Evaluation of BCNU and/or radiotherapy in the treatment of anaplastic gliomas. A cooperative clinical trial

STAT3 Blockade Inhibits Radiation-Induced Malignant Progression in Glioma

High grade gliomas (HGG) are classified into four subgroups based on transcriptional signatures and phenotypic characteristics. In particular, the proneural-to-mesenchymal transition (PMT) is associated with increased malignancy, poor prognosis, and disease recurrence, but the underlying causes of PMT are still unclear. In this study, we investigated whether radiotherapy promotes PMT using a genetically engineered mouse model of proneural HGG. We found that cranial ionizing radiation induced robust and durable PMT in tumors. Additionally, we isolated primary proneural HGG cells from mouse and human tumors and demonstrate that radiation induced a sustained cell-intrinsic mesenchymal transition associated with increased invasiveness and resistance to the alkylating agent temozolomide. Expectedly, irradiation-induced PMT was also associated with activation of the STAT3 transcription factor, and the combination of STAT3 blockade using JAK2 inhibitors with radiation abrogated the mesenchymal transition and extended survival of mice. Taken together, our data suggest that clinical JAK2 inhibitors should be tested in conjunction with radiation in patients with proneural HGG as a new strategy for blocking the emergence of therapy-resistant mesenchymal tumors at relapse.

Novel chemotherapeutics and other therapies for treating high-grade glioma

INTRODUCTION

Despite extensive research, high-grade glioma (HGG) remains a dire diagnosis with no change in the standard of care in almost a decade. However, recent advancements uncovering molecular biomarkers of brain tumors and tumor-specific antigens targeted by immunotherapies provide opportunities for novel personalized treatment regimens to improve survival.

AREAS COVERED

In this review, the authors provide a comprehensive overview of recent therapeutic advancements in HGG. Furthermore, they describe new molecular biomarkers and molecular classifications, in addition to updated research on bevacizumab, targeted molecular therapies, immunotherapy and alternative delivery methods that overcome the blood-brain barrier to reach the target tumor tissue. Challenges regarding each therapy are also outlined. The authors also provide some insight into a novel non-chemotherapeutic treatment for malignant glioma, NovoTTFA, as well as a summary of current treatment options for recurrence.

EXPERT OPINION

Current research for treating malignant gliomas are paving the path to personalized therapy, including immunotherapy, that involve integrated genomic and histolopathologic data, as well as a multi-modal treatment regimen. Immunotherapy will potentially be the next addition to the current standard of care, specialized to the antigens presented on the tumors. The results of the current trials of multi-antigen vaccines are eagerly anticipated.

A Phase III study of radiation therapy (RT) and O⁶-benzylguanine + BCNU versus RT and BCNU alone and methylation status in newly diagnosed glioblastoma and gliosarcoma: Southwest Oncology Group (SWOG) study S0001

AIMS

To determine the efficacy of methylguanine methyltransferase (MGMT) depletion + BCNU [1,3-bis(2-chloroethyl)-1- nitrosourea: carmustine] therapy and the impact of methylation status in adults with glioblastoma multiforme (GBM) and gliosarcoma.

METHODS

Methylation analysis was performed on GBM patients with adequate tissue samples. Patients with newly diagnosed GBM or gliosarcoma were eligible for this Phase III open-label clinical trial. At registration, patients were randomized to Arm 1, which consisted of therapy with O(6)-benzylguanine (O(6)-BG) + BCNU 40 mg/m(2) (reduced dose) + radiation therapy (RT) (O6BG + BCNU arm), or Arm 2, which consisted of therapy with BCNU 200 mg/m(2) + RT (BCNU arm).

RESULTS

A total of 183 patients with newly diagnosed GBM or gliosarcoma from 42 U.S. institutions were enrolled in this study. Of these, 90 eligible patients received O(6)-BG + BCNU + RT and 89 received BCNU + RT. The trial was halted at the first interim analysis in accordance with the guidelines for stopping the study due to futility (<40 % improvement among patients on the O6BG + BCNU arm). Following adjustment for stratification factors, there was no significant difference in overall survival (OS) or progression-free survival (PFS) between the two groups (one sided p = 0.94 and p = 0.88, respectively). Median OS was 11 [95 % confidence interval (CI) 8-13] months for patients in the O6BG + BCNU arm and 10 (95 % CI 8-12) months for those in the BCNU arm. PFS was 4 months for patients in each arm. Adverse events were reported in both arms, with significantly more grade 4 and 5 events in the experimental arm.

CONCLUSIONS

The addition of O(6)-BG to the standard regimen of radiation and BCNU for the treatment patients with newly diagnosed GBM and gliosarcoma did not provide added benefit and in fact caused additional toxicity.

Case-Based Review: newly diagnosed glioblastoma

Glioblastoma (WHO grade IV astrocytoma) is the most common and most aggressive primary brain tumor in adults. Optimal treatment of a patient with glioblastoma requires collaborative care across numerous specialties. The diagnosis of glioblastoma may be suggested by the symptomatic presentation and imaging, but it must be pathologically confirmed via surgery, which can have dual diagnostic and therapeutic roles. Standard of care postsurgical treatment for newly diagnosed patients involves radiation therapy and oral temozolomide chemotherapy. Despite numerous recent trials of novel therapeutic approaches, this standard of care has not changed in over a decade. Treatment options under active investigation include molecularly targeted therapies, immunotherapeutic approaches, and the use of alternating electrical field to disrupt tumor cell division. These trials may be aided by new insights into glioblastoma heterogeneity, allowing for focused evaluation of new treatments in the patient subpopulations most likely to benefit from them. Because glioblastoma is incurable by current therapies, frequent clinical and radiographic assessment is needed after initial treatment to allow for early intervention upon progressive tumor when it occurs.

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

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

Standardization and quality assurance of radiation therapy volumes for adults with high-grade gliomas

Standard treatment for Glioblastoma Multiforme (GBM) consists of a combination of chemotherapy and radiation therapy followed by adjuvant chemotherapy. While the optimal dose of radiation therapy has been established, significant variability in volume of tissue irradiated exists. In this article we review the current guidelines, patterns of care, patterns of failure, imaging advances and toxicity related to radiation therapy volumes in the treatment of GBM.

Adjuvant temozolomide-based chemoradiotherapy versus radiotherapy alone in patients with WHO III astrocytoma: The Mainz experience

BACKGROUND

It is currently unclear whether adjuvant therapy for WHO grade III anaplastic astrocytomas (AA) should be carried out as combined chemoradiotherapy with temozolomide (TMZ)--analogous to the approach for glioblastoma multiforme--or as radiotherapy (RT) alone.

PATIENTS AND METHODS

A retrospective analysis of data from 90 patients with AA, who were treated between November 1997 and February 2014. Assessment of overall (OS) and progression-free survival (PFS) was performed according to treatment categories: (1) 50%, RT + TMZ according to protocol, (2) 11%, RT + TMZ with dose reduction, (3) 26%, RT alone, and (4) 13%, individualized, primarily palliative therapy. No dose reduction was necessary in the RT alone group.

RESULTS

Median OS was 85, 69, and 43 months for treatment categories 1/2, 3, and 4, respectively. These differences were not statistically significant. PFS was 35, 29, 48, and 33 months for categories 1, 2, 3, and 4, respectively; again without significant differences between categories. In a subgroup of 39 patients with known IDH1 R132H status, the presence of this mutation correlated with significantly longer OS (p = 0.01) and PFS (p = 0.002). Complete or partial tumor resection and younger age also correlated with a significantly better prognosis, and this influence persisted in multivariate analysis. In the IDH1 R132H subgroup analysis, only this marker retained an independent prognostic value.

DISCUSSION AND CONCLUSION

A general superiority of combined chemoradiotherapy compared to RT alone could not be demonstrated. Biomarkers for predicting the benefits of combination therapy using RT and TMZ are needed for patients with AA.

Tumor pseudoprogression of spinal metastasis after radiosurgery: a novel concept and case reports

Radiosurgery for primary and metastatic tumors of the central nervous system is increasing in utility and intensity. Known complications in the brain include radiation necrosis and the well-documented phenomenon of pseudoprogression. Known complications of radiosurgery to spinal column tumors include radiation myelopathy and delayed vertebral compression fractures; however, the concept of pseudoprogression of spinal column tumors has not been previously described. The authors review 2 cases of spinal metastasis treated with stereotactic radiosurgery (SRS) and attempt to define the concept of spine tumor pseudoprogression.

Two patients who had undergone SRS to the spine for metastatic disease presented in early follow-up (3 and 7 weeks) with symptomatic complaints consisting of axial pain, radicular pain, or evidence of cord compression. In both patients, MRI revealed evidence of tumor enlargement. In one patient, the lesion had grown by 9 mm and 7.7 mm in the axial and sagittal planes, respectively. In the other patient, the tumor growth resulted in a 5-mm decrease in spinal canal diameter with epidural compression and right foraminal encroachment. Because of the absence of progressive neurological deficit, myelopathy, mechanical symptomatology of instability, or vertebral compression fracture, the first patient was treated expectantly with a corticosteroid taper and had improvement of symptoms at 1 month and near-total radiographic resolution of the tumor. In the second patient, worsening symptoms suggested a need for surgical intervention to address presumed radiosurgical failure and tumor progression. During surgery, only necrotic tumor cells were observed, without viable tumor. Follow-up imaging over 1 year showed ongoing local control.

To their knowledge, the authors report the first description of pseudoprogression involving spinal column metastasis in the literature and aim to alert the treating physician to this clinical situation. Unlike brain tumor pseudoprogression, spine tumor pseudoprogression is a relatively early posttreatment phenomenon, measured in days to 2 months. The authors believe that the acute inflammatory response associated with tumor necrosis and disruption of the tumor capillary integrity caused by radiotherapy is an important component in the development of pseudoprogression. Future studies will be fundamental in assigning clinical significance, defining the incidence and predictors, and affecting future management of this phenomenon.

Chemotherapy in glioma

The treatment of glial brain tumors begins with surgery, and standard adjuvant treatment at the end of the past millennium for high-grade glioma and high-risk low-grade glioma was radiotherapy and chemotherapy was given at recurrence. However, over the past 10 years much has changed regarding the role of chemotherapy in gliomas and it is now clear that chemotherapy has a role in the treatment of almost all newly diagnosed diffuse gliomas (WHO grade II-IV). This is the result of several prospective studies that showed survival benefit after combined chemoradiotherapy with temozolomide in glioblastoma (WHO grade IV) or after procarbazine, CCNU (lomustine) and vincristine chemotherapy in diffuse low-grade (WHO grade II) and anaplastic (WHO grade III) glioma. The current standard of treatment for diffuse gliomas is described in this overview and in addition some attention is given to targeted therapies.

Combining immunotherapy with radiation for the treatment of glioblastoma

Glioblastoma is a devastating cancer with universally poor outcomes in spite of current standard multimodal therapy. Immunotherapy is an attractive new treatment modality given its potential for exquisite specificity and its favorable side effect profile; however, clinical trials of immunotherapy in GBM have thus far shown modest benefit. Optimally combining radiation with immunotherapy may be the key to unlocking the potential of both therapies given the evidence that radiation can enhance anti-tumor immunity. Here we review this evidence and discuss considerations for combined therapy.

Postradiation imaging changes in the CNS: how can we differentiate between treatment effect and disease progression?

A familiar challenge for neuroradiologists and neuro-oncologists is differentiating between radiation treatment effect and disease progression in the CNS. Both entities are characterized by an increase in contrast enhancement on MRI and present with similar clinical signs and symptoms that may occur either in close temporal proximity to the treatment or later in the disease course. When radiation-related imaging changes or clinical deterioration are mistaken for disease progression, patients may be subject to unnecessary surgery and/or a change from otherwise effective therapy. Similarly, when disease progression is mistaken for treatment effect, a potentially ineffective therapy may be continued in the face of progressive disease. Here we describe the three types of radiation injury to the brain based on the time to development of signs and symptoms--acute, subacute and late--and then review specific imaging changes after intensity-modulated radiation therapy, stereotactic radiosurgery and brachytherapy. We provide an overview of these phenomena in the treatment of a wide range of malignant and benign CNS illnesses. Finally, we review the published data regarding imaging techniques under investigation to address this well-known problem.

Temozolomide and radiotherapy versus radiotherapy alone in high grade gliomas: a very long term comparative study and literature review

Temozolomide (TMZ) is the first line drug in the care of high grade gliomas. The combined treatment of TMZ plus radiotherapy is more effective in the care of brain gliomas then radiotherapy alone. Aim of this report is a survival comparison, on a long time (>10 years) span, of glioma patients treated with radiotherapy alone and with radiotherapy + TMZ.

MATERIALS AND METHODS

In this report we retrospectively reviewed the outcome of 128 consecutive pts with diagnosis of high grade gliomas referred to our institutions from April 1994 to November 2001. The first 64 pts were treated with RT alone and the other 64 with a combination of RT and adjuvant or concomitant TMZ.

RESULTS

Grade 3 (G3) haematological toxicity was recorded in 6 (9%) of 64 pts treated with RT and TMZ. No G4 haematological toxicity was observed. Age, histology, and administration of TMZ were statistically significant prognostic factors associated with 2 years overall survival (OS). PFS was for GBM 9 months, for AA 11.

CONCLUSIONS

The combination of RT and TMZ improves long term survival in glioma patients. Our results confirm the superiority of the combination on a long time basis.

TGF-β Regulates Survivin to Affect Cell Cycle and the Expression of EGFR and MMP9 in Glioblastoma

Transforming growth factor beta (TGF-β) is suggestive of a molecular target for cancer therapy due to its involvement in cell cycle, differentiation, and morphogenesis. Meanwhile, survivin is identified as an apoptosis inhibitor and involved in tumorgenesis. Here, we aimed to investigate the potential associations between TGF-β and survivin in glioblastoma U87 cell line. Survivin small interfering RNA (siRNA), Western blotting, and cell cycle analysis were introduced to detect relevant proteins in TGF-β pathways. In this study, we observed a concentration- and time-dependent increase of survivin expression after treatment with TGF-β1. However, the kinase inhibitors U0126 and LY294002 inhibited the upregulation of survivin in comparison with DMSO. In addition, survivin siRNA effectively abrogated survivin expression in U87 cells, therefore affected cells' entry into the S phase of cell cycle, and then repressed the expression of epidermal growth factor receptor (EGFR) and matrix metalloproteinase 9 (MMP9) in comparison with non-transfection. In conclusion, the present study shows that TGF-β upregulates survivin expression via ERK and PI3K/AKT pathway, leading to glioblastoma cell cycle progression. Thus, the blockade of survivin will allow for the treatment of glioblastoma, partially attributing to the inhibition of EGFR and MMP9 expression.

Treatment of Gliomas: How did we get here?

Over the past 30 years, the treatment of gliomas has become more multi-modality with clinical trials demonstrating that adjuvant chemo-radiation following surgery improves survival of patients. Unfortunately, this advance in therapeutic intervention has had a modest impact on patient survival, with only a 3–6 month improvement in survival during this time period. In this review, we discuss the progress made in each key aspect of glioma treatment; chemotherapy, surgery and radiation therapy. We present key clinical trials that were used as basis for current management guidelines for patients with gliomas. Ultimately, it is clear that future treatments of patients with gliomas will entail specific chronologic combinations of these three modalities in personalized regimens designed for individual patient tumor sub-type.

Bionanotechnology and the future of glioma

Designer nanoscaled materials have the potential to revolutionize diagnosis and treatment for glioma. This review summarizes current progress in nanoparticle-based therapies for glioma treatment including targeting, drug delivery, gene delivery, and direct tumor ablation. Preclinical and current human clinical trials are discussed. Although progress in the field has been significant over the past decade, many successful strategies demonstrated in the laboratory have yet to be implemented in human clinical trials. Looking forward, we provide examples of combined treatment strategies, which harness the potential for nanoparticles to interact with their biochemical environment, and simultaneously with externally applied photons or magnetic fields. We present our notion of the "ideal" nanoparticle for glioma, a concept that may soon be realized.

Treatment by specialist surgical neurooncologists improves survival times for patients with malignant glioma

OBJECT

Surgeries for CNS tumors are frequently performed by general neurosurgeons and by those who specialize in surgical neurooncology. Subspecialization in neurosurgical practice has become common and may improve patient morbidity and mortality rates. However, the potential benefits for patients of having their surgeries performed by surgical neurooncologists remain unclear. Recently, a shift in patient care to those who practice predominantly surgical neurooncology has been promoted. Evidence for this practice is lacking and therefore requires fundamental investigation.

METHODS

The authors conducted a case-control study of neurooncology patients who underwent surgery for glioblastoma and anaplastic astrocytoma during 2006–2009. Outcomes were compared for patients whose surgery was performed by general neurosurgeons (generalists) or by specialist neurooncology neurosurgeons (specialists). An electronic record database and a picture archiving and communication system were used to collect data and assess the extent of tumor resection. Mortality rates and survival times were compared. Patient comorbidity and postoperative morbidity were assessed by using the Waterlow, patient handling, and falls risk assessment scores. Effects of case mix were adjusted for by using Cox regression and a hazards model.

RESULTS

Outcomes for 135 patients (65 treated by generalists and 70 by specialists) were analyzed. Survival times were longer for patients whose surgery was performed by specialists (p = 0.026) and after correction for case mix (p = 0.019). Extent of tumor resection was greater when performed by specialists (p = 0.005) and correlated with increased survival times (p = 0.004). There was a trend toward reduced surgical deaths when surgery was performed by specialists (2.8%) versus generalists (7%) (p = 0.102), and inpatient stays were significantly shorter when surgery was performed by specialists (p = 0.008).

CONCLUSIONS

The prognosis for glioblastoma multiforme remains dire, and improved treatments are urgently needed. This study provides evidence for a survival benefit when surgery is performed by specialist neurooncology neurosurgeons. The benefit might be attributable to increased tumor resection. Furthermore, specialist neurooncology surgical care may reduce the number of surgical patient deaths and length of inpatient stay. These findings support the recommendations for subspecialization within surgical neurooncology and advocate for care of these patients by specialists.

Radiation therapy for glioma stem cells

Radiation therapy is the most effective adjuvant treatment modality for virtually all patients with high-grade glioma. Its ability to improve patient survival has been recognized for decades. Cancer stem cells provide new insights into how tumor biology is affected by radiation and the role that this cell population can play in disease recurrence. Glioma stem cells possess a variety of intracellular mechanisms to resist and even flourish in spite of radiation, and their proliferation and maintenance appear tied to supportive stimuli from the tumor microenvironment. This chapter reviews the basis for our current use of radiation to treat high-grade gliomas, and addresses this model in the context of therapeutically resistant stem cells. We discuss the available evidence highlighting current clinical efforts to improve radiosensitivity, and newer targets worthy of further development.

New developments in the pathogenesis and therapeutic targeting of the IDH1 mutation in glioma

In the last five years, IDH1 mutations in human malignancies have significantly shaped the diagnosis and management of cancer patients. Ongoing intense research efforts continue to alter our understanding of the role of the IDH1 mutation in tumor formation. Currently, evidence suggests the IDH1 mutation to be an early event in tumorigenesis with multiple downstream oncogenic consequences including maintenance of a hypermethylator phenotype, alterations in HIF signalling, and disruption of collagen maturation contributing to a cancer-promoting extracellular matrix. The most recent reports elucidating these mechanisms is described in this review with an emphasis on the pathogenesis of the IDH1 mutation in glioma. Conflicting findings from various studies are discussed, in order to highlight areas warranting further research. Finally, the latest progress in developing novel therapies against the IDH1 mutation is presented, including recent findings from ongoing phase 1 clinical trials and the exciting prospect of vaccine immunotherapy targeting the IDH1 mutant protein.

Survival of patients treated with radiation therapy for anaplastic astrocytoma

Background

Anaplastic astrocytoma (AA) represents 7% of primary brain tumors in adults. Patient-, tumor-, and treatment-related factors are thought to be predictive of survival. We retrospectively assessed the association of patient-, tumor-, and treatment-related factors with survival in AA treated with radiotherapy (RT) at our institution.

Patients and methods.

Medical records of patients with AA treated with RT between 1987 and 2007 were reviewed. Patient-, tumor-, and treatment-related variables were recorded and used to assign patients to a Radiation Therapy Oncology Group recursive partitioning analysis (RTOG RPA) classification. First use of chemotherapy was recorded. Log-rank tests and Cox regression models were used to assess for an association of patient-, tumor- and treatment-related factors with survival.

Results

One-hundred twenty-six patients were eligible for study. Median age, Karnofsky performance status, and duration of symptoms were 43 years, 90, and 8 weeks. Median radiation dose was 59.4 Gy; 61% of patients underwent tumor resection, and 17% and 41% of patients received temozolomide during and after RT. Median survival was 31 months, and 2-year survival was 58%. RTOG RPA class was associated with survival (p < 0.001), but use of temozolomide during or after RT was not (p > 0.05).

Conclusions

In this retrospective study with inherent limitations, RTOG RPA classification was associated with survival. Further studies are necessary to confirm or refute this finding.

The Role of Chemotherapy in the Treatment of Malignant Astrocytomas

Malignant astrocytomas are aggressive neoplasms with a dismal prognosis despite optimal treatment. Maximal resective surgery is traditionally complemented by radiation therapy. Chemotherapy is now used on patients as initial therapy when their functional status is congruent with further treatment. The classic agents used are nitrosoureas, but temozolomide has taken the front seat recently, with recent data demonstrating increased survival when this agent is used concurrently with radiation therapy in newly diagnosed glioblastoma patients. A new class of agents, refered to as biological modifiers, are increasingly used in clinical trials in an effort to affect the intrinsic biologic aberrations harboured by tumor cells. These drugs comprise differentiation agents, anti-angiogenic agents, matrix-metalloproteinase inhibitors and signal transduction inhibitors, among others. This article reviews the standard cytotoxic agents that have been used to treat malignant astrocytomas, and the different combination regimens offering promise. In addition, recent advances with biological modifiers are also discussed.

MR-Pathological Comparison in F98-Fischer Glioma Model Using a Human Gantry

OBJECT

This study reports our findings in assessing in vivo tumour growth with magnetic resonance imaging using a commercial magnet and antenna in F98 implanted Fischer rats. A comparison of T1 gadolinium-enhanced coronal MR scans and pathology specimens in corresponding animals was accomplished.

METHODS

One rat was used in serial experiments to establish adequate imaging parameters. Afterward, 12 animals implanted with F98 cells underwent a MR study following intervals spanning five, ten, 15 and 20 days on a 1.5T human Siemens. Using a small loop antenna, a coronal T1 weighted MRI scan with Gadolinium was performed. Images were analyzed and volumes of enhancing tumour were calculated. The animals were sacrificed after the imaging procedure and brain were harvested and processed in pathology. Pathology specimens and MR images were analyzed using image processing software. One hematoxylin + eosin (H&E) slide per specimen was compared to the corresponding MR slice depicting the largest area of enhancement.

RESULTS

The MR enhancement areas obtained were 2.18 mm2, 8.25 mm2, 21.6 mm2 and 23.17 mm2 at five, ten, 15 and 20 days. Tumour margin measurements on pathologic samples produced areas of 0.29 mm2, 4.43 mm2, 8.3 mm2, and 12.9 mm2 at five, ten, 15 and 20 days respectively.

CONCLUSION

The T1-enhancing images constantly overestimated the tumour bulk on H&E. This phenomenon is explained by enhancement of the brain around tumour, the extra-axial tumour growth, and a shrinking factor of 17% related to the fixation process. Nonetheless, the radiological tumour growth paralleled the histological samples. This technology is thus suitable to follow tumour growth in F98 implanted rats.

SDF-1/CXCR4 Axis Regulates Cell Cycle Progression and Epithelial-Mesenchymal Transition via Up-regulation of Survivin in Glioblastoma

Stromal cell-derived factor 1 (SDF-1)/CXCR4 ligand-receptor axis is widely recommended as an attractive target for cancer therapy. Meanwhile, epithelial-mesenchymal transition (EMT) process is linked to disease pathophysiology. As one of inhibitors of apoptosis proteins, survivin is implicated in the onset and development of cancer. In the present study, we tried to determine the cause-effect associations between SDF-1/CXCR4 axis and survivin expression in glioblastoma U-251 cell line. Survivin activation and inhibition were induced with exogenous SDF-1 and survivin small interfering RNA (survivin siRNA), respectively. Western blot was used to detect relevant proteins in SDF-1/CXCR4 axis. Western blot analysis revealed that survivin expression in U-251 increased in a dose- and time-dependent manner in response to SDF-1 treatment. However, the interference with MEK/ERK and PI3K/AKT pathway prohibited SDF-1-induced survivin up-regulation. Importantly, survivin knockdown abrogated cell cycle progression and the expression of snail and N-cadherin, compared with non-transfectants. In conclusion, the present study shows that SDF-1 up-regulates survivin via MEK/ERK and PI3K/AKT pathway, leading to cell cycle progression and EMT occurrence dependent on survivin. The blockade of survivin will allow for the treatment of glioblastoma.

Pattern of care of anaplastic oligodendroglioma and oligoastrocytoma in a Korean population: the Korean Radiation Oncology Group study 13-12

This study investigated the treatment of anaplastic oligodendroglial tumors across nine Korean institutions. We reviewed the medical records from 381 patients with histologically confirmed anaplastic oligodendroglioma or anaplastic oligoastrocytoma (AOA) from 2000 to 2010. Clinical factors and treatment patterns were analyzed for each year. Post-operative therapy was performed in 354 patients (94.1 %), of which 133 received radiotherapy (RT) alone and 189 received both RT and chemotherapy. RT alone was the preferred treatment toward the end of the study period (29.4 % in 2000-2001 vs. 56.3 % in 2010, P = 0.005). The use of procarbazine, lomustine, and vincristine (PCV) decreased (57.6 % in 2000-2001 vs. 28.6 % in 2010, P = 0.001) and the use of temozolomide (TMZ) increased (0 % in 2000-2001 vs. 61.9 % in 2010, P < 0.001) over the study period. A combination of chemotherapy and RT was used more often than RT alone in young patients (P = 0.036) and patients with a good performance status (P = 0.023). The 1p/19q co-deletion status and O-6-methyguanine-DNA methyltransferase methylation were analyzed since 2004 but were not significant factors for determining whether to administer chemotherapy. Among the patients who received chemotherapy, TMZ was used more often in patients with AOA (P = 0.007) and PCV was used more often in patients with either multiple lesions (P = 0.027) or the 1p/19q co-deletion (P = 0.026). Our results demonstrate that the treatment pattern for oligodendroglial tumors changed significantly across the study period. In particular, TMZ has replaced PCV, and the use of molecular markers as well as RT alone has increased, but a unified protocol remains to be established.

A historical review of classic articles in surgery field

BACKGROUND

Surgery is one of the most rapidly developing specialties in the past century. Diagnostic methods, operation technique, and knowledge of the diseases are changing continuously. In the academic history, lots of classic papers brought advances for surgery. They were accepted and cited numerously by the medical specialists all over the world. Citation analysis reflects the recognition a work has received in the scientific community by its peers.

DATA SOURCES

The articles in the field of surgery have been cited at least 1,000 times since its publication to 2011 were analyzed. By categorizing the publication year, journals, authors, institutions, countries, life citation cycles, level of evidence provided, and characteristics of the topmost articles, we intended to determine what qualities make the articles important to the specialty. The methodology used in this study was based on the Science Citation Index Expanded database of Web of Science from Thomson Reuters. According to Journal Citation Reports of 2011, it indexes 8,336 journals with citation references across 176Web of Science categories in science edition. Level of evidence of these articles was graded according to the standard provided by Oxford Centre for Evidence-Based Medicine.

CONCLUSION

Totally 36 articles have been cited at least 1,000 times since their publication to the year 2011. According to their citation histories, 35 articles were further evaluated. These topmost articles covered 8 subspecialties of surgery and were published in 17 journals. The publication year varied from 1940 to 1999 and the articles provided different level of evidence, most of which are retrospective studies of case series. Six articles were research articles including animal model, histology analysis, and laboratory research. The others were clinical articles. From the results of citation analysis, the classic articles are not always in top citations. In addition, some of these articles have no citations after several years post their publication. The introduction of a commonly used classification or scoring system is a major factor in propelling citation by other authors. The most cited articles in surgery present their long academic life in spite of their level of evidence and journal impact factor in which they were published.

Altered fractionation schedules in radiation treatment: a review

Conventionally fractionated radiotherapy is delivered in 1.8- to 2.0-Gy fractions. With increases in understanding of radiation and tumor biology, various alterations of radiotherapy schedules have been tested in clinical trials and are now regarded by some as standard treatment options. Hyperfractionation is delivered through a greater number of smaller treatment doses. Accelerated fractionation decreases the amount of time over which radiotherapy is delivered typically by increasing the number of treatments per day. Hypofractionation decreases the number of fractions delivered by increasing daily treatment doses. Furthermore, many of these schedules have been tested with concurrent chemotherapy regimens. In this review, we summarize the major clinical studies that have been conducted on altered fractionation in various disease sites.

The future of glioblastoma therapy: synergism of standard of care and immunotherapy

The current standard of care for glioblastoma (GBM) is maximal surgical resection with adjuvant radiotherapy and temozolomide (TMZ). As the 5-year survival with GBM remains at a dismal <10%, novel therapies are needed. Immunotherapies such as the dendritic cell (DC) vaccine, heat shock protein vaccines, and epidermal growth factor receptor (EGFRvIII) vaccines have shown encouraging results in clinical trials, and have demonstrated synergistic effects with conventional therapeutics resulting in ongoing phase III trials. Chemoradiation has been shown to have synergistic effects when used in combination with immunotherapy. Cytotoxic ionizing radiation is known to trigger pro-inflammatory signaling cascades and immune activation secondary to cell death, which can then be exploited by immunotherapies. The future of GBM therapeutics will involve finding the place for immunotherapy in the current treatment regimen with a focus on developing strategies. Here, we review current GBM therapy and the evidence for combination of immune checkpoint inhibitors, DC and peptide vaccines with the current standard of care.

Contemporary murine models in preclinical astrocytoma drug development

Despite 6 decades of research, only 3 drugs have been approved for astrocytomas, the most common malignant primary brain tumors. However, clinical drug development is accelerating with the transition from empirical, cytotoxic therapy to precision, targeted medicine. Preclinical animal model studies are critical for prioritizing drug candidates for clinical development and, ultimately, for their regulatory approval. For decades, only murine models with established tumor cell lines were available for such studies. However, these poorly represent the genomic and biological properties of human astrocytomas, and their preclinical use fails to accurately predict efficacy in clinical trials. Newer models developed over the last 2 decades, including patient-derived xenografts, genetically engineered mice, and genetically engineered cells purified from human brains, more faithfully phenocopy the genomics and biology of human astrocytomas. Harnessing the unique benefits of these models will be required to identify drug targets, define combination therapies that circumvent inherent and acquired resistance mechanisms, and develop molecular biomarkers predictive of drug response and resistance. With increasing recognition of the molecular heterogeneity of astrocytomas, employing multiple, contemporary models in preclinical drug studies promises to increase the efficiency of drug development for specific, molecularly defined subsets of tumors.

Migration capacity of human umbilical cord mesenchymal stem cells towards glioma in vivo

High-grade glioma is the most common malignant primary brain tumor in adults. The poor prognosis of glioma, combined with a resistance to currently available treatments, necessitates the ment of more effective tumor-selective therapies. Stem cell-based therapies are emerging as novel cell-based delivery vehicle for therapeutic agents. In the present study, we successfully isolated human umbilical cord mesenchymal stem cells by explant culture. The human umbilical cord senchymal stem cells were adherent to plastic surfaces, expressed specific surface phenotypes of mesenchymal stem cells as demonstrated by flow cytometry, and possessed multi-differentiation potentials in permissive induction media in vitro. Furthermore, human umbilical cord mesenchymal stem cells demonstrated excellent glioma-specific targeting capacity in established rat glioma models after intratumoral injection or contralateral ventricular administration in vivo. The excellent glioma-specific targeting ability and extensive intratumoral distribution of human umbilical cord mesenchymal stem cells indicate that they may serve as a novel cellular vehicle for delivering therapeutic molecules in glioma therapy.

Actin cytoskeleton organization, cell surface modification and invasion rate of 5 glioblastoma cell lines differing in PTEN and p53 status

Glioblastoma cells exhibit highly invasive behavior whose mechanisms are not yet fully understood. The present study explores the relationship between the invasion capacity of 5 glioblastoma cell lines differing in p53 and PTEN status, expression of mTOR and several other marker proteins involved in cell invasion, actin cytoskeleton organization and cell morphology. We found that two glioblastoma lines mutated in both p53 and PTEN genes (U373-MG and SNB19) exhibited the highest invasion rates through the Matrigel or collagen matrix. In DK-MG (p53wt/PTENwt) and GaMG (p53mut/PTENwt) cells, F-actin mainly occurred in the numerous stress fibers spanning the cytoplasm, whereas U87-MG (p53wt/PTENmut), U373-MG and SNB19 (both p53mut/PTENmut) cells preferentially expressed F-actin in filopodia and lamellipodia. Scanning electron microscopy confirmed the abundant filopodia and lamellipodia in the PTEN mutated cell lines. Interestingly, the gene profiling analysis revealed two clusters of cell lines, corresponding to the most (U373-MG and SNB19, i.e. p53 and PTEN mutated cells) and less invasive phenotypes. The results of this study might shed new light on the mechanisms of glioblastoma invasion.

Standard of care and future pharmacological treatment options for malignant glioma: an urgent need for screening and identification of novel tumor-specific antigens

INTRODUCTION

Malignant gliomas (MGs) represent the most common primary brain tumors in adults, the most deadly of which is grade IV glioblastoma. Patients with glioblastoma undergoing current standard-of-care therapy have a median survival of 12 - 15 months.

AREAS COVERED

Over the past 25 years, there have been modest advancements in the treatment of MGs. Assessment of therapeutic responses has continued to evolve to account for the increasing number of agents being tested in the clinic. Currently approved therapies for primary tumors have been extended for use in the setting of recurrent disease with modest efficacy. Agents initially approved for recurrent gliomas have begun to demonstrate efficacy against de novo tumors but will ultimately need to be evaluated in future studies for scheduling, timing and dosing relative to chemotherapy.

EXPERT OPINION

Screening and identification of tumor-specific mutations is critical for the advancement of effective therapy that is both safe and precise for the patient. Two unique antigens found in glioblastoma are currently being employed as targets for immunotherapeutic vaccines, one of which has advanced to Phase III testing. Whole genome sequencing of MGs has yielded two other novel mutations that offer great promise for the development of molecular inhibitors.

Anaplastic oligodendroglioma: a new treatment paradigm and current controversies

OPINION STATEMENT

Anaplastic oligodendroglial tumors have gained increasing interest with the emerging role of molecular markers and systemic chemotherapy during the past years. The long-term results of two landmark trials, RTOG 9402 and EORTC 26961, have resulted in a reconsideration of the appropriate therapeutic approaches for patients with these tumors. Both trials indicate that patients whose tumors harbor a 1p/19q co-deletion benefit particularly from the addition of procarbazine/lomustine (CCNU)/vincristine (PCV) chemotherapy to radiation therapy (RT). The median survival of patients with co-deleted tumors treated within the RTOG trial with PCV before irradiation was 14.7 years compared with 7.3 years of patients who received RT alone. Median overall survival has not been reached in the RT plus PCV arm of the EORTC trial, but a similar difference can be anticipated after a follow-up of more than 12 years. In contrast, no such benefit was observed for patients with tumors lacking 1p/19q co-deletion. Outside clinical trials, patients with anaplastic oligodendroglial tumors, and 1p/19q co-deletion therefore should be offered a combined treatment modality regimen, including radio- and chemotherapy. PCV, however, is associated with significant hematological toxicity and also nonhematological side effects, which probably translate into reduced quality of life for long-term survivors. Therefore, it might be warranted to replace PCV by temozolomide, which displays a more favorable side effect profile. Data from the NOA-04 study suggest that PCV and temozolomide have similar effects. However, long-term data on the benefit from temozolomide are lacking, making a definite answer on the equivalence of temozolomide and PCV in anaplastic oligodendroglioma (AO) impossible. The current evidence precludes RT alone for AO patients. Neither the RTOG nor the EORTC trial defined the role of chemotherapy alone. A comparison of combined modality treatment with chemotherapy alone followed by RT at progression is pending. Long-term follow-up of NOA-04 patients and results from future trials may help to clarify these questions. With more and more AO patients living 10 years or more, particular attention must be paid to late side effects, such as neurotoxicity, and careful monitoring is required for all treated patients.

Fetal radiation monitoring and dose minimization during intensity modulated radiation therapy for glioblastoma in pregnancy

We examined the fetal dose from irradiation of glioblastoma during pregnancy using intensity modulated radiation therapy (IMRT), and describe fetal dose minimization using mobile shielding devices. A case report is described of a pregnant woman with glioblastoma who was treated during the third trimester of gestation with 60 Gy of radiation delivered via a 6 MV photon IMRT plan. Fetal dose without shielding was estimated using an anthropomorphic phantom with ion chamber and diode measurements. Clinical fetal dose with shielding was determined with optically stimulated luminescent dosimeters and ion chamber. Clinical target volume (CTV) and planning target volume (PTV) coverage was 100 and 98 % receiving 95 % of the prescription dose, respectively. Normal tissue tolerances were kept below quantitative analysis of normal tissue effects in the clinic (QUANTEC) recommendations. Without shielding, anthropomorphic phantom measurements showed a cumulative fetal dose of 0.024 Gy. In vivo measurements with shielding in place demonstrated a cumulative fetal dose of 0.016 Gy. The fetal dose estimated without shielding was 0.04 % and with shielding was 0.026 % of the target dose. In vivo estimation of dose equivalent received by the fetus was 24.21 mSv. Using modern techniques, brain irradiation can be delivered to pregnant patients in the third trimester with very low measured doses to the fetus, without compromising target coverage or normal tissue dose constraints. Fetal dose can further be reduced with the use of shielding devices, in keeping with the principle of as low as reasonably achievable.

Emerging insights into barriers to effective brain tumor therapeutics

There is great promise that ongoing advances in the delivery of therapeutics to the central nervous system (CNS) combined with rapidly expanding knowledge of brain tumor patho-biology will provide new, more effective therapies. Brain tumors that form from brain cells, as opposed to those that come from other parts of the body, rarely metastasize outside of the CNS. Instead, the tumor cells invade deep into the brain itself, causing disruption in brain circuits, blood vessel and blood flow changes, and tissue swelling. Patients with the most common and deadly form, glioblastoma (GBM) rarely live more than 2 years even with the most aggressive treatments and often with devastating neurological consequences. Current treatments include maximal safe surgical removal or biopsy followed by radiation and chemotherapy to address the residual tumor mass and invading tumor cells. However, delivering effective and sustained treatments to these invading cells without damaging healthy brain tissue is a major challenge and focus of the emerging fields of nanomedicine and viral and cell-based therapies. New treatment strategies, particularly those directed against the invasive component of this devastating CNS disease, are sorely needed. In this review, we (1) discuss the history and evolution of treatments for GBM, (2) define and explore three critical barriers to improving therapeutic delivery to invasive brain tumors, specifically, the neuro-vascular unit as it relates to the blood brain barrier, the extra-cellular space in regard to the brain penetration barrier, and the tumor genetic heterogeneity and instability in association with the treatment efficacy barrier, and (3) identify promising new therapeutic delivery approaches that have the potential to address these barriers and create sustained, meaningful efficacy against GBM.

Current evidence of temozolomide and bevacizumab in treatment of gliomas

OBJECTIVE

This review article summarizes in vitro, in vivo, and clinical evidence pertaining to temozolomide (TMZ) and bevacizumab (BEV) efficacy and mechanism of action in gliomas.

METHODS

Relevant publications published before June 2013 in PubMed database were reviewed.

RESULTS

Temozolomide and BEV are current chemotherapeutic agents treating patients with high-grade glioma, including glioblastoma. In vitro and in vivo studies have proposed discordant cell death pathways for TMZ as either apoptosis or autophagy using different experimental setting details or cell lines. In addition, BEV may cause cell death through hypoxia-induced autophagy or unspecific indirect effects on cancer cells. The complexity of cancer cells in glioma has contributed to their resistance of both chemotherapies. In clinical trials, overall survival duration in glioma patients with recurrence (8-9 months) is lower than that in newly diagnosed patients (12-15 months).

CONCLUSION

Our collected data support the addition of radiotherapy, BEV, and other targeted agents to TMZ treatment, indicating prolonged survival duration in newly diagnosed patients. However, the optimal regimen for treating high-grade glioma cannot be concluded without more clinical trials.

The impact of concurrent temozolomide with adjuvant radiation and IDH mutation status among patients with anaplastic astrocytoma

This study assesses the controversial role of temozolomide (TMZ) concurrent with adjuvant radiation (RT) in patients with anaplastic astrocytoma (AA). The impact of isocitrate dehydrogenase (IDH) status on therapy and outcomes is also examined. All adult patients diagnosed with AA from 2001 to 2011 and treated with standard doses of adjuvant RT were identified retrospectively for clinical data extraction. IDH status was determined by IDH1-R132H immunostain and sequencing for other mutations in IDH1/IDH2. Cumulative survival probabilities were estimated using the Kaplan-Meier method. Cox proportional hazards regression models were fit for univariable/multivariable analyses. 136 patients had received concurrent TMZ while 29 had not. Of these, IDH status was determined on 114 and 27 patients, respectively. On univariable analysis, improved five-year survival was independently associated with concurrent TMZ (46.2 vs. 29.3%, p = 0.02) and IDH mutation (78.9 vs. 22.0%, p < 0.001). IDH mutation was additionally associated with a greater likelihood of extensive resection possibly secondary to a more favorable tumor location. Gross total/subtotal resections also led to improved survival when compared to biopsy alone on univariable analysis. On multivariable analysis, the association with five-year survival persisted for both concurrent TMZ and IDH mutation, but not with extent of surgery. Both IDH mutation and concurrent TMZ are associated with improved five-year survival in patients with AA who are receiving adjuvant RT. Secondarily, the association between five-year survival and extent of resection is lost on multivariable analysis. This suggests a possible association between IDH mutation, tumor location and consequent resectability.

The diagnosis and treatment of pseudoprogression, radiation necrosis and brain tumor recurrence

Radiation therapy is an important modality used in the treatment of patients with brain metastatic disease and malignant gliomas. Post-treatment surveillance often involves serial magnetic resonance imaging. A challenge faced by clinicians is in the diagnosis and management of a suspicious gadolinium-enhancing lesion found on imaging. The suspicious lesion may represent post-treatment radiation effects (PTRE) such as pseudoprogression, radiation necrosis or tumor recurrence. Significant progress has been made in diagnostic imaging modalities to assist in differentiating these entities. Surgical and medical interventions have also been developed to treat PTRE. In this review, we discuss the pathophysiology, clinical presentation, diagnostic imaging modalities and provide an algorithm for the management of pseudoprogression, radiation necrosis and tumor recurrence.

Carmustine induces platelet apoptosis

Carmustine is one of the alkylating chemotherapeutic agents, which are used to treat various types of cancers, such as brain tumors, Hodgkins and non-Hodgkins lymphoma and multiple myeloma. However, carmustine has the side effect of thrombocytopenia, and the mechanism is not completely understood. In this study, we show that carmustine dose-dependently induced depolarization of mitochondrial inner transmembrane potential (ΔΨm), up-regulation of Bax, down-regulation of Bcl-2 and caspase-3 activation. Carmustine did not induce surface expression of P-selectin or PAC-1 binding, whereas, obviously reduced collagen and thrombin-induced platelet aggregation. Dicumarol, c-Jun NH2-terminal kinase-specific inhibitor, reduced carmustine-induced ΔΨm depolarization in platelets. The numbers of circulating platelets were reduced, and the tail bleeding time was significantly increased in mice that were injected with carmustine. Taken together, these data indicate that carmustine induced platelet apoptosis, suggesting the possible pathogenesis of thrombocytopenia in patients treated with carmustine.

Experimental use of photodynamic therapy in high grade gliomas: a review focused on 5-aminolevulinic acid

Photodynamic therapy (PDT) consists of a laser light exposure of tumor cells photosensitized by general or local administration of a pharmacological agent. Nowadays, PDT is a clinically established modality for treatment of many cancers. 5-Aminolevulinic acid (ALA) induced protoporphyrin IX (PpIX) has proven its rational in fluoro-guided resection of malignant gliomas due to a selective tumor uptake and minimal skin sensitization. Moreover, the relatively specific accumulation of photosensitizing PPIX within the tumor cells has gained interest in the PDT of malignant gliomas. Several experimental and clinical studies have then established ALA-PDT as a valuable adjuvant therapy in the management of malignant gliomas. However, the procedure still requires optimizations in the fields of tissue oxygenation status, photosensitizer concentration or scheme of laser light illumination. In this extensive review, we focused on the methods and results of ALA-PDT for treating malignant gliomas in experimental conditions. The biological mechanisms, the effects on tumor and normal brain tissue, and finally the critical issues to optimize the efficacy of ALA-PDT were discussed.