Awake craniotomy does not lead to increased psychological complaints

BACKGROUND

Patients with brain tumours are increasingly treated by using the awake craniotomy technique. Some patients may experience anxiety when subjected to brain surgery while being fully conscious. However, there has been only limited research into the extent to which such surgeries actually result in anxiety or other psychological complaints. Previous research suggests that undergoing awake craniotomy surgery does not lead to psychological complaints, and that post-traumatic stress disorders (PTSD) are uncommon following this type of surgery. It must be noted, however, that many of these studies used small random samples.

METHOD

In the current study, 62 adult patients completed questionnaires to identify the degree to which they experienced anxiety, depressive and post-traumatic stress complaints following awake craniotomy using an awake-awake-awake procedure. All patients were cognitively monitored and received coaching by a clinical neuropsychologist during the surgery.

RESULTS

In our sample, 21% of the patients reported pre-operative anxiety. Four weeks after surgery, 19% of the patients reported such complaints, and 24% of the patients reported anxiety complaints after 3 months. Depressive complaints were present in 17% (pre-operative), 15% (4 weeks post-operative) and 24% (3 months post-operative) of the patients. Although there were some intra-individual changes (improvement or deterioration) in the psychological complaints over time, on group-level postoperative levels of psychological complaints were not increased relative to the preoperative level of complaints. The severity of post-operative PTSD-related complaints were rarely suggestive of a PTSD. Moreover, these complaints were seldom attributed to the surgery itself, but appeared to be more related to the discovery of the tumour and the postoperative neuropathological diagnosis.

CONCLUSIONS

The results of the present study do not indicate that undergoing awake craniotomy is associated with increased psychological complaints. Nevertheless, psychological complaints may well exist as a result of other factors. Consequently, monitoring the patient's mental wellbeing and offering psychological support where necessary remain important.

MR Imaging and Clinical Characteristics of Diffuse Glioneuronal Tumor with Oligodendroglioma-like Features and Nuclear Clusters

BACKGROUND AND PURPOSE

Diffuse glioneuronal tumor with oligodendroglioma-like features and nuclear clusters (DGONC) is a new, molecularly defined glioneuronal CNS tumor type. The objective of the present study was to describe MR imaging and clinical characteristics of patients with DGONC.

MATERIALS AND METHODS

Preoperative MR images of 9 patients with DGONC (median age at diagnosis, 9.9 years; range, 4.2-21.8 years) were reviewed.

RESULTS

All tumors were located superficially in the frontal/temporal lobes and sharply delineated, displaying little mass effect. Near the circle of Willis, the tumors encompassed the arteries. All except one demonstrated characteristics of low-to-intermediate aggressiveness with high-to-intermediate T2WI and ADC signals and bone remodeling. Most tumors (n = 7) showed a homogeneous ground-glass aspect on T2-weighted and FLAIR images. On the basis of the original histopathologic diagnosis, 6 patients received postsurgical chemo-/radiotherapy, 2 were irradiated after surgery, and 1 patient underwent tumor resection only. At a median follow-up of 61 months (range, 10-154 months), 6 patients were alive in a first complete remission and 2 with stable disease 10 and 21 months after diagnosis. The only patient with progressive disease was lost to follow-up. Five-year overall and event-free survival was 100% and 86±13%, respectively.

CONCLUSIONS

This case series presents radiomorphologic characteristics highly predictive of DGONC that contrast with the typical aspects of the original histopathologic diagnoses. This presentation underlines the definition of DGONC as a separate entity, from a clinical perspective. Complete resection may be favorable for long-term disease control in patients with DGONC. The efficacy of nonsurgical treatment modalities should be evaluated in larger series.

P11.37.B When to resect or biopsy for patients with supratentorial glioblastoma: a multivariable prediction model

Background

The prospects of a patient with suspected glioblastoma may rely heavily on the indication for surgical resection versus biopsy only. Biopsy percentages vary considerably across hospitals and guidelines for treatment of glioblastoma lack criteria for surgical decision-making. To identify patient and tumor characteristics associated with the decision to resect or biopsy a glioblastoma and to develop and validate a prediction model for decision support.

Material and Methods

Clinical data and pre-operative MRI scans were collected for adults who underwent first-time surgery for supratentorial glioblastoma from a registry-based cohort study of 12 hospitals from the Netherlands, Germany, France, Italy, and the United States between 1st of January 2007 and 31st of December 2011. The main outcome was the type of surgical procedure: surgical resection or biopsy only. Predictors were patient- and tumor-related characteristics. Radiological factors were extracted from MRI using an automated tumor segmentation method. A prediction model was constructed using multivariable logistic regression analysis. The model was cross-validated and externally validated with a leave-one-hospital-out approach.

Results

Out of 1053 patients treated for glioblastoma, 28% underwent biopsy only. Biopsy rates varied from 15-40% across hospitals. The prediction model showed excellent discrimination with an average area under the curve of 0.86. Of the patient-related characteristics, younger age was associated more with resection and Karnofsky Performance Score of 60 or less with biopsy. Of the tumor-related characteristics, a location in the right hemisphere, unifocality, no tumor midline crossing, and no involvement of the cortical spinal tract, were associated with resection, as well as a high expected resectability index, a location in the right occipital lobe, and a higher percentage of tumor in Schaefer’s dorsal or ventral attention, limbic, and default networks. External validation proved acceptable to outstanding discrimination with areas under the curve ranging between 0.79 and 0.92 for hospitals.

Conclusion

A prediction model is presented and validated to support the decision to resect or to biopsy a patient with a suspected supratentorial glioblastoma. In this prediction model, tumor-related characteristics were more informative than patient-related factors. This may support surgical decision-making for individual patients, or facilitate comparisons of patient cohorts between surgeons or institutions.

KS01.4.A Transcriptional evolution of glioblastoma point towards changes in bulk composition, mesenchymal sub-type as end-state, and a prognostic association with increased extracellular matrix gene expression

Background

Glioblastoma is the most prevalent and severe type of malignant brain tumor in adults. Although the genetic make-up initiating glioblastoma is increasingly better understood, a better understanding in the mechanisms that drive its evolution, heterogeneity and therapy resistance may reveal new directions for therapy development. To get better insights into glioblastoma evolution, we analyzed and deconvoluted transcriptomes of primary and recurrent glioblastoma resections.

Material and Methods

Matching primary and secondary resections from n=185 uniformly treated glioblastoma patients were collected as part of EORTC Study 1542 and RNA-sequenced. Data was extended with pairs from n=51 patients from the GLASS study. The datasets were subjected to differential and deconvolution analysis using in-house algorithms.

Results

When projecting the tumor samples into a reduced Glioblastoma Intrinsic Transcriptional Subtype space, visualization of transitions indicated that the CL subtype switches most often. As we found no more transitions from MES to other subtypes than to be expected by chance, we concluded that MES is an end-state. On average, tumor purity percentages decreased from ~67% to ~50%, mostly due to an increase in macrophages/microglia. Differential expression analysis was performed with correction for the fraction of non-malignant cells. While expression of glioblastoma associated oncogenes did not change significantly over time, marker genes for macrophages/microglia, neurons and oligodendrocytes were up-regulated whereas endothelial cell markers were down-regulated. A cluster of ~30 extracellular matrix associated (ECM) genes increased significantly over time. Single cell RNA-seq, IF-staining and RNA-ish indicated the signature is most strongly expressed near intra-tumoral vessels. Since endothelial marker genes were down-regulated over time, this suggests a form of prognostic vessel progression with a representative transcriptome signature.

Conclusion

Using a large cohort and validation set of uniformly treated patients, we demonstrate how the glioblastoma transcriptome changes over time with in particular changes the composition of the tumor and its environment. The tumor purity decrease over times suggests a more invasive phenotype or recruitment of non-malignant cells or a combination of both. A post-progression increase in expression of ECM-associated genes expressed near blood vessels was associated with poor survival. Concluding, while no consistent path for transcriptional evolution of tumor cells was observed other than transitions to the MES subtype, glioblastoma becomes more aggressive in time by (re-)organizing its environment.

P14.17 Conventional MRI criteria differentiate true tumour progression from treatment-induced effects in irradiated WHO grade 3 and 4 gliomas

BACKGROUND

Post-treatment radiological deterioration of patients with an irradiated high-grade (WHO grade 3 and 4) glioma (HGG) may be the result of true progressive disease (PD) or treatment-induced effects (TIE). Differentiation between these two entities is of great importance, but remains a diagnostic challenge. This study assesses the diagnostic value of conventional MRI characteristics to differentiate PD from TIE in treated HGGs.

MATERIAL AND METHODS

In this single-centre, retrospective cohort study, we included adult patients with a HGG, who were treated with radiotherapy and subsequently developed a new or increasing contrast-enhancing lesion on conventional follow-up MRI. TIE and PD were defined radiologically as stable/decreased for a minimum of six weeks or progressive according to the RANO criteria, and histologically as predominantly TIE without viable tumour or PD. Demographic and clinical data were retrieved. Twenty-one preselected MRI characteristics of the progressive lesions were assessed by two neuroradiologists. The statistical analysis included logistic regression to develop a) a full multivariable model b) a diagnostic model with model reduction, and a Cohen’s Kappa interrater reliability coefficient.

RESULTS

210 patients (median age 61, IQR=54–68, 189 males) with 284 lesions were included, of which 141 (50%) had PD. Median time to PD was 2 (0.7–6.1) and to TIE 0.9 (0.7–3.5) months after RT. In multivariable modelling and after model reduction, the following determinants were significant diagnostic factors: Radiation dose (Odds ratio (OR)=0.68, p=0.017), longer time since radiotherapy (OR=3.56, p<0.0005), certain enhancement patterns (soap bubble enhancement: OR=2.63, p=0.003), isointense apparent diffusion coefficient-signal (OR=2.11, p=0.036), development of multiple new lesions (OR=1.68, p=0.088) and increased marginal enhancement (OR=2.04, p=0.027). ORs of >1 indicate higher odds of PD. The Hosmer & Lemeshow test showed a good calibration (p=0.947) and the area under the ROC-curve was 0.722 (95%-CI=0.66–0.78). Interrater reliability analysis between neuroradiologists revealed moderate to near-perfect agreement for the significantly predictive items, but poor agreement for others.

CONCLUSION

In patients with irradiated high-grade gliomas, several characteristics from conventional MRI are significant predictors for the discrimination between true progression and treatment-induced effects. Interrater reliability for these characteristics was variable. Conventional MRI characteristics from this study should be incorporated into a multimodal diagnostic model that includes advanced imaging techniques.

FUNDING INFORMATION

Foundation Vrienden UMC Utrecht and The StophersenkankerNU Foundation.

P14.23 Relation between neurological deficits and location of postsurgical ischemia in glioma resection

BACKGROUND

Postoperative ischemia is a known complications of glioma resection and can lead to neurological deficits. New or worsened postoperative deficits are often transient, but some patients experience persisting effects after surgery. Neuroanatomical location of ischemia is suspected to play an important role in the development as well as persistence of neurological deficits. Therefore, the aim of this study was to investigate the spatial relation between postoperative ischemia and short-term and long-term neurological deficits.

MATERIAL AND METHODS

Postoperative ischemia was defined as new confluent areas of diffusion restriction on DWI in a retrospective database of 144 adult WHO grade II-IV supratentorial glioma patients, who received MRI within 3 days after resection in 2012–2014. New or worsened neurological deficits of any grade at discharge and after 3 months was assessed in relation to postoperative ischemia by an experienced neuro-oncologist. We manually delineated ischemic lesions and spatially normalized these to stereotaxic MNI space. Next, we performed voxel-based analysis (VBA) to identify locations of ischemia associated with new or worsened neurological deficits and corrected for multiple comparisons using family-wise error correction to eliminate false positive results. Delineations were labeled using the Harvard-Oxford cortical and subcortical atlases and a white matter atlas (XTRACT).

RESULTS

Any new or worsened neurological deficits were present in 44 (30.5%) cases at discharge and in 27 (20.9%) cases after 3 months, of which respectively 26 (18%) and 21 (16.3%) were related to ischemia. Volume of ischemia was significantly associated with deficits at discharge (P = 0.003) and after 3 months (P = 0.039). No areas of ischemia were associated with a lack of new or worsened deficits. A statistically significant cluster of 42.96cc was associated with deficits at discharge and encompassed the right frontal, insular and tempo-occipital regions. Voxels associated only with deficits at discharge included lateral occipital cortices and supramarginal gyri. A cluster of 17.68cc in the right frontal and insular lobes was significantly associated with deficits after 3 months. Overlapping areas included the right thalamus, caudate nucleus, putamen, globus pallidum, insular cortex, middle and inferior temporal gyri, corticospinal tract and superior thalamic radiation.

CONCLUSION

Transient and persisting new or worsened deficits after glioma resection were significantly associated with volume of postoperative ischemia. Ischemic lesions in right frontal and insular regions, including the basal nuclei, corticospinal tract and superior thalamic radiation were significantly associated with persisting neurological deficits after 3 months, while temporo-occipital lesions were associated with transient deficits only found at discharge.

P14.30 Voxelwise analysis of spatial distribution of postoperative ischemia in diffuse glioma

BACKGROUND

Surgical treatment of diffuse glioma is performed to reduce tumor mass effect and to pave the way for adjuvant (chemo)radiotherapy. As a complication of surgery, ischemic lesions are often found in the postoperative setting. Not only can these lesion induce neurological deficits, but their volume has also been associated with reduced survival time. Prior studies suggest areas with a singular vascular supply to be more prone to postoperative ischemic lesions, although the precise cause is yet unknown. The aim of this study was to explore the volumetric and spatial distributions of postoperative ischemic lesions and their relation to arterial territories in glioma patients.

MATERIAL AND METHODS

We accessed a retrospective database of 144 adult cases with WHO grade II-IV supratentorial gliomas, who received surgery and postoperative MRI within 3 days in 2012–2014. We identified 93 patients with postoperative ischemia, defined as new confluent diffusion restriction on DWI. Ischemic lesions were manually delineated and spatially normalized to stereotaxic MNI space. Voxel-based analysis (VBA) was performed to compare presence and absence of postoperative ischemia. False positive results were eliminated by family-wise error correction. Areas of ischemia were labeled using an arterial territory map, the Harvard-Oxford cortical and subcortical atlases and the XTRACT white matter atlas.

RESULTS

Median volume of confluent ischemia was 3.52cc (IQR 2.15–5.94). 23 cases had only ischemic lesion in the left hemisphere, 46 in the right hemisphere and 24 bilateral. Median volume was 3.08cc (IQR 1.35–5.72) in left-sided lesions and 2.47cc (1.01–4.24) in right-sided lesions. Volume of ischemic lesions was not associated with survival after 1, 2 or 5 years. A cluster of 125.18cc was found to be significantly associated with development of postoperative ischemia. 73% of this cluster was situated in the arterial territory of the right middle cerebral artery (MCA), limited by the border of the posterior cerebral artery (PCA), and the watershed area between the right MCA and the right anterior cerebral artery (ACA). Significant areas were located in the frontal lobes, spanning into the right temporo-occipital region, and predominantly included right and left thalamus, caudate nucleus, putamen, pallidum, as well as right temporal gyri and insular cortex, and parts of the right corticospinal tract, longitudinal fasciculi and superior thalamic radiation.

CONCLUSION

We found slightly more and larger ischemic lesions in the right than left hemisphere after glioma resection. A statistically significant cluster of voxels of postoperative ischemia was found in the territory of the right MCA and watershed area of the right ACA. Exploration of the spatial distribution of these lesions could help elucidate their etiology and form the basis for predicting clinically relevant postoperative ischemia.

P13.10 Glioblastoma within the subventricular zone associates with increased mesenchymal transition: an intratumoral gene expression analysis

BACKGROUND

Involvement of the subventricular zone (SVZ) in GBM is associated with poor prognosis and suggested to associate with specific tumor-biological characteristics. The SVZ microenvironment can influence gene expression and migration in GBM cells in preclinical models. We aimed to investigate whether the SVZ microenvironment has any influence on intratumoral gene expression patterns in GBM patients.

MATERIAL AND METHODS

The publicly available Ivy GBM database contains clinical, radiological and whole exome sequencing data from multiple regions from en bloc resected GBMs. SVZ involvement of the various tissue samples was evaluated on MRI scans. In the tumors that contacted the SVZ, we performed gene expression analyses and gene set enrichment analyses to compare gene (set) expression in tumor regions within the SVZ to tumor regions outside the SVZ, within the same tumors. We also compared these samples to GBMs that made no contact with the SVZ.

RESULTS

Within GBMs that contacted the SVZ, tissue samples within the SVZ showed enrichment of gene sets involved in (epithelial-)mesenchymal transition, NF-κB and STAT3 signaling, angiogenesis and hypoxia, compared to the samples outside of the SVZ region from the same tumors (p<0.05, FDR<0.25). Comparison of GBM samples within the SVZ region to samples from tumors that did not contact the SVZ yielded similar results. In contrast, we observed no difference in gene set enrichment when comparing the samples outside of the SVZ from SVZ-contacting GBMs with samples from GBMs that did not contact the SVZ at all.

CONCLUSION

GBM samples in the SVZ region associate with increased (epithelial-)mesenchymal transition and angiogenesis/hypoxia signaling, possibly mediated by the SVZ microenvironment.

The use of (18)F-FDG PET to differentiate progressive disease from treatment induced necrosis in high grade glioma

In the follow-up of patients treated for high grade glioma, differentiation between progressive disease (PD) and treatment-induced necrosis (TIN) is challenging. The purpose of this study is to evaluate the diagnostic accuracy of FDG PET for the differentiation between TIN and PD after high grade glioma treatment. We retrospectively identified patients between January 2011 and July 2013 that met the following criteria: age >18; glioma grade 3 or 4; treatment with radiotherapy or chemoradiotherapy; new or progressive enhancement on post treatment MRI; FDG PET within 4 weeks of MRI. Absolute and relative (to contralateral white matter) values of SUVmax and SUVpeak were determined in new enhancing lesions on MRI. The outcome of PD or TIN was determined by neurosurgical biopsy/resection, follow-up MRI, or clinical deterioration. The association between FDG PET and outcome was analyzed with univariate logistic regression and ROC analysis for: all lesions, lesions >10, >15, and >20 mm. We included 30 patients (5 grade 3 and 25 grade 4), with 39 enhancing lesions on MRI. Twenty-nine lesions represented PD and 10 TIN. Absolute and relative values of SUVmax and SUVpeak showed no significant differences between PD and TIN. ROC analysis showed highest AUCs for relative SUVpeak in all lesion sizes. Relative SUVpeak for lesions >20 mm showed reasonable discriminative properties [AUC 0.69 (0.41–0.96)]. FDG PET has reasonable discriminative properties for differentiation of PD from TIN in high grade gliomas larger than 20 mm. Overall diagnostic performance is insufficient to guide clinical decision-making.

Growth regulation of astrocytes and C6 cells by TGFbeta1: correlation with gap junctions

Transforming growth factor (TGF) beta1 enhanced in vitro [3H]thymidine incorporation into C6 cells and reduced that of astrocytes in the presence of a high serum concentration. It concomitantly raised the gap junction intercellular communication (GJIC) in normal astrocytes but reduced the coupling of C6 cells, and respectively increased or decreased the proportion of P2-phosphorylated connexin (Cx) 43 isoform in these cells. Finally, octanol, which inhibited GJIC in both cell types, increased the thymidine incorporation in C6 cells, but neither altered the proliferation of astrocytes nor their response to TGFbeta1. These data indicate that an inhibition of gap junction intercellular communication, due to an altered phosphorylation of connexin 43, may contribute to the proliferative response of C6 glioblastoma cells to TGFbeta1.

Pharmacological modulation of the bystander effect in the herpes simplex virus thymidine kinase/ganciclovir gene therapy system: effects of dibutyryl adenosine 3',5'-cyclic monophosphate, alpha-glycyrrhetinic acid, and cytosine arabinoside

The herpes simplex virus type 1 thymidine kinase (HSV1-tk) suicide gene/ganciclovir system was first applied to the treatment of glioblastoma tumors, but was hampered by the low gene transfection yield. Fortunately, the gap junction-dependent diffusion of phosphorylated ganciclovir metabolites from transfected cells to their neighbors proved to enhance the overall benefit of this strategy. However, as tumor cells are often gap junction-deficient, we sought to restore this property pharmacologically and hence to improve the efficacy of the treatment. We demonstrated that this approach was feasible in glioblastoma cells using dibutyryl adenosine 3',5'-cyclic monophosphate (cAMP) (100 microM) as a pharmacological inducer of gap junctions. alpha-Glycyrrhetinic acid (25 microM), on the other hand, strongly inhibited both gap junction-mediated intercellular communication and the bystander effect, thus confirming the role of gap junctions in HSV-tk-mediated bystander killing. Using cytosine arabinoside as a growth inhibitor, we underlined the role of tumor cell proliferation in the sensitivity of HSV-tk-transfected cells to ganciclovir and demonstrated its correlation with the importance of the bystander effect.