Predictors of Progression in a Series of 81 Adult Patients Surgically Managed for an Intracranial Hemangioblastoma: Implications for the Postoperative Follow-Up

The aim was to identify predictors of progression in a series of patients managed for an intracranial hemangioblastoma, in order to guide the postoperative follow-up modalities. The characteristics of 81 patients managed for an intracranial hemangioblastoma between January 2000 and October 2022 were retrospectively analyzed. The mean age at diagnosis was of 48 ± 16 years. Eleven (14%) patients had von Hippel-Lindau disease. The most frequent tumor location was the cerebellar hemispheres (n = 51, 65%) and 11 (14%) patients had multicentric hemangioblastomas. A gross total resection was achieved in 75 (93%) patients. Eighteen (22%) patients had a local progression, with a median progression-free survival of 56 months 95% CI [1;240]. Eleven (14%) patients had a distant progression (new hemangioblastoma and/or growth of an already known hemangioblastoma). Local progression was more frequent in younger patients (39 ± 14 years vs. 51 ± 16 years; p = 0.005), and those with von Hippel-Lindau disease (n = 8, 44% vs. n = 3, 5%, p < 0.0001), multiple cerebral locations (n = 3, 17% vs. n = 2, 3%, p = 0.02), and partial tumoral resection (n = 4, 18% vs. n = 1, 2%, p = 0.0006). Therefore, it is advisable to propose a postoperative follow-up for at least 10 years, and longer if at least one predictor of progression is present.

5-ALA induced PpIX fluorescence spectroscopy in neurosurgery: a review

The review begins with an overview of the fundamental principles/physics underlying light, fluorescence, and other light-matter interactions in biological tissues. It then focuses on 5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PpIX) fluorescence spectroscopy methods used in neurosurgery (e.g., intensity, time-resolved) and in so doing, describe their specific features (e.g., hardware requirements, main processing methods) as well as their strengths and limitations. Finally, we review current clinical applications and future directions of 5-ALA-induced protoporphyrin IX (PpIX) fluorescence spectroscopy in neurosurgery.

Natural Course and Prognosis of Primary Spinal Glioblastoma: A Nationwide Study

BACKGROUND AND OBJECTIVES

Primary spinal glioblastoma is extremely rare. The dramatic neurological deterioration and unresectability of primary spinal glioblastoma makes it a particularly disabling malignant neoplasm. Since it is a rare and heterogeneous disease, the assessment of prognostic factors remains limited.

METHODS

Primary spinal glioblastomas were identified from The French Brain Tumor Database and the Club de Neuro-Oncologie of the Société Française de Neurochirurgie retrospectively. Inclusion criteria were age ≥ 18 years at diagnosis, spinal location, histopathological diagnosis of newly glioblastoma according to the 2016 World Health Organization classification, and surgical management between 2004 and 2016. Diagnosis was confirmed by a centralized neuropathological review. The primary outcome was overall survival. Therapeutic interventions and neurological outcomes were also collected.

RESULTS

Thirty-three patients with an histopathologically confirmed primary spinal glioblastoma (median age 50.9 years) were included (27 centers). The median overall survival (OS) was 13.1 months (range 2.5-23.7) and the median progression-free survival was 5.9 months (range 1.6-10.2). In multivariable analyses using Cox model, ECOG PS at 0-1 was the only independent predictor of longer OS [Hazard Ratio: 0.13, 95%CI 0.02-0.801; p=0.02], whereas a Karnofsky PS score <60 [Hazard Ratio: 2.89, 95%CI 1.05-7.92; p=0.03] and a cervical anatomical location [Hazard Ratio: 4.14, 95%CI 1.32-12.98; p=0.01] were independent predictors of shorter OS. The ambulatory status (Frankel D-E) [Hazard Ratio: 0.38, 95%CI 0.07-1.985; p=0.250] was not an independent prognostic factor while the concomitant standard radiochemotherapy with temozolomide (Stupp protocol) [Hazard Ratio: 0.35, 95%CI 0.118-1.05; p=0.06] was at the limit of significance.

DISCUSSION

Preoperative ECOG PS, Karnofsky PS score and the location are independent predictors of overall survival of primary spinal glioblastomas in adults. Further analyses are required to capture the survival benefit of concomitant standard radiochemotherapy with temozolomide.

Outcomes of Unruptured Low-Grade Brain Arteriovenous Malformations Using TOBAS (Treatment of Brain Arteriovenous Malformations Study) Criteria

BACKGROUND

Treatment of an unruptured brain arteriovenous malformation (bAVM) is a matter of debate, especially for low-grade bAVM (Spetzler-Martin grade I and II). The aim is to compare the outcomes of patients with low-grade unruptured bAVM after interventional or medical management in a pragmatic manner.

METHODS

Adults with unruptured low-grade bAVM diagnosed between 2006 and 2016 were included. The primary end points were death from all causes and disabling stroke that resulted in a modified Rankin Scale (mRS) score >2 at last follow-up.

RESULTS

Eighty-four patients presented with an unruptured Spetzler-Martin low-grade bAVM. Among these patients, 55 (65.5%) were treated and 29 (34.5%) were untreated, with no differences regarding clinical and radiologic characteristics. The modality of treatment was embolization in 25.5%, radiosurgery (alone, 30.9%; with embolization, 18.2%), and surgery (alone, 5.5%; with embolization, 20%). The rupture rate was 6.7% person-year in the untreated group; 12.7% (n = 7) of treated and 16.7% (n = 5) of untreated patients achieved the primary evaluation criteria (P = 0.744). Using a Kaplan-Meier curve, the probability of reaching this criterion at 5 years was not different between groups (P = 0.07). Complications resulting in an mRS score >2 at last follow-up occurred in 9.1%, in 80% of cases after embolization.

CONCLUSIONS

This study shows no differences between treated and untreated low-grade bAVM. Embolization seems to carry a high risk of complication and should be used with caution. The small number of cases must encourage cautious interpretations especially because of the spontaneous high-rupture rate. One major interest is to investigate center habits in pathology when treatment standards are limited.

Intraoperative cerebral blood flow monitoring in neurosurgery: A review of contemporary technologies and emerging perspectives

Intraoperative monitoring of cerebral blood flow (CBF) has become an invaluable adjunct to vascular and oncological neurosurgery, reducing the risk of postoperative morbidity and mortality. Several technologies have been developed during the last two decades, including laser-based techniques, videomicroscopy, intraoperative MRI, indocyanine green angiography, and thermography. Although these technologies have been thoroughly studied and clinically applied outside the operative room, current practice lacks an optimal technology that perfectly fits the workflow within the neurosurgical operative room. The different available technologies have specific strengths but suffer several drawbacks, mainly including limited spatial and/or temporal resolution. An optimal CBF monitoring technology should meet particular criteria for intraoperative use: excellent spatial and temporal resolution, integration in the operative workflow, real-time quantitative monitoring, ease of use, and non-contact technique. We here review the main contemporary technologies for intraoperative CBF monitoring and their current and potential future applications in neurosurgery.

OS02.4.A Molecular characterization of adult cerebellar glioblastomas identifies distinct prognosis subgroups

BACKGROUND

Adult cerebellar glioblastomas (cGBM) are very rare and recent studies have shown that they constitute a heterogeneous group of gliomas. The aim of the present study was to characterize the prevalence and prognostic significance of major driver molecular alterations in a large series of cGBM.

MATERIAL AND METHODS

Adults with histologically proven cGBM diagnosed between 2003 and 2017 were identified from the French brain tumor database and the Club de Neuro-Oncologie of the Société Française de Neurochirurgie. Tumors were reviewed and reclassified according to WHO 2016. Targeted sequencing was performed, including determination of H3F3A, TERTp, IDH1/2, FGFR1, BRAF and EGFR status.

RESULTS

A total of 83 adult patients (median age 57 years) with cGBM (hemispheric n= 47, vermian n=14 or both n=22) were identified. Median overall survival was 10 months. Main molecular alterations observed were TERT promoter, H3F3A K27M, hotspot FGFR1 (N546 and K656), BRAF mutations, EGFR amplification and ATRX loss of expression in 19.2%, 18.8%, 10.9%, 2.6%, 19.5% and 22.7% of patients, respectively. cGBM could be classified into 6 mutually exclusive subgroups associated with age at diagnosis and prognosis: pTERT and/or EGFR amplified tumors (n=22, 26.5%, median age = 62 years, median OS = 4 months), H3K27M-mutant tumors (n=15, 18.1%, median age = 48 years, median OS =8 months), tumors with MAPK pathway activating mutations (FGFR1, BRAF) or occurring in NF1 patients (n=15, 18.1%, median age = 41 years, median OS = 57 months), radiation-induced tumors (n=5, 6%, median age = 47 years, median OS = 5 months), IDH-mutant tumors (n=1) and unclassified tumors (n=25, 30.1%, median age = 63 years, median OS = 17 months). In multivariate analysis, MAPK activating mutations and ATRX loss of expression were independently associated with a better outcome and pTERT/EGFR alterations with a worse outcome.

CONCLUSION

About 18% of tumors diagnosed as cGBM harbor actionable MAPK activating genetic alterations. Targeted sequencing enables to classify these tumors into clinically relevant subgroups.

Alterations of cerebral microcirculation in peritumoral edema: feasibility of in vivo sidestream dark-field imaging in intracranial meningiomas

Background

Intracranial meningiomas display a variable amount of peritumoral brain edema (PTBE), which can significantly impact perioperative morbidity. The role of microcirculatory disturbances in the pathogenesis of PTBE is still debated. The aim of this study was to microscopically demonstrate and intraoperatively quantify, for the first time, the alterations to microcirculation in PTBE using sidestream dark-field (SDF) imaging.

Methods

Adult patients with WHO grade I meningiomas were recruited over a 9-month period and divided into 2 groups depending on the absence (NE group) or the presence (E group) of PTBE. In vivo intraoperative microcirculation imaging was performed in the peritumoral area before and after microsurgical resection.

Results

Six patients were included in the NE group and 6 in the E group. At the baseline in the NE group, there was a minor decrease in microcirculatory parameters compared to normal reference values, which was probably due to the mass effect. In contrast, microcirculatory parameters in the E group were significantly altered, affecting both vessel density and blood flow values, with a drop of approximately 50% of normal values. Surgical resection resulted in a quasi-normalization of microcirculation parameters in the NE group, whereas in the E group, even if all parameters statistically significantly improved, post-resection values remained considerably inferior to those of the normal reference pattern.

Conclusion

Our study confirmed significant alterations of microcirculatory parameters in PTBE in meningiomas. Further in vivo SDF imaging studies may explore the possible correlation between the severity of these microcirculatory alterations and the postoperative neurological outcome.

Positional cranial deformation in children: A plea for the efficacy of the cranial helmet in children

BACKGROUND

Cranial deformations have historically aroused the interest of people worldwide. One of the more debated points about positional plagiocephaly is the choice of the treatment. In this article, the senior author (CM) shares his experience on almost 30 years of use of the helmet molding therapy in children with deformation plagiocephaly.

METHODS AND POPULATION

We retrospectively and systematically reviewed the cases of 2188 patients (75% males and 25% females) presenting positional head deformity and treated between 1991 and 2013 with a cranial helmet. To assess the effectiveness of the helmet, we compared the cranial index in bilateral plagiocephaly and the Cranial Diagonals Difference (CDD) in unilateral plagiocephaly at the beginning and at the end of the treatment.

RESULTS

The cranial indexes ranged between 94.4% and 124.2% before the treatment and decreased significantly between 86.8% and 121.4% after the treatment (P<0.01). The CDD ranged between 0.3 cm and 4.5 cm with an average of 1.50±0.54 cm before the treatment and decreased significantly between 0.1 cm and 2.5 cm with an average of 0.72±0.37 cm after the treatment (P<0.01). For unilateral plagiocephaly, at the beginning of the treatment, 2.5% children presented a mild plagiocephaly, 19.6% a moderate plagiocephaly and 77.9% a severe plagiocephaly. At the end of the treatment, the deformation was classified as mild in 40.2% children, moderate in 44.3% children and severe in 15.5% children with significantly less children in the most severe subgroups (P<0.01) Facial symmetry pre-existed before the treatment in 13.7% of children. This rate was significantly increased at the end of the treatment to 66.7% (P<0.01). In only 8 cases (0.2%), the helmet therapy did not allow to obtain correct clinical results and a surgical posterior cranial remodeling was performed.

CONCLUSIONS

The results observed in this series confirms that cranial helmet is a simple and well tolerated alternative which bring satisfying results. Its success implies a good collaboration with parents and a management both by orthoptist, physiotherapist and doctor. Nevertheless, it remains many controversies in the literature concerning in particular long-term cosmetic and functional outcomes. A long-term multicentric prospective study could enable to remove doubts.

P14.88 Comparison of SNaPshot PCR and digital droplet PCR for the identification of TERT promoter in non-diagnostic biopsies from glioma patients

BACKGROUND

We previously showed that TERT promotor (pTERT) mutations can be detected in a high proportion of non-diagnostic biopsies from glioma patients using SNaPshot PCR. The aim of the present study was to assess the diagnostic value of digital droplet PCR (ddPCR) in this setting.

MATERIAL AND METHODS

pTERT mutations were retrospectively assessed using SNaPshot PCR and ddPCR in the non-diagnostic biopsies of 14 adult patients who underwent an initial non-diagnostic needle biopsy that led to perform another biopsy that finally demonstrated a pTERT-mutant glioma.

RESULTS

Median age at diagnosis was 69 years and the median interval between the initial and final biopsy was 22 days. The initial biopsy consisted of unspecific infiltrating glial cells (n=10), hemorrhage, necrosis and/or fibrosis (n=4). Using SNaPshot PCR, the final biopsy found an IDH-WT pTERT-mutant glioma in 12 cases (glioblastoma n=12), an IDH-mutant pTERT-mutant oligodendroglioma in one case and an IDH-WT pTERT-WT glioblastoma in one case. Retrospectively, a pTERT mutation was identified by both ddPCR and SNaPshot in the non-diagnostic biopsies in 85% (11 /13) of pTERT mutant-gliomas. No mutation was detected in the non-diagnostic biopsies of IDH-WT pTERT-WT gliomas using either technique. Overall, a pTERT mutation were detected in 79% (11/14) of non-diagnostic biopsies.

CONCLUSION

Digital Droplet PCR, as SNaPshot PCR, enables the identification of pTERT mutations in a high rate of non-diagnostic biopsies from glioma patients. The sensitivity of both techniques seems similar in this setting.

OS5.5 Characteristics of high-grade gliomas with H3 G34 mutation in adults

BACKGROUND

H3 G34-mutant high-grade gliomas occur primarily in children but can also be encountered in adults. The aim of the present study was to describe the characteristics of H3 G34-mutant high-grade gliomas in adults.

MATERIAL AND METHODS

We analysed the characteristics of 17 adult H3 G34-mutant high-grade gliomas and compared them with those of adult grade IV gliomas with H3 K27M mutation (n=21), IDH mutation (n=42) and TERT promoter (pTERT) mutation (n=88).

RESULTS

Median age at diagnosis in H3 G34-mutant gliomas was 25 years (range: 19–33 y). All tumors had a hemispheric location. The radiological presentation was suggestive of a high-grade glioma in 6 patients but in 10 patients it initially suggested another diagnosis due to absent or faint contrast enhancement (n=9) or the presence of an initial intratumoral haemorrhage (n=1). In non- or faint contrast-enhancing cases, diffusion-weighted imaging (DWI) was more helpful to suspect an aggressive tumor than MR spectroscopy and perfusion MRI. All H3 G34-mutant gliomas were classified as IDH wildtype glioblastomas. PNET-like foci were observed in 8 cases and most cases were immunonegative for ATRX (92%) and Olig2 (81%) and demonstrated MGMT promoter methylation (82%). The clinical, radiological and histological presentation of H3 G34-mutant gliomas was different from that of midline H3 K27M-mutant diffuse gliomas and from that of IDH-mutant and IDH-wildtype pTERT-mutant glioblastomas. Median overall survival of G34-mutant gliomas was 23.9 months compared to 19.6 months (p=0.16), 13.7 months (p=0.45) and 58 months (p=2.3x10-10) in H3 K27M-mutant diffuse gliomas, IDHwt pTERT-mutant and IDH-mutant glioblastomas, respectively.

CONCLUSION

Adults H3 G34-mutant high-grade gliomas are associated with distinct characteristics and a poor prognosis. DWI seems helpful to identify cases that present as non-contrast enhancing lesions and can wrongly suggest another diagnosis in these young patients.

OS8.4 Impact of brain invasion assessment on outcome in intracranial grade II meningiomas

BACKGROUND

Brain invasion has already been identified as an independent criterion of meningioma recurrence by Jääskaläinen’s in 1986. While it was only suggested that meningiomas harbouring brain invasion could be staged as grade II in the 2007 WHO Classification of Tumours of the Central Nervous System, brain invasion was clearly listed as a grade II atypical meningioma criterion for the first time in the 2016 version. Since 2007, brain invasion has been carefully screened during the histopathological characterisation of meningiomas in our centre thanks to specific training of the neuropathology department staff. Furthermore, neurosurgeons are asked to provide well-preserved and grossly orientable tumours borders whenever possible. The aim of the present study was to compare the characteristics of patients diagnosed with grade II meningiomas before and after this change of practices.

MATERIAL AND METHODS

We retrospectively reviewed the characteristics of 125 patients with grade II meningiomas diagnosed between 2011 and 2014 (group A) and compared them to those of 166 patients with grade II meningiomas diagnosed between 1998 and 2005 (group B).

RESULTS

Tumour location and socio-demographic parameters were comparable in group A and B with a median age of 62 years in both groups (p=0.18). There were more de novo meningiomas in group A (84% vs 68.7%, p=0.004). Brain invasion was found in 59% in group A and 9% in group B (p=0.00001) while median Ki67 labelling was of 8.4% in group A and 10.5% in group B (p=0.04). Consistently, tumour borders were irregular in 52% in group A and 29% in group B (p=0.0002). Progression free survival was similar in the two groups (65 vs 66 months, p=0.92) but grade progression was more frequently observed in group B (18.9% vs 0%, p=0.006). In group A, meningiomas that were classified as grade II exclusively based on brain infiltration (n=33, group A-bi) had a similar progression rate compared to meningiomas with other criteria of atypia (27% vs 25%, p=0.98) and a similar time to progression (32 vs 32 months, p=0.74). The median time to progression of group A-bi meningiomas was also comparable to that of the other 258 pooled meningiomas (32 vs 40 months, p=0.40).

CONCLUSION

In accordance with the 2016 WHO Classification of Tumours of the Central Nervous System, the outcome of meningiomas defined as atypical solely based on brain infiltration seems to be comparable to that of meningiomas with other criteria of atypia. Appropriate coordination between neurosurgeons and neuropathologists is mandatory to optimally assess this criterion.

P04.18 Management of diffuse gliomas using hypnosis-aided awake surgery: oncological and functional preliminary results in a series of 16 cases

BACKGROUND

Awake resection of diffuse gliomas aims to find a tailored onco-functional balance for each patient. Hypnosis represents an innovative technique able to optimize the comfort and well-being of the patient during such procedures. The aim of the present study is to analyse the oncological and functional outcome in a cohort of patients operated on with hypnosis-aided awake surgery.

MATERIAL AND METHODS

All consecutive adult patients that underwent hypnosis-aided resection for a diffuse glioma between January 2018 and January 2019 were recorded. Neurological and cognitive status were assessed preoperatively and at 3 months postoperatively. Extent of tumor resection was quantified by a radiologist on magnetic resonance imaging.

RESULTS

Sixteen patients (6 males and 10 females), with a mean age of 39 years, were included. Gliomas were revealed by epileptic seizures (62.5%), motor deficit (6.25%) or incidentally discovered (31.25%) and were either located in the right hemisphere (50%) or in the left hemisphere (50%), with a mean initial volume of 42 mL. Histologically, there were six grade II-astrocytomas, three grade III-astrocytomas, five grade II-oligodendroglioma, one grade III-oligodendroglioma and one ganglioglioma. Under HAS, the awake-time after the anaesthesia drugs stop was short, because low doses of drugs were required thanks to the hypnotic state. All patients were able to reliably performed the different tests until functional subcortical limits were reached. Postoperative magnetic resonance imaging showed complete resection in 8 cases (50%), subtotal resection in 2 cases (12.5%) and partial resection in 6 cases (37.5%), with a mean resection rate of 84.6%. At 3 months after surgery, there was only a new motor deficit (6.25%). The language and neuropsychological assessments were improved in 7 patients (43.75%), stable in 7 patients (43.75%) and deteriorated in some tests in 2 patients (12.5%). After surgery, no patient reported negative emotion concerning the awake glioma resection and all patient declared being ready for a second awake resection in the future, if indicated.

CONCLUSION

According to these preliminary results, hypnosis-aided awake resection of diffuse gliomas appears to be safe and effective from an onco-functional viewpoint and parallelly contributes to decrease intra-operative pain, anxiety and major discomfort.

Optimization of high-grade glioma resection using 5-ALA fluorescence-guided surgery: A literature review and practical recommendations from the neuro-oncology club of the French society of neurosurgery

BACKGROUND

When feasible, the surgical resection is the standard first step of the management of high-grade gliomas. 5-ALA fluorescence-guided-surgery (5-ALA-FGS) was developed to ease the intra-operative delineation of tumor borders in order to maximize the extent of resection.

METHODS

A Medline electronic database search was conducted. English language studies from January 1998 until July 2018 were included, following the PRISMA guidelines.

RESULTS

5-ALA can be considered as a specific tool for the detection of tumor remnant but has a weaker sensibility (level 2). 5-ALA-FGS is associated with a significant increase in the rate of gross total resection reaching more than 90% in some series (level 1). Consistently, 5-ALAFGS improves progression-free survival (level 1). However, the gain in overall survival is more debated. The use of 5-ALA-FGS in eloquent areas is feasible but requires simultaneous intraoperative electrophysiologic functional brain monitoring to precisely locate and preserve eloquent areas (level 2). 5-ALA is usable during the first resection of a glioma but also at recurrence (level 2). From a practical standpoint, 5-ALA is orally administered 3 hours before the induction of anesthesia, the recommended dose being 20 mg/kg. Intra-operatively, the procedure is performed as usually with a central debulking and a peripheral dissection during which the surgeon switches from white to blue light. Provided that some precautions are observed, the technique does not expose the patient to particular complications.

CONCLUSION

Although 5-ALA-FGS contributes to improve gliomas management, there are still some limitations. Future methods will be developed to improve the sensibility of 5-ALA-FGS.

[Glioblastoma, innovations in surgery]

One of the innovative principles in glioblastoma surgery consists in making the tumour fluorescent in order for it to be more easily visualised during the procedure. 5-aminolevulinic acid (5-ALA) undergoes an enzyme transformation, turning into another molecule, protoporphyrine IX (PPIX) whose property is fluorescence. It emits red light when it is stimulated by blue light.