similarly graded tumors without atypical features. Here, the prognostic significance of atypical features in benign meningiomas was determined.

METHODS

Data from patients diagnosed with WHO Grade I benign meningiomas per the 2007 WHO criteria and who underwent surgery between 2002 and 2012 were retrospectively reviewed. Patients were stratified by the absence or presence of 1 to 2 atypical features with review of the clinical and histological factors.

RESULTS

A total of 148 patients met the inclusion criteria (n = 77 with atypia; n = 71 without atypia). The median follow-up duration after pathological diagnosis was 37.5 months. Thirty patients had progression/recurrence (P/R) after initial treatment, and 22 (73%) of 30 patients with P/R had 1–2 atypical features. The presence of atypical features was significantly associated with P/R (p = 0.03) and independent of the MIB-1 labeling index. The 1-year and 5-year actuarial rates of P/R were 9.6% versus 1.4% and 30.8% versus 13.8% fortumors with and without atypical features, respectively. Higher Simpson grade resection (II–IV vs I) was associated with the increased risk of P/R (p < 0.001). Stratification of patients into low-risk (Simpson Grade I), intermediate-risk (Simpson Grade II–IV with no atypical features), and high-risk groups (Simpson Grade II–IV with atypical features) was significantly correlated with increased risk of P/R (p < 0.001).

CONCLUSIONS

Patients with benign meningiomas with atypical features and those undergoing Simpson Grade II–IV resection are at significantly increased risk of P/R. Patients with these features may benefit from the consideration of additional surgery and/or radiation therapy.

Imaging and extent of surgical resection predict risk of meningioma recurrence better than WHO histopathological grade

BACKGROUND

Risk stratification of meningiomas by histopathological grade alone does not reliably predict which patients will progress/recur after treatment. We sought to determine whether preoperative imaging and clinical characteristics could predict histopathological grade and/or improve prognostication of progression/recurrence (P/R).

METHODS

We retrospectively reviewed preoperative MR and CT imaging features of 144 patients divided into low-grade (2007 WHO grade I; n = 118) and high-grade (2007 WHO grades II/III; n = 26) groups that underwent surgery between 2002 and 2013 (median follow-up of 49 months).

RESULTS

Multivariate analysis demonstrated that the risk factors most strongly associated with high-grade histopathology were male sex, low apparent diffusion coefficient (ADC), absent calcification, and high peritumoral edema. Remarkably, multivariate Cox proportional hazards analysis demonstrated that, in combination with extent of resection, ADC outperformed WHO histopathological grade for predicting which patients will suffer P/R after initial treatment. Stratification of patients into 3 risk groups based on non-Simpson grade I resection and low ADC as risk factors correlated with the likelihood of P/R (P < .001). The high-risk group (2 risk factors; n = 39) had a 45% cumulative incidence of P/R, whereas the low-risk group (0 risk factors; n = 31) had no P/R events at 5 years after treatment. Independent of histopathological grade, high-risk patients who received adjuvant radiotherapy had a lower 5-year crude rate of P/R than those without (17% vs 59%; P = .04).

CONCLUSIONS

Patients with non-Simpson grade I resection and low ADC meningiomas are at significantly increased risk of P/R and may benefit from adjuvant radiotherapy and/or additional surgery.