Stupp Protocol Research Articles

P13.01.A 11C-METHIONIN PET FOR RADIOTHERAPY TREATMENT PLANNING IN PATIENTS WITH RAPID EARLY PROGRESSION AFTER GLIOBLASTOMA SURGERY: PROSPECTIVE PHASE II TRIAL

Abstract BACKGROUND Radiotherapy (RT) is a standard treatment for nearly all glioblastoma patients following initial surgery. Few retrospective studies indicate negative prognostic instances of progression during the planning magnetic resonance (MR) (up to 1 week before initiating RT), termed Rapid Early Progression (REP). The optimal RT management for REP patients remains uncertain. The objective of this prospective phase II trial (NCT05608395) is to assess impact of 11C-Methionine PET used for RT planning in REP glioblastoma patients. It is one of the first prospective clinical interventional trials focused on this specific cohort of patients. MATERIAL AND METHODS We enrolled glioblastoma, IDHwt, or Astrocytoma, IDHmt, WHO grade IV patients, who developed REP characterized by 1) increase in postoperative residuum by ≥ 25%, 2) appearance of new contras enhancing lesion, 3) unequivocal progression of the unresected satelite. Patients received treatment based on the Stupp or Perry protocol. Treatment response was evaluated using RANO criteria. RT target volumes were delineated as follows: Gross tumor volume included tumor cavity, enhancing lesion and 11C-MET PET (1.3 tumor-to-background ratio). The clinical target volume was GTV plus a modified 2cm margin reflecting surrounding organs at risk. Volumetric analyses of different radiotherapy target volume were performed using EclipseTM software including patterns of failure. RESULTS During 12/2020 - 12/2023, total of 31 patients were enrolled (16 treated via abbreviated RT course); median age 60 years, ECOG 0-1 in 28 patients, median follow up 20 months. No effect of 11C-MET PET - based radiotherapy treatment planning of GBM patients with REP was observed on PFS (median 3.4 months comparing to 4.9 in historical control cohort) and OS (12.3 months comparing to 15.7 months). Median MET volume was 7.3cm3 (43% of MRI volume), MET avidity was presented in 7 patients et least 1cm beyond MRI volume. Central recurrence was presented in 87% patients. CONCLUSION The optimal treatment of patients with REP is unknown and needs to be studied in more details including dose escalation studies with reduced target margins potentialy directed also by aminoacid PET examination. Adjustment of target radiotherapy volumes using 11C-MET PET did not lead to improved PFS or OS. Supported by NU20-03-00148.

PROLONGED SURVIVAL IN IDH-WILDTYPE GLIOBLASTOMA: CASE REPORTS, LITERATURE REVIEW AND CURRENT PERSPECTIVES OF MOLECULAR BEHAVIOR

Abstract AIMS Glioblastoma remains one of the most aggressive primary brain tumours, with a median survival of around 12 months despite advances in treatment. However, rare cases of long-term survival challenge this prognosis. The evaluation of age, tumour location, surgical approach and strategies, adjuvant therapy, and molecular behavior provides valuable prognostic and predictive information in patients with glioblastoma. METHOD We present a case report of two patients diagnosed with wild-type glioblastoma who have survived over 10 years post-primary surgery. A review of epidemiological data, preoperative and postoperative radiological reports, surgical approach, and histology reports were studied. Additionally, we review the current literature to explore current nuances in High-Grade Glioma Wild Type prognosis and potential future directions. Three major medical database engines, PubMed (Medline), Scopus (ELSEVIER), and Cochrane were used to conduct a thorough literature search. RESULTS Both patients underwent maximal safe resection followed by the Stupp Protocol, comprising adjuvant chemotherapy with temozolomide and radiotherapy. Our case report highlights two exceptional cases of prolonged survival in Glioblastoma patients, both under 51 years-old at the moment of diagnosis, early diagnosis with isolated lobar lesions, no compromise of deep white matter, and achieving maximal safe resection and functional independence. Molecular analysis revealed specific genetic in common, including IDH Wild Type, p53 mutation, retained ATRX expression, TERT mutation, and MGMT promoter methylation, consistent with a favourable prognosis. Moreover, patients without recurrence often exhibit distinct molecular profiles, such as MGMT promoter methylation, suggesting a potential subtype associated with prolonged survival. CONCLUSION Our case reports and literature review highlight the possibility of prolonged survival in Glioblastoma patients. The age, tumor location at the time of diagnosis, comprehensive treatment approaches, may contribute to improved outcomes. Molecular profiling, particularly assessing genetic mutations and MGMT promoter methylation, holds promise for identifying patients with a higher likelihood of prolonged survival.

Efficacy and Cognitive Outcomes of Gamma Knife Radiosurgery in Glioblastoma Management for Elderly Patients.

Gamma Knife Radiosurgery (GKRS), a specific type of Stereotactic Radiosurgery (SRS), has developed as a significant modality in the treatment of glioblastoma, particularly in conjunction with standard chemotherapy. The goal of this study is to evaluate the efficacy of combining GKRS with surgical resection and chemotherapy in enhancing therapeutic effects for glioblastoma patients aged 55 years and older. This prospective clinical study, conducted in accordance with the STROBE guidelines, involved 49 glioblastoma patients aged 55 years and older, treated between January 2013 and January 2023. Data were collected prospectively, and strict adherence to the STUPP protocol was maintained. Only patients who conformed to the STUPP protocol were included in the analysis. Due to concerns regarding the cognitive impairment associated with conventional radiotherapy, and at the patients' request, a radiosurgery plan was offered. Radiosurgery was administered for 4-8 weeks following surgical resection. Any patients who had not received previous radiotherapy received open surgical tumor removal, followed by GKRS along with adjuvant chemotherapy. In this prospective clinical study of 49 glioblastoma patients aged 55 years and older, the average lifespan post-histopathological diagnosis was established at 22.3 months (95% CI: 12.0-28.0 months). The median time before disease progression was 14.3 months (95% CI: 13.0-29.7 months). The median duration until the first recurrence after treatment was 15.2 months, with documented cases varying between 4 and 33 months. The Gamma Knife Radiosurgery (GKRS) treatment involved a median marginal recommended dose of 12.5 Gy, targeting an average volume of 5.7 cm3 (range: 1.6-39 cm3). Local recurrence occurred in 21 patients, while distant recurrence was identified in 8 patients. Within the cohort, 34 patients were subjected to further therapeutic approaches, including reoperation, a second GKRS session, the administration of bevacizumab and irinotecan, and PCV chemotherapy. A cognitive function assessment revealed that the patients treated with GKRS experienced significantly less cognitive decline compared to the historical controls, who were treated with conventional radiotherapy. The median MMSE scores declined by 1.9 points over 12 months, and the median MoCA scores declined by 2.9 points. This study demonstrates that Gamma Knife Radiosurgery (GKRS), when integrated with surgical resection and adjuvant chemotherapy, offers a substantial benefit for glioblastoma patients aged 55 years and older. The data reveal that GKRS not only prolongs overall survival and progression-free survival but also significantly reduces cognitive decline compared to conventional radiotherapy. These findings underscore the efficacy and safety of GKRS, advocating for its incorporation into standard treatment protocols for older glioblastoma patients. The potential of GKRS to improve patient outcomes while preserving cognitive function is compelling and warrants further research to optimize and confirm its role in glioblastoma management.

Fotemustine in recurrent high‑grade glioma: MRI neuro‑radiological findings.

The use of fotemustine (FTM) has been authorized in certain countries for the treatment of recurrent high-grade gliomas (HGG) after Stupp therapy. However, to the best of our knowledge, no studies have assessed changes in magnetic resonance imaging (MRI) during treatment with FTM monotherapy. The aim of the present study was to assess the neuroradiological findings in a cohort of patients with recurrent HGG treated with FTM monotherapy. Patients with HGG already undergoing the Stupp protocol were retrospectively included. MRIs (pre- and post-FTM treatment) were analyzed by two neuroradiologists in consensus: Volume and diffusion values of the contrast-enhanced component were measured on T1-weighted volumetric sequences after gadolinium injection and on apparent diffusion coefficient (ADC) maps, respectively. A total of 19 patients [median age, 49 years; interquartile range (IQR), 43-57 years] were included, 17 of whom had glioblastoma and 2 had astrocytoma isocitrate dehydrogenase-mutated grade 4. The median duration of FTM therapy was 4 months (IQR, 2-6 months). The median tumor volume measured on the contrast-enhanced component was 2,216 mm3 (IQR, 768-13,169 mm3) at baseline and 9,217 mm3 (IQR, 3,455-16,697 mm3) at the end of treatment, with a median change of +38% (IQR, -45-+574%). A total of seven patients showed a volume decrease. ADC value analysis of the enhancement area demonstrated no significant difference between the pre- and the post-FTM treatment periods (P=0.36); however, in three patients, the decreases in ADC levels were particularly marked. In conclusion, the present study described a series of patients with recurrent HGG treated with FTM in monotherapy, demonstrating a prevalent increase in lesion enhancement and three cases of marked restrictions on diffusion-weighted imaging. Further prospective studies are required to corroborate such preliminary results.

Prognostic Factors for Patients with Primary Gliosarcoma: A Single-Center Retrospective Study

Primary gliosarcoma is a rare form of malignant central nervous system (CNS) tumor, with limited understanding regarding its prognostic determinants and effective therapeutic interventions. The medical records of patients diagnosed with gliosarcoma at Tangdu Hospital between March 2011 and June 2023 were retrospectively analyzed in this study. Patients with a prior history of glioma or those who received preoperative chemoradiotherapy were excluded. Survival analyses were conducted using Kaplan-Meier and Cox regression analysis. A total of 77 patients were included in the final analysis with a median age of 57 years (range 13-83). The predominant symptom leading to diagnosis was headache, and the temporal lobe was the most frequently affected site. Univariate analysis revealed that age ≤ 65 years, complete resection, Ki67 ≤ 25%, postoperative Karnofsky Performance Status (KPS) ≥ 70, adherence to the Stupp protocol, and additional active therapy upon relapse were associated with enhanced survival. Furthermore, multivariate analysis identified complete resection, aged ≤ 65 years, Stupp protocol treatment, and active therapy following relapse were independent predictors of overall survival (OS). Notably, one patient experienced subcutaneous metastasis during treatment. The present study's findings suggest that optimal management of primary gliosarcoma entails maximal safe resection, combined with adjuvant radiotherapy and chemotherapy with temozolomide, followed by salvage therapy in case of recurrence. However, the risk of metastases should be carefully monitored during the treatment course.

Temozolomide (TMZ) in the Treatment of Glioblastoma Multiforme-A Literature Review and Clinical Outcomes.

Glioblastoma multiforme (GBM) is one of the most aggressive primary tumors of the central nervous system. It is associated with a very poor prognosis, with up to half of patients failing to survive the first year after diagnosis. It develops from glial tissue and belongs to the adult-type diffuse glioma group according to the WHO classification of 2021. Therapy for patients with GBM is currently based on surgical resection, radiation therapy, and chemotherapy, but despite many efforts, there has been minimal progress in tumor management. The most important chemotherapeutic agent in the treatment of this tumor is temozolomide (TMZ), a dacarbazine derivative that presents alkylating activity. It is usually administered to patients concurrently with radiation therapy after surgical resection of the tumor, which is defined as the Stupp protocol. Temozolomide demonstrates relatively good efficacy in therapy, but it could also present with several side effects. The resistance of GBM to the drug is currently the subject of work by specialists in the field of oncology, and its use in various regimens and patient groups may bring therapeutic benefits in the future. The aim of this review paper is to summarize the relevance of TMZ in the treatment of GBM based on recent reports.

Retrospective Analysis of Glioblastoma Outcomes.

This retrospective mono-center study focuses on 144 cases of glioblastoma treated over a time span of 12 years in our clinic in Romania. We offer critical insight into the dreadful aspect of this tumor by highlighting the principal characteristics such as localization, the genetic information of each case, progression-free survival (PFS), and overall survival (OS). A tenth of our patients underwent a second surgical procedure, providing a comparable OS to the other part of our study group, proving that surgical treatment as salvage therapy is a viable option. Also, our research reinforces the fact that utilizing the Karnofsky Performance Scale is a great predictor of patient outcomes in glioblastoma patients. Even though radiotherapy and chemotherapy have mild effects in the context of this oncological disease, our research shows that O6-methylguanine-DNA methyltransferase (MGMT) methylation status and epidermal growth factor receptor (EGFR) amplification have an important effect on OS. Moreover, the particularity of our study, that our patients did not start adjuvant therapy right after surgery, highlighted by a low OS compared to the international literature, sheds light on the fact that chemotherapy and radiotherapy must be started right after the surgical procedure, according to the Stupp protocol. To sum up, our research takes into consideration the factors that influence patient survival and outcome in the battle against glioblastoma.

Amino-acid PET as a prognostic tool after post Stupp protocol temozolomide therapy in high-grade glioma patients

PurposeThis study aimed to evaluate the prognostic performance of amino-acid PET in high-grade gliomas (HGG) patients at the time of temozolomide (TMZ) treatment discontinuation, after the Stupp protocol.MethodsThe analysis included consecutive HGG patients with dynamic [18F]FDOPA PET imaging within 3 months of the end of TMZ therapy, post-Stupp protocol. Static and dynamic PET parameters, responses to RANO criteria for MRI and clinical and histo-molecular factors were correlated to progression-free (PFS).ResultsThirty-two patients (59.4 [54.0;67.6] years old, 13 (41%) women) were included. Static PET parameters peak tumor-to-background ratio and metabolic tumor volume (respective thresholds of 1.9 and 1.5 mL) showed the best 84% accuracies for predicting PFS at 6 months (p = 0.02). These static PET parameters were also independent predictor of PFS in multivariate analysis (p ≤ 0.05).ConclusionIn HGG patients having undergone a Stupp protocol, the absence of significant PET uptake after TMZ constitutes a favorable prognostic factor.

Single institution analysis of glioblastoma multiforme (GBM) outcomes based on year of diagnosis: A 17 year review.

e14023 Background: GBM is the most common brain tumour in adults. The latest WHO classification excludes IDH mutated tumours, acknowledging their favourable prognosis. MGMT methylation is a prognostic biomarker and predicts level of benefit from Temozolomide. The standard of care management includes maximal surgical resection followed by radiotherapy with concurrent and adjuvant Temozolomide. This has remained largely unchanged for nearly 20 years. We analysed 17 years of newly diagnosed GBM cases attending Medical Oncology at our institution to assess outcome advancements. Methods: Demographic information, clinicopathological characteristics, surgery, radiotherapy and systemic anti-cancer treatment data were collected from the charts of patients diagnosed with GBM and seen by the Medical Oncology department at Cork University Hospital between 2005-2021. The study population was divided into 2 time periods: 2005-2016 and 2017-2021. Overall survival was recorded. Baseline characteristics was compared across time periods using the Chi-Square test. Univariate and multivariate analysis was performed to assess impact of different variables on overall survival. Results: The analysis comprised 306 patients, with 142 and 164 diagnosed between 2005-2016 and 2017-2021 respectively. Median age was 62 years (range 17-86) and patients were predominantly male (65%). Patients in the earlier time period were more likely to have ECOG performance status 0-1 (80% vs 65% p = 0.011) and were more likely to commence treatment on Stupp protocol (99% vs 80% p = <0.001). IDH and MGMT testing were less prevalent in the earlier time period. Median overall survival (mOS) for the entire cohort was 11.6 months. Univariate analysis revealed correlations between overall survival and time period of diagnosis, age >65, MGMT status, ECOG performance status, steroid use, surgery, re-resection, and completion of adjuvant chemoradiation protocols. The mOS was 12.3 months in the earlier time period and 10.4 months in the later time period (HR = 1.35 p = 0.012). Time period of diagnosis remained an independent prognostic factor for poor outcome on multivariate analysis. Notably, mOS during the COVID-19 pandemic (2020-2021) was 10.6 months, showing no difference from other time periods. Conclusions: Despite advances in our knowledge regarding the molecular biology of GBM, prognosis remains poor. Our institution’s 17 year survival data indicates no improvement over time emphasising the urgent need for new treatment strategies. Notably, the more recent time period had an increased number of frailer patients who were too unwell to commence any adjuvant treatment, possibly indicating a lower referral threshold which may have negatively impacted mOS in that cohort. Additionally, the absence of IDH status assessment in the earlier era means some IDH mutant patients were likely included, thereby inflating the mOS for that cohort.

Survival analysis and associated factors of highgrade glioma patients

High-grade gliomas are the most common primary brain tumors in adults, and they usually have a quick fatal course. Average survival is 18 months, mainly, because of tumor resistance to Stupp protocol. To determine high-grade glioma patient survival and the effect of persuasion variables on survival. We conducted a longitudinal descriptive study in which 80 untreated recently diagnosed high-grade glioma patients participated. A survey was conducted regarding their exposure to some risk factors, degree of genetic instability in peripheral blood using micronucleus quantification on binuclear lymphocytes, micronuclei in reticulocytes and sister-chromatid exchanges in lymphocytes. In the statistical analysis, this study constructed life tables, used the Kaplan-Meier, and the log-rank test, and in the multivariate analysis, a Cox proportional hazards model was constructed. Eighty patients' clinical, demographic and lifestyle characteristics were analyzed, as well as their survival rates and the average survival time is 784 days (interquartile range: 928). Factors like age, exposure at work to polycyclic hydrocarbons and the number of sister-chromatid exchanges in lymphocytes in the first sampling was significantly survivalrelated in the multivariate analysis. We determined that only three of the analyzed variables have an important effect on survival time when it comes to high-grade glioma patients.

Overcoming Resistance to Temozolomide in Glioblastoma: A Scoping Review of Preclinical and Clinical Data

Glioblastoma (GB) is the most common and most aggressive primary brain tumor in adults, with an overall survival almost 14.6 months. Optimal resection followed by combined temozolomide chemotherapy and radiotherapy, also known as Stupp protocol, remains the standard of treatment; nevertheless, resistance to temozolomide, which can be obtained throughout many molecular pathways, is still an unsurpassed obstacle. Several factors influence the efficacy of temozolomide, including the involvement of other DNA repair systems, aberrant signaling pathways, autophagy, epigenetic modifications, microRNAs, and extracellular vesicle production. The blood–brain barrier, which serves as both a physical and biochemical obstacle, the tumor microenvironment’s pro-cancerogenic and immunosuppressive nature, and tumor-specific characteristics such as volume and antigen expression, are the subject of ongoing investigation. In this review, preclinical and clinical data about temozolomide resistance acquisition and possible ways to overcome chemoresistance, or to treat gliomas without restoration of chemosensitinity, are evaluated and presented. The objective is to offer a thorough examination of the clinically significant molecular mechanisms and their intricate interrelationships, with the aim of enhancing understanding to combat resistance to TMZ more effectively.

Long term follow-up of patients with newly diagnosed glioblastoma treated by intraoperative photodynamic therapy: an update from the INDYGO trial (NCT03048240)

PurposeGlioblastoma remains incurable despite optimal multimodal management. The interim analysis of open label, single arm INDYGO pilot trial showed actuarial 12-months progression-free survival (PFS) of 60% (median 17.1 months), actuarial 12-months overall survival (OS) of 80% (median 23.1 months). We report updated, exploratory analyses of OS, PFS, and health-related quality of life (HRQOL) for patients receiving intraoperative photodynamic therapy (PDT) with 5-aminolevulinic acid hydrochloride (5-ALA HCl).MethodsTen patients were included (May 2017 – April 2021) for standardized therapeutic approach including 5-ALA HCl fluorescence-guided surgery (FGS), followed by intraoperative PDT with a single 200 J/cm2 dose of light. Postoperatively, patients received adjuvant therapy (Stupp protocol) then followed every 3 months (clinical and cerebral MRI) and until disease progression and/or death. Procedure safety and toxicity occurring during the first four weeks after PDT were assessed. Data concerning relapse, HRQOL and survival were prospectively collected and analyzed.ResultsAt the cut-off date (i.e., November 1st 2023), median follow-up was 23 months (9,7–71,4). No unacceptable or unexpected toxicities and no treatment-related deaths occurred during the study. Kaplan–Meier estimated 23.4 months median OS, actuarial 12-month PFS rate 60%, actuarial 12-month, 24-month, and 5-year OS rates 80%, 50% and 40%, respectively. Four patients were still alive (1 patient free of recurrence).ConclusionAt 5 years-follow-up, intraoperative PDT with surgical maximal excision as initial therapy and standard adjuvant treatment suggests an increase of time to recurrence and overall survival in a high proportion of patients. Quality of life was maintained without any severe side effects.Trial registration NCT numberNCT03048240. EudraCT number: 2016–002706-39.

Response assessment of GBM during immunotherapy by delayed contrast treatment response assessment maps.

Assessing the treatment response of glioblastoma multiforme during immunotherapy (IT) is an open issue. Treatment response assessment maps (TRAMs) might help distinguish true tumor progression (TTP) and pseudoprogression (PsP) in this setting. We recruited 16 naïve glioblastoma patients enrolled in a phase II trial consisting of the Stupp protocol (a standardized treatment for glioblastoma involving combined radiotherapy and chemotherapy with temozolomide, followed by adjuvant temozolomide) plus IT with dendritic cells. Patients were followed up till progression or death; seven underwent a second surgery for suspected progression. Clinical, immunological, and MRI data were collected from all patients and histology in case of second surgery. Patients were classified as responders (progression-free survival, PFS > 12 months), and non-responders (PFS ≤ 12), HIGH-NK (natural killer cells, i.e., immunological responders), and LOW-NK (immunological non-responders) based on immune cell counts in peripheral blood. TRAMs differentiate contrast-enhancing lesions with different washout dynamics into hypothesized tumoral (conventionally blue-colored) vs. treatment-related (red-colored). Using receiver operating characteristic (ROC) curves, a threshold of -0.066 in VBlue/VCE (volume of the blue portion of tumoral area/volume of contrast enhancement) variation between values obtained in the MRI performed before PsP/TTP and at TTP/PSP allowed to discriminate TTP from PsP with a sensitivity of 71.4% and a specificity of 100%. Among HIGH-NK patients, at month 6 there was a significant reduction compared to baseline and month 2 in median "blue" volumes. In conclusion, in our pilot study TRAMs support the discrimination between tumoral and treatment-related enhancing features in immunological responders vs. non-responders, the distinction between PsP and TTP, and might provide surrogate markers of immunological response.

Hypofractionated re-irradiation with bevacizumab for relapsed chemorefractory glioblastoma after prior high dose radiotherapy: a feasible option for patients with large-volume relapse.

There remains no standard of care for patients with recurrent and chemorefractory glioblastoma. Re-irradiation (reRT) provides an additional management option. However, published series predominantly focus on small reRT volumes utilizing stereotactic hypofractionated regimens. Concerns regarding toxicity have limited utilisation of reRT for larger recurrences, however this may be mitigated with use of bevacizumab (BEV). A prospective database of patients managed with the EORTC-NCIC (Stupp) protocol 60Gy chemoradiotherapy protocol for glioblastoma between 2007 and 2021 was reviewed for those patients receiving reRT for chemorefractory relapse. Serial MRI and PET were used to establish true progression and exclude patients with pseudoprogression or radionecrosis from reRT. The primary endpoint was overall survival (OS) from date of reRT. Prognostic factors were also assessed. 447 patients managed for glioblastoma under the Stupp protocol were identified, of which 372 had relapsed and were thus eligible for reRT. 71 patients underwent reRT. Median relapse-free survival from diagnosis for the reRT and overall cohorts were similar at 11.6 months (95%CI:9.4-14.2) and 11.8 months (95%CI:9.4-14.2) respectively. 60/71 (85%) reRT patients had received BEV prior to reRT and continued concurrent BEV during reRT. Of the 11 patients not managed with BEV during reRT, 10 required subsequent salvage BEV. ReRT patients were younger (median 53 vs. 59 years, p < 0.001), had better performance status (86% vs. 69% ECOG 0-1, p = 0.002) and more commonly had MGMT promoter-methylated tumours (54% vs. 40%, p = 0.083) compared to non-reRT patients. Median reRT PTV volume was 135cm3 (IQR: 69-207cm3). Median OS from reRT to death was 7.1 months (95%CI:6.3-7.9). Patients aged < 50, 50-70 and > 70 years had post-reRT median OS of 7.7, 6.4 and 6.0 months respectively (p = 0.021). Median post-reRT survival was longer for patients with ECOG performance status 0-1 compared to 2-3 (8.1 vs. 6.3 months, p = 0.039). PTV volume, site of relapse, MGMT promoter-methylation status and extent of initial surgical resection were not associated with post-reRT survival. ReRT was well-tolerated. Out of the 6 patients (8%) admitted to hospital after reRT, only one was for reRT toxicity. This was a CTCAE grade 3 radiation necrosis event in a patient managed without prior BEV. Patients with recurrent glioblastoma who have been previously treated with 60Gy radiotherapy have a meaningful survival benefit from large volume re-irradiation which is well tolerated. ReRT should not be ignored as a salvage treatment option in patients with chemorefractory progressive disease.

Abstract 6171: Evolution of the spatial myeloid-lymphoid engagement in glioblastoma under temozolomide treatment

Abstract The current standard of care for glioblastoma (GBM), encompassing surgery, chemotherapy, and radiation, fails to extend patient survival beyond ~12-15 months. Even advanced immunotherapies, such as checkpoint blockade and chimeric antigen receptor-armored T-cell therapies, are ineffective in GBM due to tissue-specific niche-dependent escape strategies employed by glioma cells. Immune effectiveness, a finely regulated spatial and context-dependent process, underpins such a dismal state of the present therapeutic options. Herein, we applied CO-Detection by indEXing (CODEX), a state-of-the-art multiplex imaging platform, to elucidate the immune cell networks of the tumor microenvironment. By harnessing computational tools on multiplexed regions of interest across whole-slide images, we characterize the immune repertoire of GBMs by studying intratumor heterogeneity across space-histological territories- and time, matching pre- and post-treatment tissue sections of GBMs from seven patients under treatment (Stupp protocol). We aimed to assess changes in the interactions between the two main compartments of the immune system, myeloid and lymphoid, pre- and post-treatment using spatial statistics. We designed a computational workflow for the georeferencing, classification, and phenotyping individual cells of CODEX images across 105 regions of interest, representative of a mosaic of histologically defined cellular tumor (CT) or infiltrating tumor. We defined six major immune phenotypes and evaluated their spatial association with Cd45-Nestin+Olig2+ glioma cells. We modeled the GBM ecosystem and the cells’ spatial coexistence as spatial point processes that allowed the projection of coexistence networks. After stringent quality control, we detected and phenotyped 2.3M cells. Despite interpatient heterogeneity, some patients maintained an even immune composition, while others showed an enrichment in microglia, particularly in CT. Spatial network analyses revealed an increased coexistence between myeloid and lymphoid cells after treatments despite T cells being canonically considered moderately abundant. Quantitatively, the immune meta-network displayed higher edge density and lower modularity post-treatment compared with pre-treatment, reflecting increased lymphoid-myeloid engagement. In summary, we detected an increased spatial myeloid-lymphoid engagement in GBM undergoing chemo-radiation treatments. Spatiotemporal rearrangement of tumor-immune interactions indicates mechanisms implicated in disease recurrence and resistance to standard treatment, opening the frontiers for developing new targeted immunotherapies. Citation Format: Simon P. Castillo, Afrooz Jahedi, Pravesh Gupta, Jason T. Huse, Kasthuri Kannan, Yinyin Yuan, Krishna P. Bhat. Evolution of the spatial myeloid-lymphoid engagement in glioblastoma under temozolomide treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6171.

Abstract 7395: Histology-based prognosis prediction using deep learning outperforms and is independent of the MGMT methylation status in patients with glioblastoma

Abstract Introduction: MGMT gene promoter methylation status is today the only biomarker of survival for GBM patients and predicts favorable response to temozolomide (TMZ). Here we propose a deep learning-based model using histology data (H&amp;E slides) to predict the prognosis of patients with Glioblastoma (GBM) treated by standard of care (SOC). Methods: We included TCGA GBM patients and selected only patients treated after 2005 (Stupp protocol start); compliant to WHO 2021 classification; treated by surgery and adjuvant therapy; with a follow-up superior to median overall survival (OS) (14.5 months). Short and long survivor labels were defined based on median OS cut-off. A deep learning pipeline was trained to predict these labels from the H&amp;E slides (baseline surgery samples). First, the slides were automatically segmented into tissue and background, divided into a regular grid of tiles (112 × 112µm), and tiles were vectorized using a vision transformer-based feature extractor trained on H&amp;E slides of 5,500 patients with 16 cancer subtypes (GBM excluded). In the second step, ABMIL deep learning model was trained to predict the survival category using the bag of tile features available from step 1 for each patient. The cohort was divided into five folds with even numbers of short and long survivors. For each fold, 50 ABMIL models were trained on the remaining folds and ensembled to predict the category of the patients in the fold. Training hyperparameters were tuned on a separated cohort excluding GBM patients. Results: After filtering, we analyzed n = 192 TCGA GBM patients including 154 patients with a known MGMT promoter methylation status. Our histology-based model had an accuracy of 0.661 and a ROC AUC of 0.706. It stratified the population into short and long survivors with an Hazard Ratio (HR) of 0.48 (95% CI 0.34-0.69). Our model outperformed the MGMT methylation status that had an HR of 0.57 (95% CI 0.40-0.83). Moreover, our model was independent of MGMT methylation status and the combination of both was able to further improve prognosis prediction: we applied our model independently to the 91 patients with an unmethylated MGMT status (predicted: 43 low, 48 high) and to the 63 patients with a methylated MGMT status (predicted: 30 low, 33 high), and obtained HR of 0.42 (95% CI 0.27-0.67) and 0.49 (95% CI 0.28-0.86) respectively. Conclusion: Having selected patients treated by the latest SOC and classified as GBM by the latest WHO criteria, we propose a model predicting survival based on histological specimens available in routine care, which outperformed the current unique biomarker MGMT methylation status. The combination of this status and our model improves prognosis predictions compared to each strategy alone. Citation Format: Lucas Fidon, Celine Thiriez, Alexandre Grimaldi, Omar Darwiche Domingues, Charles Maussion, Caroline Hoffmann. Histology-based prognosis prediction using deep learning outperforms and is independent of the MGMT methylation status in patients with glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7395.

Glioblastoma Therapy: Past, Present and Future.

Glioblastoma (GB) stands out as the most prevalent and lethal form of brain cancer. Although great efforts have been made by clinicians and researchers, no significant improvement in survival has been achieved since the Stupp protocol became the standard of care (SOC) in 2005. Despite multimodality treatments, recurrence is almost universal with survival rates under 2 years after diagnosis. Here, we discuss the recent progress in our understanding of GB pathophysiology, in particular, the importance of glioma stem cells (GSCs), the tumor microenvironment conditions, and epigenetic mechanisms involved in GB growth, aggressiveness and recurrence. The discussion on therapeutic strategies first covers the SOC treatment and targeted therapies that have been shown to interfere with different signaling pathways (pRB/CDK4/RB1/P16ink4, TP53/MDM2/P14arf, PI3k/Akt-PTEN, RAS/RAF/MEK, PARP) involved in GB tumorigenesis, pathophysiology, and treatment resistance acquisition. Below, we analyze several immunotherapeutic approaches (i.e., checkpoint inhibitors, vaccines, CAR-modified NK or T cells, oncolytic virotherapy) that have been used in an attempt to enhance the immune response against GB, and thereby avoid recidivism or increase survival of GB patients. Finally, we present treatment attempts made using nanotherapies (nanometric structures having active anti-GB agents such as antibodies, chemotherapeutic/anti-angiogenic drugs or sensitizers, radionuclides, and molecules that target GB cellular receptors or open the blood-brain barrier) and non-ionizing energies (laser interstitial thermal therapy, high/low intensity focused ultrasounds, photodynamic/sonodynamic therapies and electroporation). The aim of this review is to discuss the advances and limitations of the current therapies and to present novel approaches that are under development or following clinical trials.

Treatment outcome of IDH1/2 wildtype CNS WHO grade 4 glioma histologically diagnosed as WHO grade II or III astrocytomas

BackgroundIsocitrate dehydrogenase (IDH)1/2 wildtype (wt) astrocytomas formerly classified as WHO grade II or III have significantly shorter PFS and OS than IDH mutated WHO grade 2 and 3 gliomas leading to a classification as CNS WHO grade 4. It is the aim of this study to evaluate differences in the treatment-related clinical course of these tumors as they are largely unknown.MethodsPatients undergoing surgery (between 2016–2019 in six neurosurgical departments) for a histologically diagnosed WHO grade 2–3 IDH1/2-wt astrocytoma were retrospectively reviewed to assess progression free survival (PFS), overall survival (OS), and prognostic factors.ResultsThis multi-center study included 157 patients (mean age 58 years (20–87 years); with 36.9% females). The predominant histology was anaplastic astrocytoma WHO grade 3 (78.3%), followed by diffuse astrocytoma WHO grade 2 (21.7%). Gross total resection (GTR) was achieved in 37.6%, subtotal resection (STR) in 28.7%, and biopsy was performed in 33.8%. The median PFS (12.5 months) and OS (27.0 months) did not differ between WHO grades. Both, GTR and STR significantly increased PFS (P < 0.01) and OS (P < 0.001) compared to biopsy. Treatment according to Stupp protocol was not associated with longer OS or PFS compared to chemotherapy or radiotherapy alone. EGFR amplification (P = 0.014) and TERT-promotor mutation (P = 0.042) were associated with shortened OS. MGMT-promoter methylation had no influence on treatment response.ConclusionsWHO grade 2 and 3 IDH1/2 wt astrocytomas, treated according to the same treatment protocols, have a similar OS. Age, extent of resection, and strong EGFR expression were the most important treatment related prognostic factors.

Reassessing the efficacy of bevacizumab in newly diagnosed glioblastoma: A systematic review and external pseudodata-based analysis.

First-line use of bevacizumab for glioblastoma (GBM) was evaluated in 2 phase 3 randomized controlled trials (RCT), demonstrating an impact on progression-free survival but not overall survival (OS). However, the crossover events of these trials raised concerns regarding the reliability of this latter analysis. In this study, we conducted an external control-based reassessment of the bevacizumab efficacy in newly diagnosed GBM (ndGBM) against the standard Stupp protocol. A systematic review of the literature was conducted to identify the phase 3 RCTs in ndGBM incorporating the Stupp protocol as an arm. For the selected studies, we extracted individual patient survival pseudodata of the Stupp protocol arm by digitizing the Kaplan-Meier plots. A comprehensive pipeline was established to select suitable control studies as external benchmarks. Among the 13 identified studies identified in our systematic review, 4 studies resulted as comparable with the AVAglio trial and 2 with the RTOG 0825. Pooled individual patient pseudodata analysis showed no differences in terms of OS when bevacizumab was added to the Stupp protocol. The external-controlled-based reassessment of the bevacizumab treatment in ndGBM confirmed its lack of efficacy in extending OS. Our study includes a summary table of individual patient survival pseudodata from all phase 3 RCTs in ndGBM employing the Stupp protocol and provides a pipeline that offers comprehensive guidance for conducting external control-based assessments in ndGBM.

NEO212, temozolomide conjugated to NEO100, exerts superior therapeutic activity over temozolomide in preclinical chemoradiation models of glioblastoma.

The chemotherapeutic standard of care for patients with glioblastoma (GB) is radiation therapy (RT) combined with temozolomide (TMZ). However, during the twenty years since its introduction, this so-called Stupp protocol has revealed major drawbacks, because nearly half of all GBs harbor intrinsic treatment resistance mechanisms. Prime among these are the increased expression of the DNA repair protein O6-guanine-DNA methyltransferase (MGMT) and cellular deficiency in DNA mismatch repair (MMR). Patients with such tumors receive very little, if any, benefit from TMZ. We are developing a novel molecule, NEO212 (TMZ conjugated to NEO100), that harbors the potential to overcome these limitations. We used mouse models that were orthotopically implanted with GB cell lines or primary, radioresistant human GB stem cells, representing different treatment resistance mechanisms. Animals received NEO212 (or TMZ for comparison) without or with RT. Overall survival was recorded, and histology studies quantified DNA damage, apoptosis, microvessel density, and impact on bone marrow. In all tumor models, replacing TMZ with NEO212 in a schedule designed to mimic the Stupp protocol achieved a strikingly superior extension of survival, especially in TMZ-resistant and RT-resistant models. While NEO212 displayed pronounced radiation-sensitizing, DNA-damaging, pro-apoptotic, and anti-angiogenic effects in tumor tissue, it did not cause bone marrow toxicity. NEO212 is a candidate drug to potentially replace TMZ within the standard Stupp protocol. It has the potential to become the first chemotherapeutic agent to significantly extend overall survival in TMZ-resistant patients when combined with radiation.