STMO-6 Impact of the extent of resection on the survival of patients with lower grade gliomas using awake brain mapping

Purpose: The aim of this study was to assess the effect of the extent of resection (EOR) of tumors on survival in a series of patients with lower-grade gliomas (LGGs) who underwent awake brain mapping. Methods: We retrospectively analyzed 126 patients with LGGs in the dominant and non-dominant hemisphere who underwent awake brain surgery at the same institution between December 2012 and May 2020. Results: The median progression-free survival (PFS) rate of patients with LGGs in the group with an EOR >100 %, including supratotal resection (n = 47; median survival [MS], not reached), was significantly higher than that in the group with an EOR <100% (n = 79; MS, 43.1 months; 95% CI: 37.8–48.4 months; p = 0.04). In patients with diffuse astrocytomas and anaplastic astrocytomas, the group with EOR >100 %, including supratotal resection (n = 25; MS, not reached), demonstrated a significantly better PFS rate than did the group with an EOR <100% (n = 45; MS, 35.8 months; 95% CI: 19.9–51.6 months; p = 0.03). Supratotal or gross total resection was correlated with better PFS in IDH-mutant type of diffuse astrocytomas and anaplastic astrocytomas (n = 19; MS, not reached vs. n = 35; MS, 40.6 months; 95% CI: 22.3–59.0 months; p = 0.02). By contrast, supratotal or gross total resection was not associated with longer PFS rates in patients with IDH-wild type of diffuse astrocytomas and anaplastic astrocytomas. Conclusions: It is noteworthy that supratotal or gross total resection significantly correlated with better PFS in IDH-mutant type of WHO grade II and III astrocytic tumors. In light of our finding that EOR did not correlate with PFS in patients with aggressive IDH-wild type of diffuse astrocytomas and anaplastic astrocytomas, we suggest treatments that are more intensive will be needed for the control of these tumors.

Patterns of recurrence according to the extent of resection in patients with IDH–wild-type glioblastoma: a retrospective study

OBJECTIVE In glioblastoma (GBM) patients, controlling the microenvironment around the tumor using various treatment modalities, including surgical intervention, is essential in determining the outcome of treatment. This study was conducted to elucidate whether recurrence patterns differ according to the extent of resection (EOR) and whether this difference affects prognosis. METHODS This single-center study included 358 eligible patients with histologically confirmed isocitrate dehydrogenase (IDH)–wild-type GBM from November 1, 2005, to December 31, 2018. Patients were assigned to one of three separate groups according to EOR: supratotal resection (SupTR), gross-total resection (GTR), and subtotal resection (STR) groups. The patterns of recurrence were classified as local, marginal, and distant based on the range of radiation. The relationship between EOR and recurrence pattern was statistically analyzed. RESULTS Observed tumor recurrence rates for each group were as follows: SupTR group, 63.4%; GTR group, 75.3%; and STR group, 80.5% (p = 0.072). Statistically significant differences in patterns of recurrences among groups were observed with respect to local recurrence (SupTR, 57.7%; GTR, 76.0%; STR, 82.8%; p = 0.036) and distant recurrence (SupTR, 50.0%; GTR, 30.1%; STR, 23.2%; p = 0.028). Marginal recurrence showed no statistical difference between groups. Both overall survival and progression-free survival were significantly increased in the SupTR group compared with the STR and GTR groups (p < 0.0001). CONCLUSIONS In this study, the authors investigated the association between EOR and patterns of recurrence in patients with IDH–wild-type GBM. The findings not only show that recurrence patterns differ according to EOR but also provide clinical evidence supporting the hypothesized mechanism by which distant recurrence occurs.

STMO-3 Mid- to long-term outcome of supratotal resection of IDH1 wild-type glioblastoma based on 11C-methionine PET: a retrospective, single-center study

Purpose Mid- to long-term outcome in glioblastoma (GBM) patients following supratotal resection (SupTR), involving complete resection both of contrast-enhancing enhanced (CE) tumors and areas of methionine (Met) uptake on 11C-Met positron emission tomography (Met-PET), are not clarified. Methods A retrospective, single-center review was performed in newly diagnosed, IDH1 wild-type GBM patients, comparing SupTR with gross total resection (GTR), in which only CE tumor tissue was completely resected. Only patients who were operated on until November 2019 were included for evaluation of mid- to long-term outcome. Following resection, all patients underwent standard radiotherapy and temozolomide treatment, and were followed for progression-free survival (PFS) and overall survival (OS). Results Among the 30 patients included in this study, 7 underwent SupTR and 23 underwent GTR. Awake craniotomy with cortical and subcortical mapping was more frequently performed in the SupTR group than in the GTR group. During the follow-up period, significantly different patterns of disease progression were observed between groups. Although more than 80% of recurrences were local in the GTR group, all recurrences in the SupTR group were distant. Median PFS in the GTR and SupTR groups was 8.8 months (95% confidence interval [CI], 5.2–14.9) and 27.8 months (95% CI, 6.0-not estimable) respectively (p=0.08 by log-rank test). Median OS was 17.7 months (95% CI, 14.2–35.1) in GTR and not reached (95% CI, 30.5-not estimable) in SupTR, respectively; this difference was statistically significant (p=0.03 by log-rank test). No postoperative neurocognitive impairment was observed in SupTR patients. Conclusion Compared to GTR alone, SupTR strategy with aggressive resection of both CE tumors and Met uptake area in GBM patients under awake craniotomy with functional preservation results in a survival benefit associated with better local control.

A Consensus Definition of Supratotal Resection for Anatomically Distinct Primary Glioblastoma: An AANS/CNS Section on Tumors Survey of Neurosurgical Oncologists

Introduction: Supratotal resection (SpTR) of glioblastoma may be associated with improved survival, but published results have varied in part from lack of consensus on the definition and appropriate use of SpTR. A previous small survey of neurosurgical oncologists with expertise performing SpTR found resection 1-2 cm beyond contrast enhancement was an acceptable definition and glioblastoma involving the right frontal and bilateral anterior temporal lobes were considered most amenable to SpTR. The general neurosurgical oncology community has not yet confirmed the practicality of this definition. Methods Seventy-six general neurosurgical oncology members of the AANS/CNS Tumor Section were surveyed using a crowdsourcing approach. Participants were presented with 11 definitions of SpTR and rated each definition’s appropriateness. Participants additionally reviewed magnetic resonance imaging for 10 anatomically distinct glioblastomas and assessed the tumor location's eloquence, perceived equipoise of enrolling patients in a randomized trial comparing gross total to SpTR, and their personal treatment plans. Results Fifty-two neurosurgeons (73.2%) agreed that resection 1-2 cm beyond contrast enhancement was an acceptable definition for SpTR. Cases were divided into three anatomically distinct groups by perceived equipoise between gross total and SpTR. The best clinical trial candidates were right anterior temporal (n=58, 76.3%) and right frontal (n=55, 73.3%) glioblastomas. Conclusion Support exists within the neurosurgical oncology community to adopt the proposed consensus definition of SpTR of glioblastoma and to treat right anterior temporal and right frontal glioblastomas using SpTR. A smaller proportion of general neurosurgical oncologists than SpTR experts consider SpTR feasible in the left anterior temporal lobe.

Supratotal Resection of Periventricular Glioblastomas and Pathomorphological Rationale for Extensive Removal of Subventricular Zone

The aim of the research was to reveal the pathomorphological patterns of periventricular glioblastoma (PVG) dissemination and assess the rationale for extended surgical removal of subventricular zone (SVZ) as a step towards supratotal resection.A total of 54 patients (16 females and 38 males, mean age 48.9 ± 13.4 years, range 22–69) with PVG were prospectively included in the study. Standard preoperative evaluation included an MRI using 3D T1 with Gd-enhancement, T2, and T2-FLAIR series. The neuronavigation system was used to identify the SVZ and to remove of ventricular wall, additionally to image-guided total tumor resection. The pathomorphological assessment of PVG features with the description of the SVZ and changes in perifocal brain matter was performed by two pathologists.The median Karnofsky Performance Scale (KPS) score raised from 67.8 to 81.9 in the postoperative period. The overall median survival was 13.0 ± 2.7 months. The low postoperative KPS score (p = 0.05) and basal ganglia invasion (p = 0.008) significantly decreased survival rates.Microscopically, the typical multilayer structure of SVZ was disrupted. The invasive spread of tumor cells in thesubventricular space was identified. The ependymal layer had prominent dystrophic alterations of cells and destruction of intracellular connections. The hyperplastic reaction on neoplastic process was typical for adjacent ependyma.The pathomorphological identification of periventricular glioblastoma invasion in the subependymal space supports the supratotal tumor resection with removal of adjacent SVZ as a potential source for relapse.

The concept of the “Hexahedron” in the supratotal resection of the frontal gliomas: A technical note

OBJECTIVE To evaluate the value of the concept of the “Hexahedron” in the supratotal resection (SPTR) of frontal gliomas in both dominant and nondominant hemispheres . METHODS All consecutive patients who underwent SPTR for frontal gliomas under the guidance from the concept of the “Hexahedron” were retrospectively analysed for lesion location, pathology, extent of resection (EOR), and complications from May 2020 to June 2021. Volumetric EOR was measured and classified as SPTR, (in which the volume of the postoperative cavity was larger than the preoperative tumour volume), gross total resection (GTR, > 95% by volume) or subtotal resection (STR, ≤ 95% by volume) after independent radiological review. RESULTS Six men and two women (mean age: 47.13 years; range: 26–69 years) were included. All eight patients underwent frontal craniotomy combined frontotemporal craniotomy for resection of frontal gliomas. Neuropathological examination confirmed a diagnosis of glioblastoma WHO Grade IV in 4 patients, anaplastic oligodendroglioma WHO Grade III in 1, anaplastic astrocytoma WHO Grade III in 2 and diffuse astrocytoma WHO Grade II in 1. SPTR was achieved in six patients and STR was achieved in two. The main postoperative complications were contralateral paresis in 2 patients and memory disturbances in 1 patient. There were no cases of rebleeding or secondary operation during hospitalization. CONCLUSIONS In the presented eight cases the concept of the “Hexahedron” allowed for safe surgical supratotal resection of frontal gliomas.

Supratotal Resection of Glioblastoma Allows Better Survival Outcomes Than Gross Total Resection

Objective: Supra-total resection (SupTR) of glioblastoma allows superior long-term disease control and increases overall survival. On the other hand, aggressive conventional approaches, including gross total resections (GTR), are limited by the impairment risk of adjacent eloquent areas, which may cause severe postoperative functional morbidity. This study aimed to analyze institutional cases with respect to the potential survival benefits of additional resection, including lobectomy, as a paradigm for SupTR in patients of glioblastoma.Methods: Between 2014 and 2018, 15 patients with glioblastoma underwent GTR and additional lobectomy at our institution. The postoperative Karnofsky performance score (KPS), progression-free survival (PFS), and overall survival (OS) were analyzed for the patients.Results: Patients with SupTR showed significantly prolonged PFS and OS. The median PFS and OS values for the entire study group were 33.5 months (95% confidence intervals [CI]: 18.5–57.3 months) and 49.1 months (95% CI: 24.7–86.6 months), respectively. Multivariate analysis revealed that O6-DNA-methylguanine methyltransferase (MGMT) promoter methylation status was the only predictor for both superior PFS (p = 0.03, OR 5.7, 95% CI 1.0–49.8) and OS (p = 0.04, OR 6.5, 95% CI 1.1–40.2). There was no significant difference between the pre- and post-operative KPS scores. Conclusions: Our results strongly suggest that SupTR with lobectomy allows superior PFS and OS without negatively affecting the patient performance.

The benefit of early surgery on overall survival in incidental low-grade glioma patients: A multicenter study

Background The role of surgery for incidentally discovered diffuse incidental low-grade gliomas (iLGGs) is debatable and poorly documented in current literature. Objective The aim was to identify factors that influence survival for patients that underwent surgical resection of iLGGs in a large multicenter population. Methods Clinical, radiological, and surgical data were retrospectively analyzed in 267 patients operated for iLGG from 4 neurosurgical Centers. Univariate and multivariate analyses were performed to identify predictors of overall survival (OS) and tumor recurrence (TR). Results The OS rate was 92.41%. The 5- and 10-year estimated OS rates were 98.09% and 93.2%, respectively. OS was significantly longer for patients with a lower preoperative tumor volume (P = .001) and higher extent of resection (EOR) (P = .037), regardless the WHO-defined molecular class (P = .2). In the final model, OS was influenced only by the preoperative tumor volume (P = .006), while TR by early surgery (P = .028). A negative association was found between preoperative tumor volumes and EOR (rs = −0.44, P &lt; .001). The median preoperative tumor volume was 15 cm3. The median EOR was 95%. Total or supratotal resection of T2-FLAIR abnormality was achieved in 61.62% of cases. Second surgery was performed in 26.22%. The median time between surgeries was 5.5 years. Histological evolution to high-grade glioma was detected in 22.85% of cases (16/70). Permanent mild deficits were observed in 3.08% of cases. Conclusions This multicenter study confirms the results of previous studies investigating surgical management of iLGGs and thereby strengthens the evidence in favor of early surgery for these lesions.