Multi-institutional validation of a preoperative scoring system which predicts survival for patients with glioblastoma

Federated learning enables big data for rare cancer boundary detection

Although machine learning (ML) has shown promise across disciplines, out-of-sample generalizability is concerning. This is currently addressed by sharing multi-site data, but such centralization is challenging/infeasible to scale due to various limitations. Federated ML (FL) provides an alternative paradigm for accurate and generalizable ML, by only sharing numerical model updates. Here we present the largest FL study to-date, involving data from 71 sites across 6 continents, to generate an automatic tumor boundary detector for the rare disease of glioblastoma, reporting the largest such dataset in the literature (n = 6, 314). We demonstrate a 33% delineation improvement for the surgically targetable tumor, and 23% for the complete tumor extent, over a publicly trained model. We anticipate our study to: 1) enable more healthcare studies informed by large diverse data, ensuring meaningful results for rare diseases and underrepresented populations, 2) facilitate further analyses for glioblastoma by releasing our consensus model, and 3) demonstrate the FL effectiveness at such scale and task-complexity as a paradigm shift for multi-site collaborations, alleviating the need for data-sharing.

Ventricular entry during surgical resection is associated with intracranial leptomeningeal dissemination in glioblastoma patients

PURPOSE

Glioblastoma (GBM) is associated with a poorer prognosis when leptomeningeal dissemination (LMD) occurs. Recently, the role of both ventricular entry (VE) during surgery and subventricular zone localization of tumors in promoting LMD in GBM patients has been debated. This article investigates the role of VE in causing LMD in GBM patients.

METHODS

We conducted a retrospective analysis of GBMs operated on at our Institution between March 2018 and December 2020. We collected pre- and post-surgical images, anamnestic information, and surgical reports.

RESULTS

Two hundred cases were collected. The GBM localization was periventricular in 69.5% of cases, and there was a VE during the surgical procedure in 51% of cases. The risk of post-surgical LMD in the case of VE was 16%. The rate of LMD was higher in the case of VE than not-VE (27.4% vs. 4%, p < 0.0001). The rate of LMD in periventricular GBM was 19% (p = 0.1131).

CONCLUSION

According to our data, VE is an independent factor associated with a higher rate of post-surgical LMD, and the periventricular localization is not independently correlated to this negative outcome. Neurosurgeons should avoid VE when possible. The correct surgical strategy should be founded on balancing the need for maximal EOR and the risks associated with VE.

The Prognostic Value of NANO Scale Assessment in IDH-Wild-Type Glioblastoma Patients

Background

IDH-wild-type glioblastoma (GBM) is the most frequent brain-derived malignancy. Despite intense research efforts, it is still associated with a very poor prognosis. Several parameters were identified as prognostic, including general physical performance. In neuro-oncology (NO), special emphasis is put on focal deficits and cognitive (dys-)function. The Neurologic Assessment in Neuro-Oncology (NANO) scale was proposed in order to standardize the assessment of neurological performance in NO. This study evaluated whether NANO scale assessment provides prognostic information in a standardized collective of GBM patients.

Methods

The records of all GBM patients treated between 2014 and 2019 at our facility were retrospectively screened. Inclusion criteria were age over 18 years, at least 3 months postoperative follow-up, and preoperative and postoperative cranial magnetic resonance imaging. The NANO scale was assessed pre- and postoperatively as well as at 3 months follow-up. Univariate and multivariate survival analyses were carried to investigate the prognostic value.

Results

One hundred and thirty-one patients were included. In univariate analysis, poor postoperative neurological performance (HR 1.13, p = 0.004), poor neurological performance at 3 months postsurgery (HR 1.37, p < 0.001), and neurological deterioration during follow-up (HR 1.38, p < 0.001), all assessed via the NANO scale, were associated with shorter survival. In multivariate analysis including other prognostic factors such as the extent of resection, adjuvant treatment regimen, or age, NANO scale assessment at 3 months postoperative follow-up was independently associated with survival prediction (HR 1.36, p < 0.001). The optimal NANO scale cutoff for patient stratification was 3.5 points.

Conclusion

Neurological performance assessment employing the NANO scale might provide prognostic information in patients suffering from GBM.

Combination of the Distance From Tumor Edge to Subventricular Zone and IDH Mutation Predicts Prognosis of Patients With Glioma

Both subventricular zone (SVZ) contact and isocitrate dehydrogenase 1 (IDH1) mutation have been reported to be related to the outcome of glioma, respectively. However, far too little attention has been paid to the role of tumor edge-SVZ distance in the outcome of glioma. We aim to assess the value of tumor-SVZ distance, as well as combined tumor-SVZ distance and IDH status, in predicting the outcome of gliomas (WHO grade II-IV). Here, the MR images and clinical data from 146 patients were included in the current study. The relationship between survival and the tumor-SVZ distance as well as survival and combination of tumor-SVZ distance and IDH status were determined via univariate and multivariate analyses. In univariate analysis of tumor-SVZ distance, the patients were divided into three types (SVZ involvement, tumor-SVZ distance from 0 to 10 mm, and tumor-SVZ distance >10 mm). The results showed that the OS (p = 0.02) and PFS (p = 0.002) for the patients had a positive correlation with the tumor-SVZ distance. In addition, simple linear correlation found a significant relationship between the two parameters (OS and PFS) and tumor-SVZ distance in patients with non-SVZ-contacting glioma. Combination analysis of the tumor-SVZ distance and IDH status showed that IDH1 mutation and SVZ non-involvement enable favorable outcomes, whereas IDH1 wild type with SVZ involvement indicates a significantly worse prognosis in all patients. Moreover, in patients with non-SVZ-contacting glioma, IDH1 mutation concurrent with tumor-SVZ distance >10 mm has better OS and PFS. IDH1 wild type and tumor-SVZ distance from 0 to 10 mm suggest poorer OS and PFS. Multivariate analysis showed WHO grade IV, SVZ involvement, tumor-SVZ distance from 0 to 10 mm, IDH1 mutation, gross total resection, and chemotherapy serve as independent predictors of OS. WHO grade IV, SVZ involvement, tumor-SVZ distance from 0 to 10 mm, IDH1 mutation, and chemotherapy serve as independent predictors of PFS of patients with glioma. In conclusion, tumor-SVZ distance and IDH1 mutation status are the determinants affecting patient outcome.

Effects of ventricular entry on patient outcome during glioblastoma resection

OBJECTIVE

Tumor proximity to the ventricle and ventricular entry (VE) during surgery have both been associated with worse prognoses; however, the interaction between these two factors is poorly understood. Given the benefit of maximal tumor resection, it is imperative for surgical planning and technique to know if VE has negative consequences for patient survival and tumor dissemination.

METHODS

The University of California, San Francisco tumor registry was searched for patients with newly diagnosed and recurrent supratentorial glioblastoma (GBM) who underwent resection by the senior author between 2013 and 2018. Tumor location with respect to the subventricular zone (SVZ), size, and extent of resection were assessed using pre- and postoperative imaging. VE was determined by postoperative imaging and/or the operative report.

RESULTS

In this 200-patient cohort of newly diagnosed and recurrent GBM, 26.5% of patients had VE during resection. Patients with VE were more likely to have preexisting subependymal disease (41.5% vs 15.0%, p < 0.001). Comparing patients with VE to those without VE, there was no difference in the rates of postoperative hydrocephalus (1.9% vs 4.8%, p = 0.36), ventriculoperitoneal shunting (0% vs 3.4%, p = 0.17), pseudomeningoceles (7.5% vs 5.4%, p = 0.58), or subdural hematomas (11.3% vs 3.4%, p = 0.07). Importantly, rates of subsequent leptomeningeal disease (7.5% vs 10.2%, p = 0.57) and distant parenchymal recurrence (17.0% vs 23.1%, p = 0.35) were not different between the groups. Newly diagnosed patients with tumors contacting the SVZ (type I or II) had worse survival than patients with tumors that did not contact the SVZ (type III or IV) (1.27 vs 1.84 years, p = 0.014, HR 1.8, 95% CI 1.08-3.03), but VE was not associated with worse survival in these patients with high-risk SVZ type I and II tumors (1.15 vs 1.68 years, p = 0.151, HR 0.59, 95% CI 0.26-1.34).

CONCLUSIONS

VE was well tolerated, with postoperative complications being rare events. There was no increase in leptomeningeal spread or distant parenchymal recurrence in patients with VE. Finally, although survival was worse for patients with preoperative subependymal disease, VE did not change survival for patients with tumors contacting the ventricle. Therefore, VE during GBM resection is not associated with adverse patient outcomes and should be used by surgeons to enhance extent of resection.■ CLASSIFICATION OF EVIDENCE Type of question: therapeutic; study design: retrospective cohort; evidence: class II.

The prognostic value of peri-operative neurological performance in glioblastoma patients

BACKGROUND

IDH-wild-type glioblastoma (GBM) is a disease with devastating prognosis. First-line therapy consists of gross total resection and adjuvant radiotherapy with concomitant temozolomide. Several clinical parameters have been identified to provide prognostic value. We investigated whether peri-operative overall neurological performance could also be used to evaluate patients' prognosis.

METHODS

All patients with histologically diagnosed GBM between 2014 and 2017 over 18 years and MRI within 72 h after surgery were reviewed. To quantify neurological performance, the medical research council neurological performance score (MRC-NPS) was used. Univariate analysis with Kaplan-Meier estimate and log-rank test was performed. Survival prediction and multivariate analysis were performed employing Cox proportional hazard regression.

RESULTS

One hundred thirty-nine patients were included. In univariate analysis, survival decreased with increasing post-operative MRC-NPS scale. Moreover, post-operative MRC-NPS of 4 was statistically significant associated with reduced overall survival when analyzed for complete (p = 0.027) and partial resection (p = 0.002) as well as unilobar (p = 0.003) and multilobar tumor location (p < 0.0005). In multivariate analysis, extent of resection (hazard ratio (HR) 3.142), adjuvant therapy regimen (HR 3.001), tumor location (HR 2.005), and post-operative MRC-NPS (HR 2.310) had significant influence on overall survival.

CONCLUSION

We propose the post-operative neurological performance as an independent prognostic factor for GBM patients.

Malignancy Index Using Intraoperative Flow Cytometry is a Valuable Prognostic Factor for Glioblastoma Treated With Radiotherapy and Concomitant Temozolomide

BACKGROUND

Intraoperative prediction of radiochemosensitivity is desirable for improving the clinical management of glioblastoma (GBM) patients. We have previously developed an original technique for intraoperative flow cytometry (iFC) and defined a malignancy index (MI).

OBJECTIVE

To determine whether MI correlates with prognosis in GBM patients who underwent the standard treatment protocol of radiotherapy and temozolomide administration.

METHODS

The current study included 102 patients with GBM that had been newly diagnosed from 2010 to 2015 who underwent our iFC analysis and received the standard treatment protocol. We evaluated MI values in each patient, then statistically analyzed the relationship between MI and prognosis using survival analysis that include other clinicopathological factors (age, sex, Karnofsky performance status [KPS], extent of resection, second-line bevacizumab, O6-methylguanine-DNA methyltransferase [MGMT] status, MIB-1 labeling index, and mutation of the isocitrate dehydrogenase 1 gene [IDH1]).

RESULTS

Log-rank test revealed that age, KPS, extent of resection, MGMT status, IDH1 mutation, and high MI (≥26.3%) significantly correlated with overall survival. Multivariate analysis with Cox regression modeling identified MI as the most significant prognostic factor (hazard ratio = 2.246; 95% confidence interval = 1.347-3.800; P = .0019). MI showed strong correlation with IDH1 mutation status in chi-square test (P = .0023). In addition, log-rank test revealed that MI affects overall survival more strongly in patients with IDH1 wildtype than those with IDH1 mutant.

CONCLUSION

MI from an iFC study may help predict the prognosis in patients with GBM who receive the standard treatment. Survival can be related to sensitivity to radio-chemotherapy.

Extending the resection beyond the contrast-enhancement for glioblastoma: feasibility, efficacy, and outcomes

OBJECT

It is becoming well-established that increasing extent of resection with decreasing residual volume is associated with delayed recurrence and prolonged survival for patients with glioblastoma (GBM). These prior studies are based on evaluating the contrast-enhancing (CE) tumour and not the surrounding fluid attenuated inversion recovery (FLAIR) volume. It therefore remains unclear if the resection beyond the CE portion of the tumour if it translates into improved outcomes for patients with GBM.

METHODS

Adult patients who underwent resection of a primary glioblastoma at a tertiary care institution between January 1, 2007 and December 31, 2012 and underwent radiation and temozolomide chemotherapy were retrospectively reviewed. Pre and postoperative MRI images were measured for CE tumour and FLAIR volumes. Multivariate proportional hazards were used to assess associations with both time to recurrence and death. Values with p < 0.05 were considered statistically significant.

RESULTS

245 patients met the inclusion criteria. The median [IQR] preoperative CE and FLAIR tumour volumes were 31.9 [13.9-56.1] cm³ and 78.3 [44.7-115.6] cm³, respectively. Following surgery, the median [IQR] postoperative CE and FLAIR tumour volumes were 1.9 [0-7.1] cm³ and 59.7 [29.7-94.2] cm³, respectively. In multivariate analyses, the postoperative FLAIR volume was not associated with recurrence and/or survival (p > 0.05). However, the postoperative CE tumour volume was significantly associated with both recurrence [HR (95%CI); 1.026 (1.005-1.048), p = 0.01] and survival [HR (95%CI); 1.027 (1.007-1.032), p = 0.001]. The postoperative FLAIR volume was also not associated with recurrence and/or survival among patients who underwent gross total resection of the CE portion of the tumour as well as those who underwent supratotal resection.

CONCLUSIONS

In this study, the volume of CE tumour remaining after resection is more important than FLAIR volume in regards to recurrence and survival for patients with GBM.

Brachyury-YAP Regulatory Axis Drives Stemness and Growth in Cancer

Molecular factors that define stem cell identity have recently emerged as oncogenic drivers. For instance, brachyury, a key developmental transcriptional factor, is also implicated in carcinogenesis, most notably of chordoma, through mechanisms that remain elusive. Here, we show that brachyury is a crucial regulator of stemness in chordoma and in more common aggressive cancers. Furthermore, this effect of brachyury is mediated by control of synthesis and stability of Yes-associated protein (YAP), a key regulator of tissue growth and homeostasis, providing an unexpected mechanism of control of YAP expression. We further demonstrate that the brachyury-YAP regulatory pathway is associated with tumor aggressiveness. These results elucidate a mechanism of controlling both tumor stemness and aggressiveness through regulatory coupling of two developmental factors.

A Comparative Analysis of the Usefulness of Survival Prediction Models for Patients with Glioblastoma in the Temozolomide Era: The Importance of Methylguanine Methyltransferase Promoter Methylation, Extent of Resection, and Subventricular Zone Location

OBJECTIVE

Several survival prediction models for patients with glioblastoma have been proposed, but none is widely used. This study aims to identify the predictors of overall survival (OS) and to conduct an independent comparative analysis of 5 prediction models.

METHODS

Multi-institutional data from 159 patients with newly diagnosed glioblastoma who received adjuvant temozolomide concomitant chemoradiotherapy (CCRT) were collected. OS was assessed by Cox proportional hazards regression and adjusted for known prognostic factors. An independent CCRT patient cohort was used to externally validate the 1) RTOG (Radiation Therapy Oncology Group) recursive partitioning analysis (RPA) model, 2) Yang RPA model, and 3) Wee RPA model, Chaichana model, and the RTOG nomogram model. The predictive accuracy for each model at 12-month survival was determined by concordance indices. Calibration plots were performed to ascertain model prediction precision.

RESULTS

The median OS for patients who received CCRT was 19.0 months compared with 12.7 months for those who did not (P < 0.001). Independent predictors were: 1) subventricular zone II tumors (hazard ratio [HR], 1.6; 95% confidence interval [CI], 1.0-2.5); 2) methylguanine methyltransferase promoter methylation (HR, 0.36; 95% CI, 0.2-0.6); and 3) extent of resection of >85% (HR, 0.59; 95% CI, 0.4-0.9). For 12-month OS prediction, the RTOG nomogram model was superior to the RPA models with a c-index of 0.70. Calibration plots for 12-month survival showed that none of the models was precise, but the RTOG nomogram performed relatively better.

CONCLUSIONS

The RTOG nomogram best predicted 12-month OS. Methylguanine methyltransferase promoter methylation status, subventricular zone tumor location, and volumetric extent of resection should be considered when constructing prediction models.

Kindlin-2 interacts with β-catenin and YB-1 to enhance EGFR transcription during glioma progression

Kindlin-2 promotes carcinogenesis through regulation of cell-cell and cell-extracellular matrix adhesion. However, the role of Kindlin-2 in glioma has not been elucidated. We investigated Kindlin-2 expression in 188 human glioma tissue samples. High Kindlin-2 expression was correlated with high pathological grade and a worse prognosis. Kindlin-2 promoted glioma cell motility and proliferation both in vitro and in vivo. Importantly, Kindlin-2 activated the EGFR pathway and increased EGFR mRNA levels. In addition to up-regulating Y-box binding protein-1 (YB-1) and β-catenin expression, Kindlin-2 formed a transcriptional complex with YB-1 and β-catenin that bound to the EGFR promoter and enhanced transcription. The β-catenin/YB-1/EGFR pathway was required for Kindlin-2-mediated functions. Our data provide a better understanding of the mechanisms underlying glioma progression, and suggest that Kindlin-2 may be a biomarker and therapeutic target in glioma.

Elderly patients with newly diagnosed glioblastoma: can preoperative imaging descriptors improve the predictive power of a survival model?

The purpose of this study was to identify independent prognostic factors among preoperative imaging features in elderly glioblastoma patients and to evaluate whether these imaging features, in addition to clinical features, could enhance the predictive power of survival models. This retrospective study included 108 patients ≥65 years of age with newly diagnosed glioblastoma. Preoperative clinical features (age and KPS), postoperative clinical features (extent of surgery and postoperative treatment), and preoperative MRI features were assessed. Univariate and multivariate cox proportional hazards regression analyses for overall survival were performed. The integrated area under the receiver operating characteristic curve (iAUC) was calculated to evaluate the added value of imaging features in the survival model. External validation was independently performed with 40 additional patients ≥65 years of age with newly diagnosed glioblastoma. Eloquent area involvement, multifocality, and ependymal involvement on preoperative MRI as well as clinical features including age, preoperative KPS, extent of resection, and postoperative treatment were significantly associated with overall survival on univariate Cox regression. On multivariate analysis, extent of resection and ependymal involvement were independently associated with overall survival and preoperative KPS showed borderline significance. The model with both preoperative clinical and imaging features showed improved prediction of overall survival compared to the model with preoperative clinical features (iAUC, 0.670 vs. 0.600, difference 0.066, 95% CI 0.021-0.121). Analysis of the validation set yielded similar results (iAUC, 0.790 vs. 0.670, difference 0.123, 95% CI 0.021-0.260), externally validating this observation. Preoperative imaging features, including eloquent area involvement, multifocality, and ependymal involvement, in addition to clinical features, can improve the predictive power for overall survival in elderly glioblastoma patients.

Predicting surgical outcome in patients with glioblastoma multiforme using pre-operative magnetic resonance imaging: development and preliminary validation of a grading system

The lack of a simple, objective and reproducible system to describe glioblastoma multiforme (GBM) represents a major limitation in comparative effectiveness research. The objectives of this study were therefore to develop such a grading system and to validate it on patients who underwent surgical resection. A systematic review of the literature was performed to identify features on pre-operative magnetic resonance imaging (MRI) that predict the surgical outcome of patients with GBM. In all, the five most important features of GBM on pre-operative MRI were as follows: periventricular or deep location, corpus callosum or bilateral location, eloquent location, size and associated oedema. These were then used to develop a grading system. To validate this grading system, a retrospective cohort study of all adult patients with supratentorial GBM who underwent surgical resection between the 1 January 2014 and the 31 June 2015 was performed. There was a substantial agreement between the two neurosurgeons grading GBM (Cohen’s κ was 0.625; standard error 0.066). High-complexity lesions were significantly less likely to result in complete resection of contrast-enhancing tumour than low-complexity lesions (50.0 versus 3.4%; p = 0.0007). The proposed grading system may allow for the standardised communication of anatomical features of GBM identified on pre-operative MRI.

Decreased survival in glioblastomas is specific to contact with the ventricular-subventricular zone, not subgranular zone or corpus callosum

The clinical effect of radiographic contact of glioblastoma (GBM) with neurogenic zones (NZ)-the ventricular-subventricular (VSVZ) and subgranular (SGZ) zones-and the corpus callosum (CC) remains unclear and, in the case of the SGZ, unexplored. We investigated (1) if GBM contact with a NZ correlates with decreased survival; (2) if so, whether this effect is associated with a specific NZ; and (3) if radiographic contact with or invasion of the CC by GBM is associated with decreased survival. We retrospectively identified 207 adult patients who underwent cytoreductive surgery for GBM followed by chemotherapy and/or radiation. Age, preoperative Karnofsky performance status score (KPS), and extent of resection were recorded. Preoperative MRIs were blindly analyzed to calculate tumor volume and assess its contact with VSVZ, SGZ, CC, and cortex. Overall (OS) and progression free (PFS) survivals were calculated and analyzed with multivariate Cox analyses. Among the 207 patients, 111 had GBM contacting VSVZ (VSVZ+GBMs), 23 had SGZ+GBMs, 52 had CC+GBMs, and 164 had cortex+GBMs. VSVZ+, SGZ+, and CC+ GBMs were significantly larger in size relative to their respective non-contacting controls. Multivariate Cox survival analyses revealed GBM contact with the VSVZ, but not SGZ, CC, or cortex, as an independent predictor of lower OS, PFS, and early recurrence. We hypothesize that the VSVZ niche has unique properties that contribute to GBM pathobiology in adults.

Influence of glioblastoma contact with the lateral ventricle on survival: a meta-analysis

The ventricular-subventricular zone (V-SVZ), which lies in the walls of the lateral ventricles (LV), is the largest neurogenic niche within the adult brain. Whether radiographic contact with the LV influences survival in glioblastoma (GBM) patients remains unclear. We assimilated and analyzed published data comparing survival in GBM patients with (LV+GBM) and without (LV-GBM) radiographic LV contact. PubMed, EMBASE, and Cochrane electronic databases were searched. Fifteen studies with survival data on LV+GBM and LV-GBM patients were identified. Their Kaplan-Meier survival curves were digitized and pooled for generation of median overall (OS) and progression free (PFS) survivals and log-rank hazard ratios (HRs). The log-rank and reported multivariate HRs after accounting for the common predictors of GBM survival were analyzed separately by meta-analyses. The calculated median survivals (months) from pooled data were 12.95 and 16.58 (OS), and 4.54 and 6.25 (PFS) for LV+GBMs and LV-GBMs, respectively, with an overall log-rank HRs of 1.335 [1.204-1.513] (OS) and 1.387 [1.225-1.602] (PFS). Meta-analysis of log-rank HRs resulted in summary HRs of 1.58 [1.35-1.85] (OS, 10 studies) and 1.41 [1.22-1.64] (PFS, 5 studies). Meta-analysis of multivariate HRs resulted in summary HRs of 1.35 [1.14-1.58] (OS, 6 studies) and 1.64 [0.88-3.05] (PFS, 3 studies). Patients with GBM contacting the LV have lower survival. This effect may be independent of the common predictors of GBM survival, suggesting a clinical influence of V-SVZ contact on GBM biology.

Socioeconomic status does not affect prognosis in patients with glioblastoma multiforme

Background:

Glioblastoma multiforme (GBM) is an aggressive malignancy, but there is marked heterogeneity in survival time. Health care disparities have demonstrated significance in oncologic outcomes but have not been clearly examined in this patient population. We investigated the role of sociodemographic variables in the prognosis of adult patients diagnosed with GBM.

Methods:

This retrospective analysis included patients with a histologically confirmed diagnosis of GBM, who underwent resection or biopsy at a single institution from 2000 to 2014. Socioeconomic status (SES) was determined by household income according to the US Census zip code tabulation areas and the US national poverty level. Multivariate Cox proportional hazards analysis calculated effects on patient survival.

Results:

Thirty percent of 218 subjects were of low SES, 57% mid, and 13% high. Low SES patients tended to be male (62%), Caucasian (92%), unmarried (91%), have dependents (100%), and limited to high school education (55%). SES did not predict insurance or employment status. SES was associated with marital status and number of cohabitants (P < 0.0001) but not clinical trial enrollment. Multivariate analysis demonstrated no relationship between SES and survival. Shorter prognosis was associated with history of military service (hazard ratio [HR] 2.06, P = 0.0125), elderly patients (HR 1.70, P = 0.0158), and multifocal disease (HR 1.75, P = 0.0119). Longer prognosis was associated with gross total resection (HR 0.49, P = 0.0009), radiation therapy (HR 0.12, P < 0.0001), and temozolomide (HR 0.28, P < 0.0001).

Conclusions:

SES alone does not predict prognosis in patients with newly diagnosed GBM. Sociodemographic variables such as old age, military service record, and insurance type may have a prognostication role.

Anatomical Involvement of the Subventricular Zone Predicts Poor Survival Outcome in Low-Grade Astrocytomas

The subventricular zone (SVZ) has been implicated in the origination, development, and biological behavior of gliomas. Tumor-SVZ contact is also postulated to be a poor prognostic factor in glioblastomas. We aimed to evaluate the prognostic consequence of the anatomical involvement of low-grade gliomas with the SVZ. To that end, we reviewed 143 patients with diffuse astrocytomas, and tumor lesions were manually delineated on magnetic resonance images. We initially investigated the prognostic role of SVZ contact in all patients. Additionally, we investigated the influence of the anatomical proximity of the tumor lesion centroids to the SVZ in the SVZ-involved patient cohorts, as well as location within the SVZ. We found SVZ contact with tumors to be a significant prognostic factor of overall survival in all patients with diffuse astrocytomas (p = 0.027). In the SVZ-involved cohort, a shorter distance from the tumor centroid to the SVZ (≤30 mm) correlated with shorter overall survival (p = 0.022) on univariate analysis. However, there was no significant difference in overall survival with respect to the SVZ region involved with the tumor (p = 0.930). Multivariate analysis showed that a shorter distance between the tumor centroid and the SVZ (p = 0.039) was significantly associated with poor overall survival in SVZ-involved patients. Hence, this study helps establish the prognostic role of the anatomical interaction of tumors with the SVZ in low-grade astrocytomas.

Complications of glioma surgery

Even with current advances in adjunctive therapies, including radiation, chemotherapy, and various clinical trials of gene therapy and immunotherapy, surgical resection remains one of the most effective treatment for intra-axial gliomas. Survival in these patients has been shown to be related to the extent of resection. In some cases, it can provide cures of long-term remission; in others, it can provide disease control when combined with the above adjunctive treatments. However, surgical resection carries its own risks and complications. These complications can be broadly divided into neurologic, regional, and systemic, including direct cortical and vascular injury, surgical wound complications, and postsurgical medical complications. Certain patient characteristics, including Karnofsky performance status score (KPS) and pathology of the tumor, have been shown to have an impact on the risk of postsurgical complications. Advancement in preoperative and intraoperative adjunct technology such as cortical mapping and navigation has improved the surgeon's ability to safely and maximally resect the tumors. It is therefore important to understand the perioperative complications after craniotomy and tumor resection and factors affecting morbidity and mortality in order for surgeons to optimally select and counsel patients who will benefit the most from surgical resection. This chapter will focus on the complications associated with craniotomy for intrinsic glioma and ways of avoiding these events.

Delivery of local therapeutics to the brain: working toward advancing treatment for malignant gliomas

Malignant gliomas, including glioblastoma and anaplastic astrocytomas, are characterized by their propensity to invade surrounding brain parenchyma, making curative resection difficult. These tumors typically recur within two centimeters of the resection cavity even after gross total removal. As a result, there has been an emphasis on developing therapeutics aimed at achieving local disease control. In this review, we will summarize the current developments in the delivery of local therapeutics, namely direct injection, convection-enhanced delivery and implantation of drug-loaded polymers, as well as the application of these therapeutics in future methods including microchip drug delivery and local gene therapy.

The influence of hyperglycemia during radiotherapy on survival in patients with primary glioblastoma

BACKGROUND AND PURPOSE

Metabolism in tumor cells depends mainly on glycolysis and thus hyperglycemia has been shown to influence tumor properties in various tumor entities. In this retrospective study we set out to determine if hyperglycemic serum levels during radiation therapy impact patient survival and progression patterns in primary glioblastoma (GBM).

MATERIAL AND METHODS

We retrospectively analyzed glucose serum levels, survival and progression patterns on magnetic resonance imaging (MRI) in 262 GBM patients receiving radiation therapy. Hyperglycemia was classified as mild (> 180 mg/dL) or excessive (≥ 300 mg/dL), and isolated (one hyperglycemic event) or persistent (≥ 3 hyperglycemic events). The multivariate Cox proportional hazards ratio was used to assess the influence of cofactors on survival.

RESULTS

Persistent mild (HR = 2.23; p < 0.001) and excessive hyperglycemia (HR = 2.51; p < 0.001) were associated with a decrease in overall survival rates, even when considering the covariate corticosteroid therapy. Here metabolic imbalances did not affect the progression-free interval (p = 0.402), the occurrence of distant (p = 0.587) and multifocal progression (p = 0.445).

CONCLUSION

Our findings support the theory that hyperglycemia during radiation therapy in GBM patients is an unfavorable prognostic cofactor for survival and is detrimental to the survival rates independent of corticosteroid therapy. However, no significant effects of hyperglycemic metabolism on the progression-free interval and recurrence patterns were found.

Risk of surgical site infection in 401 consecutive patients with glioblastoma with and without carmustine wafer implantation

OBJECTIVES

Patients with glioblastoma (GBM) have an inherently shortened survival because of their disease. It has been recently shown that carmustine wafers in addition to other therapies (surgery, temozolomide, and radiation) can further extend survival. There is concern, however, that these therapies may increase infection risk. The goals of this study were to calculate the incidence of postoperative infection, evaluate if carmustine wafers changes the risk of infection and identify factors independently associated with an infection following GBM surgery.

METHODS

All patients who underwent non-biopsy, surgical resection of an intracranial GBM from 2007 to 2011 at a single institution were retrospectively reviewed. Stepwise multivariate proportional hazards regression analysis was used to identify factors associated with infection, including the use of carmustine wafers. Variables with P < 0.05 were considered statistically significant.

RESULTS

Four hundred and one patients underwent resection of an intracranial GBM during the reviewed period, and 21 (5%) patients developed an infection at a median time of 40 [28-286] days following surgery. The incidence of infection was not higher in patients who had carmustine wafers, and this remained true in multivariate analyses to account for differences in treatment cohorts. The factors that remained significantly associated with an increased risk of infection were prior surgery [RR (95% CI); 2.026 (1.473-4.428), P = 0.01], diabetes mellitus [RR (95% CI); 6.090 (1.380-9.354)], P = 0.02], and increasing duration of hospital stay [RR (95% CI); 1.048 (1.006-1.078); P = 0.02], where the greatest risk occurred with hospital stays > 5 days [RR (95% CI); 3.904 (1.003-11.620), P = 0.05].

DISCUSSION

These findings may help guide treatment regimens aimed at minimizing infection for patients with GBM.

Prediction of clinical outcome in glioblastoma using a biologically relevant nine-microRNA signature

BACKGROUND

Glioblastoma is the most aggressive primary brain tumor, and is associated with a very poor prognosis. In this study we investigated the potential of microRNA expression profiles to predict survival in this challenging disease.

METHODS

MicroRNA and mRNA expression data from glioblastoma (n = 475) and grade II and III glioma (n = 178) were accessed from The Cancer Genome Atlas. LASSO regression models were used to identify a prognostic microRNA signature. Functionally relevant targets of microRNAs were determined using microRNA target prediction, experimental validation and correlation of microRNA and mRNA expression data.

RESULTS

A 9-microRNA prognostic signature was identified which stratified patients into risk groups strongly associated with survival (p = 2.26e-09), significant in all glioblastoma subtypes except the non-G-CIMP proneural group. The statistical significance of the microRNA signature was higher than MGMT methylation in temozolomide treated tumors. The 9-microRNA risk score was validated in an independent dataset (p = 4.50e-02) and also stratified patients into high- and low-risk groups in lower grade glioma (p = 5.20e-03). The majority of the 9 microRNAs have been previously linked to glioblastoma biology or treatment response. Integration of the expression patterns of predicted microRNA targets revealed a number of relevant microRNA/target pairs, which were validated in cell lines.

CONCLUSIONS

We have identified a novel, biologically relevant microRNA signature that stratifies high- and low-risk patients in glioblastoma. MicroRNA/mRNA interactions identified within the signature point to novel regulatory networks. This is the first study to formulate a survival risk score for glioblastoma which consists of microRNAs associated with glioblastoma biology and/or treatment response, indicating a functionally relevant signature.

Risk factors for glioblastoma therapy associated complications

OBJECTIVE

Thromboembolic events, seizures, neurologic symptoms and adverse effects from corticosteroids and chemotherapies are frequent clinical complications seen in Glioblastoma (GB) patients. The exact impact these have on dismal patient outcome has not been fully elucidated. We aimed at assessing treatment associated complications, evaluating the impact on survival and defining risk factors.

METHODS

Two hundred and thirty three consecutive adult patients operated on for newly diagnosed GB at a single tertiary institution over a 5-year-period (2006-2011) were assessed. Demographic parameters (age, gender, comorbidity status quantified by the Charlson-comorbidity-index (CCI), functional status computed by the Karnofsky Performance Scale (KPS), tumor characteristics (size, location, IDH-1 mutation and MGMT-Promotor-methylation-status) and treatment parameters (volumetrically quantified extent of resection and adjuvant therapy) were retrospectively reviewed. Complications assessed were recorded as neurological (N), surgical (S) and medical (M). Independent risk factor analysis was performed by the univariate and multivariate logistic regression method. Survival analysis was plotted by the Kaplan-Meier-method, influence of complication occurrence was evaluated by the log-rank test.

RESULTS

One hundred and fifty nine (68.2%) patients had a total of 281 complications (90 N, 174 M and 17 S). Univariate analysis identified age (P=0.003), KPS<70 (P=0.002), CCI>3 (P=0.03), eloquent tumor location (P=0.001) and therapy other than the standard radio-chemotherapy with temozolomide therapy (P=0.034) as risk factors for complications. Multivariate analysis extracted the eloquent tumor location (P=0.007, odds ratio 1.94) as a significant predictor for complications. Having a complication significantly decreased patient survival (P=0.015).

CONCLUSIONS

Complications significantly decrease GB patient survival. Age, poor functional status, other than standard adjuvant therapy and eloquent tumor location proved as significant risk factors for encountering a therapy associated complication. Not extensive surgery or tumor size but surgery at eloquent locations impacts complication occurrence the strongest with a 2 fold increased complication occurrence risk.

Hypoxia-cultured human adipose-derived mesenchymal stem cells are non-oncogenic and have enhanced viability, motility, and tropism to brain cancer

Adult human adipose-derived mesenchymal stem cells (hAMSCs) are multipotent cells, which are abundant, easily collected, and bypass the ethical concerns that plague embryonic stem cells. Their utility and accessibility have led to the rapid development of clinical investigations to explore their autologous and allogeneic cellular-based regenerative potential, tissue preservation capabilities, anti-inflammatory properties, and anticancer properties, among others. hAMSCs are typically cultured under ambient conditions with 21% oxygen. However, physiologically, hAMSCs exist in an environment of much lower oxygen tension. Furthermore, hAMSCs cultured in standard conditions have shown limited proliferative and migratory capabilities, as well as limited viability. This study investigated the effects hypoxic culture conditions have on primary intraoperatively derived hAMSCs. hAMSCs cultured under hypoxia (hAMSCs-H) remained multipotent, capable of differentiation into osteogenic, chondrogenic, and adipogenic lineages. In addition, hAMSCs-H grew faster and exhibited less cell death. Furthermore, hAMSCs-H had greater motility than normoxia-cultured hAMSCs and exhibited greater homing ability to glioblastoma (GBM) derived from brain tumor-initiating cells from our patients in vitro and in vivo. Importantly, hAMSCs-H did not transform into tumor-associated fibroblasts in vitro and were not tumorigenic in vivo. Rather, hAMSCs-H promoted the differentiation of brain cancer cells in vitro and in vivo. These findings suggest an alternative culturing technique that can enhance the function of hAMSCs, which may be necessary for their use in the treatment of various pathologies including stroke, myocardial infarction, amyotrophic lateral sclerosis, and GBM.

Association of overall survival in patients with newly diagnosed glioblastoma with contrast-enhanced perfusion MRI: Comparison of intraindividually matched T1 - and T2 (*) -based bolus techniques

BACKGROUND

To compare intraindividual dynamic susceptibility contrast (DSC) and dynamic contrast enhanced (DCE) MR perfusion parameters and determine the association of DCE parameters with overall survival (OS) with the established predictive DSC parameter cerebral blood volume (CBV) in patients with newly diagnosed glioblastoma.

METHODS

Perfusion data were analyzed retrospectively, and included scans performed preoperatively at 3.0 Tesla in 37 patients (25 males, 12 females, 39-83 years, median 65) later diagnosed with glioblastoma. All patients received standard treatment consisting of surgery and radiochemotherapy. Images were spatially coregistered and maximum region of interest-based DCE and DSC parameter measurements compared and thresholds identified using multivariate linear regression, Pearson's correlation coefficients and using receiver operating characteristic analysis. Survival analysis was performed using Kaplan-Meier curves.

RESULTS

While both, elevated volume transfer constant (K(trans) ) (>0.29 min(-1) ; P = 0.041) and CBV (>23.7 mL/100 mL; P < 0.001) were significantly associated with OS, elevated CBV was associated with worse OS compared with elevated K(trans) . K(trans) was significantly correlated with the leakage correction factor K2 but not with CBV.

CONCLUSION

The combined use of DSC and DCE MR perfusion may provide additional information of prognostic value for glioblastoma patient survival prediction. As K(trans) was not tightly coupled to CBV, both parameters may reflect different stages in the pathogenetic sequence of glioblastoma growth.

A comparison of long-term survivors and short-term survivors with glioblastoma, subventricular zone involvement: a predictive factor for survival?

OBJECTIVE

Long-term survival is rare in patients with glioblastoma (GBM). We set out to determine prognostic factors for patients with favorable and poor prognosis in regard of tumor localization to the subventricular zone (SZV).

METHODS

We reviewed the clinical records, pre-operative and post-operative MRI imaging of 50 LTS long-term survivors (LTS) (> 3 years) and 50 short-term survivors (STS) (< 1 year) with glioblastoma. These groups were matched for clinical characteristics being consistently associated with prolonged or shortened survival. All patients had undergone initial surgery or biopsy to confirm GBM diagnosis followed by radio- or chemoradiotherapy.

RESULTS

LTS had a median progression-free survival PFS of 25, 4 months (2, 3-97, 8 months) and overall-survival (OS) of 55, 9 months (38, 2-98, 6 months) compared to STS who had a significantly lower PFS of 4, 2 months (1, 4-10, 2 months) and OS of 6, 6 months (2, 2-11, 6 months) (each p < 0,001).Survival analysis showed that age under 60 years (p < 0,001), total resection status (p < 0,001) and tumor localization without SVZ contact (p = 0,05) were significant factors for prolonged survival.

CONCLUSION

Our findings underline that survival in GBM patients is heterogeneous and influenced by multiple factors. This study confirms that tumor location with regard to the SVZ is significantly associated with survival.