Do glioma patients derive any therapeutic benefit from taking a higher cumulative dose of temozolomide regimens?: a meta-analysis

Treatments of gliosarcoma of the brain: a systematic review and meta-analysis

Gliosarcoma (GSM) is a rare central nervous system tumor. Clinical management of it is similar to glioblastoma (GBM). However, due to a few comparative studies exist, uncertainty and disagreements remain in the literatures. To assess the available evidence on the value of different treatments and to carry out an up-to-date evaluation to summarize the evidence for the optimal treatment in GSM patients. Free words were used to search for the relevant studies without language limitations in electronic databases including PubMed, Ovid EMBASE, Cochrane Central Register of Controlled Trials from inception to September 15, 2019. Pooled hazard ratio (HR) with 95% confidence interval (CI) were calculated using a random-effects model. The main endpoint was all-cause mortality. Overall, 10 studies published between 2008 and 2018 including 803 patients were selected for the meta-analysis. Temozolomide (TMZ)-dominated chemotherapy was associated with a reduced risk of overall survival (OS), with HR 0.49 (95% CI 0.37-0.66). The pooled HR of OS was 0.40 (95% CI 0.29-0.56) between radiotherapy and without radiotherapy. The pooled HR (0.52, 95% CI 0.32-0.85) indicated gross total resection (GTR) had a positive impact on OS in GSM. In patients with GSM, survival benefits as currently performed are associated with TMZ-dominated chemotherapy and high-dose radiotherapy. Our systematic review and meta-analysis also demonstrate GTR is associated with a reduction in all-cause mortality in patients with primary GSM.

A Systematic Review of Glioblastoma-Targeted Therapies in Phases II, III, IV Clinical Trials

Glioblastoma (GBM), the most frequent and aggressive glial tumor, is currently treated as first line by the Stupp protocol, which combines, after surgery, radiotherapy and chemotherapy. For recurrent GBM, in absence of standard treatment or available clinical trials, various protocols including cytotoxic drugs and/or bevacizumab are currently applied. Despite these heavy treatments, the mean overall survival of patients is under 18 months. Many clinical studies are underway. Based on clinicaltrials.org and conducted up to 1 April 2020, this review lists, not only main, but all targeted therapies in phases II-IV of 257 clinical trials on adults with newly diagnosed or recurrent GBMs for the last twenty years. It does not involve targeted immunotherapies and therapies targeting tumor cell metabolism, that are well documented in other reviews. Without surprise, the most frequently reported drugs are those targeting (i) EGFR (40 clinical trials), and more generally tyrosine kinase receptors (85 clinical trials) and (ii) VEGF/VEGFR (75 clinical trials of which 53 involving bevacizumab). But many other targets and drugs are of interest. They are all listed and thoroughly described, on an one-on-one basis, in four sections related to targeting (i) GBM stem cells and stem cell pathways, (ii) the growth autonomy and migration, (iii) the cell cycle and the escape to cell death, (iv) and angiogenesis.

The impact of extended adjuvant temozolomide in newly diagnosed glioblastoma multiforme: a meta-analysis and systematic review

Surgical resection followed by concurrent radiation therapy and temozolomide (TMZ) chemotherapy is the current standard treatment for glioblastoma multiforme (GBM). The present metaanalysis investigated the impact of prolonged TMZ maintenance therapy (more than 6 cycles) in comparison with standard TMZ maintenance therapy (exactly six cycles) on overall survival (OS) and progression-free survival (PFS) of patients with GBM. A meta-analysis of the literature was conducted using Medline, PubMed, EMBASE and the Cochrane Library in accordance with PRISMA guidelines. Seven articles involving 1018 patients were included. The overall survival was higher in the case group (>6 cycles TMZ) compared to the control group (6 cycles TMZ) (Z=2.375, P=0.018). The lower and upper limits were between 1.002-10.467 months. The case group had higher progression-free survival compared with the control group (Z=3.84; P<0.001). The lower and upper limits were between 2.559-7.894 months. Evidence from this meta-analysis suggests that prolonged TMZ therapy compared to the standard 6-cycle TMZ therapy was associated with higher survival in patients with glioblastoma.

β-escin selectively targets the glioblastoma-initiating cell population and reduces cell viability

Glioblastoma multiforme (GBM) is a highly aggressive tumour of the central nervous system and is associated with an extremely poor prognosis. Within GBM exists a subpopulation of cells, glioblastoma-initiating cells (GIC), which possess the characteristics of progenitor cells, have the ability to initiate tumour growth and resist to current treatment strategies. We aimed at identifying novel specific inhibitors of GIC expansion through use of a large-scale chemical screen of approved small molecules. Here, we report the identification of the natural compound β-escin as a selective inhibitor of GIC viability. Indeed, β-escin was significantly cytotoxic in nine patient-derived GIC, whilst exhibiting no substantial effect on the other human cancer or control cell lines tested. In addition, β-escin was more effective at reducing GIC growth than current clinically used cytotoxic agents. We further show that β-escin triggers caspase-dependent cell death combined with a loss of stemness properties. However, blocking apoptosis could not rescue the β-escin-induced reduction in sphere formation or stemness marker activity, indicating that β-escin directly modifies the stem identity of GIC, independent of the induction of cell death. Thus, this study has repositioned β-escin as a promising potential candidate to selectively target the aggressive population of initiating cells within GBM.

On glioblastoma and the search for a cure: where do we stand?

Although brain tumours have been documented and recorded since the nineteenth century, 2016 marked 90 years since Percival Bailey and Harvey Cushing coined the term "glioblastoma multiforme". Since that time, although extensive developments in diagnosis and treatment have been made, relatively little improvement on prognosis has been achieved. The resilience of GBM thus makes treating this tumour one of the biggest challenges currently faced by neuro-oncology. Aggressive and robust development, coupled with difficulties of complete resection, drug delivery and therapeutic resistance to treatment are some of the main issues that this nemesis presents today. Current treatments are far from satisfactory with poor prognosis, and focus on palliative management rather than curative intervention. However, therapeutic research leading to developments in novel treatment stratagems show promise in combating this disease. Here we present a review on GBM, looking at the history and advances which have shaped neurosurgery over the last century that cumulate to the present day management of GBM, while also exploring future perspectives in treatment options that could lead to new treatments on the road to a cure.

Comparative Study of Adjuvant Temozolomide Six Cycles Versus Extended 12 Cycles in Newly Diagnosed Glioblastoma Multiforme

INTRODUCTION

Studies have shown promising survival with the use of Extended Temozolomide (E-TMZ) as compared to Conventional six cycles of Temozolomide (C-TMZ) in malignant gliomas; however, the reports are mostly limited to retrospective studies with significant bias.

AIM

This study assesses the impact of six versus 12 cycles of adjuvant Temozolomide (TMZ) on Overall Survival (OS) in newly diagnosed postoperative patients of Glioblastoma Multiforme (GBM).

MATERIALS AND METHODS

Between January 2012 and July 2013, 40 postoperative patients of GBM between age 18-65 years and Karnofsky Performance Score (KPS) ≥70 were included. Patients were randomized to receive radiation (60 Gray in 30 fractions over six weeks) with concomitant TMZ (75 mg/m²/day) and adjuvant therapy with either six (C-TMZ arm) or 12 cycles (E-TMZ arm) of TMZ (150-200 mg/m² for five days, repeated four weekly). Twenty patients were treated in each arm. Toxicity was assessed using Common Terminology Criteria for Adverse Events (CTCAE) version 3.0. OS and Progression Free Survival (PFS) were calculated from the time of diagnosis. Kaplan Meier method was used for survival analysis. A p-value of <0.05 was taken as significant and SPSS version 12.0 was used for all statistical analysis.

RESULTS

Median number of adjuvant TMZ cycles was six and 12 in C-TMZ and E-TMZ arm respectively. Overall, 5% and 15% patients respectively in C-TMZ and E-TMZ arm had haematological toxicity ≥ 3 in grade. Median follow up in C-TMZ and E-TMZ arm were 14.65 months and 19.85 months. Median PFS was 12.8 months and 16.8 months in C-TMZ and E-TMZ arm respectively (p=0.069). Median OS was 15.4 months vs. 23.8 months in C-TMZ and E-TMZ arm respectively (p=0.044).

CONCLUSION

Our study showed that E-TMZ is well tolerated and leads to a significant increase in PFS as well as OS in newly diagnosed patients of GBM. Further prospective randomized studies are needed to validate the findings of our study.

Temozolomide with or without Radiotherapy in Patients with Newly Diagnosed Glioblastoma Multiforme: A Meta-Analysis

BACKGROUND/AIM

The current meta-analysis evaluated the survival outcomes of newly diagnosed glioblastoma patients treated with radiotherapy (RT) alone and with RT + temozolomide (TMZ).

METHODS

Relevant studies were identified by an extensive literature search in Medline, Current Contents and Cochrane databases by 2 independent reviewers using the terms "glioblastoma multiforme/glioblastoma, TMZ, radiation therapy/RT and survival."

RESULTS

Results revealed a median survival of 13.41-19 months in the combined treatment group, as opposed to 7.7-17.1 months in the RT-alone group. Progression-free survival (PFS) was also significantly different between the 2 groups (RT + TMZ, 6.3-13 months; RT-alone, 5-7.6 months). While there was no significant difference in the 6-month survival and 6-month PFS rates between the RT + TMZ and RT groups (pooled OR 0.690; p = 0.057 and OR 0.429, p = 0.052, respectively), the 1-year survival and 1-year PFS rates showed significant difference (OR 0.469; p = 0.030 and OR 0.245, p < 0.001, respectively).

CONCLUSIONS

Concomitant RT + TMZ is more effective and improves the overall survival and PFS in patients with newly diagnosed glioblastoma.