The role of early magnetic resonance imaging in predicting survival on bevacizumab for recurrent glioblastoma: Results from a prospective clinical trial (CABARET)

Carcinoembryonic antigen-expressing oncolytic measles virus derivative in recurrent glioblastoma: a phase 1 trial

Measles virus (MV) vaccine strains have shown significant preclinical antitumor activity against glioblastoma (GBM), the most lethal glioma histology. In this first in human trial (NCT00390299), a carcinoembryonic antigen-expressing oncolytic measles virus derivative (MV-CEA), was administered in recurrent GBM patients either at the resection cavity (Group A), or, intratumorally on day 1, followed by a second dose administered in the resection cavity after tumor resection on day 5 (Group B). A total of 22 patients received study treatment, 9 in Group A and 13 in Group B. Primary endpoint was safety and toxicity: treatment was well tolerated with no dose-limiting toxicity being observed up to the maximum feasible dose (2×107 TCID50). Median OS, a secondary endpoint, was 11.6 mo and one year survival was 45.5% comparing favorably with contemporary controls. Other secondary endpoints included assessment of viremia, MV replication and shedding, humoral and cellular immune response to the injected virus. A 22 interferon stimulated gene (ISG) diagonal linear discriminate analysis (DLDA) classification algorithm in a post-hoc analysis was found to be inversely (R = -0.6, p = 0.04) correlated with viral replication and tumor microenvironment remodeling including proinflammatory changes and CD8 + T cell infiltration in post treatment samples. This data supports that oncolytic MV derivatives warrant further clinical investigation and that an ISG-based DLDA algorithm can provide the basis for treatment personalization.

Molecular and functional imaging in cancer-targeted therapy: current applications and future directions

Targeted anticancer drugs block cancer cell growth by interfering with specific signaling pathways vital to carcinogenesis and tumor growth rather than harming all rapidly dividing cells as in cytotoxic chemotherapy. The Response Evaluation Criteria in Solid Tumor (RECIST) system has been used to assess tumor response to therapy via changes in the size of target lesions as measured by calipers, conventional anatomically based imaging modalities such as computed tomography (CT), and magnetic resonance imaging (MRI), and other imaging methods. However, RECIST is sometimes inaccurate in assessing the efficacy of targeted therapy drugs because of the poor correlation between tumor size and treatment-induced tumor necrosis or shrinkage. This approach might also result in delayed identification of response when the therapy does confer a reduction in tumor size. Innovative molecular imaging techniques have rapidly gained importance in the dawning era of targeted therapy as they can visualize, characterize, and quantify biological processes at the cellular, subcellular, or even molecular level rather than at the anatomical level. This review summarizes different targeted cell signaling pathways, various molecular imaging techniques, and developed probes. Moreover, the application of molecular imaging for evaluating treatment response and related clinical outcome is also systematically outlined. In the future, more attention should be paid to promoting the clinical translation of molecular imaging in evaluating the sensitivity to targeted therapy with biocompatible probes. In particular, multimodal imaging technologies incorporating advanced artificial intelligence should be developed to comprehensively and accurately assess cancer-targeted therapy, in addition to RECIST-based methods.

The relationship between the degree of brain edema regression and changes in cognitive function in patients with recurrent glioma treated with bevacizumab and temozolomide

Background

This retrospective study aims to assess the impacts on cognitive status and quality of life in recurrent high-grade glioma patients treated with temozolomide (TMZ), either alone or in combination with bevacizumab (BEV), and explore the relationship between the brain edema regression, BEV use, and cognitive status.

Methods

A total of 125 patients with recurrent high-grade glioma were enrolled in this study, of which 65 patients were treated with BEV (5-10 mg/kg IV every 2 weeks) plus TMZ (200 mg/m² every 28 days, d1-5), and 60 patients were treated with TMZ (200 mg/m² every 28 days, d1-5) alone. The treatment response was evaluated using the Response Assessment in Neuro-Oncology (RANO) criteria. Tumor-associated edema was evaluated with T2WI magnetic resonance imaging (MRI) and quantitative T2 mapping sequence, and an Edema Regression Index was designed to quantify volumetric changes in edema imaging after every treatment cycle. Cognitive intelligence state and quality of life were evaluated using the Mini-Mental State Examination (MMSE) and the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (QLQ-C30).

Results

Radiologically, the partial response rate was 78.5% in the BEV + TMZ group and 38.3% in the TMZ group. After the first cycle of treatment, the mean score of the MMSE was 21.1±2.0 and 24.1±1.4 (P<0.001) in the TMZ group and the BEV + TMZ group, respectively. In the functioning domains of the QLQ-C30, scales of physical functioning, emotional functioning and cognitive functioning were 43.0±7.0 vs. 61.7±12.5 (P<0.001), 44.5±8.8 vs. 63.4±6.9 (P<0.001) and 42.4±8.8 vs. 63.7±12.0 (P<0.001) in the TMZ group and the BEV + TMZ group, respectively. In the BEV + TMZ group, a correlation between the Edema Regression Index and improvement in cognitive status and quality of life was observed. Patients with Edema Regression Index scores higher than 50% gained a 25.6% increase in the mean MMSE score from 19.9±1.6 to 25.0±1.1 (P<0.001). In the BEV + TMZ group, physical functioning, emotional functioning, and cognitive functioning increased by 76.8%, 53.1%, and 81.5%, respectively, while scores of nausea/vomiting decreased by 40.3% to 32.1. Patients with no evident edema observed in the pre-BEV MRI scans were given a prolonged four-cycle course of BEV. No significant improvement was observed in the MMSE score and the QLQ score with additional cycles of BEV.

Conclusions

A close relationship was observed between Edema Regression Index and a change in cognitive function in patients treated with BEV and TMZ. Compared with TMZ alone, the combination of TMZ and BEV could improve the cognitive function and quality of life of patients with recurrent high-grade gliomas. The Edema Regression Index could be used as a surrogate imaging biomarker to predict patients who may or may not gain cognitive benefit from the combination therapy of TMZ and BEV, which warrants further prospective clinical studies for validation.

Interval brain imaging for adults with cerebral glioma

BACKGROUND

Clinical practice guidelines suggest that magnetic resonance imaging (MRI) of the brain should be performed at certain time points or intervals distant from diagnosis (interval or surveillance imaging) of cerebral glioma, to monitor or follow up the disease; it is not known, however, whether these imaging strategies lead to better outcomes among patients than triggered imaging in response to new or worsening symptoms.

OBJECTIVES

To determine the effect of different imaging strategies (in particular, pre-specified interval or surveillance imaging, and symptomatic or triggered imaging) on health and economic outcomes for adults with glioma (grades 2 to 4) in the brain.

SEARCH METHODS

The Cochrane Gynaecological, Neuro-oncology and Orphan Cancers (CGNOC) Group Information Specialist searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and Embase up to 18 June 2019 and the NHS Economic Evaluation Database (EED) up to December 2014 (database closure).

SELECTION CRITERIA

We included randomised controlled trials, non-randomised controlled trials, and controlled before-after studies with concurrent comparison groups comparing the effect of different imaging strategies on survival and other health outcomes in adults with cerebral glioma; and full economic evaluations (cost-effectiveness analyses, cost-utility analyses and cost-benefit analyses) conducted alongside any study design, and any model-based economic evaluations on pre- and post-treatment imaging in adults with cerebral glioma.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane review methodology with two authors independently performing study selection and data collection, and resolving disagreements through discussion. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included one retrospective, single-institution study that compared post-operative imaging within 48 hours (early post-operative imaging) with no early post-operative imaging among 125 people who had surgery for glioblastoma (GBM: World Health Organization (WHO) grade 4 glioma). Most patients in the study underwent maximal surgical resection followed by combined radiotherapy and temozolomide treatment. Although patient characteristics in the study arms were comparable, the study was at high risk of bias overall. Evidence from this study suggested little or no difference between early and no early post-operative imaging with respect to overall survival (deaths) at one year after diagnosis of GBM (risk ratio (RR) 0.86, 95% confidence interval (CI) 0.61 to 1.21; 48% vs 55% died, respectively; very low certainty evidence) and little or no difference in overall survival (deaths) at two years after diagnosis of GBM (RR 1.06, 95% CI 0.91 to 1.25; 86% vs 81% died, respectively; very low certainty evidence). No other review outcomes were reported. We found no evidence on the effectiveness of other imaging schedules. In addition, we identified no relevant economic evaluations assessing the efficiency of the different imaging strategies.

AUTHORS' CONCLUSIONS

The effect of different imaging strategies on survival and other health outcomes remains largely unknown. Existing imaging schedules in glioma seem to be pragmatic rather than evidence-based. The limited evidence suggesting that early post-operative brain imaging among GBM patients who will receive combined chemoradiation treatment may make little or no difference to survival needs to be further researched, particularly as early post-operative imaging also serves as a quality control measure that may lead to early re-operation if residual tumour is identified. Mathematical modelling of a large glioma patient database could help to distinguish the optimal timing of surveillance imaging for different types of glioma, with stratification of patients facilitated by assessment of individual tumour growth rates, molecular biomarkers and other prognostic factors. In addition, paediatric glioma study designs could be used to inform future research of imaging strategies among adults with glioma.

Whole genome and biomarker analysis of patients with recurrent glioblastoma on bevacizumab: A subset analysis of the CABARET trial

The CABARET trial (ACTRN12610000915055) reported no difference in overall survival (OS) between patients with recurrent glioblastoma (GBM) randomized to either bevacizumab monotherapy or bevacizumab plus carboplatin. However, a subset of patients showed durable responses and prolonged survival, with recorded survival times of over 30 months in five of 122 patients (4%). Patient selection for bevacizumab therapy would be enhanced if a predictive biomarker of response or survival could be identified; this biomarker sub-study attempted to identify novel biomarkers. Patients who opted to participate in this sub-study and who had adequate biospecimens for analysis (n = 54) were retrospectively evaluated for the expression of a series of tumor proteins. Immunohistochemistry (IHC) was used to measure the expression of 19 proteins previously implicated in cancer treatment response to bevacizumab. MGMT promoter methylation was also assessed. Tumor DNA from five patients with outlying survival duration ('poor' and 'exceptional' survivors) was subjected to whole genome sequencing (WGS). No single protein expression level, including VEGF-A, predicted OS in the cohort. WGS of poor and exceptional survivors identified a gain in Chromosome 19 that was exclusive to the exceptional survivors. Validation of this finding requires examination of a larger independent cohort.

Cerebral blood volume and apparent diffusion coefficient - Valuable predictors of non-response to bevacizumab treatment in patients with recurrent glioblastoma

BACKGROUND

Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults. The core of standard of care for newly diagnosed GBM was established in 2005 and includes maximum feasible surgical resection followed by radiation and temozolomide, with subsequent temozolomide with or without tumor-treating fields. Unfortunately, nearly all patients experience a recurrence. Bevacizumab (BV) is a commonly used second-line agent for such recurrences, but it has not been shown to impact overall survival, and short-term response is variable.

METHODS

We collected MRI perfusion and diffusion images from 54 subjects with recurrent GBM treated only with radiation and temozolomide. They were subsequently treated with BV. Using machine learning, we created a model to predict short term response (6 months) and overall survival. We set time thresholds to maximize the separation of responders/survivors versus non-responders/short survivors.

RESULTS

We were able to segregate 21 (68%) of 31 subjects into unlikely to respond categories based on Progression Free Survival at 6 months (PFS6) criteria. Twenty-two (69%) of 32 subjects could similarly be identified as unlikely to survive long using the machine learning algorithm.

CONCLUSION

With the use of machine learning techniques to evaluate imaging features derived from pre- and post-treatment multimodal MRI, it is possible to identify an important fraction of patients who are either highly unlikely to respond, or highly likely to respond. This can be helpful is selecting patients that either should or should not be treated with BV.

Comparative Histologic and Molecular Analysis of 2 Recurrent Lesions Showing Different Magnetic Resonance Imaging Responses After Bevacizumab Treatment: Report of a Case of Anaplastic Astrocytoma

BACKGROUND

We report the case of a patient with anaplastic astrocytoma whose 2 recurrent lesions showed different imaging responses from one another after bevacizumab treatment. Histologic and genetic features of this patient are also described.

CASE DESCRIPTION

A 31-year-old patient with left temporal anaplastic astrocytoma had surgery, local radiotherapy, and chemotherapy. Recurrent lesions appeared in the cerebellar vermis and left cerebellar hemisphere, and the patient was started on biweekly bevacizumab. Subsequently, the 2 enhanced lesions showed different response patterns on magnetic resonance imaging. Although the lesion in the cerebellar vermis showed an enlargement of enhancing mass, the lesion in the left cerebellar hemisphere showed disappearance of enhancement. We resected the cerebellar vermis lesion and performed biopsy on the cerebellar hemisphere lesion. The specimens were investigated. Both recurrent lesions showed higher Ki-67 labeling indices and pericyte proliferation, and less angiogenesis compared with the initial specimen. Transmission electron microscopy showed a reduction in the distance between the endothelial cells and tumor cells in both recurrent lesions, compared with the initial lesion. However, the tight junctions in the vermian lesion were still disrupted compared with the initial lesion and the cerebellar hemispheric lesion. Genetic analysis of the initial specimen showed proneural signature; however, the recurrent vermian lesion exhibited decreased expression of proneural markers.

CONCLUSIONS

We report a case of anaplastic astrocytoma with 2 different imaging responses to bevacizumab. Our analysis suggests that differences in tight junctions possibly contributed to the changes on magnetic resonance imaging observed after bevacizumab treatment.