Phase III trial of accelerated hyperfractionation with or without difluromethylornithine (DFMO) versus standard fractionated radiotherapy with or without DFMO for newly diagnosed patients with glioblastoma multiforme

Tumor cell-derived spermidine promotes a pro-tumorigenic immune microenvironment in glioblastoma via CD8+ T cell inhibition

The glioblastoma microenvironment is enriched in immunosuppressive factors that potently interfere with the function of cytotoxic T lymphocytes. Cancer cells can directly impact the immune system, but the mechanisms driving these interactions are not completely clear. Here we demonstrate that the polyamine metabolite spermidine is elevated in the glioblastoma tumor microenvironment. Exogenous administration of spermidine drives tumor aggressiveness in an immune-dependent manner in pre-clinical mouse models via reduction of CD8+ T cell frequency and phenotype. Knockdown of ornithine decarboxylase, the rate-limiting enzyme in spermidine synthesis, did not impact cancer cell growth in vitro but did result in extended survival. Furthermore, glioblastoma patients with a more favorable outcome had a significant reduction in spermidine compared to patients with a poor prognosis. Our results demonstrate that spermidine functions as a cancer cell-derived metabolite that drives tumor progression by reducing CD8+T cell number and function.

Glioma Metabolic Feedback In Situ: A First-In-Human Pharmacodynamic Trial of Difluoromethylornithine + AMXT-1501 Through High-Molecular Weight Microdialysis

BACKGROUND AND OBJECTIVES

No new drug has improved survival for glioblastoma since temozolomide in 2005, due in part to the relative inaccessibility of each patient's individualized tumor biology and its response to therapy. We have identified a conserved extracellular metabolic signature of enhancing high-grade gliomas enriched for guanidinoacetate (GAA). GAA is coproduced with ornithine, the precursor to protumorigenic polyamines through ornithine decarboxylase (ODC). AMXT-1501 is a polyamine transporter inhibitor that can overcome tumoral resistance to the ODC inhibitor, difluoromethylornithine (DFMO). We will use DFMO with or without AMXT-1501 to identify candidate pharmacodynamic biomarkers of polyamine depletion in patients with high-grade gliomas in situ . We aim to determine (1) how blocking polyamine production affects intratumoral extracellular guanidinoacetate abundance and (2) the impact of polyamine depletion on the global extracellular metabolome within live human gliomas in situ.

METHODS

DFMO, with or without AMXT-1501, will be administered postoperatively in 15 patients after clinically indicated subtotal resection for high-grade glioma. High-molecular weight microdialysis catheters implanted into residual tumor and adjacent brain will be used for postoperative monitoring of extracellular GAA and polyamines throughout therapeutic intervention from postoperative day (POD) 1 to POD5. Catheters will be removed on POD5 before discharge.

EXPECTED OUTCOMES

We anticipate that GAA will be elevated in tumor relative to adjacent brain although it will decrease within 24 hours of ODC inhibition with DFMO. If AMXT-1501 effectively increases the cytotoxic impact of ODC inhibition, we expect an increase in biomarkers of cytotoxicity including glutamate with DFMO + AMXT-1501 treatment when compared with DFMO alone.

DISCUSSION

Limited mechanistic feedback from individual patients' gliomas hampers clinical translation of novel therapies. This pilot Phase 0 study will provide in situ feedback during DFMO + AMXT-1501 treatment to determine how high-grade gliomas respond to polyamine depletion.

Prognosis prediction for glioblastoma multiforme patients using machine learning approaches: Development of the clinically applicable model

BACKGROUND AND PURPOSE

We aimed to develop a clinically applicable prognosis prediction model predicting overall survival (OS) and progression-free survival (PFS) for glioblastoma multiforme (GBM) patients.

MATERIALS AND METHODS

All 467 patients treated with concurrent chemoradiotherapy at Yonsei Cancer Center from 2016 to 2020 were included in this study. We developed a conventional linear regression, Cox proportional hazards (COX), and non-linear machine learning algorithms, random survival forest (RSF) and survival support vector machine (SVM) based on 16 clinical variables. After backward feature selection and hyperparameter tuning using grid search, we repeated 100 times of cross-validations to combat overfitting and enhance the model performance. Harrell's concordance index (C-index) and integrated brier score (IBS) were employed as quantitative performance metrics.

RESULTS

In both predictions, RSF performed much better than COX and SVM. (For OS prediction: RSF C-index = 0.72 90%CI [0.71-0.72] and IBS = 0.12 90%CI [0.10-0.13]; For PFS prediction: RSF C-index = 0.70 90%CI [0.70-0.71] and IBS = 0.12 90%CI [0.10-0.14]). Permutation feature importance confirmed that MGMT promoter methylation, extent of resection, age, cone down planning target volume, and subventricular zone involvement are significant prognostic factors for OS. The importance of the extent of resection and MGMT promoter methylation was much higher than other selected input factors in PFS. Our final models accurately stratified two risk groups with root mean square errors less than 0.07. The sensitivity analysis revealed that our final models are highly applicable to newly diagnosed GBM patients.

CONCLUSION

Our final models can provide a reliable outcome prediction for individual GBM. The final OS and PFS predicting models we developed accurately stratify high-risk groups up to 5-years, and the sensitivity analysis confirmed that both final models are clinically applicable.

Key Clinical Principles in the Management of Glioblastoma

Glioblastoma is the most common and aggressive primary brain tumor in the adult population and leads to considerable morbidity and mortality. It has a dismal prognosis with average survival of 15-18 months, and the current standard-of-care treatment paradigm includes maximal surgical resection and postoperative concurrent chemoradiotherapy and maintenance chemotherapy, with consideration of Tumor Treating Fields. There is a major emphasis to enroll patients onto ongoing clinical trials to further improve treatment outcomes, given the aggressive nature of the disease course and poor patient survival. Recent research efforts have focused on radiotherapy dose intensification, regulation of the tumor microenvironment, and exploration of immunotherapeutic approaches to overcome the barriers to treatment. This review article outlines the current evidence-based management principles as well as reviews recent clinical trial data and ongoing clinical studies evaluating novel therapeutic options.

Antibody Delivery into the Brain by Radiosensitizer Nanoparticles for Targeted Glioblastoma Therapy

Background

Glioblastoma is the most lethal primary brain malignancy in adults. Standard of care treatment, consisting of temozolomide (TMZ) and adjuvant radiotherapy (RT), mostly does not prevent local recurrence. The inability of drugs to enter the brain, in particular antibody-based drugs and radiosensitizers, is a crucial limitation to effective glioblastoma therapy.

Methods

Here, we developed a combined strategy using radiosensitizer gold nanoparticles coated with insulin to cross the blood-brain barrier and shuttle tumor-targeting antibodies (cetuximab) into the brain.

Results

Following intravenous injection to an orthotopic glioblastoma mouse model, the nanoparticles specifically accumulated within the tumor. Combining targeted nanoparticle injection with TMZ and RT standard of care significantly inhibited tumor growth and extended survival, as compared to standard of care alone. Histological analysis of tumors showed that the combined treatment eradicated tumor cells, and decreased tumor vascularization, proliferation, and repair.

Conclusions

Our findings demonstrate radiosensitizer nanoparticles that effectively deliver antibodies into the brain, target the tumor, and effectively improve standard of care treatment outcome in glioblastoma.

The use of radiosensitizing agents in the therapy of glioblastoma multiforme-a comprehensive review

BACKGROUND

Glioblastoma is the most common malignant brain tumor in human adults. Despite several improvements in resective as well as adjuvant therapy over the last decades, its overall prognosis remains poor. As a means of improving patient outcome, the possibility of enhancing radiation response by using radiosensitizing agents has been tested in an array of studies.

METHODS

A comprehensive review of clinical trials involving radiation therapy in combination with radiosensitizing agents on patients diagnosed with glioblastoma was performed in the National Center for Biotechnology Information's PubMed database.

RESULTS

A total of 96 papers addressing this matter were published between 1976 and 2021, of which 63 matched the subject of this paper. All papers were reviewed, and their findings discussed in the context of their underlining mechanisms of radiosensitization.

CONCLUSION

In the history of glioblastoma treatment, several approaches of optimizing radiation-effectiveness using radiosensitizers have been made. Even though several different strategies and agents have been explored, clear evidence of improved patient outcome is still missing. Tissue-selectiveness and penetration of the blood-brain barrier seem to be major roadblocks; nevertheless, modern strategies try to circumvent these obstacles, using novel sensitizers based on preclinical data or alternative ways of delivery.

A Boronated Derivative of Temozolomide Showing Enhanced Efficacy in Boron Neutron Capture Therapy of Glioblastoma

There is an incontestable need for improved treatment modality for glioblastoma due to its extraordinary resistance to traditional chemoradiation therapy. Boron neutron capture therapy (BNCT) may play a role in the future. We designed and synthesized a ¹⁰B-boronated derivative of temozolomide, TMZB. BNCT was carried out with a total neutron radiation fluence of 2.4 ± 0.3 × 10¹¹ n/cm². The effects of TMZB in BNCT were measured with a clonogenic cell survival assay in vitro and PET/CT imaging in vivo. Then, ¹⁰B-boronated phenylalanine (BPA) was tested in parallel with TMZB for comparison. The IC50 of TMZB for the cytotoxicity of clonogenic cells in HS683 was 0.208 mM, which is comparable to the IC50 of temozolomide at 0.213 mM. In BNCT treatment, 0.243 mM TMZB caused 91.2% ± 6.4% of clonogenic cell death, while 0.239 mM BPA eliminated 63.7% ± 6.3% of clonogenic cells. TMZB had a tumor-to-normal brain ratio of 2.9 ± 1.1 and a tumor-to-blood ratio of 3.8 ± 0.2 in a mouse glioblastoma model. BNCT with TMZB in this model caused 58.2% tumor shrinkage at 31 days after neutron irradiation, while the number for BPA was 35.2%. Therefore, by combining the effects of chemotherapy from temozolomide and radiotherapy with heavy charged particles from BNCT, TMZB-based BNCT exhibited promising potential for therapeutic applications in glioblastoma treatment.

Accelerated hyper-versus normofractionated radiochemotherapy with temozolomide in patients with glioblastoma: a multicenter retrospective analysis

Background and purpose

The standard treatment of glioblastoma patients consists of surgery followed by normofractionated radiotherapy (NFRT) with concomitant and adjuvant temozolomide chemotherapy. Whether accelerated hyperfractionated radiotherapy (HFRT) yields comparable results to NFRT in combination with temozolomide has only sparsely been investigated. The objective of this study was to compare NFRT with HFRT in a multicenter analysis.

Materials and methods

A total of 484 glioblastoma patients from four centers were retrospectively pooled and analyzed. Three-hundred-ten and 174 patients had been treated with NFRT (30 × 1.8 Gy or 30 × 2 Gy) and HFRT (37 × 1.6 Gy or 30 × 1.8 Gy twice/day), respectively. The primary outcome of interest was overall survival (OS) which was correlated with patient-, tumor- and treatment-related variables via univariable and multivariable Cox frailty models. For multivariable modeling, missing covariates were imputed using multiple imputation by chained equations, and a sensitivity analysis was performed on the complete-cases-only dataset.

Results

After a median follow-up of 15.7 months (range 0.8–88.6 months), median OS was 16.9 months (15.0–18.7 months) in the NFRT group and 14.9 months (13.2–17.3 months) in the HFRT group (p = 0.26). In multivariable frailty regression, better performance status, gross-total versus not gross-total resection, MGMT hypermethylation, IDH mutation, smaller planning target volume and salvage therapy were significantly associated with longer OS (all p < 0.01). Treatment differences (HFRT versus NFRT) had no significant effect on OS in either univariable or multivariable analysis.

Conclusions

Since HFRT with temozolomide was not associated with worse OS, we assume HFRT to be a potential option for patients wishing to shorten their treatment time.

[Epidemiological, clinical, therapeutic and evolutionary features of patients with glioblastoma: series of cases managed in the Department of Hematology-Oncology at the Mohammed VI University Hospital Center in Marrakech in 2016 and 2017]

Glioblastoma is the most common primary malignant brain tumour. Despite advances in diagnostic and therapeutic treatments, it is still associated with poor outcome The purpose of this study of cases is to describe the epidemiological, clinical, therapeutic and evolutionary features of patients with glioblastoma admitted to the Department of Hematology-Oncology (DHO) in Marrakech in 2016 and 2017. We conducted a literature review of epidemiological, clinical, radiological, anatomopathological, therapeutic and evolutionary data from 40 patients. Glioblastoma accounted for 47.6% of treated intracranial tumours. The average age of patients was 52.4±12.3 years. Functional impotence and signs of intracranial hypertension were the main symptoms. Tumours mainly occurred in the parietal region (44%) and were large (57.5%). Aphasia was related to tumour size (p=0.042). Nine cases had glioblastomas-IDH1-wild and one case had glioblastoma-IDH1-mutant. On admission, patients had poor performance-status. This was due to a prolonged time between surgery and DHO admission (p= 0.034). Patients with sensory impairments were older (62.5±3 years) than those without sensory impairments (51.2±12 years) (p=0,045). In-patient women received chemoradiotherapy (1.5±1 month) earlier than men (2.3±1.2 months) (p=0.03). Survival was 13.6±5.3 months; it was unrelated to the time to surgery (p=0.076), the time to DHO (p=0.058), and the time to chemoradiotherapy (p=0.073). The epidemiological, clinical, radiological and evolutionary features of our sample were comparable to literature data. The molecular profiling was not systematically realized. Despite prolonged treatment times, no link to survival was detected.

Novel Radiation Approaches

The standard of care treatment for glioblastoma is surgical resection followed by radiotherapy to 60 Gy with concurrent and adjuvant temozolomide with or without tumor-treating fields. Advanced imaging techniques are under evaluation to better guide radiotherapy target volume delineation and allow for dose escalation. Particle therapy, in the form of protons, carbon ions, and boron neutron capture therapy, are being assessed as strategies to improve the radiotherapeutic ratio. Stereotactic, hypofractionated, pulsed-reduced dose-rate, and particle radiotherapy are re-irradiation techniques each uniquely suited for different clinical scenarios. Novel radiotherapy approaches, such as FLASH, represent promising advancements in radiotherapy for glioblastoma.

Loss of TGFβ signaling increases alternative end-joining DNA repair that sensitizes to genotoxic therapies across cancer types

Among the pleotropic roles of transforming growth factor-β (TGFβ) signaling in cancer, its impact on genomic stability is least understood. Inhibition of TGFβ signaling increases use of alternative end joining (alt-EJ), an error-prone DNA repair process that typically functions as a "backup" pathway if double-strand break repair by homologous recombination or nonhomologous end joining is compromised. However, the consequences of this functional relationship on therapeutic vulnerability in human cancer remain unknown. Here, we show that TGFβ broadly controls the DNA damage response and suppresses alt-EJ genes that are associated with genomic instability. Mechanistically based TGFβ and alt-EJ gene expression signatures were anticorrelated in glioblastoma, squamous cell lung cancer, and serous ovarian cancer. Consistent with error-prone repair, more of the genome was altered in tumors classified as low TGFβ and high alt-EJ, and the corresponding patients had better outcomes. Pan-cancer analysis of solid neoplasms revealed that alt-EJ genes were coordinately expressed and anticorrelated with TGFβ competency in 16 of 17 cancer types tested. Moreover, regardless of cancer type, tumors classified as low TGFβ and high alt-EJ were characterized by an insertion-deletion mutation signature containing short microhomologies and were more sensitive to genotoxic therapy. Collectively, experimental studies revealed that loss or inhibition of TGFβ signaling compromises the DNA damage response, resulting in ineffective repair by alt-EJ. Translation of this mechanistic relationship into gene expression signatures identified a robust anticorrelation that predicts response to genotoxic therapies, thereby expanding the potential therapeutic scope of TGFβ biology.

Advances in radiotherapy and comprehensive treatment of high-grade glioma: immunotherapy and tumor-treating fields

High-grade gliomas (HGGs) are the most common primary malignant brain tumors. They have a high degree of malignancy and show invasive growth. The personal treatment plan for HGG is based on the patient's age, performance status, and degree of tumor invasion. The basic treatment plan for HGG involves tumor resection, radiotherapy (RT) with concomitant temozolomide (TMZ), and adjuvant TMZ chemotherapy. The basic radiation technology includes conventional RT, three-dimensional conformal RT, intensity-modulated RT, and stereotactic RT. As our understanding of tumor pathogenesis has deepened, so-called comprehensive treatment schemes have attracted attention. These combine RT with chemotherapy, molecular targeted therapy, immunotherapy, or tumor-treating fields. These emerging treatments are expected to improve the prospects of patients with HGG. In the present article, we review the recent advances in RT and comprehensive treatment for patients with newly diagnosed and recurrent HGG.

Spermidine as a target for cancer therapy

Spermidine, as a natural component from polyamine members, is originally isolated from semen and also existed in many natural plants, and can be responsible for cell growth and development in eukaryotes. The supplementation of spermidine can extend health and lifespan across species. Although the elevated levels of polyamines and the regulation of rate-limiting enzymes for polyamine metabolism have been identified as the biomarkers in many cancers, recent epidemiological data support that an increased uptake of spermidine as a caloric restriction mimic can reduce overall mortality associated with cancers. The possible mechanisms between spermidine and cancer development may be related to the precise regulation of polyamine metabolism, anti-cancer immunosurveillance, autophagy, and apoptosis. Increased intake of polyamine seems to suppress tumorigenesis, but appears to accelerate the growth of established tumors. Based on these observations and the absolute requirement for polyamines in tumor growth, spermidine could be a rational target for chemoprevention and clinical therapeutics of cancers.

External beam radiation dose escalation for high grade glioma

BACKGROUND

This is an updated version of the original Cochrane Review published in Issue 8, 2016. High grade glioma (HGG) is a rapidly growing brain tumour in the supporting cells of the nervous system, with several subtypes such as glioblastoma (grade IV astrocytoma), anaplastic (grade III) astrocytoma and anaplastic (grade III) oligodendroglioma. Studies have investigated the best strategy to give radiation to people with HGG. Conventional fractionated radiotherapy involves giving a daily radiation dose (called a fraction) of 180 cGy to 200 cGy. Hypofractionated radiotherapy uses higher daily doses, which reduces the overall number of fractions and treatment time. Hyperfractionated radiotherapy which uses a lower daily dose with a greater number of fractions and multiple fractions per day to deliver a total dose at least equivalent to external beam daily conventionally fractionated radiotherapy in the same time frame. The aim is to reduce the potential for late toxicity. Accelerated radiotherapy (dose escalation) refers to the delivery of multiple fractions per day using daily doses of radiation consistent with external beam daily conventionally fractionated radiotherapy doses. The aim is to reduce the overall treatment time; typically, two or three fractions per day may be delivered with a six to eight hour gap between fractions.

OBJECTIVES

To assess the effects of postoperative external beam radiation dose escalation in adults with HGG.

SEARCH METHODS

We searched CENTRAL, MEDLINE Ovid and Embase Ovid to August 2019 for relevant randomised phase III trials.

SELECTION CRITERIA

We included adults with a pathological diagnosis of HGG randomised to the following external beam radiation regimens: daily conventionally fractionated radiotherapy versus no radiotherapy; hypofractionated radiotherapy versus daily conventionally fractionated radiotherapy; hyperfractionated radiotherapy versus daily conventionally fractionated radiotherapy or accelerated radiotherapy versus daily conventionally fractionated radiotherapy.

DATA COLLECTION AND ANALYSIS

The primary outcomes were overall survival and adverse effects. The secondary outcomes were progression free survival and quality of life. We used the standard methodological procedures expected by Cochrane. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

Since the last version of this review, we identified no new relevant trials for inclusion. We included 11 randomised controlled trials (RCTs) with 2062 participants and 1537 in the relevant arms for this review. There was an overall survival benefit for people with HGG receiving postoperative radiotherapy compared to the participants receiving postoperative supportive care. For the four pooled RCTs (397 participants), the overall hazard ratio (HR) for survival was 2.01 favouring postoperative radiotherapy (95% confidence interval (CI) 1.58 to 2.55; P < 0.00001; moderate-certainty evidence). Although these trials may not have completely reported adverse effects, they did not note any significant toxicity attributable to radiation. Progression free survival and quality of life could not be pooled due to lack of data. Overall survival was similar between hypofractionated and conventional radiotherapy in five trials (943 participants), where the HR was 0.95 (95% CI 0.78 to 1.17; P = 0.63; very low-certainty evidence. The trials reported that hypofractionated and conventional radiotherapy were well tolerated with mild acute adverse effects. These trials only reported one participant in the hypofractionated arm developing symptomatic radiation necrosis that required surgery. Progression free survival and quality of life could not be pooled due to the lack of data. Overall survival was similar between hypofractionated and conventional radiotherapy in the subset of two trials (293 participants) which included participants aged 60 years and older with glioblastoma. For this category, the HR was 1.16 (95% CI 0.92 to 1.46; P = 0.21; high-certainty evidence). There were two trials which compared hyperfractionated radiotherapy versus conventional radiation and one trial which compared accelerated radiotherapy versus conventional radiation. However, the results could not be pooled. The conventionally fractionated radiotherapy regimens were 4500 cGy to 6000 cGy given in 180 cGy to 200 cGy daily fractions, over five to six weeks. All trials generally included participants with World Health Organization (WHO) performance status from 0 to 2 and Karnofsky performance status of 50 and higher. The risk of selection bias was generally low among these RCTs. The number of participants lost to follow-up for the outcome of overall survival was low. Attrition, performance, detection and reporting bias for the outcome of overall survival was low. There was unclear attrition, performance, detection and reporting bias relating to the outcomes of adverse effects, progression free survival and quality of life.

AUTHORS' CONCLUSIONS

Postoperative conventional daily radiotherapy probably improves survival for adults with good performance status and HGG compared to no postoperative radiotherapy. Hypofractionated radiotherapy has similar efficacy for survival compared to conventional radiotherapy, particularly for individuals aged 60 years and older with glioblastoma. There are insufficient data regarding hyperfractionation versus conventionally fractionated radiation (without chemotherapy) and for accelerated radiation versus conventionally fractionated radiation (without chemotherapy). There are HGG subsets who have poor prognosis even with treatment (e.g. glioblastoma histology, older age and poor performance status). These HGG individuals with poor prognosis have generally been excluded from randomised trials based on poor performance status. No randomised trial has compared comfort measures or best supportive care with an active intervention using radiotherapy or chemotherapy in these people with poor prognosis. Since the last version of this review, we found no new relevant studies. The search identified three new trials, but all were excluded as none had a conventionally fractionated radiotherapy arm.

Treatment of newly diagnosed glioblastoma in the elderly: a network meta-analysis

BACKGROUND

A glioblastoma is a fatal type of brain tumour for which the standard of care is maximum surgical resection followed by chemoradiotherapy, when possible. Age is an important consideration in this disease, as older age is associated with shorter survival and a higher risk of treatment-related toxicity.

OBJECTIVES

To determine the most effective and best-tolerated approaches for the treatment of elderly people with newly diagnosed glioblastoma. To summarise current evidence for the incremental resource use, utilities, costs and cost-effectiveness associated with these approaches.

SEARCH METHODS

We searched electronic databases including the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and Embase to 3 April 2019, and the NHS Economic Evaluation Database (EED) up to database closure. We handsearched clinical trial registries and selected neuro-oncology society conference proceedings from the past five years.

SELECTION CRITERIA

Randomised trials (RCTs) of treatments for glioblastoma in elderly people. We defined 'elderly' as 70+ years but included studies defining 'elderly' as over 65+ years if so reported.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods for study selection and data extraction. Where sufficient data were available, treatment options were compared in a network meta-analysis (NMA) using Stata software (version 15.1). For outcomes with insufficient data for NMA, pairwise meta-analysis were conducted in RevMan. The GRADE approach was used to grade the evidence.

MAIN RESULTS

We included 12 RCTs involving approximately 1818 participants. Six were conducted exclusively among elderly people (either defined as 65 years or older or 70 years or older) with newly diagnosed glioblastoma, the other six reported data for an elderly subgroup among a broader age range of participants. Most participants were capable of self-care. Study quality was commonly undermined by lack of outcome assessor blinding and attrition. NMA was only possible for overall survival; other analyses were pair-wise meta-analyses or narrative syntheses. Seven trials contributed to the NMA for overall survival, with interventions including supportive care only (one trial arm); hypofractionated radiotherapy (RT40; four trial arms); standard radiotherapy (RT60; five trial arms); temozolomide (TMZ; three trial arms); chemoradiotherapy (CRT; three trial arms); bevacizumab with chemoradiotherapy (BEV_CRT; one trial arm); and bevacizumab with radiotherapy (BEV_RT). Compared with supportive care only, NMA evidence suggested that all treatments apart from BEV_RT prolonged survival to some extent. Overall survival High-certainty evidence shows that CRT prolongs overall survival (OS) compared with RT40 (hazard ratio (HR) 0.67, 95% confidence interval (CI) 0.56 to 0.80) and low-certainty evidence suggests that CRT may prolong overall survival compared with TMZ (TMZ versus CRT: HR 1.42, 95% CI 1.01 to 1.98). Low-certainty evidence also suggests that adding BEV to CRT may make little or no difference (BEV_CRT versus CRT: HR 0.83, 95% CrI 0.48 to 1.44). We could not compare the survival effects of CRT with different radiotherapy fractionation schedules (60 Gy/30 fractions and 40 Gy/15 fractions) due to a lack of data. When treatments were ranked according to their effects on OS, CRT ranked higher than TMZ, RT and supportive care only, with the latter ranked last. BEV plus RT was the only treatment for which there was no clear benefit in OS over supportive care only.   One trial comparing tumour treating fields (TTF) plus adjuvant chemotherapy (TTF_AC) with adjuvant chemotherapy alone could not be included in the NMA as participants were randomised after receiving concomitant chemoradiotherapy, not before. Findings from the trial suggest that the intervention probably improves overall survival in this selected patient population. We were unable to perform NMA for other outcomes due to insufficient data. Pairwise analyses were conducted for the following. Quality of life Moderate-certainty narrative evidence suggests that overall, there may be little difference in QoL between TMZ and RT, except for discomfort from communication deficits, which are probably more common with RT (1 study, 306 participants, P = 0.002). Data on QoL for other comparisons were sparse, partly due to high dropout rates, and the certainty of the evidence tended to be low or very low. Progression-free survival High-certainty evidence shows that CRT increases time to disease progression compared with RT40 (HR 0.50, 95% CI 0.41 to 0.61); moderate-certainty evidence suggests that RT60 probably increases time to disease progression compared with supportive care only (HR 0.28, 95% CI 0.17 to 0.46), and that BEV_RT probably increases time to disease progression compared with RT40 alone (HR 0.46, 95% CI 0.27 to 0.78). Evidence for other treatment comparisons was of low- or very low-certainty. Severe adverse events Moderate-certainty evidence suggests that TMZ probably increases the risk of grade 3+ thromboembolic events compared with RT60 (risk ratio (RR) 2.74, 95% CI 1.26 to 5.94; participants = 373; studies = 1) and also the risk of grade 3+ neutropenia, lymphopenia, and thrombocytopenia. Moderate-certainty evidence also suggests that CRT probably increases the risk of grade 3+ neutropenia, leucopenia and thrombocytopenia compared with hypofractionated RT alone. Adding BEV to CRT probably increases the risk of thromboembolism (RR 16.63, 95% CI 1.00 to 275.42; moderate-certainty evidence). Economic evidence There is a paucity of economic evidence regarding the management of newly diagnosed glioblastoma in the elderly. Only one economic evaluation on two short course radiotherapy regimen (25 Gy versus 40 Gy) was identified and its findings were considered unreliable.

AUTHORS' CONCLUSIONS

For elderly people with glioblastoma who are self-caring, evidence suggests that CRT prolongs survival compared with RT and may prolong overall survival compared with TMZ alone. For those undergoing RT or TMZ therapy, there is probably little difference in QoL overall. Systemic anti-cancer treatments TMZ and BEV carry a higher risk of severe haematological and thromboembolic events and CRT is probably associated with a higher risk of these events. Current evidence provides little justification for using BEV in elderly patients outside a clinical trial setting. Whilst the novel TTF device appears promising, evidence on QoL and tolerability is needed in an elderly population. QoL and economic assessments of CRT versus TMZ and RT are needed. More high-quality economic evaluations are needed, in which a broader scope of costs (both direct and indirect) and outcomes should be included.

Optimized Image-Based Surrogate Endpoints in Targeted Therapies for Glioblastoma: A Systematic Review and Meta-Analysis of Phase III Randomized Controlled Trials

Objective

We aimed to determine the optimized image-based surrogate endpoints (IBSEs) in targeted therapies for glioblastoma through a systematic review and meta-analysis of phase III randomized controlled trials (RCTs).

Materials and Methods

A systematic search of OVID-MEDLINE and EMBASE for phase III RCTs on glioblastoma was performed in December 2017. Data on overall survival (OS) and IBSEs, including progression-free survival (PFS), 6-month PFS (6moPFS), 12-month PFS (12moPFS), median PFS, and objective response rate (ORR) were extracted. Weighted linear regression analysis for the hazard ratio for OS and the hazard ratios or odds ratios for IBSEs was performed. The associations between IBSEs and OS were evaluated. Subgroup analyses according to disease stage (newly diagnosed glioblastoma versus recurrent glioblastoma), types of test treatment, and types of response assessment criteria were performed.

Results

Twenty-three phase III RCTs published between 2000 and 2017, including 8387 patients, met the inclusion criteria. OS showed strong correlations with PFS (standardized β coefficient [R] = 0.719), 6moPFS (R = 0.647), and 12moPFS (R = 0.638). OS showed no correlations with median PFS and ORR. In subgroup analysis according to types of therapies, PFS showed the highest correlations with OS in targeted therapies for cell cycle pathways (R = 0.913) and growth factor receptors and their downstream pathways (R = 0.962). 12moPFS showed the highest correlation with OS in antiangiogenic therapy (R = 0.821). The response assessment in neuro-oncology criteria provided higher correlation coefficients between OS and IBSEs than the Macdonald criteria.

Conclusion

Overall, PFS is an optimized IBSE in targeted therapies for glioblastoma; however, 12moPFS is optimal in antiangiogenic therapy.

Accelerated hyperfractionated radiochemotherapy with temozolomide is equivalent to normofractionated radiochemotherapy in a retrospective analysis of patients with glioblastoma

Background

Current standard of treatment for newly diagnosed patients with glioblastoma (GBM) is surgical resection with adjuvant normofractionated radiotherapy (NFRT) combined with temozolomide (TMZ) chemotherapy. Hyperfractionated accelerated radiotherapy (HFRT) which was known as an option from randomized controlled trials before the temozolomide era has not been compared to the standard therapy in a randomized setting combined with TMZ.

Methods

Data of 152 patients with newly diagnosed GBM treated from 10/2004 until 7/2018 at a single tertiary care institution were extracted from a clinical database and retrospectively analyzed. Thirty-eight patients treated with NFRT of 60 Gy in 30 fractions (34 with simultaneous and 2 with sequential TMZ) were compared to 114 patients treated with HFRT of 54.0 Gy in 30 fraction of 1.8 Gy twice daily (109 with simultaneous and 3 with sequential TMZ). The association between treatment protocol and other variables with overall survival (OS) was assessed using univariable and multivariable Cox regression analysis; the latter was performed using variables selected by the LASSO method.

Results

Median overall survival (OS) was 20.3 month for the entire cohort. For patients treated with NFRT median OS was 24.4 months compared to 18.5 months in patients treated with HFRT (p = 0.131). In univariable regression analysis the use of dexamethasone during radiotherapy had a significant negative impact on OS in both patient groups, HR 2.21 (95% CI 1.47–3.31, p = 0.0001). In multivariable analysis adjusted for O6-methylguanine-DNA methyl-transferase (MGMT) promotor methylation status, salvage treatment and secondary GBM, the use of dexamethasone was still a negative prognostic factor, HR 1.95 (95% CI 1.21–3.13, p = 0.006). Positive MGMT-methylation status and salvage treatment were highly significant positive prognostic factors. There was no strong association between treatment protocol and OS (p = 0.504).

Conclusions

Our retrospective analysis supports the hypothesis of equivalence between HFRT and the standard protocol of treatment for GBM. For those patients who are willing to obtain the benefit of shortening the course of radiochemotherapy, HFRT may be an alternative with comparable efficacy although it was not yet tested in a large prospective randomized study against the current standard. The positive influence of salvage therapy and negative impact of concomitant use of corticosteroids should be addressed in future prospective trials. To confirm our results, we plan to perform a pooled analysis with other tertiary clinics in order to achieve better statistical reliability.

Inability of positive phase II clinical trials of investigational treatments to subsequently predict positive phase III clinical trials in glioblastoma

Background

Glioblastoma is the most common primary malignant brain tumor in adults, but effective therapies are lacking. With the scarcity of positive phase III trials, which are increasing in cost, we examined the ability of positive phase II trials to predict statistically significant improvement in clinical outcomes of phase III trials.

Methods

A PubMed search was conducted to identify phase III clinical trials performed in the past 25 years for patients with newly diagnosed or recurrent glioblastoma. Trials were excluded if they did not examine an investigational chemotherapy or agent, if they were stopped early owing to toxicity, if they lacked prior phase II studies, or if a prior phase II study was negative.

Results

Seven phase III clinical trials in newly diagnosed glioblastoma and 4 phase III clinical trials in recurrent glioblastoma met the inclusion criteria. Only 1 (9%) phase III study documented an improvement in overall survival and changed the standard of care.

Conclusion

The high failure rate of phase III trials demonstrates the urgent need to increase the reliability of phase II trials of treatments for glioblastoma. Strategies such as the use of adaptive trial designs, Bayesian statistics, biomarkers, volumetric imaging, and mathematical modeling warrant testing. Additionally, it is critical to increase our expectations of phase II trials so that positive findings increase the probability that a phase III trial will be successful.

Stereotactic Radiosurgery for Neurosurgical Patients: A Historical Review and Current Perspectives

Today, stereotactic radiosurgery is an effective therapy for a variety of intracranial pathology that were treated solely with open neurosurgery in the past. The technique was developed from the combination of therapeutic radiation and stereotactic devices for the precise localization of intracranial targets. Although stereotactic radiosurgery was originally performed as a partnership between neurosurgeons and radiation oncologists, this partnership has weakened in recent years, with some procedures being performed without neurosurgeons. At the same time, neurosurgeons across the United States and Canada have found their stereotactic radiosurgery training during residency inadequate. Although neurosurgeons, residency directors, and department chairs agree that stereotactic radiosurgery education and exposure during neurosurgery training could be improved, a limited number of resources exist for this kind of education. This review describes the history of stereotactic radiosurgery, assesses the state of its use and education today, and provides recommendations for the improvement of neurosurgical education in stereotactic radiosurgery for the future.

Highlighting the need for reliable clinical trials in glioblastoma

INTRODUCTION

Several recent phase III studies have attempted to improve the dismal survival seen in glioblastoma patients, with disappointing results despite prior promising phase II data. Areas covered: A literature review of prior phase II and phase III studied in glioblastoma was performed to help identify possible areas of concern. Numerous issues in previous phase II trials for glioblastoma were found that may have contributed to these discouraging outcomes and discordant results. Expert commentary: These concerns include the improper selection of therapeutics warranting investigation in a phase III trial, suboptimal design of phase II studies (often lacking a control arm), absence of molecular data, the use of imaging criteria as a surrogate endpoint, and a lack of pharmacodynamic testing. Hopefully, by recognizing prior phase II trial limitations that contributed to failed phase III trials, we can adapt quickly to improve our ability to accurately discover survival-prolonging treatments for glioblastoma patients.

Long-Term Outcome of Postoperative Irradiation in Patients with Newly Diagnosed WHO Grade III Anaplastic Gliomas

Purpose

Patients with anaplastic gliomas have a more favorable overall survival than patients with glioblastomas. In most analyses, WHO grade III and IV tumors are not analyzed separately. The present analysis reports outcome after postoperative radiotherapy in patients with WHO grade III gliomas.

Patients and methods

Between January 1988 and January 2007, 127 patients with WHO grade III tumors were treated with radiotherapy; the histological classification was pure astrocytoma in 104 patients, oligoastrocytoma in 12 and pure oligodendroglioma in 11 patients. Median age was 48 years. After the primary diagnosis, a biopsy had been performed in 72 patients; subtotal and total resections were performed in 37 and 18 patients, respectively. In all patients radiotherapy was applied with a median dose of 60 Gy in conventional fractionation. The median follow-up time was 18 months.

Results

Median overall survival was 17 months. Overall survival was significantly influenced by the extent of surgery. Median overall survival was 32 months after complete resection, 36 months after subtotal resection, and 12 months after biopsy. Median overall survival was 7 months for patients with anaplastic astrocytomas, 44 months for patients with mixed tumors, and 47 months for those with pure oligodendrogliomas. Age significantly influenced overall survival. Median progression-free survival was 9 months; the extent of neurosurgical resection significantly influenced progression-free survival.

Conclusion

Patients with WHO grade III anaplastic astrocytomas, oligodendrogliomas and oligoastrocytomas show favorable overall survival after postoperative radiotherapy compared with glioblastoma patients and should therefore be analyzed separately. Radiochemotherapy might further improve outcome.

Polyamines and Cancer

This chapter provides an overview of how the polyamine pathway has been exploited as a target for the treatment and prevention of multiple forms of cancer, since this pathway is disrupted in all cancers. It is divided into three main sections. The first explores how the polyamine pathway has been targeted for chemotherapy, starting from the first drug to target it, difluoromethylornithine (DFMO) to the large variety of polyamine analogues that have been synthesised and tested throughout the years with all their potentials and pitfalls. The second section focuses on the use of polyamines as vectors for drug delivery. Knowing that the polyamine transport system is upregulated in cancers and that polyamines naturally bind to DNA, a range of polyamine analogues and polyamine-like structures have been synthesised to target epigenetic regulators, with encouraging results. Furthermore, the use of polyamines as transport vectors to introduce toxic/bioactive/fluorescent agents more selectively to the intended target in cancer cells is discussed. The last section concentrates on chemoprevention, where the different strategies that have been undertaken to interfere with polyamine metabolism and function for antiproliferative intervention are outlined and discussed.

A comparison between oral chemotherapy combined with radiotherapy and radiotherapy for newly diagnosed glioblastoma: A systematic review and meta-analysis

The prognosis of glioblastoma (GBM), a major subtype of grade IV glioma, is rather poor nowadays. The efficiency of chemotherapy serving as the adjunct to radiotherapy (RT) for treating GBM is still controversial. In this study, we aim to investigate the overall survival (OS) and progression-free survival (PFS) in patients with newly diagnosed GBM received RT plus chemotherapy or with RT alone.Literatures were searched from the PubMed, Embase, and Cochrane Library between January 2001 and June 2015. Study selection was conducted based on the following criteria: randomized clinical trial (RCT) of adjuvant RT plus chemotherapy versus RT alone; studies comparing OS and/or PFS; and studies including cases medically confirmed of newly diagnosed GBM.Five RCTs (1655 patients) were eligible in this study. The meta-analysis showed a significant improvement in OS of patients treated with RT plus oral chemotherapy compared with that of RT alone (hazard ratio 0.70; 95% confidence interval, 0.56-0.88, P = .002).Adjuvant chemotherapy confers a survival benefit in patients newly diagnosed with GBM.

Adult Glioblastoma

Glioblastoma (GBM) is a rare tumor and one of the most challenging malignancies to treat in all of oncology. Although advances have been made in the treatment of GBM, encouraging outcomes typically are not observed; patients diagnosed with these tumors generally have a dismal prognosis and poor quality of life as the disease progresses. This review summarizes the clinical presentation of GBM, diagnostic methods, evidentiary basis for the current standards of care, and investigational approaches to treat or manage GBM. Because the track record for developing effective therapies for GBM has been dismal, we also review the challenges to successful therapeutic and biomarker development.

Difluoromethylornithine in cancer: new advances

Difluoromethylornithine (DFMO; eflornithine) is an irreversible suicide inhibitor of the enzyme ornithine decarboxylase which is involved in polyamine synthesis. Polyamines are important for cell survival, thus DFMO was studied as an anticancer agent and as a chemoprevention agent. DFMO exhibited mainly cytostatic activity and had single agent efficacy as well as activity in combination with other chemotherapeutic drugs for some cancers and leukemias. Herewith, we summarize the current knowledge of the anticancer and chemopreventive properties of DFMO and assess the status of clinical trials.

External beam radiation dose escalation for high grade glioma

BACKGROUND

The incidence of high grade glioma (HGG) is approximately 5 per 100,000 person-years in Europe and North America.

OBJECTIVES

To assess the effects of postoperative external beam radiation dose escalation in adults with HGG.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2015, Issue 9), MEDLINE (1977 to October 2015) and Embase (1980 to end October 2015) for relevant randomised phase III trials.

SELECTION CRITERIA

We included adults with a pathological diagnosis of HGG randomised to the following external beam radiation regimens.1. Daily conventionally fractionated radiation therapy versus no radiation therapy.2. Hypofractionated radiation therapy versus daily conventionally fractionated radiation therapy.3. Hyperfractionated radiation therapy versus daily conventionally fractionated radiation therapy.4. Accelerated radiation therapy versus daily conventionally fractionated radiation therapy.

DATA COLLECTION AND ANALYSIS

The primary outcomes were overall survival and adverse effects. The secondary outcomes were progression-free survival and quality of life. We used the standard methodological procedures expected by Cochrane. We used the GRADE approach, as outlined by Cochrane, to interpret the overall quality of the evidence from included studies.

MAIN RESULTS

We included 11 randomised controlled trials (RCTs) with a total of 2062 participants and 1537 in the relevant arms for this review. There was an overall survival benefit for HGG participants receiving postoperative radiotherapy compared to the participants receiving postoperative supportive care. For the four pooled RCTs (397 participants), the overall hazard ratio (HR) for survival was 2.01 (95% confidence interval (CI) 1.58 to 2.55, P < 0.00001), moderate GRADE quality evidence favouring postoperative radiotherapy. Although these trials may not have completely reported adverse effects, they did not note any significant toxicity attributable to radiation. Progression free survival and quality of life could not be pooled due to lack of data.Overall survival was similar between hypofractionated versus conventional radiotherapy in five trials (943 participants), where the HR was 0.95 (95% CI 0.78 to 1.17, P = 0.63), very low GRADE quality evidence. The trials reported that hypofractionated and conventional radiotherapy were well tolerated with mild acute adverse effects. These trials only reported one patient in the hypofractionated arm developing symptomatic radiation necrosis that required surgery. Progression free survival and quality of life could not be pooled due to the lack of data.Overall survival was also similar between hypofractionated versus conventional radiotherapy in the subset of two trials (293 participants) which included 60 years and older participants with glioblastoma. For this category, the HR was 1.16 (95% CI 0.92 to 1.46, P = 0.21), high GRADE quality evidence.There were two trials which compared hyperfractionated radiation therapy versus conventional radiation and one trial which compared accelerated radiation therapy versus conventional radiation. However, the results could not be pooled.The conventionally fractionated radiation therapy regimens were 4500 to 6000 cGy given in 180 to 200 cGy daily fractions, over 5 to 6 weeks.All these trials generally included participants with World Health Organization (WHO) performance status from 0 to 2 and Karnofsky performance status of 50 and higher.The risk of selection bias was generally low among these randomized trials. The number of participants lost to follow-up for the outcome of overall survival was low. Attrition, performance, detection and reporting bias for the outcome of overall survival was low. There was unclear attrition, performance, detection and reporting bias relating to the outcomes of adverse effects, progression free survival and quality of life.

AUTHORS' CONCLUSIONS

Postoperative conventional daily radiotherapy improves survival for adults with good performance status and HGG as compared to no postoperative radiotherapy.Hypofractionated radiation therapy has similar efficacy for survival as compared to conventional radiotherapy, particularly for individuals aged 60 and older with glioblastoma.There is insufficient data regarding hyperfractionation versus conventionally fractionated radiation (without chemotherapy) and for accelerated radiation versus conventionally fractionated radiation (without chemotherapy).There are HGG subsets who have poor prognosis even with treatment (e.g. glioblastoma histology, older age and poor performance status). These poor prognosis HGG individuals have generally been excluded from the randomised trials based on poor performance status. No randomised trial has compared comfort measures or best supportive care with an active intervention using radiotherapy or chemotherapy in these poor prognosis patients.

Accelerated hyperfractionation plus temozolomide in glioblastoma

Introduction

Hyperfractionated (HFRT) or accelerated hyperfractionated radiotherapy (AHFRT) have been discussed as a potential treatment for glioblastoma based on a hypothesized reduction of late radiation injury and prevention of repopulation. HFRT and AHFRT have been examined extensively in the pre-Temozolomide era with inconclusive results. In this study we examined the role of accelerated hyperfractionation in the Temozolomide era.

Materials and methods

Sixty-four patients who underwent AHFRT (62 of which received Temozolomide) were compared to 67 patients who underwent normofractionated radiotherapy (NFRT) (64 of which received TMZ) between 02/2009 and 10/2014. Follow-up data were analyzed until 01/2015.

Results

Median progression-free survival (PFS) was 6 months for the entire cohort. For patients treated with NFRT median PFS was 7 months, for patients treated with AHFRT median PFS was 6 months. Median overall survival (OS) was 13 months for all patients. For patients treated with NFRT median OS was 15 months, for patients treated with AHFRT median OS was 10 months. The fractionation regimen was not a predictor of PFS or OS in univariable- or multivariable analysis. There was no difference in acute toxicity profiles between the two treatment groups.

Conclusions

Univariable and multivariable analysis did not show significant differences between NFRT and AHFRT fractionation regimens in terms of PFS or OS. The benefits are immanent: the regimen does significantly shorten hospitalization time in a patient collective with highly impaired life expectancy. We propose that the role of AHFRT + TMZ should be further examined in future prospective trials.

A concurrent ultra-fractionated radiation therapy and temozolomide treatment: A promising therapy for newly diagnosed, inoperable glioblastoma

We report on a phase II clinical trial to determine the effect of a concurrent ultra-fractionated radiotherapy and temozolomide treatment in inoperable glioblastoma patients. A phase II study opened; patients over 18 years of age who were able to give informed consent and had histologically proven, newly diagnosed inoperable diagnosed and supratentorial glioblastoma were eligible. Three doses of 0.75 Gy spaced apart by at least 4 hr were delivered daily, 5 days a week for six consecutive weeks for a total of 67.5 Gy. Chemotherapy was administered during the same period, which consisted of temozolomide given at a dose of 75 mg/m(2) for 7 days a week. After a 4-week break, chemotherapy was resumed for up to six cycles of adjuvant temozolomide treatment, given every 28 days, according to the standard 5-day regimen. Tolerance and toxicity were the primary endpoints; survival and progression-free survival were the secondary endpoints. In total, 40 patients were enrolled in this study, 29 men and 11 women. The median age was 58 years, and the median Karnofsky performance status was 80. The concomitant ultra-fractionated radiotherapy and temozolomide treatment was well tolerated. Complete responses were seen in four patients, and partial responses were reported in seven patients. The median survival from the initial diagnosis was 16 months. Several long-term survivors were noted. Concurrent ultra-fractionated radiation therapy and temozolomide treatment are well accepted by the patients. The results showed encouraging survival rates for these unfavorable patients.

Radiation Therapy Intensification for Solid Tumors: A Systematic Review of Randomized Trials

PURPOSE

To systematically review the outcomes of randomized trials testing radiation therapy (RT) intensification, including both dose escalation and/or the use of altered fractionation, as a strategy to improve disease control for a number of malignancies.

METHODS AND MATERIALS

We performed a literature search to identify randomized trials testing RT intensification for cancers of the central nervous system, head and neck, breast, lung, esophagus, rectum, and prostate. Findings were described qualitatively. Where adequate data were available, pooled estimates for the effect of RT intensification on local control (LC) or overall survival (OS) were obtained using the inverse variance method.

RESULTS

In primary central nervous system tumors, esophageal cancer, and rectal cancer, randomized trials have not demonstrated that RT intensification improves clinical outcomes. In breast cancer and prostate cancer, dose escalation has been shown to improve LC or biochemical disease control but not OS. Radiation therapy intensification may improve LC and OS in head and neck and lung cancers, but these benefits have generally been limited to studies that did not incorporate concurrent chemotherapy.

CONCLUSIONS

In randomized trials, the benefits of RT intensification have largely been restricted to trials in which concurrent chemotherapy was not used. Novel strategies to optimize the incorporation of RT in the multimodality treatment of solid tumors should be explored.

Simultaneous integrated vs. sequential boost in VMAT radiotherapy of high-grade gliomas

BACKGROUND

In 20 patients with high-grade gliomas, we compared two methods of planning for volumetric-modulated arc therapy (VMAT): simultaneous integrated boost (SIB) vs. sequential boost (SEB). The investigation focused on the analysis of dose distributions in the target volumes and the organs at risk (OARs).

METHOD

After contouring the target volumes [planning target volumes (PTVs) and boost volumes (BVs)] and OARs, SIB planning and SEB planning were performed. The SEB method consisted of two plans: in the first plan the PTV received 50 Gy in 25 fractions with a 2-Gy dose per fraction. In the second plan the BV received 10 Gy in 5 fractions with a dose per fraction of 2 Gy. The doses of both plans were summed up to show the total doses delivered. In the SIB method the PTV received 54 Gy in 30 fractions with a dose per fraction of 1.8 Gy, while the BV received 60 Gy in the same fraction number but with a dose per fraction of 2 Gy.

RESULTS

All of the OARs showed higher doses (Dmax and Dmean) in the SEB method when compared with the SIB technique. The differences between the two methods were statistically significant in almost all of the OARs. Analysing the total doses of the target volumes we found dose distributions with similar homogeneities and comparable total doses.

CONCLUSION

Our analysis shows that the SIB method offers advantages over the SEB method in terms of sparing OARs.

A Phase 2 Study of Concurrent Radiation Therapy, Temozolomide, and the Histone Deacetylase Inhibitor Valproic Acid for Patients With Glioblastoma

PURPOSE

Valproic acid (VPA) is an antiepileptic agent with histone deacetylase inhibitor (HDACi) activity shown to sensitize glioblastoma (GBM) cells to radiation in preclinical models. We evaluated the addition of VPA to standard radiation therapy (RT) plus temozolomide (TMZ) in patients with newly diagnosed GBM.

METHODS AND MATERIALS

Thirty-seven patients with newly diagnosed GBM were enrolled between July 2006 and April 2013. Patients received VPA, 25 mg/kg orally, divided into 2 daily doses concurrent with RT and TMZ. The first dose of VPA was given 1 week before the first day of RT at 10 to 15 mg/kg/day and subsequently increased up to 25 mg/kg/day over the week prior to radiation. VPA- and TMZ-related acute toxicities were evaluated using Common Toxicity Criteria version 3.0 (National Cancer Institute Cancer Therapy Evaluation Program) and Cancer Radiation Morbidity Scoring Scheme for toxicity and adverse event reporting (Radiation Therapy Oncology Group/European Organization for Research and Treatment).

RESULTS

A total of 81% of patients took VPA according to protocol. Median overall survival (OS) was 29.6 months (range: 21-63.8 months), and median progression-free survival (PFS) was 10.5 months (range: 6.8-51.2 months). OS at 6, 12, and 24 months was 97%, 86%, and 56%, respectively. PFS at 6, 12, and 24 months was 70%, 43%, and 38% respectively. The most common grade 3/4 toxicities of VPA in conjunction with RT/TMZ therapy were blood and bone marrow toxicity (32%), neurological toxicity (11%), and metabolic and laboratory toxicity (8%). Younger age and class V recursive partitioning analysis (RPA) results were significant for both OS and PFS. VPA levels were not correlated with grade 3 or 4 toxicity levels.

CONCLUSIONS

Addition of VPA to concurrent RT/TMZ in patients with newly diagnosed GBM was well tolerated. Additionally, VPA may result in improved outcomes compared to historical data and merits further study.

Polyamines metabolism and breast cancer: state of the art and perspectives

Breast cancer (BC) is a common disease that generally occurs in women over the age of 50, and the risk is especially high for women over 60 years of age. One of the major BC therapeutic problems is that tumors initially responsive to chemotherapeutic approaches can progress to more aggressive forms poorly responsive to therapies. Polyamines (PAs) are small polycationic alkylamines, naturally occurring and essential for normal cell growth and development in eukaryotes. The intracellular concentration of PA is maintained within strongly controlled contents, while a dysregulation occurs in BC cells. Polyamines facilitate the interactions of transcription factors, such as estrogen receptors with their specific response element, and are involved in the proliferation of ER-negative and highly invasive BC tumor cells. Since PA metabolism has a critical role in cell death and proliferation, it represents a potential target for intervention in BC. The goal of this study was to perform a literature search reviewing the association between PA metabolism and BC, and the current evidence supporting the BC treatment targeting PA metabolism. We here describe in vitro and in vivo models, as well as the clinical trials that have been utilized to unveil the relationship between PA metabolism and BC. Polyamine pathway is still an important target for the development of BC chemotherapy via enzyme inhibitors. Furthermore, a recent promising strategy in breast anticancer therapy is to exploit the self-regulatory nature of PA metabolism using PA analogs to affect PA homeostasis. Nowadays, antineoplastic compounds targeting the PA pathway with novel mechanisms are of great interest and high social impact for BC chemotherapy.

Radiation and concomitant chemotherapy for patients with glioblastoma multiforme

Postoperative external beam radiotherapy was considered the standard adjuvant treatment for patients with glioblastoma multiforme until the advent of using the drug temozolomide (TMZ) in addition to radiotherapy. High-dose volume should be focal, minimizing whole brain irradiation. Modern imaging, using several magnetic resonance sequences, has improved the planning target volume definition. The total dose delivered should be in the range of 60 Gy in fraction sizes of 1.8-2.0 Gy. Currently, TMZ concomitant and adjuvant to radiotherapy has become the standard of care for glioblastoma multiforme patients. Radiotherapy dose-intensification and radiosensitizer approaches have not improved the outcome. In spite of the lack of high quality evidence, stereotactic radiotherapy can be considered for a selected group of patients. For elderly patients, data suggest that the same survival benefit can be achieved with similar morbidity using a shorter course of radiotherapy (hypofractionation). Elderly patients with tumors that exhibit methylation of the O-6-methylguanine-DNA methyltransferase promoter can benefit from TMZ alone.

Feasibility and outcomes of hypofractionated simultaneous integrated boost-intensity modulated radiotherapy for malignant gliomas: a preliminary report

PURPOSE

The aim of this study was to assess the feasibility and efficacy of hypofractionated simultaneous integrated boost-intensity modulated radiotherapy (SIB-IMRT) using three-layered planning target volumes (PTV) for malignant gliomas.

MATERIALS AND METHODS

We conducted a retrospective analysis of 12 patients (WHO grade IV-10; III-2) postoperatively treated with SIB-IMRT with concurrent temozolomide. Three-layered PTVs were contoured based on gadolinium-enhanced magnetic resonance imaging as follows; high risk PTV (H-PTV) as the area of surgical bed including residual gross tumor with a 0.5 cm margin; low risk PTV (L-PTV) as the area surrounding the high risk PTV with 1.5 cm margin; moderate risk PTV (M-PTV) as a line at one-third the distance from high risk PTV to low risk PTV. Total dose to high risk PTV was 70 Gy in 8 and 62.5 Gy in 4 patients.

RESULTS

The median follow-up time was 52 months in surviving patients. The 2- and 5-year overall survival (OS) rates were 66.6% and 47.6%, respectively. The 2- and 5-year progression-free survival (PFS) rates were 57.1% and 45.7%, respectively. The median OS and PFS were 48 and 31 months, respectively. Six patients (50%) progressed: in-field only in one, out-field or disseminated in 4, and both in one patient. All patients completed planned treatments without a toxicity-related gap. Asymptomatic radiation necrosis was observed in 4 patients at post-radiotherapy 9-31 months.

CONCLUSION

An escalated dose of hypofractionated SIB-IMRT using three-layered PTVs can be safely performed in patients with malignant glioma, and might contribute to better tumor control and survival.

Pseudoprogression after glioma therapy: a comprehensive review

Over the last decade, pseudoprogression as a clinically significant entity affecting both glioma patient management and the conduct of clinical trials has been recognized as a significant issue. The authors have summarized the literature relative to the incidence, chronological sequence, therapy-relatedness, impact of O-6-methylguanine-DNA methyltransferase methylation status and clinical features of pseudoprogression. Evidence regarding numerous neuroradiologic techniques to differentiate pseudoprogression from tumor recurrence is summarized. The implications of pseudoprogression on prognosis and clinical trial design are substantial, and are reviewed. Relative to this, the overlapping terms pseudoprogression and radiation necrosis are clarified to produce an appropriate basis for future consideration and research regarding this important biological phenomenon.

Difluoromethylornithine: the proof is in the polyamines

In this issue (beginning on page 1368), Kreul and colleagues report a retrospective review of long-term efficacy and toxicity for subjects participating in a phase III study of difluoromethylornithine (DFMO) for prevention of nonmelanoma skin cancer (NMSC). They conclude that those treated with DFMO had a nonsignificant, persistent decrease in NMSC after completion of treatment and that treatment with DFMO did not result in late toxicity after the discontinuation of treatment. We review the data on DFMO as a chemopreventive agent for skin and other cancers, discuss the necessary qualities of a cancer chemopreventive agent, and reflect on the requirements for a well-conducted cancer chemoprevention study, including the rationale for long-term follow-up in cancer prevention studies.

Treatment outcome and prognostic factors of adult glioblastoma multiforme

INTRODUCTION

This study aimed to report the characteristics, prognostic factors and treatment outcome of 223 patients with glioblastoma multiforme (GBM).

SUBJECTS AND METHOD

This retrospective study was carried out by reviewing the medical records of 223 adult patients diagnosed at a tertiary academic hospital between 1990 and 2008. Patients' follow up ranged from 1 to 69 months (median 11 months). Surgery was attempted in all patients in whom complete resection in 15 patients (7%), subtotal resection in 77 patients (34%), partial resection in 73 patients (33%) and biopsy alone in 58 patients (26%) were done. In addition, we performed a literature review of PubMed to find out and analyze major related series. In all, we collected and analyzed the data of 33 major series including more than 11,000 patients with GBM.

RESULTS

There were 141 men and 82 women. The median progression free- and overall survival were 6 (95% CI=5.711-8.289) and 11 (95% CI=9.304-12.696) months respectively. In univariate analysis for overall survival, age (P=0.003), tumor size (P<0.013), performance status (P<0.001), the extent of surgical resection (P=0.009), dose of radiation (P<0.001), and adjuvant chemotherapy (P<0.001) were prognostic factors. However, in multivariate analysis, only radiation dose, extent of surgical resection, and adjuvant chemotherapy were independent prognostic factors for overall survival.

CONCLUSION

The prognosis of adult patients with GBM remains poor; however, complete surgical resection and adjuvant treatments improve progression-free and overall survival.

The role of radiotherapy and chemotherapy in the treatment of primary adult high grade gliomas: assessment of patients for these treatment approaches and the common immediate side effects

Gliomas are the commonest primary brain tumours in adults. They are usually classified and graded according to the criteria by the World Health Organisation. High-grade gliomas are the most malignant primary brain tumours. Conventional therapies include surgery, radiotherapy, and chemotherapy. The tumours often demonstrate high levels of resistance to these conventional therapies, and in spite of treatment advances the prognosis remains poor.

Combined modality approaches in the management of adult glioblastoma

Over the past two decades, management of newly diagnosed glioblastoma has undergone significant evolution. While surgery has long been a mainstay of management for this disease, and while radiotherapy has a proven survival role, initial efforts at radiotherapy dose escalation, use of radiosurgery, brachytherapy, and altered fractionation did not improve patient survival. Recently, multiple modality therapy integrating maximal safe resection, postoperative radiation, and new systemic therapies have resulted in improved patient outcomes compared with older regimens utilizing surgery and postoperative radiation alone. Numerous trials are currently underway investigating the combination of surgery, radiation, and systemic therapy with targeted agents to find ways to further improve outcomes for adults with glioblastoma.

The mechanisms by which polyamines accelerate tumor spread

Increased polyamine concentrations in the blood and urine of cancer patients reflect the enhanced levels of polyamine synthesis in cancer tissues arising from increased activity of enzymes responsible for polyamine synthesis. In addition to their de novo polyamine synthesis, cells can take up polyamines from extracellular sources, such as cancer tissues, food, and intestinal microbiota. Because polyamines are indispensable for cell growth, increased polyamine availability enhances cell growth. However, the malignant potential of cancer is determined by its capability to invade to surrounding tissues and metastasize to distant organs. The mechanisms by which increased polyamine levels enhance the malignant potential of cancer cells and decrease anti-tumor immunity are reviewed. Cancer cells with a greater capability to synthesize polyamines are associated with increased production of proteinases, such as serine proteinase, matrix metalloproteinases, cathepsins, and plasminogen activator, which can degrade surrounding tissues. Although cancer tissues produce vascular growth factors, their deregulated growth induces hypoxia, which in turn enhances polyamine uptake by cancer cells to further augment cell migration and suppress CD44 expression. Increased polyamine uptake by immune cells also results in reduced cytokine production needed for anti-tumor activities and decreases expression of adhesion molecules involved in anti-tumor immunity, such as CD11a and CD56. Immune cells in an environment with increased polyamine levels lose anti-tumor immune functions, such as lymphokine activated killer activities. Recent investigations revealed that increased polyamine availability enhances the capability of cancer cells to invade and metastasize to new tissues while diminishing immune cells' anti-tumor immune functions.

Initial testing (stage 1) of the polyamine analog PG11047 by the pediatric preclinical testing program

BACKGROUND

PG11047 is a novel conformationally restricted analog of the natural polyamine, spermine that lowers cellular endogenous polyamine levels and competitively inhibits natural polyamine functions leading to cancer cell growth inhibition. The activity of PG11047 was evaluated against the PPTP's in vitro and in vivo panels.

PROCEDURES

PG11047 was evaluated against the PPTP in vitro panel using 96 hr exposure at concentrations ranging from 10 nM to 100 µM. It was tested against the PPTP in vivo panels at a dose of 100 mg/kg administered by the intraperitoneal route weekly for 6 weeks.

RESULTS

In vitro PG11047 demonstrated a concentration-response pattern consistent with cytostatic activity. The median EC(50) for PG11047 was 71 nM. Cell lines of the Ewing sarcoma panel had a lower median EC(50) value compared to the remaining cell lines in the panel, while cell lines of the neuroblastoma panel had a higher median EC(50) value. In vivo PG11047 induced significant differences in EFS distribution compared to control in 5 of 32 (15.6%) of the evaluable solid tumor xenografts and in 0 of 7 (0%) of the evaluable ALL xenografts. The single case of tumor regression occurred in an ependymoma xenograft.

CONCLUSIONS

Further pediatric development of PG11047 will require better defining a target population and identifying combinations for which there is a tumor-selective cytotoxic effect. The regression observed for an ependymoma xenograft and the exquisite sensitivity of some Ewing sarcoma cell lines to the antiproliferative effects of PG11047 provide leads for further preclinical investigations.