Supramaximal Resection Research Articles

SURG-47. SUPRAMAXIMAL RESECTION IMPROVES OVERALL SURVIVAL IN PATIENTS WITH MGMT-UNMETHYLATED GLIOBLASTOMA

Abstract INTRODUCTION Glioblastoma is highly resistant to radio- and chemotherapy and its heterogeneity is a therapeutic challenge. O6-methylguanine–DNA methyltransferase (MGMT) promotor methylation is an established biomarker for favorable effect of chemotherapy. Supramaximal resection has proven predict the best overall survival (OS), but whether this benefit applies equally to patients with different MGMT-promotor methylation status is still to be debated. MATERIAL AND METHODS Population based retrospective study that examined all adult patients in South-Eastern Norway that underwent resection for IDH wildtype glioblastoma between January 2019 and December 2021. Extent of resection (EOR) was classified according to RANO resect classification and MGMT-promotor methylation status by pyrosequencing-qPCR. RESULTS The study included 281 patients. MGMT-promotor methylated patients (MGMT+) had a median OS of 18.4 months compared to 13.1 months in MGMT-unmethylated (MGMT-) patients (p<0.0001). Patients with supramaximal resection had a median OS of 20.4 months compared to 14.9 months (p<0.01) with maximal resection. For patients with supramaximal resection we found no significant difference in median OS (25.5 vs. 18.3 months (p=0.24)) dependent on MGMT-status. Separated analysis between MGMT-status and EOR showed a median survival of 18.3, 13.4 (p<0.001), and 8.5 (p<0.001) months for MGMT-, and 25.5, 18.4 (p=.99), and 9.0 (p<0.001) months for MGMT+ in patients where supramaximal-, maximal-, and submaximal resection was achieved, respectively. CONCLUSIONS Patients with supramaximal resection and MGMT+ have a 50% 2-years survival probability. In patients where supramaximal resection was achieved, survival benefit was not dependent on MGMT-status. There was a significant improved survival in MGMT- patients between supramaximal and maximal resection, that was not present for MGMT+ patients. Intraoperative molecular diagnosis has the potential to guide the surgical strategy dependent on MGMT-promotor methylation status, especially in tumors where supramaximal resection has a higher risk of new neurological deficits.

SURG-14. PATTERNS OF PROGRESSION OF TEMPORAL LOBE GLIOBLASTOMAS: EVIDENCE FOR THE ROLE OF TEMPORAL LOBECTOMY

Abstract Glioblastomas extend beyond the contrast-enhancing tumor, and supramaximal resections into non-enhancing (NE) tumor improves survival. Yet, supramaximal resection is difficult to achieve in most cases. For temporal lobe tumors, supramaximal anterior temporal lobe resection is feasible and safe. Case series have shown a survival advantage by resecting the anterior temporal lobe. This study aims to explore patterns of tumor progression in temporal lobe glioblastomas and whether the presence of NE tumor in the temporal tip could be used as a biomarker to predict the site of progression. We searched a single institution tumor database looking for patients who had glioblastomas in the temporal lobe, who underwent complete resection of enhancing tumor, and went on to have chemoradiotherapy. Patients needed to have imaging demonstrating first progression. We determined pre-operatively if NE tumor had extended into the temporal tip. At progression, the direction of tumor progression was recorded and assessed if it would have been resected should a lobectomy have been performed. We identified 55 patients that fulfilled our entry criteria (mean age 57.7 years, range 19.6-72.9; 37 male). In 16 cases, the anterior temporal lobe was resected; these patients were not used in further assessments. In 25 cases (64.1%), the tumor progressed into the residual anterior temporal lobe. In 16 cases (41.0%), a lobectomy would have encompassed the area of progression. NE tumor was seen in the tip in 28 cases (71.8%). This could predict progression into the anterior temporal lobe with a sensitivity of 76.2% (95%CI: 54.9-90.6%) and specificity of 33.1% (95%CI: 11.8-61.6%). The likelihood ratio of tumor progression was 1.14 (95%CI: 0.75-1.74). We conclude that temporal lobe glioblastomas most commonly progress into the anterior temporal lobe, but NE tumor is not a suitable predictive biomarker. Developing suitable biomarkers and biomarker-driven trials of temporal lobectomy for glioblastomas are needed.

SURG-24. MAXIMAL SAFE RESECTION OF INSULAR GLIOMAS: AN EVALUATION OF SURGICAL AND PROGNOSTIC OUTCOMES IN 461 CASES

Abstract INTRODUCTION Insular gliomas are challenging to resect due to nearby functional cortical/subcortical structures and delicate Sylvian/sub-insular vascularity. Motor/language mapping and surgical experience are necessary for maximal safe resection (MSR). METHODS Outcomes were retrospectively evaluated following MSR in the largest single-institution series to date. 461 cases, between 1997 and 2022, were classified according to the Berger-Sanai system. Contrast-enhancing (CETV) and non-contrast-enhancing (nCETV) tumor volumes were calculated manually. RESULTS The final cohort comprised 226 high-grade (IDH-mutant, n=82) and 226 low-grade (IDH-mutant, n=101) tumors. Median nCETV was 47.7ml (grade 2, n=226), 72.6ml (grade 3, n=136), and 46.8ml (grade 4, n=90). Median CETV was 22ml for grade 3 and 13.6ml for grade 4 tumors. Most were classified as Zone I (37%), IV (8.6%), or I+IV (15%). For high-grade tumors, median CE-EOR was 96.1% (range, 29.7-100), which was highest in Zone I (100%), and supra-maximal resection was achieved in 5 cases. For low-grade tumors, median nCE-EOR was 82.4% (range, 28.4-100), which was highest in Zone 4 (85%). Additionally, initial nCETV in low-grade tumors was not associated with nCE-EOR, even when controlling for location. New postoperative motor deficits by discharge were significantly higher in Zones II (24%), I+II (22%), and III (23%). For dominant-hemisphere tumors, language deficits were highest in Zone I+II (44%), Giant (32%), and Zone II+III (29%) tumors. At 3 months, language deficits persisted in Giant (7.1%) tumors and motor deficits persisted in Giant (6.4%) and Zone II (5.9%) tumors. Median overall survival (OS) was 114.6 (grade 2), 108.6 (grade 3), and 14.7 (grade 4) months. In primary high-grade tumors, OS was longer with CE-EOR > 97.1% (36.8 vs.14.7 months, p=.04) and nCE-EOR of > 80.8% (91.3 vs. 20.2 months, p<.001). CONCLUSIONS In a high-volume academic center, surgical resection of insular gliomas with cortical/subcortical mapping can achieve excellent EOR with minimal language and motor morbidity.

The Infiltrative Margins in Glioblastoma: Important Is What Has Been Left behind.

Supramaximal resection beyond the contrast-enhancing tumor borders represents an emerging surgical strategy for patients with newly diagnosed glioblastoma. A recent study provides evidence detailing the interactive effects of more aggressive surgery on other clinical predictors of outcome, supporting guidance for surgical decision-making and informing clinical trialists about the need to stratify for extent of resection. See related article by Park et al., p. 4866.

Combined Fluorescence-Guided Surgery with 5-Aminolevulinic Acid and Fluorescein in Glioblastoma: Technical Description and Report of 100 Cases.

Fluorescence-guided resection (FGR) of glioblastomas has been previously explored with the use of 5-amivelulinic acid (5-ALA) and sodium fluoresceine (SF), allowing us to maximize the extent of resection (EoR). In this study, we highlight the most relevant concerns regarding this technique and present the methods and results from the experience of our center. A case series of 100 patients operated on in AOU Città della Salute e della Scienza in Turin with a histological diagnosis of glioblastoma (grade IV, according to WHO 2021) was retrospectively analyzed. Both 5-ALA and SF were administered and intraoperatively assessed with an optical microscope. 5-ALA is the only approved drug for FGR in glioblastoma, reporting an increased EoR. Nevertheless, SF can be positively used in addition to 5-ALA to reduce the risk of false positives without increasing the rate of adverse effects. In our experience, SF was used to guide the initial phase of resection while 5-ALA was used to visualize tumor spots within the surgical cavity. In 96% of cases, gross total resection was achieved, with supra-maximal resection in 11% of cases. Combined FGR using 5-ALA and SF seems to be a promising method of increasing the extent of resection and to improving the prognosis in glioblastoma patients.

Supramaximal resection: retrospective study on IDH-wildtype Glioblastomas based on the new RANO-Resect classification.

The prognostic value of the extent of resection in the management of Glioblastoma is a long-debated topic, recently widened by the 2022 RANO-Resect Classification, which advocates for the resection of the non-enhancing disease surrounding the main core of tumors (supramaximal resection, SUPR) to achieve additional survival benefits. We conducted a retrospective analysis to corroborate the role of SUPR by the RANO-Resect Classification in a single center, homogenous cohort of patients. Records of patients operated for WHO-2021 Glioblastomas at our institution between 2007 and 2018 were retrospectively reviewed; volumetric data of resected lesions were computed and classified by RANO-Resect criteria. Survival and correlation analyses were conducted excluding patients below near-total resection. 117 patients met the inclusion criteria, encompassing 45 near-total resections (NTR), 31 complete resections (CR), and 41 SUPR. Median progression-free and overall survival were 11 and 15months for NTR, 13 and 17months or CR, 20 and 24months for SUPR, respectively (p < 0.001), with inverse correlation observed between survival and FLAIR residual volume (r -0.28). SUPR was not significantly associated with larger preoperative volumes or higher rates of postoperative deficits, although it was less associated with preoperative neurological deficits (OR 3.37, p = 0.003). The impact of SUPR on OS varied between MGMT unmethylated (HR 0.606, p = 0.044) and methylated (HR 0.273, p = 0.002) patient groups. Results of the present study support the validity of supramaximal resection by the new RANO-Resect classification, also highlighting a possible surgical difference between tumors with methylated and unmethylated MGMT promoter.

Prognostic Evaluation of Surgical Re-Resection for Recurrent Glioblastoma Using the Novel RANO Classification for Extent of Resection by The RANO Resect Group

INTRODUCTION: The value of re-resection in recurrent glioblastoma remains unclear since leaving certain tumor deliberately behind appears ethically not justified. METHODS: The international RANO resect group retrospectively compiled an eight-center cohort of patients with first recurrence from a previously resected glioblastoma. The associations of re-resection and clinical factors with outcome were analyzed. Propensity score-matched analyses were constructed to minimize potential confounders when comparing the different RANO classes. RESULTS: We identified 681 patients with first recurrence of IDH-wildtype glioblastomas, including 310 patients who underwent re-resection. The use of re-resection was associated with prolonged survival also when stratifying for molecular and clinical confounders on multivariate analysis; and ≤ 1 cm3 residual CE tumor translated into improved survival compared to non-surgical management. Accordingly, ‘maximal resection’ (class 2) had superior survival compared to ‘submaximal resection’ (class 3). Adjuvant (radio-)chemotherapy further augmented the beneficial effects of lower residual CE tumor. Conversely, ‘supramaximal resection’ of non-CE tumor (class 1) was not associated with prolonged survival but frequently accompanied by post-operative deficits, hampering further treatment. The prognostic role of residual CE tumor was confirmed in propensity score analyses. CONCLUSIONS: Maximal extent of re-resection measured as residual CE tumor is highly prognostic in recurrent glioblastoma. The RANO classification serves to stratify patients accordingly. While the optimal adjuvant therapy awaits evaluation, our study supports that (radio-)chemotherapy consolidates the effects of re-resection.

Minimally invasive keyhole approach for supramaximal frontal glioma resections: technical note.

The authors aimed to review the frontal lobe's surgical anatomy, describe their keyhole frontal lobectomy technique, and analyze the surgical results. Patients with newly diagnosed frontal gliomas treated using a keyhole approach with supramaximal resection (SMR) from 2016 to 2022 were retrospectively reviewed. Surgeries were performed on patients asleep and awake. A human donor head was dissected to demonstrate the surgical anatomy. Kaplan-Meier curves were used for survival analysis. Of the 790 craniotomies performed during the study period, those in 47 patients met our inclusion criteria. The minimally invasive approach involved four steps: 1) debulking the frontal pole; 2) subpial dissection identifying the sphenoid ridge, olfactory nerve, and optic nerve; 3) medial dissection to expose the falx cerebri and interhemispheric structures; and 4) posterior dissection guided by motor mapping, avoiding crossing the inferior plane defined by the corpus callosum. A fifth step could be added for nondominant lesions by resecting the inferior frontal gyrus. Perioperative complications were recorded in 5 cases (10.6%). The average hospital length of stay was 3.3 days. High-grade gliomas had a median progression-free survival of 14.8 months and overall survival of 23.9 months. Keyhole approaches enabled successful SMR of frontal gliomas without added risks. Robust anatomical knowledge and meticulous surgical technique are paramount for obtaining successful resections.

SUPRAMAX-study: supramaximal resection versus maximal resection for glioblastoma patients: study protocol for an international multicentre prospective cohort study (ENCRAM 2201)

IntroductionA greater extent of resection of the contrast-enhancing (CE) tumour part has been associated with improved outcomes in glioblastoma. Recent results suggest that resection of the non-contrast-enhancing (NCE) part might...

291 Supra-maximal Extent of Resection is Associated With Improved Progression-Free Survival in Patients With IDH Wild-Type Glioblastoma Once Negative TERT Promoter Molecular Margins are Achieved

INTRODUCTION: The standard of care for isocitrate dehydrogenase (IDH) wild-type GBM involves safe maximal resection with subsequent chemoradiation. TERT promoter (TERTp) mutations are clonal in &gt;85% of IDH wild-type GBMs, detectable in all tumor cells. Advances in surgical management have focused on optimizing maximal resection given the positive correlation between extent of resection (EOR) and post-operative outcomes. METHODS: TERTp mutation detection in margin specimens was performed via a novel 30min qPCR-based method. A machine learning algorithm incorporating preoperative anatomic and intraoperative characteristics was developed using 148 patients to predict EOR. This model was prospectively applied to 44 patients to assess the correlation between a TERTp mutation negative margin and survival in cases when GTR was predicted. RESULTS: Retrospective analysis of 148 patients who underwent resection of GBM revealed significant improvement in 36-month survival with residual volume (RV) &lt;4.9 cc). The primary predictive characteristics for achieving this RV were tumor volume, ventricular contact, multifocality, and Sawaya grade. Prospective analysis of 44 patients showed that, in cases where GTR was predicted and achieved, 26% obtained a TERTp negative margin. Although small, this group's PFS was significantly prolonged (0% vs 75% event-free at 30 months, p = 0.02), and a numerically superior prolonged OS was observed, while survival in GTR with positive molecular margin was indistinguishable from STR. CONCLUSIONS: These findings provide novel evidence supporting the utility of supramaximal resection targeting a “molecular margin” to maximize postoperative survival for a subset of patients with “localized” GBM. Further study is warranted to assess intraoperative, quantitative testing of TERTp mutation in GBM specimens to guide marginal resection in these patients.

Applying the en-bloc technique in corpus callosum glioblastoma surgery contributes to maximal resection and better prognosis: a retrospective study.

Corpus callosum glioblastoma (ccGBM) is a specific type of GBM and has worse outcomes than other non-ccGBMs. We sought to identify whether en-bloc resection of ccGBMs based on T2-FLAIR imaging contributes to clinical outcomes and can achieve a satisfactory balance between maximal resection and preservation of neurological function. A total of 106 adult ccGBM patients (including astrocytoma, WHO grade 4, IDH mutation, and glioblastoma) were obtained from the Department of Neurosurgery in Nanfang Hospital between January 2008 and December 2018. The clinical data, including gender, age, symptoms, location of tumor, involvement of eloquent areas, extent of resection (EOR), pre- and postoperative Karnofsky Performance Status (KPS) scales, and National Institute of Health stroke scale (NIHSS) scores were collected. Propensity score matching (PSM) analysis was applied to control the confounders for analyzing the relationship between the en-bloc technique and EOR, and the change in the postoperative KPS scales and NIHSS scores. Applying the en-bloc technique did not negatively affect the postoperative KPS scales compared to no-en-bloc resection (P = 0.851 for PSM analysis) but had a positive effect on preserving or improving the postoperative NIHSS scores (P = 0.004 for PSM analysis). A positive correlation between EOR and the en-bloc technique was identified (r = 0.483, P < 0.001; r = 0.720, P < 0.001 for PSM analysis), indicating that applying the en-bloc technique could contribute to enlarged maximal resection. Further survival analysis confirmed that applying the en-bloc technique and achieving supramaximal resection could significantly prolong OS and PFS, and multivariate analysis suggested that tumor location, pathology, EOR and the en-bloc technique could be regarded as independent prognostic indicators for OS in patients with ccGBMs, and pathology, EOR and the en-bloc technique were independently correlated with patient's PFS. Interestingly, the en-bloc technique also provided a marked reduction in the risk of tumor recurrence compared with the no-en-bloc technique in tumors undergoing TR, indicating that the essential role of the en-bloc technique in ccGBM surgery (HR: 0.712; 95% CI: 0.535-0.947; P = 0.02). The en-bloc technique could contribute to achieving an enlarged maximal resection and could significantly prolong overall survival and progression-free survival in patients with ccGBMs.

Extent of Resection and Outcomes of Patients with Primary Malignant Brain Tumors.

We have level II evidence that attempting a gross total resection of newly diagnosed suspected glioblastoma is preferred when a maximally safe resection can be attempted. This recommendation extends to elderly patients and those with butterfly gliomas. However, in cases where patients are poor surgical candidates, or for lesions in eloquent areas, subtotal resection or biopsy may be indicated. Recent studies have discussed "supramaximal surgery," which is defined in different ways by different teams, but there is not enough evidence, yet, to make a consistent recommendation for supramaximal resection for specific patients.

SURG-21. THE PROGNOSTIC ROLE OF RE-RESECTION FOR RECURRENT GLIOBLASTOMA: A REPORT OF THE RANO RESECT GROUP USING A NOVEL CLASSIFICATION FOR EXTENT OF RESECTION

Abstract BACKGROUND The role of re-resection in recurrent glioblastoma remains controversial since leaving certain tumor volumes deliberately behind cannot be ethically justified. We aimed to (I) analyze the prognostic value of re-resection using the novel RANO resect classification for quantification of residual tumor, and (II) explore factors that favorably consolidate the effects of re-resection on outcome. METHODS The RANO resect group retrospectively accumulated a global, eight-center cohort of patients with first recurrence from a previously resected glioblastoma. The associations of re-resection and clinical factors with outcome were analyzed. Propensity score-matched analyses were constructed to mimic randomized clinical trials comparing different residual tumor volumes. RESULTS We analyzed 681 patients with first recurrence of IDH-wildtype glioblastoma, including 310 patients who underwent re-resection at first recurrence. The use of re-resection was associated with prolonged survival also when stratifying for molecular and clinical confounders (HR:0.65, CI:0.5-0.8; p = 0.001). Smaller post-operative contrast-enhancing (CE) tumor volumes were favorably associated with outcome of re-resected patients (HR per cm3:1.04, CI:1.0-1.1; p = 0.009), and ≤ 1 cm3 residual CE tumor translated into improved survival compared to non-surgical management. Accordingly, ‘maximal resection’ (class 2) had superior survival compared to ‘submaximal resection’ (class 3) (mOS after recurrence: 12 vs. 9 months; p = 0.003). Adjuvant chemotherapy further augmented the beneficial effects of lower residual CE tumor. Conversely, ‘supramaximal resection’ of non-CE tumor (class 1) was not associated with prolonged survival but frequently accompanied by post-operative deficits, hampering further treatment. The prognostic role of residual CE tumor was confirmed in propensity score analyses. CONCLUSION Residual CE tumor is highly prognostic in recurrent glioblastoma and the RANO resect classification serves to stratify patients accordingly. Chemotherapy may favorably contribute to the prognostic associations of re-resection. When pursuing re-resection of non-CE tumor, intraoperative mapping strategies to minimize the risk of post-operative deficits are recommended.

Supramaximal resection based on en-bloc technique reduces tumor burden and prolongs survival in primary supratentorial lobar glioblastoma.

Resection beyond the contrast-enhanced zone contributed to reduce tumor burden and prolong survival in glioblastomas. The optimal extent of resection (EOR) and how to achieve it are worthy of continuous investigation for obtaining a satisfactory balance between maximal resection and the preservation of neurological function. A total of 340 adult supratentorial lobar glioblastomas (included astrocytoma, WHO 4, IDH mutation and glioblastoma) were retrospectively evaluated. The clinical data, EOR, technique of resection, postoperative complications, overall survival (OS) and progression-free survival (PFS) were assessed by univariate, multivariate and propensity score matched analysis. Histological staining was performed to comprehend the effect of the membranous structures and the cell distribution in tumoral and peritumoral regions. Supramaximal resection (SMR) was confirmed as resection with 100% EORCE and > 50% EORnCE in glioblastomas by Cox proportional hazards model. Histological results showed SMR reduced the cell density of surgical edge compared to total resection. En-bloc technique based on membranous structures, which had blocking effect on tumoral invasion, contributed to achieve SMR. Moreover, applying en-bloc technique and achieving SMR did not additionally deteriorate neurological function and had similarly effects on the improvement of neurological function. Multivariate analysis confirmed that IDH1 status, technique of resection and EOR were independently correlated with PFS, and > 64 years old, IDH1 status, technique of resection, EOR and preoperative NIHSS were independently correlated with OS. Applying en-bloc technique and achieving SMR, which could reduce tumor burden and did not increase additional complications, both had remarkedly positive effects on clinical outcomes in patients with primary supratentorial lobar glioblastomas.

Supramaximal Resection Can Prolong the Survival of Patients with Cortical Glioblastoma: A Volumetric Study.

We aimed to retrospectively determine the resection rate of fluid-attenuated inversion recovery (FLAIR) lesions to evaluate the clinical effects of supramaximal resection (SMR) on the survival of patients with glioblastoma (GBM). Thirty-three adults with newly diagnosed GBM who underwent gross total tumor resection were enrolled. The tumors were classified into cortical and deep-seated groups according to their contact with the cortical gray matter. Pre- and postoperative FLAIR and gadolinium-enhanced T1-weighted imaging tumor volumes were measured using a three-dimensional imaging volume analyzer, and the resection rate was calculated. To evaluate the association between SMR rate and outcome, we subdivided patients whose tumors were totally resected into the SMR and non-SMR groups by moving the threshold value of SMR in 10% increments from 0% and compared their overall survival (OS) change. An improvement in OS was observed when the threshold value of SMR was 30% or more. In the cortical group (n = 23), SMR (n = 8) tended to prolong OS compared with gross total resection (GTR) (n = 15), with the median OS of 69.6 and 22.1 months, respectively (p = 0.0945). Contrastingly, in the deep-seated group (n = 10), SMR (n = 4) significantly shortened OS compared with GTR (n = 6), with median OS of 10.2 and 27.9 months, respectively (p = 0.0221). SMR could help prolong OS in patients with cortical GBM when 30% or more volume reduction is achieved in FLAIR lesions, although the impact of SMR for deep-seated GBM must be validated in larger cohorts.

Supramaximal versus gross total resection in Glioblastoma, IDH wild-type and Astrocytoma, IDH-mutant, grade 4, effect on overall and progression free survival: systematic review and meta-analysis.

To synthesize the evidence on the impact on progression-free survival (PFS) and overall survival (OS) of supramaximal resection (SMR) over gross total resection (GTR) in Glioblastoma, IDH wild-type and Astrocytoma, IDH-mutant, grade 4 (Glioblastoma). The PubMed, Scopus, Web of Science, Ovid and Cochrane databases were systematically searched (up to November 30, 2022). Studies reporting OS and PFS on adult humans with a suspected Glioblastoma, treated either with a SMR or GTR were included. Hazard ratios were estimated for each study and treatment effects were calculated through DerSimonian and Laird random effects models. The literature search yielded 14 studies published between 2013 and 2022, enrolling a total of 6779 patients. Analysis of the included studies reveals significantly better clinical outcomes favoring SMR over GTR in terms of PFS (HR 0.67; p = 0.0007), and OS (HR 0.7; p = 0.0001). Glioblastoma, IDH wild-type and Astrocytoma, IDH-mutant, grade 4, are aggressive tumors with a very short long-term OS. SMR is an effective therapeutic approach contributing to increased PFS and OS in patients with this catastrophic disease.

The surgical management of diffuse gliomas: Current state of neurosurgical management and future directions.

After recent updates to the World Health Organization pathological criteria for diagnosing and grading diffuse gliomas, all major North American and European neuro-oncology societies recommend a maximal safe resection as the initial management of a diffuse glioma. For neurosurgeons to achieve this goal, the surgical plan for both low- and high-grade gliomas should be to perform a supramaximal resection when feasible based on preoperative imaging and the patient's performance status, utilizing every intraoperative adjunct to minimize postoperative neurological deficits. While the surgical approach and technique can vary, every effort must be taken to identify and preserve functional cortical and subcortical regions. In this summary statement on the current state of the field, we describe the tools and technologies that facilitate the safe removal of diffuse gliomas and highlight intraoperative and postoperative management strategies to minimize complications for these patients. Moreover, we discuss how surgical resections can go beyond cytoreduction by facilitating biological discoveries and improving the local delivery of adjuvant chemo- and radiotherapies.

Prognostic evaluation of surgical re-resection for recurrent glioblastoma using the novel RANO classification for extent of resection: A report of the RANO resect group.

2010 Background: The clinical effects of re-resection for recurrent glioblastoma remain controversial, and the role of post-operative tumor volume is unclear since leaving certain tumor volumes deliberately behind cannot be ethically justified. A surgical classification system was previously proposed for stratification based upon residual contrast-enhancing (CE) tumor: RANO class 1 was defined as ‘supramaximal CE resection’ (including non-CE tumor removal), class 2 as ‘maximal CE resection’, class 3 as ‘submaximal CE resection’, and class 4 as ‘biopsy’. We aimed to (I) explore the prognostic role of extent of re-resection using this classification and (II) define clinical factors which consolidate the effects of re-resection. Methods: The RANO resect group retrospectively compiled a global, eight-center cohort of patients with first recurrence from a previously resected glioblastoma. The combined associations of re-resection and clinical factors with outcome were analyzed. Kaplan-Meier survival analysis and log-rank test were applied to calculate survival, and Cox’s proportional hazard regression models to adjust for multiple variables (significance level: p ≤ 0.05). A propensity score-matched analysis was constructed to mimic a randomized clinical trial comparing the different RANO classes. Results: We encountered 681 patients with first recurrence of IDH-wildtype glioblastoma, including 310 patients who underwent re-resection at first recurrence. The use of re-resection was associated with prolonged survival also when stratifying for molecular and clinical confounders on multivariate analysis including pre-operative tumor volume, MGMT promotor status, and non-surgical therapies (HR: 0.65, CI: 0.5-0.8; p = 0.001); and ≤1 cm3 residual CE tumor translated into improved survival compared to non-surgical management. Accordingly, ‘maximal resection’ (class 2) had superior survival compared to ‘submaximal resection’ (class 3) (median OS after recurrence: 12 vs. 9 months; p = 0.003). Adjuvant chemotherapy further augmented the beneficial effects of lower residual CE tumor. Conversely, ‘supramaximal resection’ of non-CE tumor (class 1) was not associated with prolonged survival but frequently accompanied by post-operative deficits, hampering further treatment. The prognostic role of residual CE tumor was confirmed in propensity score analyses. Conclusions: Extent of resection for recurrent glioblastoma as quantified by residual CE tumor is highly prognostic and the RANO resect classification may serve to stratify patients accordingly. Chemotherapy may favorably contribute to the prognostic associations of re-resection. When pursuing resection of non-CE tumor, intraoperative mapping strategies to minimize the risk of post-operative deficits are recommended.

Prognostic evaluation of re-resection for recurrent glioblastoma using the novel RANO classification for extent of resection: A report of the RANO resect group.

The value of re-resection in recurrent glioblastoma remains controversial as a randomized trial that specifies intentional incomplete resection cannot be justified ethically. Here, we aimed to (1) explore the prognostic role of extent of re-resection using the previously proposed Response Assessment in Neuro-Oncology (RANO) classification (based upon residual contrast-enhancing (CE) and non-CE tumor), and to (2) define factors consolidating the surgical effects on outcome. The RANO resect group retrospectively compiled an 8-center cohort of patients with first recurrence from previously resected glioblastomas. The associations of re-resection and other clinical factors with outcome were analyzed. Propensity score-matched analyses were constructed to minimize confounding effects when comparing the different RANO classes. We studied 681 patients with first recurrence of Isocitrate Dehydrogenase (IDH) wild-type glioblastomas, including 310 patients who underwent re-resection. Re-resection was associated with prolonged survival even when stratifying for molecular and clinical confounders on multivariate analysis; ≤1 cm3 residual CE tumor was associated with longer survival than non-surgical management. Accordingly, "maximal resection" (class 2) had superior survival compared to "submaximal resection" (class 3). Administration of (radio-)chemotherapy in the absence of postoperative deficits augmented the survival associations of smaller residual CE tumors. Conversely, "supramaximal resection" of non-CE tumor (class 1) was not associated with prolonged survival but was frequently accompanied by postoperative deficits. The prognostic role of residual CE tumor was confirmed in propensity score analyses. The RANO resect classification serves to stratify patients with re-resection of glioblastoma. Complete resection according to RANO resect classes 1 and 2 is prognostic.

Update for astrocytomas: medical and surgical management considerations.

Astrocytomas include a wide range of tumors with unique mutations and varying grades of malignancy. These tumors all originate from the astrocyte, a star-shaped glial cell that plays a major role in supporting functions of the central nervous system (CNS), including blood-brain barrier (BBB) development and maintenance, water and ion regulation, influencing neuronal synaptogenesis, and stimulating the immunological response. In terms of epidemiology, glioblastoma (GB), the most common and malignant astrocytoma, generally occur with higher rates in Australia, Western Europe, and Canada, with the lowest rates in Southeast Asia. Additionally, significantly higher rates of GB are observed in males and non-Hispanic whites. It has been suggested that higher levels of testosterone observed in biological males may account for the increased rates of GB. Hereditary syndromes such as Cowden, Lynch, Turcot, Li-Fraumeni, and neurofibromatosis type 1 have been linked to increased rates of astrocytoma development. While there are a number of specific gene mutations that may influence malignancy or be targeted in astrocytoma treatment, O 6-methylguanine-DNA methyltransferase (MGMT) gene function is an important predictor of astrocytoma response to chemotherapeutic agent temozolomide (TMZ). TMZ for primary and bevacizumab in the setting of recurrent tumor formation are two of the main chemotherapeutic agents currently approved in the treatment of astrocytomas. While stereotactic radiosurgery (SRS) has debatable implications for increased survival in comparison to whole-brain radiotherapy (WBRT), SRS demonstrates increased precision with reduced radiation toxicity. When considering surgical resection of astrocytoma, the extent of resection (EoR) is taken into consideration. Subtotal resection (STR) spares the margins of the T1 enhanced magnetic resonance imaging (MRI) region, gross total resection (GTR) includes the margins, and supramaximal resection (SMR) extends beyond the margin of the T1 and into the T2 region. Surgical resection, radiation, and chemotherapy are integral components of astrocytoma treatment.