Concurrent chemoradiotherapy versus radiotherapy alone for "biopsy-only" glioblastoma multiforme

Systemic and local immunosuppression in glioblastoma and its prognostic significance

The effectiveness of tumor therapy, especially immunotherapy and oncolytic virotherapy, critically depends on the activity of the host immune cells. However, various local and systemic mechanisms of immunosuppression operate in cancer patients. Tumor-associated immunosuppression involves deregulation of many components of immunity, including a decrease in the number of T lymphocytes (lymphopenia), an increase in the levels or ratios of circulating and tumor-infiltrating immunosuppressive subsets [e.g., macrophages, microglia, myeloid-derived suppressor cells (MDSCs), and regulatory T cells (Tregs)], as well as defective functions of subsets of antigen-presenting, helper and effector immune cell due to altered expression of various soluble and membrane proteins (receptors, costimulatory molecules, and cytokines). In this review, we specifically focus on data from patients with glioblastoma/glioma before standard chemoradiotherapy. We discuss glioblastoma-related immunosuppression at baseline and the prognostic significance of different subsets of circulating and tumor-infiltrating immune cells (lymphocytes, CD4+ and CD8+ T cells, Tregs, natural killer (NK) cells, neutrophils, macrophages, MDSCs, and dendritic cells), including neutrophil-to-lymphocyte ratio (NLR), focus on the immune landscape and prognostic significance of isocitrate dehydrogenase (IDH)-mutant gliomas, proneural, classical and mesenchymal molecular subtypes, and highlight the features of immune surveillance in the brain. All attempts to identify a reliable prognostic immune marker in glioblastoma tissue have led to contradictory results, which can be explained, among other things, by the unprecedented level of spatial heterogeneity of the immune infiltrate and the significant phenotypic diversity and (dys)functional states of immune subpopulations. High NLR is one of the most repeatedly confirmed independent prognostic factors for shorter overall survival in patients with glioblastoma and carcinoma, and its combination with other markers of the immune response or systemic inflammation significantly improves the accuracy of prediction; however, more prospective studies are needed to confirm the prognostic/predictive power of NLR. We call for the inclusion of dynamic assessment of NLR and other blood inflammatory markers (e.g., absolute/total lymphocyte count, platelet-to-lymphocyte ratio, lymphocyte-to-monocyte ratio, systemic immune-inflammation index, and systemic immune response index) in all neuro-oncology studies for rigorous evaluation and comparison of their individual and combinatorial prognostic/predictive significance and relative superiority.

Radio-chemotherapy feasibility for biopsy-only unresectable IDH wild-type glioblastomas (BO-GBM)

Background

"Biopsy-only" glioblastoma (BO-GBM) is a heterogeneous, understudied group of patients associated with a poor outcome. Our objective was to explore the pattern of care and prognosis associated with BO-GBM in our center.

Methods

Patients with IDH wild-type BO-GBM included in a prospective regional cohort initiated in 2014 and closed in 2017 were retrospectively reviewed for patient characteristics, MRI findings, treatment allocation, and delivery.

Results

Of 535 patients included in the cohort, 137 patients were included in the present analysis. The median age was 66 years old and the median KPS was 70. Forty-six patients (33.6%) were referred to radiotherapy and chemotherapy (RT-TMZ) regimen, 75 (54.7%), considered unfitted for RT, received chemotherapy upfront (CT) and 16 (11.7%) were referred to palliative care (PC). Regarding the first group, 91% of patients completed the RT-TMZ. In the CT group, 11 of 75 patients (14.7%) underwent radiotherapy after chemotherapy upfront. Median overall survival was 12.3 months (95% CI, 15.30-24.16), 5.7 months (95% CI, 6.22-9.20), and 1.9 months (95% CI, 1.43-5.08) in RT-TMZ, CT, and PC groups, respectively. In multivariate analyses, progression-free survival was impacted by baseline KPS (P < .001) and MGMT status (P = .004). Overall survival was impacted by baseline KPS (P < .001) and age (P = .030).

Conclusion

BO-GBM constitute a large and heterogeneous population in which one-third of patients is amenable to the standard of care, with survival outcome close to one of the patients who underwent surgery. Reliable criteria are needed to help select patients for adequate treatment while new strategies are warranted for BO-GBM unfit for RT.

Impact of radiotherapy delay following biopsy for patients with unresected glioblastoma

OBJECTIVE

Because of the aggressive nature of glioblastoma, patients with unresected disease are encouraged to begin radiotherapy within approximately 1 month after craniotomy. The aim of this study was to investigate the potential association between time interval from biopsy to radiotherapy with overall survival in patients with unresected glioblastoma.

METHODS

Patients with unresected glioblastoma diagnosed between 2010 and 2014 who received adjuvant radiotherapy and concurrent chemotherapy were identified in the National Cancer Database. Demographic and clinical data were compared using chi-square and Wilcoxon rank-sum tests. Survival was analyzed using the Kaplan-Meier method and Cox proportional hazards regression modeling.

RESULTS

Among 3456 patients with unresected glioblastoma, initiation of radiotherapy within 3 weeks of biopsy was associated with a higher hazard of death compared with later initiation of radiotherapy. After excluding patients who received radiotherapy within 3 weeks of biopsy to minimize the effects of confounders associated with short time intervals from biopsy to radiotherapy, the median interval from biopsy to radiotherapy was 32 days (IQR 27-39 days). Overall, 1782 (66.82%) patients started radiotherapy within 5 weeks of biopsy, and 885 (33.18%) patients started radiotherapy beyond 5 weeks of biopsy. On multivariable analysis, there was no significant difference in overall survival between these two groups (HR 0.96, 95% CI 0.88-1.50; p = 0.374).

CONCLUSIONS

In patients with unresected glioblastoma, a longer time interval from biopsy to radiotherapy does not appear to be associated with worse overall survival. However, external validation of these findings is necessary given that selection bias is a significant limitation of this study.

An Integrated Monte Carlo Model for Heterogeneous Glioblastoma Treated with Boron Neutron Capture Therapy

BACKGROUND

Glioblastomas (GBMs) are notorious for their aggressive features, e.g., intrinsic radioresistance, extensive heterogeneity, hypoxia, and highly infiltrative behaviours. The prognosis has remained poor despite recent advances in systemic and modern X-ray radiotherapy. Boron neutron capture therapy (BNCT) represents an alternative radiotherapy technique for GBM. Previously, a Geant4 BNCT modelling framework was developed for a simplified model of GBM.

PURPOSE

The current work expands on the previous model by applying a more realistic in silico GBM model with heterogeneous radiosensitivity and anisotropic microscopic extensions (ME).

METHODS

Each cell within the GBM model was assigned an α/β value associated with different GBM cell lines and a 10B concentration. Dosimetry matrices corresponding to various MEs were calculated and combined to evaluate cell survival fractions (SF) using clinical target volume (CTV) margins of 2.0 & 2.5 cm. SFs for the BNCT simulation were compared with external X-ray radiotherapy (EBRT) SFs.

RESULTS

The SFs within the beam region decreased by more than two times compared to EBRT. It was demonstrated that BNCT results in markedly reduced SFs for both CTV margins compared to EBRT. However, the SF reduction as a result of the CTV margin extension using BNCT was significantly lower than using X-ray EBRT for one MEP distribution, while it remained similar for the other two MEP models.

CONCLUSIONS

Although the efficiency of BNCT in terms of cell kill is superior to EBRT, the extension of the CTV margin by 0.5 cm may not increase the BNCT treatment outcome significantly.

Surgical cytoreduction of deep-seated high-grade glioma through tubular retractor

OBJECTIVE

Maximal safe resection is the goal of surgical treatment for high-grade glioma (HGG). Deep-seated hemispheric gliomas present a surgical challenge due to safety concerns and previously were often considered inoperable. The authors hypothesized that use of tubular retractors would allow resection of deep-seated gliomas with an acceptable safety profile. The purpose of this study was to describe surgical outcomes and survival data after resection of deep-seated HGG with stereotactically placed tubular retractors, as well as to discuss the technical advances that enable such procedures.

METHODS

This is a retrospective review of 20 consecutive patients who underwent 22 resections of deep-seated hemispheric HGG with the Viewsite Brain Access System by a single surgeon. Patient demographics, survival, tumor characteristics, extent of resection (EOR), and neurological outcomes were recorded. Cannulation trajectories and planned resection volumes depended on the relative location of white matter tracts extracted from diffusion tractography. The surgical plans were designed on the Brainlab system and preoperatively visualized on the Surgical Theater virtual reality SNAP platform. Volumetric assessment of EOR was obtained on the Brainlab platform and confirmed by a board-certified neuroradiologist.

RESULTS

Twenty adult patients (18 with IDH-wild-type glioblastomas and 2 with IDH-mutant grade IV astrocytomas) and 22 surgeries were included in the study. The cohort included both newly diagnosed (n = 17; 77%) and recurrent (n = 5; 23%) tumors. Most tumors (64%) abutted the ventricular system. The average preoperative and postoperative tumor volumes measured 33.1 ± 5.3 cm3 and 15.2 ± 5.1 cm3, respectively. The median EOR was 93%. Surgical complications included 2 patients (10%) who developed entrapment of the temporal horn, necessitating placement of a ventriculoperitoneal shunt; 1 patient (5%) who suffered a wound infection and pulmonary embolus; and 1 patient (5%) who developed pneumonia. In 2 cases (9%) patients developed new permanent visual field deficits, and in 5 cases (23%) patients experienced worsening of preoperative deficits. Preoperative neurological or cognitive deficits remained the same in 9 cases (41%) and improved in 7 (32%). The median overall survival was 14.4 months in all patients (n = 20) and in the newly diagnosed IDH-wild-type glioblastoma group (n = 16).

CONCLUSIONS

Deep-seated HGGs, which are surgically challenging and frequently considered inoperable, are amenable to resection through tubular retractors, with an acceptable safety profile. Such cytoreductive surgery may allow these patients to experience an overall survival comparable to those with more superficial tumors.

Efficacy of Laser Interstitial Thermal Therapy (LITT) for Newly Diagnosed and Recurrent IDH Wild-type Glioblastoma

Background

Treatment options for unresectable new and recurrent glioblastoma remain limited. Laser ablation has demonstrated safety as a surgical approach to treat primary brain tumors. The LAANTERN prospective multicenter registry (NCT02392078) data was analyzed to determine clinical outcomes for patients with new and recurrent IDH wild-type glioblastoma.

Methods

Demographics, intraprocedural data, adverse events, KPS, health-economics, and survival data were prospectively collected then analyzed on IDH wild-type newly diagnosed and recurrent glioblastoma patients who were treated with laser ablation at 14 US centers between January 2016 and May 2019. Data was monitored for accuracy. Statistical analysis included individual variable summaries, multivariable differences in survival, and median survival numbers.

Results

A total of 29 new and 60 recurrent IDH wild-type WHO grade 4 glioblastoma patients were treated. Positive MGMT promoter methylation status was present in 5/29 of new and 23/60 of recurrent patients. Median physician-estimated extent of ablation was 91-99%. Median overall-survival was 9.73 months (95% confidence interval: 5.16, 15.91) for newly diagnosed patients and median post-procedure survival was 8.97 (6.94, 12.36) months for recurrent patients. Median overall-survival for newly diagnosed patients receiving post-LITT chemo/radiation was 16.14 months (6.11, not reached). Factors associated with improved survival were MGMT promoter methylation, adjuvant chemotherapy within 12 weeks, and tumor volume &lt;3cc.

Conclusions

Laser ablation is a viable option for patients with new and recurrent glioblastoma. Median overall survival for IDH wild type newly diagnosed glioblastoma is comparable to outcomes observed in other tumor resection studies when those patients undergo radiation and chemotherapy following LITT.

Utility of Administrative Databases and Big Data on Understanding Glioma Treatment—A Systematic Review

Background Gliomas are a heterogeneous group of tumors where large multicenter clinical and genetic studies have become increasingly popular in their understanding. We reviewed and analyzed the findings from large databases in gliomas, seeking to understand clinically relevant information.

Methods A systematic review was performed for gliomas studied using large administrative databases up to January 2020 (e.g., National Inpatient Sample [NIS], National Surgical Quality Improvement Program [NSQIP], and Surveillance, Epidemiology, and End Results Program [SEER], National Cancer Database [NCDB], and others).

Results Out of 390 screened studies, 122 were analyzed. Studies included a wide range of gliomas including low- and high-grade gliomas. The SEER database (n = 83) was the most used database followed by NCDB (n = 28). The most common pathologies included glioblastoma multiforme (GBM) (n = 67), with the next category including mixes of grades II to IV glioma (n = 31). Common study themes involved evaluation of descriptive epidemiological trends, prognostic factors, comparison of different pathologies, and evaluation of outcome trends over time. Persistent health care disparities in patient outcomes were frequently seen depending on race, marital status, insurance status, hospital volume, and location, which did not change over time. Most studies showed improvement in survival because of advances in surgical and adjuvant treatments.

Conclusions This study helps summarize the use of clinical administrative databases in gliomas research, informing on socioeconomic issues, surgical outcomes, and adjuvant treatments over time on a national level. Large databases allow for some study questions that would not be possible with single institution data; however, limitations remain in data curation, analysis, and reporting methods.

TP53 Mutation and Extraneural Metastasis of Glioblastoma: Insights From an Institutional Experience and Comprehensive Literature Review

Extraneural metastases of glioblastoma (GBM), although rare, are becoming an increasingly recognized occurrence. Currently, the biological mechanism underlying this rare occurrence is not understood. To explore the potential genomic drivers of extraneural metastasis in GBM, we present the molecular features of 4 extraneural metastatic GBMs, along with a comprehensive review and analysis of previously reported cases that had available molecular characterization. In addition to our 4 cases, 42 patients from 35 publications are reviewed. To compare the molecular profiles between GBM cases with extraneural metastasis and the general GBM population, genomic data from GBM samples in The Cancer Genome Atlas (TCGA) database were also analyzed. We found that 64.5% (20/31) of the cases with extraneural metastasis that were tested for TP53 changes had at least 1 TP53 pathogenic variant detected in either 1 or both primary and metastatic tumors. In contrast, TP53 mutation was significantly less frequent in the unselected GBM from TCGA (22.6%, 56/248) (P=0.000). In addition, O-6-methylguanine-DNA methyltransferase (MGMT) promoter methylation was more common in unselected TCGA GBM cases (48.6%, 170/350) than in cases with extraneural metastasis (31.8%, 7/22), although not statistically significant. Although isocitrate dehydrogenase (IDH) mutation is a rare occurrence in high-grade astrocytomas, IDH-mutant grade 4 astrocytomas are at least as likely to metastasize as IDH wild-type GBMs; 3 metastatic cases definitively harbored an IDH1 (p.R132H) mutation in our analysis. Our findings not only provide potential biomarkers for earlier screening of extraneural metastasis, but could also suggest clues to understanding biological mechanisms underlying GBM metastasis, and for the development of therapeutic modalities.

Multifocal high-grade glioma radiotherapy safety and efficacy

Background

Multifocal manifestation of high-grade glioma is a rare disease with very unfavourable prognosis. The pathogenesis of multifocal glioma and pathophysiological differences to unifocal glioma are not fully understood. The optimal treatment of patients suffering from multifocal high-grade glioma is not defined in the current guidelines, therefore individual case series may be helpful as guidance for clinical decision-making.

Methods

Patients with multifocal high-grade glioma treated with conventionally fractionated radiation therapy (RT) in our institution with or without concomitant chemotherapy between April 2011 and April 2019 were retrospectively analysed. Multifocality was neuroradiologically assessed and defined as at least two independent contrast-enhancing foci in the MRI T1 contrast-enhanced sequence. IDH mutational status and MGMT methylation status were assessed from histopathology records. GTV, PTV as well as the V30Gy, V45Gy and D2% volumes of the brain were analysed. Overall and progression-free survival were calculated from the diagnosis until death and from start of radiation therapy until diagnosis of progression of disease in MRI for all patients.

Results

20 multifocal glioma cases (18 IDH wild-type glioblastoma cases, one diffuse astrocytic glioma, IDH wild-type case with molecular features of glioblastoma and one anaplastic astrocytoma, IDH wild-type case) were included into the analysis. Resection was performed in two cases and stereotactic biopsy only in 18 cases before the start of radiation therapy. At the start of radiation therapy patients were 61 years old in median (range 42–84 years). Histopathological examination showed IDH wild-type in all cases and MGMT promotor methylation in 11 cases (55%). Prescription schedules were 60 Gy (2 Gy × 30), 59.4 Gy (1.8 Gy × 33), 55 Gy (2.2 Gy × 25) and 50 Gy (2.5 Gy × 20) in 15, three, one and one cases, respectively. Concomitant temozolomide chemotherapy was applied in 16 cases, combined temozolomide/lomustine chemotherapy was applied in one case and concomitant bevacizumab therapy in one case. Median number of GTVs was three. Median volume of the sum of the GTVs was 26 cm³. Median volume of the PTV was 425.7 cm³ and median PTV to brain ratio 32.8 percent. Median D2% of the brain was 61.5 Gy (range 51.2–62.7) and median V30Gy and V45 of the brain were 59.9 percent (range 33–79.7) and 40.7 percent (range 14.9–64.1), respectively. Median survival was eight months (95% KI 3.6–12.4 months) and median progression free survival after initiation of RT five months (95% CI 2.8–7.2 months). Grade 2 toxicities were detected in eight cases and grade 3 toxicities in four cases consisting of increasing edema in three cases and one new-onset seizure. One grade 4 toxicity was detected, which was febrile neutropenia related to concomitant chemotherapy.

Conclusion

Conventionally fractionated RT with concomitant chemotherapy could safely be applied in multifocal high-grade glioma in this case series despite large irradiation treatment fields.

Laser Interstitial Thermal Therapy in Patients with Newly Diagnosed Glioblastoma: A Systematic Review

BACKGROUND

Laser interstitial thermal therapy (LITT) is a minimal invasive neurosurgical technique for the treatment of brain tumors. Results of LITT have been reported in a case series of patients with deep seated and/or recurrent glioblastoma or cerebral metastases. With this review we aim to summarize the currently available evidence regarding safety and effectiveness of LITT in patients with newly diagnosed glioblastoma (nGBM).

METHODS

A literature search was performed using electronic databases (PubMed and Embase). Papers were assessed for the methodological quality using the Risk Of Bias In Non- randomised Studies - of Interventions (ROBINS-I) tool, and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) was used to assess the quality of the evidence.

RESULTS

We identified 835 papers of which only 11 articles were eligible for our review. All papers suffered from serious or critical risk of bias, and the quality of evidence was graded as very low according to the GRADE criteria. None of the studies was randomized and reporting of confounders and other parameters was poor. Median overall survival (OS) ranged from 4.1 to 32 months and progression free survival (PFS) from 2 to 31 months. The mean complication rate was 33.7%. No quality of life or cost-effectiveness data were reported.

CONCLUSIONS

Due to the low quality of the studies, it is not possible to draw firm conclusions regarding the (cost) effectiveness of LITT in patients with newly diagnosed glioblastoma. The low quality of evidence shows the need for a well-designed prospective multicenter randomized controlled trial.

Nanotechnology and Nanocarrier-Based Drug Delivery as the Potential Therapeutic Strategy for Glioblastoma Multiforme: An Update

Simple Summary

Glioblastoma multiforme (GBM) are among the most lethal tumors. The highly invasive nature and presence of GBM stem cells, as well as the blood brain barrier (BBB) which limits chemotherapeutic drugs from entering the tumor mass, account for the high chance of treatment failure. Recent developments have found that nanoparticles can be conjugated to liposomes, dendrimers, metal irons, or polymeric micelles, which enhance the drug-loaded compounds to efficiently penetrate the BBB, thus offering new possibilities for overcoming GBM stem cell-mediated resistance to chemotherapy and radiation therapy. In addition, there have been new emerging strategies that use nanocarriers for successful GBM treatment in animal models. This review highlights the recent development of nanotechnology and nanocarrier-based drug delivery for treatment of GBMs, which may be a promising therapeutic strategy for this tumor entity.

Abstract

Glioblastoma multiforme (GBM) is the most common and malignant brain tumor with poor prognosis. The heterogeneous and aggressive nature of GBMs increases the difficulty of current standard treatment. The presence of GBM stem cells and the blood brain barrier (BBB) further contribute to the most important compromise of chemotherapy and radiation therapy. Current suggestions to optimize GBM patients’ outcomes favor controlled targeted delivery of chemotherapeutic agents to GBM cells through the BBB using nanoparticles and monoclonal antibodies. Nanotechnology and nanocarrier-based drug delivery have recently gained attention due to the characteristics of biosafety, sustained drug release, increased solubility, and enhanced drug bioactivity and BBB penetrability. In this review, we focused on recently developed nanoparticles and emerging strategies using nanocarriers for the treatment of GBMs. Current studies using nanoparticles or nanocarrier-based drug delivery system for treatment of GBMs in clinical trials, as well as the advantages and limitations, were also reviewed.

Laser interstitial thermal therapy in neuro-oncology applications

Background:

Laser interstitial thermal therapy (LITT) is a minimally invasive surgical treatment for multiple intracranial pathologies that are of growing interest to neurosurgeons and their patients and is emerging as an effective alternative to standard of care open surgery in the neurosurgical armamentarium. This option was initially considered for those patients with medical comorbidities and lesion-specific characteristics that confer excessively high risk for resection through a standard craniotomy approach but indications are changing.

Methods:

The PubMed database was searched for studies in the English literature on LITT for the treatment of primary and metastatic brain tumors, meningiomas, as well as for radiation necrosis (RN) in previously irradiated brain tumors.

Results:

This review provides an update of the relevant literature regarding application of LITT in neurosurgical oncology for the treatment of de novo and recurrent primary gliomas and brain metastases radiographically regrowing after previous irradiation as recurrent tumor or RN. In addition, this review details the limited experience of LITT with meningiomas and symptomatic peritumoral edema after radiosurgery. The advantages and disadvantages, indications, and comparisons to standard of care treatments such as craniotomy for open surgical resection are discussed for each pathology. Finally, the literature on cost-benefit analyses for LITT are reviewed.

Conclusion:

The studies discussed in this review have helped define the role of LITT in neurosurgical oncology and delineate optimal patient selection and tumor characteristics most suitable to this intervention.

Patterns of management and outcomes of unifocal versus multifocal glioblastoma

BACKGROUND

Glioblastoma (GBM) presents as a solitary lesion (unifocal), or as multiple discrete lesions (multifocal). Multifocal GBM may have a worse prognosis as compared to unifocal GBM, but existing data are limited to small institutional series. The purpose of the present study was to evaluate demographic and clinical characteristics of patients with unifocal versus multifocal GBM to highlight demographic differences and clinical outcomes for two groups of patients.

METHODS

The National Cancer Database (NCDB) was queried (2004-2016) for patients newly diagnosed with either unifocal or multifocal GBM. Statistics included Kaplan-Meier overall survival (OS) analysis, along with Cox proportional hazards modeling.

RESULTS

Of 45,268 total patients, 37,483 (82.8%) had unifocal GBM and 7,785 (17.2%) had multifocal GBM. Patients with unifocal GBM more frequently received gross total resection (GTR) (41.2% versus 25.8%, p < 0.001) and conventionally fractionated radiation therapy (RT) (48.2% versus 42.7%, p < 0.001). Patients with multifocal GBM had a higher rate of surgery with biopsy only (34.0% compared to 24.1%, p < 0.001). Median OS was 12.8 months versus 8.3 months (p < 0.001) for patients with unifocal GBM or multifocal GBM, respectively. On multivariate analysis, factors associated with improved OS included unifocal disease, MGMT methylation, RT use, and chemotherapy use.

CONCLUSIONS

This is the largest study to date describing outcomes for patients with multifocal GBM, and it shows that multifocal GBM is associated with a decreased use both of GTR and conventionally fractionated RT, as well as worse median OS. Further research is needed to improve clinical outcomes for patients with multifocal GBM.

Risk Factors for Cognitive Impairment in High-Grade Glioma Patients Treated with Postoperative Radiochemotherapy

Purpose

Fractionated radiotherapy as well as concomitant and adjuvant chemotherapy such as temozolomide for postoperative high-grade glioma (HGG) patients improves progression-free survival and overall survival. Multiple factors such as chemotherapy, radiotherapy, tumor grade, residual tumor volume, and genetic modifications might play a role in the formation of cognitive impairment. The risk factors of cognitive impairment in postoperative patients with HGG receiving radiotherapy and chemotherapy remains a concern in this population. The purpose of this study was to identify risk factors for cognitive impairment in patients of postoperative HGG.

Materials and Methods

A total of 229 patients with HGG who underwent surgery were analyzed. Cognitive impairment was defined as a decrease of Cognitive Assessment Montreal (MoCA)’s score in at least two cognitive domains or any MoCA’s score of less than 26 points at the time of study compared with baseline level. Multiple potential risk factors including methylated status of the O⁶-methylguanine-DNA methyltransferase (MGMT) promoter, glioma World Health Organization (WHO) grade, residual tumor volume, education, and sex were analyzed. Cox univariate and multivariate regression analysis was used to detect the significant risk factors for cognitive impairment.

Results

At the end of follow-up among the 229 patients, 147 patients (67%) developed cognitive impairment. 82 patients (36%) remained in normal cognitive condition. In multivariate analysis, unmethylated MGMT promoter (hazard ratio [HR], 1.679; 95% confidence interval [CI], 1.212 to 2.326; p=0.002), glioblastoma (HR, 1.550; 95% CI, 1.117 to 2.149; p=0.009), and residual tumor volume > 5.58 cm³ (HR, 1.454; 95% CI, 1.047 to 2.020; p=0.026) were independent risk factors for cognitive impairment.

Conclusion

Methylated status of the MGMT promoter, glioma WHO grade, and residual tumor volume might be risk factors for the cognitive impairment in postoperative patients with HGG.

Interstitial high-dose-rate brachytherapy in the primary treatment of inoperable glioblastoma multiforme

Purpose

To report our results of image-guided interstitial (IRT) high-dose-rate (HDR) brachytherapy (BRT) in the primary treatment of patients with inoperable glioblastoma multiforme (GBM) in the pre-temozolomide period.

Material and methods

Between 1994 and 2004, 17 patients were treated with HDR BRT for inoperable GBM. Of those, only 11 patients were treated with IRT BRT, and the remaining six patients received combined IRT BRT and external beam radiotherapy (EBRT). Patient’s median age was 59.3 years (range, 29-83 years) and median tumor volume was 39.3 cm³ (range, 2-162 cm³). The prescribed HDR dose was median 40 Gy (range, 30-40 Gy), delivered twice daily in 5.0 Gy fractions over four consecutive days. Survival from BRT, toxicity as well as the impact of several prognostic factors was evaluated.

Results

At a median follow-up of 9.3 months, the median overall survival for the whole population, after BRT alone, and combined BRT with EBRT was 9.3, 7.3, and 10.1 months, respectively. Of the prognostic variables evaluated in univariate analysis, i.e., age, Karnofsky performance score, BRT dose, and tumor volume, only the latter one reached statistical significance. Two patients (11.7%) developed treatment-associated adverse events, with one (5.8%) symptomatic radionecrosis and one (5.8%) severe convulsion episode, respectively.

Conclusions

For patients with inoperable GBM, IRT HDR BRT alone or in combination with EBRT is a safe and effective irradiation method providing palliation without excessive toxicity.

Hypofractionated short-course radiotherapy in elderly patients with glioblastoma multiforme: an analysis of the National Cancer Database

For elderly patients with glioblastoma multiforme (GBM), randomized trials have shown similar survival with hypofractionated short-course radiotherapy (SCRT) compared to conventionally fractionated long-course radiotherapy (LCRT). We evaluated the adoption of SCRT along with associated factors and survival in a national patient registry. Using the National Cancer Data Base (NCDB), we identified patients aged ≥70 years with GBM, diagnosed between 1998 and 2011, who received SCRT (34-42 Gy in 2.5-3.4 Gy fractions), or LCRT (58-63 Gy in 1.8-2.0 Gy fractions). Crude and adjusted hazard ratios (HR) were calculated using Cox regression modeling. 4598 patients were identified, 304 (6.6%) in the SCRT group and 4294 (93.4%) in the LCRT group. Median follow-up was 8.4 months. Median age was 78 versus 75 years, respectively (P < 0.0001). Patients who received SCRT had higher Charlson-Deyo comorbidity scores versus LCRT (score of ≥2: 16.9% vs. 10.8%, respectively; P = 0.006), and were more likely to be female (53.0% vs. 44.6%, P = 0.005). Patients who received SCRT were less likely to undergo chemotherapy (42.8% vs. 79.3%, P < 0.0001), more likely to undergo biopsy only (34.5% vs. 19.5%, P < 0.0001), and more likely to receive treatment at academic/research programs (49.2% vs. 37.2%, P = 0.0001). Median survival was 4.9 months versus 8.9 months, respectively (P < 0.0001). The survival detriment with SCRT persisted on multivariable analysis [HR 1.51 (95% CI: 1.33-1.73, P < 0.0001)], adjusting for age, gender, race, comorbidities, diagnosis year, facility type, surgery, and chemotherapy. In conclusion, hypofractionated SCRT was associated with worse survival compared to conventionally fractionated LCRT for elderly patients with GBM. Patients who received SCRT were older with worse comorbidities, and were less likely to undergo chemotherapy or resection.

The role of radiation in treating glioblastoma: here to stay

Despite numerous efforts over the past several decades, few therapeutic breakthroughs in the treatment of GBM have been realized, and even these have yielded only incrementally modest gains. Radiotherapy remains a crucial component in the management of this disease. In this review, the historical basis for inclusion of radiotherapy as part of the therapeutic regimen for GBM is examined. Additionally, an overview of the evidence supporting the modern role of radiotherapy is provided along with a discussion of standard and emerging combined modality therapies. Finally, GBM management guidelines from three professional societies are reviewed.

Multimodality imaging and mathematical modelling of drug delivery to glioblastomas

Patients diagnosed with glioblastoma, an aggressive brain tumour, have a poor prognosis, with a median overall survival of less than 15 months. Vasculature within these tumours is typically abnormal, with increased tortuosity, dilation and disorganization, and they typically exhibit a disrupted blood-brain barrier (BBB). Although it has been hypothesized that the 'normalization' of the vasculature resulting from anti-angiogenic therapies could improve drug delivery through improved blood flow, there is also evidence that suggests that the restoration of BBB integrity might limit the delivery of therapeutic agents and hence their effectiveness. In this paper, we apply mathematical models of blood flow, vascular permeability and diffusion within the tumour microenvironment to investigate the effect of these competing factors on drug delivery. Preliminary results from the modelling indicate that all three physiological parameters investigated-flow rate, vessel permeability and tissue diffusion coefficient-interact nonlinearly to produce the observed average drug concentration in the microenvironment.