A Fully Automated Post-Surgical Brain Tumor Segmentation Model for Radiation Treatment Planning and Longitudinal Tracking

Glioblastoma (GBM) has a poor survival rate even with aggressive surgery, concomitant radiation therapy (RT), and adjuvant chemotherapy. Standard-of-care RT involves irradiating a lower dose to the hyperintense lesion in T2-weighted fluid-attenuated inversion recovery MRI (T2w/FLAIR) and a higher dose to the enhancing tumor on contrast-enhanced, T1-weighted MRI (CE-T1w). While there have been several attempts to segment pre-surgical brain tumors, there have been minimal efforts to segment post-surgical tumors, which are complicated by a resection cavity and postoperative blood products, and tools are needed to assist physicians in generating treatment contours and assessing treated patients on follow up. This report is one of the first to train and test multiple deep learning models for the purpose of post-surgical brain tumor segmentation for RT planning and longitudinal tracking. Post-surgical FLAIR and CE-T1w MRIs, as well as their corresponding RT targets (GTV1 and GTV2, respectively) from 225 GBM patients treated with standard RT were trained on multiple deep learning models including: Unet, ResUnet, Swin-Unet, 3D Unet, and Swin-UNETR. These models were tested on an independent dataset of 30 GBM patients with the Dice metric used to evaluate segmentation accuracy. Finally, the best-performing segmentation model was integrated into our longitudinal tracking web application to assign automated structured reporting scores using change in percent cutoffs of lesion volume. The 3D Unet was our best-performing model with mean Dice scores of 0.72 for GTV1 and 0.73 for GTV2 with a standard deviation of 0.17 for both in the test dataset. We have successfully developed a lightweight post-surgical segmentation model for RT planning and longitudinal tracking.

A Novel Approach to Determining Tumor Progression Using a Three-Site Pilot Clinical Trial of Spectroscopic MRI-Guided Radiation Dose Escalation in Glioblastoma

Glioblastoma (GBM) is a fatal disease, with poor prognosis exacerbated by difficulty in assessing tumor extent with imaging. Spectroscopic MRI (sMRI) is a non-contrast imaging technique measuring endogenous metabolite levels of the brain that can serve as biomarkers for tumor extension. We completed a three-site study to assess survival benefits of GBM patients when treated with escalated radiation dose guided by metabolic abnormalities in sMRI. Escalated radiation led to complex post-treatment imaging, requiring unique approaches to discern tumor progression from radiation-related treatment effect through our quantitative imaging platform. The purpose of this study is to determine true tumor recurrence timepoints for patients in our dose-escalation multisite study using novel methodology and to report on median progression-free survival (PFS). Follow-up imaging for all 30 trial patients were collected, lesion volumes segmented and graphed, and imaging uploaded to our platform for visual interpretation. Eighteen months post-enrollment, the median PFS was 16.6 months with a median time to follow-up of 20.3 months. With this new treatment paradigm, incidence rate of tumor recurrence one year from treatment is 30% compared to 60-70% failure under standard care. Based on the delayed tumor progression and improved survival, a randomized phase II trial is under development (EAF211).

A Potential New Treatment for High-Grade Glioma: A Study Assessing Repurposed Drug Combinations against Patient-Derived High-Grade Glioma Cells

Repurposed drugs have demonstrated in vitro success against high-grade gliomas; however, their clinical success has been limited due to the in vitro model not truly representing the clinical scenario. In this study, we used two distinct patient-derived tumour fragments (tumour core (TC) and tumour margin (TM)) to generate a heterogeneous, clinically relevant in vitro model to assess if a combination of repurposed drugs (irinotecan, pitavastatin, disulfiram, copper gluconate, captopril, celecoxib, itraconazole and ticlopidine), each targeting a different growth promoting pathway, could successfully treat high-grade gliomas. To ensure the clinical relevance of our data, TC and TM samples from 11 different patients were utilized. Our data demonstrate that, at a concentration of 100µm or lower, all drug combinations achieved lower LogIC₅₀ values than temozolomide, with one of the combinations almost eradicating the cancer by achieving cell viabilities below 4% in five of the TM samples 6 days after treatment. Temozolomide was unable to stop tumour growth over the 14-day assay, while combination 1 stopped tumour growth, with combinations 2, 3 and 4 slowing down tumour growth at higher doses. To validate the cytotoxicity data, we used two distinct assays, end point MTT and real-time IncuCyte life analysis, to evaluate the cytotoxicity of the combinations on the TC fragment from patient 3, with the cell viabilities comparable across both assays. The local administration of combinations of repurposed drugs that target different growth promoting pathways of high-grade gliomas have the potential to be translated into the clinic as a novel treatment strategy for high-grade gliomas.

The Effect of Disulfiram and Copper on Cellular Viability, ER Stress and ALDH Expression of Human Meningioma Cells

(1) Background: Meningiomas are the most common intracranial tumors in adults; currently there is no effective chemotherapy for malignant meningiomas. The effect of disulfiram (DSF)/Copper (Cu) on meningiomas remains unclear; (2) Methods: The impact of DSF/Cu on cell viability of meningioma adhesion cells (MgACs) and sphere cells (MgSCs) was assessed via MTS assay. The effects of DSF/Cu on intracellular Cu levels, cell senescence, and apoptosis were analyzed using CopperGreen, C12FDG, and Annexin V assays. Intracellular ALDH isoform expression and canonical pathway expression after DSF/Cu treatment were analyzed using mRNA microarray and Ingenuity Pathway Analysis, with further verification through qRT-PCR and immunoblotting; (3) Results: The viability of MgACs and MgSCs were inhibited by DSF/Cu. DSF/Cu increased intracellular Cu levels and cellular senescence. DSF/Cu also induced ER stress in MgACs and activated the PERK/eIF2 pathway for further adaptive response, apoptosis, and autophagy. Finally, DSF/Cu inhibited the expression of different ALDH isoforms in MgACs and MgSCs; (4) Conclusions: DSF/Cu exerts cytotoxic effects against both meningioma cells and stem-like cells and has treatment potential for meningioma.

Improving temozolomide biopharmaceutical properties in glioblastoma multiforme (GBM) treatment using GBM-targeting nanocarriers

Glioblastoma multiforme (GBM) is the most common primary brain cancer. GBM has aggressive development, and the pharmacological treatment remains a challenge due to GBM anatomical characteristics' (the blood-brain barrier and tumor microenvironment) and the increasing resistance to marketed drugs, such as temozolomide (TMZ), the first-line drug for GBM treatment. Due to physical-chemical properties such as short half-life time and the increasing resistance shown by GBM cells, high doses and repeated administrations are necessary, leading to significant adverse events. This review will discuss the main molecular mechanisms of TMZ resistance and the use of functionalized nanocarriers as an efficient and safe strategy for TMZ delivery. GBM-targeting nanocarriers are an important tool for the treatment of GBM, demonstrating to improve the biopharmaceutical properties of TMZ and repurpose its use in anti-GBM therapy. Technical aspects of nanocarriers will be discussed, and biological models highlighting the advantages and effects of functionalization strategies in TMZ anti-GBM activity. Finally, conclusions regarding the main findings will be made in the context of new perspectives for the treatment of GBM using TMZ as a chemotherapy agent, improving the sensibility and biological anti-tumor effect of TMZ through functionalization strategies.

Notable response of a young adult with recurrent glioblastoma multiforme to vincristine-irinotecan-temozolomide and bevacizumab

Glioblastoma multiforme is a malignant central nervous system (CNS) disease with dismal prognosis. Current treatment modalities only offer modest activity and usually of short duration, so there is an urgent need for the conduct of clinical trials exploring new treatment options and modalities. The vincristine-irinotecan-temozolomide and bevacizumab (VITb) regimen is an option of special interest, as it has produced encouraging results in young patients with various relapsed/refractory childhood and adolescence solid tumors, with an acceptable toxicity profile. With the current report, we present the case of a young male patient who was treated for GBM in second relapse at out institution, after previous surgical attempts and two radiotherapy sessions in conjunction with temozolomide and experienced a major and long-lasting response, weaned off steroids, to the VITb regimen followed by bevacizumab maintenance. The above case is discussed in the context of the existing literature regarding available evidence of synergy between the drugs used and the activity of certain components of the combination (i.e. combination of temozolomide-irinotecan ± vincristine, or bevacizumab-irinotecan in GBM) or the complete VITb regimen in other pediatric/adolescence solid tumors and the few cases reported with GBM.

Mechanisms of EGFR Resistance in Glioblastoma

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults. Despite numerous efforts to target epidermal growth factor receptor (EGFR), commonly dysregulated in GBM, approaches directed against EGFR have not achieved the same degree of success as seen in other tumor types, particularly as compared to non-small cell lung cancer (NSCLC). EGFR alterations in glioblastoma lie primarily in the extracellular domain, unlike the kinase domain alterations seen in NSCLC. Small molecule inhibitors are difficult to develop for the extracellular domain. Monoclonal antibodies can be developed to target the extracellular domain but must contend with the blood brain barrier (BBB). We review the role of EGFR in GBM, the history of trialed treatments, and the potential paths forward to target the pathway that may have greater success.

O6-Methylguanine-DNA Methyltransferase (MGMT): Challenges and New Opportunities in Glioma Chemotherapy

Chemoresistance has been a significant problem affecting the efficacy of drugs targeting tumors for decades. MGMT, known as O⁶-methylguanine-DNA methyltransferase, is a DNA repair enzyme that plays an important role in chemoresistance to alkylating agents. Hence, MGMT is considered a promising target for tumor treatment. Several methods are employed to detect MGMT, each with its own advantages and disadvantages. Some of the detection methods are; immunohistochemistry, methylation-specific PCR (MSP), pyrophosphate sequencing, MGMT activity test, and real-time quantitative PCR. Methylation of MGMT promoter is a key predictor of whether alkylating agents can effectively control glioma cells. The prognostic value of MGMT in glioma is currently being explored. The expression of MGMT gene mainly depends on epigenetic modification–methylation of CpG island of MGMT promoter. CpG island covers a length of 762 bp, with 98 CpG sites located at the 5' end of the gene, ranging from 480 to 1,480 nucleotides. The methylation sites and frequencies of CpG islands vary in MGMT-deficient tumor cell lines, xenografts of glioblastoma and in situ glioblastoma. Methylation in some regions of promoter CpG islands is particularly associated with gene expression. The change in the methylation status of the MGMT promoter after chemotherapy, radiotherapy or both is not completely understood, and results from previous studies have been controversial. Several studies have revealed that chemotherapy may enhance MGMT expression in gliomas. This could be through gene induction or selection of high MGMT-expressing cells during chemotherapy. Selective survival of glioma cells with high MGMT expression during alkylating agent therapy may change MGMT status in case of recurrence. Several strategies have been pursued to improve the anti-tumor effects of temozolomide. These include the synthesis of analogs of O⁶-meG such as O⁶-benzylguanine (O⁶-BG) and O⁶-(4-bromothenyl) guanine (O⁶-BTG), RNAi, and viral proteins. This review describes the regulation of MGMT expression and its role in chemotherapy, especially in glioma. Targeting MGMT seems to be a promising approach to overcome chemoresistance. Further studies exploring new agents targeting MGMT with better curative effect and less toxicity are advocated. We anticipate that these developments will improve the current poor prognosis of glioma patients.

Temozolomide radiochemotherapy for high-grade glioma patients with hemodialysis: a case series of 7 patients

Background

The pharmacokinetics of temozolomide (TMZ) in patients with severe renal impairments (creatinine clearance, <36 mL/min/m²) or in hemodialysis (HD) patients has not been investigated. TMZ and its metabolic products are mainly excreted in urine, as retention of these in the body may result in increased adverse events in HD patients.

Methods

Seven HD patients with high-grade gliomas from 6 institutions were included in the study. Patient characteristics, treatment schedule, clinical course, pathological/molecular findings, and adverse events were evaluated.

Results

The histopathological diagnoses were isocitrate dehydrogenase (IDH) wild-type glioblastoma in 4 cases, not other specified (NOS) glioblastoma in 2 cases, and IDH-mutant anaplastic astrocytoma in 1 case. Five of the 7 patients completed radiotherapy (48-60 Gy) with concomitant TMZ (75 mg/m²) followed by adjuvant 5-day TMZ (150 mg/m²) every 28 days. During the entire course of treatment with TMZ, severe (Common Terminology Criteria for Adverse Events [CTCAE] ≥ Grade 3) lymphocytopenia occurred in 57%, neutropenia in 0%, and thrombocytopenia in 14% of the patients. Generally, the frequency and degree of myelosuppression do not increase in HD patients with high-grade gliomas. Two of the 7 (28.5%) patients died of infectious disease despite having no direct correlation to myelosuppression; that is similar to the death rate of 21.9% resulting from infection in HD patients in Japan.

Conclusions

Decreasing the dose of TMZ might not be required in HD patients with high-grade gliomas during concomitant radiochemotherapy and maintenance therapy. However, careful clinical and hematological observation is required to avoid critical hematotoxicity and infection.

Temozolomide lymphodepletion enhances CAR abundance and correlates with antitumor efficacy against established glioblastoma

Adoptive transfer of T cells expressing chimeric antigen receptors (CARs) is an effective immunotherapy for B-cell malignancies but has failed in some solid tumors clinically. Intracerebral tumors may pose challenges that are even more significant. In order to devise a treatment strategy for patients with glioblastoma (GBM), we evaluated CARs as a monotherapy in a murine model of GBM. CARs exhibited poor expansion and survival in circulation and failed to treat syngeneic and orthotopic gliomas. We hypothesized that CAR engraftment would benefit from host lymphodepletion prior to immunotherapy and that this might be achievable by using temozolomide (TMZ), which is standard treatment for these patients and has lymphopenia as its major side effect. We modelled standard of care temozolomide (TMZSD) and dose-intensified TMZ (TMZDI) in our murine model. Both regimens are clinically approved and provide similar efficacy. Only TMZDI pretreatment prompted dramatic CAR proliferation and enhanced persistence in circulation compared to treatment with CARs alone or TMZSD + CARs. Bioluminescent imaging revealed that TMZDI + CARs induced complete regression of 21-day established brain tumors, which correlated with CAR abundance in circulation. Accordingly, TMZDI + CARs significantly prolonged survival and led to long-term survivors. These findings are highly consequential, as it suggests that GBM patients may require TMZDI as first line chemotherapy prior to systemic CAR infusion to promote CAR engraftment and antitumor efficacy. On this basis, we have initiated a phase I trial in patients with newly diagnosed GBM incorporating TMZDI as a preconditioning regimen prior to CAR immunotherapy (NCT02664363).

MGMT testing allows for personalised therapy in the temozolomide era

Adjuvant temozolomide (TMZ)-based chemoradiation is the standard of care for most glioblastoma patients (GBMs); however, a large proportion of these patients do not respond to TMZ. Silencing of the O(6)-methylguanine-DNA methyltransferase (MGMT) promoter is thought to induce chemosensitivity, and testing for methylation may allow for patient stratification; however, this has yet to become routine clinical practice despite an abundance of literature on the subject. The databases PubMed, Embase, The Cochrane Library, Science Direct and Medline were searched for relevant articles published between 1999 and 2015. Articles utilising MGMT testing in glioblastomas, and treatment of glioblastomas with temozolomide were assessed. Immunohistochemistry, methylation-specific PCR (MSP), reverse transcriptase PCR, pyrosequencing and bisulphite sequencing were the main testing methods identified. Nested-MSP techniques produced poor correlation with survival, whilst bisulphite sequencing showed no evident benefit over MSP. Testing is limited by sample quality and contamination; however, efforts are made to minimise this. Strong evidence for MGMT-based personalised therapy was presented in the elderly but remains controversial in the entire GBM population. MGMT testing presents many obstacles yet to be overcome, and these warrant attention prior to the routine implementation of MGMT testing to aid decision making in GBMs. However, there is evidence to support its use, particularly in the elderly.

Treatment of anaplastic glioma

Anaplastic gliomas have received increasing attention over the past years. As opposed to glioblastoma, where the focus has been on the evaluation of novel compounds (with mainly disappointing results), in anaplastic gliomas relevant progress was generated with genotoxic therapies and translational work on biomarkers. Anaplastic gliomas are classified using single biomarkers, namely isocitrate dehydrogenase (IDH) or the related CpG island methylator phenotype (CIMP), alpha-thalassemia/mental retardation syndrome X-linked (ATRX), telomerase reverse transcriptase (TERT), p53, 1p/19q, and O(6)-methylguanine DNA-methyltransferase (MGMT). With these molecular biomarkers, three main prognostically distinct groups have been defined: (i) CIMP-negative anaplastic gliomas, which have a similar prognosis as glioblastoma, (ii) CIMP-positive 1p/19q intact, and (iii) CIMP-positive 1p/19q codeleted gliomas. In the CIMP-negative, mainly IDH wild-type group, MGMT promoter methylation may be used to identify patients who benefit from alkylating chemotherapy. The mutually exclusive ATRX losses and 1p/19q codeletions are used to subcategorize anaplastic tumors with a mixed histology according to microscopic features. This eliminates the biological basis and clinical necessity for the diagnosis of mixed gliomas (anaplastic oligoastrocytomas). Retrospective long-term analysis of the EORTC 26951 and RTOG 9402 trials revealed that patients with tumors harboring 1p/19q codeletions benefit from addition of procarbazine, lomustine, and vincristine (PCV) chemotherapy to primary radiotherapy. RTOG 9402 suggests that this may be the case also for patients with 1p/19q intact tumors, but IDH mutation. Future developments in addition to the ongoing CATNON and CODEL trials, will focus on further refinement of the molecular predictors and development of treatments that not only increase survival but also maintain neurological function, cognition, and health-related quality of life.

Trial of a 5-day dosing regimen of temozolomide in patients with relapsed small cell lung cancers with assessment of methylguanine-DNA methyltransferase

OBJECTIVES

Small cell lung cancers (SCLCs) are characterized by aberrantly methylated O(6)-methyl-guanine-DNA methyltransferase (MGMT). Epigenetic silencing of MGMT is associated with loss of MGMT activity and improved sensitivity to alkylating agents in glioblastomas. We have reported the activity of temozolomide, a non-classical alkylating agent, in patients with relapsed sensitive or refractory SCLCs, given at 75 mg/m2/day for 21 of 28 days. However, prolonged myelosuppression was noted. We therefore evaluated a 5-day dosing schedule of temozolomide and examined MGMT as a predictive biomarker for temozolomide treatment in SCLC.

MATERIALS AND METHODS

Patients with sensitive or refractory SCLCs and progression after one or two prior chemotherapy regimens received temozolomide 200 mg/m2/day for 5 consecutive days in 28-day cycles. The primary endpoint was tolerability. We also assessed MGMT promoter methylation status by PCR and MGMT expression by immunohistochemistry in tumor specimens.

RESULTS

Of 25 patients enrolled, 5 experienced grade 3 or 4 toxicity (anemia, thrombocytopenia, neutropenia, and constipation). The partial response rate was 12% [95% CI: 3-31%], with partial responses in 2 refractory patients. We were able to obtain tumor samples for more than half of patients for MGMT testing.

CONCLUSION

Temozolomide 200 mg/m2/day for 5 days in 28-day cycles is tolerable and active in patients with relapsed SCLCs. No treatment-limiting prolonged cytopenias were observed, making this our preferred schedule for further studies. Acquisition of archived biospecimens is feasible and necessary in order to continue evaluating the role of MGMT as a predictive biomarker in SCLCs.

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.

Thymosin β 4 gene silencing decreases stemness and invasiveness in glioblastoma

Thymosin beta 4 is a pleiotropic actin-sequestering polypeptide that is involved in wound healing and developmental processes. Thymosin beta 4 gene silencing promotes differentiation of neural stem cells whereas thymosin beta 4 overexpression initiates cortical folding of developing brain hemispheres. A role of thymosin beta 4 in malignant gliomas has not yet been investigated. We analysed thymosin beta 4 staining on tissue microarrays and performed interrogations of the REMBRANDT and the Cancer Genome Atlas databases. We investigated thymosin beta 4 expression in seven established glioma cell lines and seven glioma-initiating cell lines and induced or silenced thymosin beta 4 expression by lentiviral transduction in LNT-229, U87MG and GS-2 cells to study the effects of altered thymosin beta 4 expression on gene expression, growth, clonogenicity, migration, invasion, self-renewal and differentiation capacity in vitro, and tumorigenicity in vivo. Thymosin beta 4 expression increased with grade of malignancy in gliomas. Thymosin beta 4 gene silencing in LNT-229 and U87MG glioma cells inhibited migration and invasion, promoted starvation-induced cell death in vitro and enhanced survival of glioma-bearing mice. Thymosin beta 4 gene silencing in GS-2 cells inhibited self-renewal and promoted differentiation in vitro and decreased tumorigenicity in vivo. Gene expression analysis suggested a thymosin beta 4-dependent regulation of mesenchymal signature genes and modulation of TGFβ and p53 signalling networks. We conclude that thymosin beta 4 should be explored as a novel molecular target for anti-glioma therapy.

Low incidence of pseudoprogression by imaging in newly diagnosed glioblastoma patients treated with cediranib in combination with chemoradiation

BACKGROUND

Chemoradiation (CRT) can significantly modify the radiographic appearance of malignant gliomas, especially within the immediate post-CRT period. Pseudoprogression (PsP) is an increasingly recognized phenomenon in this setting, and is thought to be secondary to increased permeability as a byproduct of the complex process of radiation-induced tissue injury, possibly enhanced by temozolomide. We sought to determine whether the addition of a vascular endothelial growth factor (VEGF) signaling inhibitor (cediranib) to conventional CRT had an impact on the frequency of PsP, by comparing two groups of patients with newly diagnosed glioblastoma before, during, and after CRT.

METHODS

All patients underwent serial magnetic resonance imaging as part of institutional review board-approved clinical studies. Eleven patients in the control group received only chemoradiation, whereas 29 patients in the study group received chemoradiation and cediranib until disease progression or toxicity. Response assessment was defined according to Response Assessment in Neuro-Oncology criteria, and patients with enlarging lesions were classified into true tumor progressions (TTP) or PsP, based on serial radiographic follow-up.

RESULTS

Two patients in the study group (7%) showed signs of apparent early tumor progression, and both were subsequently classified as TTP. Six patients in the control group (54%) showed signs of apparent early tumor progression, and three were subsequently classified as TTP and three as PsP. The frequency of PsP was significantly higher in the control group.

CONCLUSION

Administration of a VEGF inhibitor during and after CRT modifies the expression of PsP by imaging.

O6-methylguanine DNA methyltransferase as a promising target for the treatment of temozolomide-resistant gliomas

Temozolomide (TMZ) is an alkylating agent currently used as first-line therapy for gliomas treatment due to its DNA-damaging effect. However, drug resistance occurs, preventing multi-cycle use of this chemotherapeutic agent. One of the major mechanisms of cancer drug resistance is enhanced activity of a DNA repair enzyme, O(6)-methylguanine-DNA-methyltransferase (MGMT), which counteracts chemotherapy-induced DNA alkylation and is a key component of chemoresistance. MGMT repairs TMZ-induced DNA lesions, O(6)-meG, by transferring the alkyl group from guanine to a cysteine residue. This review provides an overview of recent advances in the field, with particular emphasis on the inhibitors of MGMT and underlying mechanisms. Literature search was performed through PubMed and all relevant articles were reviewed, with particular attention to MGMT, its role in TMZ-resistant gliomas, effects of MGMT inhibitors and the underlying mechanisms. Several strategies are currently being pursued to improve the therapeutic efficacy of TMZ via inhibition of MGMT to reduce chemoresistance and improve overall survival. MGMT may be a promising target for the treatment of TMZ-resistant gliomas.

Personalized care in neuro-oncology coming of age: why we need MGMT and 1p/19q testing for malignant glioma patients in clinical practice

Histological subtyping and grading by malignancy are the cornerstones of the World Health Organization (WHO) classification of tumors of the central nervous system. They shall provide clinicians with guidance as to the course of disease to be expected and the choices of treatment to be made. Nonetheless, patients with histologically identical tumors may have very different outcomes, notably in patients with astrocytic and oligodendroglial gliomas of WHO grades II and III. In gliomas of adulthood, 3 molecular markers have undergone extensive studies in recent years: 1p/19q chromosomal codeletion, O(6)-methylguanine methyltransferase (MGMT) promoter methylation, and mutations of isocitrate dehydrogenase (IDH) 1 and 2. However, the assessment of these molecular markers has so far not been implemented in clinical routine because of the lack of therapeutic implications. In fact, these markers were considered to be prognostic irrespective of whether patients were receiving radiotherapy (RT), chemotherapy, or both (1p/19q, IDH1/2), or of limited value because testing is too complex and no chemotherapy alternative to temozolomide was available (MGMT). In 2012, this situation has changed: long-term follow-up of the Radiation Therapy Oncology Group 9402 and European Organisation for Research and Treatment of Cancer 26951 trials demonstrated an overall survival benefit from the addition to RT of chemotherapy with procarbazine/CCNU/vincristine confined to patients with anaplastic oligodendroglial tumors with (vs without) 1p/19q codeletion. Furthermore, in elderly glioblastoma patients, the NOA-08 and the Nordic trial of RT alone versus temozolomide alone demonstrated a profound impact of MGMT promoter methylation on outcome by therapy and thus established MGMT as a predictive biomarker in this patient population. These recent results call for the routine implementation of 1p/19q and MGMT testing at least in subpopulations of malignant glioma patients and represent an encouraging step toward the development of personalized therapeutic approaches in neuro-oncology.

Limited impact of prognostic factors in patients with recurrent glioblastoma multiforme treated with a bevacizumab-based regimen

Bevacizumab has demonstrated activity in patients with recurrent glioblastoma. However, the impact of prognostic factors associated with recurrent glioblastoma treated with cytotoxic agents has not been determined in patients treated with bevacizumab. To analyze the prognostic factors and clinical benefits of bevacizumab and irinotecan treatment in patients with recurrent glioblastoma. This monocentric study retrospectively analyzed all patients with recurrent glioblastoma who were treated with at least one cycle of bevacizumab and irinotecan at our institution from April 2007 to May 2010. Multivariate analysis was used to analyze prognostic factors for overall survival (OS) from the initiation of bevacizumab administration. Among the 100 patients that were identified (M/F: 65/35), the median age was 57.9 years (range: 18-76). Karnofsky Performance Status (KPS) was <70 in 44 patients and ≥ 70 in 56 patients; 83 % of the patients were on steroids. The median tumor area was 2012 mm². The median progression free survival was 3.9 months (CI 95 %: 3.4-4.3). The median OS was 6.5 months (CI 95 %: 5.6-7.4). Multivariate analysis revealed that OS was affected by KPS (p = 0.024), but not by gender, age, steroid treatment, number of previous lines of treatment, tumor size, or time from initial diagnosis. KPS was improved in 30 patients, including 14/44 patients with an initial KPS <70. The median duration of maintained functional independence (KPS ≥ 70) was 3.75 months (CI 95 %: 2.9-4.6). The median OS from initial diagnosis was 18.9 months (CI 95 %: 17.5-20.3). In patients with recurrent glioblastoma treated with bevacizumab, KPS was revealed as the only factor to impact OS. The clinical benefits associated with this regimen appear valuable. A positive impact of bevacizumab administration on OS of patients with glioblastoma multiforme is suggested.

Bridging science and clinical practice: how to use molecular markers when caring for a patient with brain cancer

Technical advances in genomic and proteomic profiling and bioinformatics have resulted in the identification of a large number of possible prognostic, predictive, and diagnostic molecular markers in glial tumors. Increasingly, clinical trials are incorporating tissue analyses to prospectively and retrospectively study the value of these and yet-to-be defined markers. Once validated, markers form the basis for increasingly stringent classification schemes and the development of personalized, targeted therapies. Descriptions of molecular marker findings, many not validated as clinically relevant, are filling pathology reports, and patients arrive to clinic with the latest journal article requesting marker assessment. Although some practitioners may choose to incorporate these findings into clinical decision making, empirical data supporting these decisions is limited to a few specific circumstances. This article reviews three markers-codeletion of 1p/19q, methylation of the O6-methylguanine-DNA methyltransferase (MGMT) promoter, and the presence of IDH1/2 mutation-for which there exists high or moderate levels of evidence of current clinical utility for guiding diagnostic, prognostic, and treatment decisions.

Treatment options in newly diagnosed glioblastoma

OPINION STATEMENT

Regardless of MGMT status, standard of care for a patient with newly diagnosed glioblastoma (GBM), age ≤70 years, and adequate functional status is radiation and concurrent temozolomide followed by adjuvant temozolomide. For elderly patients, recent studies have suggested that standard radiation, hypofractionated radiation, or single agent temozolomide are acceptable treatment options. Randomized phase III studies of bevacizumab in combination with radiation and temozolomide for newly diagnosed GBM have completed accrual. Preliminary results reveal a clear progression-free survival benefit. Overall survival appears unchanged although follow-up has not fully matured and cross-over to bevacizumab upon progression among control patients may limit definitive conclusions. Although bevacizumab in the upfront setting may be considered for a subset of patients, it should not be used routinely in newly diagnosed patients until final results are available. Clinical trials evaluating promising therapeutics given in combination with standard temozolomide chemoradiation are critically needed.

Patterns of relapse in glioblastoma multiforme following concomitant chemoradiotherapy with temozolomide

OBJECTIVE

Different methods for contouring target volumes are currently in use in the UK when irradiating glioblastomas post operatively. Both one- and two-phase techniques are offered at different centres. 90% of relapses are recognised to occur locally when using radiotherapy alone. The objective of this evaluation was to determine the pattern of relapse following concomitant radiotherapy with temozolomide (RT-TMZ).

METHODS

A retrospective analysis of patients receiving RT-TMZ between 2006 and 2010 was performed. Outcome data including survival were calculated from the start of radiotherapy. Analysis of available serial cross-sectional imaging was performed from diagnosis to first relapse. The site of first relapse was defined by the relationship to primary disease. Central relapse was defined as progression of the primary enhancing mass or the appearance of a new enhancing nodule within 2 cm.

RESULTS

105 patients were identified as receiving RT-TMZ. 34 patients were not eligible for relapse analysis owing to either lack of progression or unsuitable imaging. Patterns of first relapse were as follows: 55 (77%) patients relapsed centrally within 2 cm of the original gadolinium-enhanced mass on MRI, 13 (18%) patients relapsed >4 cm from the original enhancement and 3 (4%) relapsed within the contralateral hemisphere.

CONCLUSION

Central relapse remains the predominant pattern of failure following RT-TMZ. Single-phase conformal radiotherapy using a 2-cm margin from the original contrast-enhanced mass is appropriate for the majority of these patients.

ADVANCES IN KNOWLEDGE

Central relapse remains the predominant pattern of failure following chemoradiotherapy for glioblastomas.

Prospective study of carmustine wafers in combination with 6-month metronomic temozolomide and radiation therapy in newly diagnosed glioblastoma: preliminary results

OBJECT

Locoregional chemotherapy with carmustine wafers, positioned at surgery and followed by radiation therapy, has been shown to prolong survival in patients with newly diagnosed glioblastoma, as has concomitant radiochemotherapy with temozolomide. A combination of carmustine wafers with the Stupp treatment regimen has only been investigated in retrospective studies.

METHODS

In a single-institution prospective study, the authors assessed 12-month progression-free survival (PFS), toxicity, and overall survival in patients with glioblastoma treated with surgery, carmustine wafers, radiotherapy, and 6-month metronomic temozolomide chemotherapy. Thirty-five patients with de novo glioblastoma, between the ages of 18 and 70 years, and with Karnofsky Performance Scale scores of at least 70, were included in the study. Patients were followed monthly and assessed using MRI every 2 months.

RESULTS

After a median follow-up of 15 months, the median time to tumor progression was 12.5 months and median survival was 17.8 months. Due to toxicity (mostly hematological), 7 patients had to prematurely stop temozolomide treatment. Twenty-two patients developed Grade 3 CD4(+) lymphocytopenia. Three patients developed oral-esophageal candidiasis, 2 developed pneumonia, and 1 developed a dorsolumbar zoster. Early intracranial hypertension was observed in 1 patient, and 1 was treated empirically for suspected brain abscess. One patient died of Legionella pneumonia soon after repeat surgery.

CONCLUSIONS

Overall, this treatment schedule produced promising results in terms of PFS without a marked increase in toxicities as compared with the Stupp regimen. However, the gain in median survival using this schedule was less clear. Only prospective comparative trials will determine whether these preliminary results will translate into a long-term survival advantage with an acceptable toxicity profile.

"One week on-one week off": efficacy and side effects of dose-intensified temozolomide chemotherapy: experiences of a single center

To evaluate in a single center retrospectively the efficacy and tolerability of a weekly regimen, which alternates temozolomide (TMZ) in patients with recurrent or progressive high-grade glioma (HGG). From January 2005 until June 2011, 54 patients with recurrent or progressive HGG were treated with TMZ 150 mg/m²/day on days 1-7 and 15-21 of a 28-day cycle ("one week on-one week off" scheme; TMZ 7/14) with individual dose adjustment depending on toxicity. The majority of patients (n = 48, 89 %) was treated at first tumor recurrence or progression. All patients had received prior radiotherapy with or without concomitantly administered TMZ and, optionally, adjuvant chemotherapy. After initiation of TMZ 7/14, MRI was obtained every 8-12 weeks. Tumor response or progression was assessed according to Macdonald criteria. Blood examinations were performed weekly. Toxicity was evaluated according to Common Terminology Criteria for Adverse Events (CTCAE; version 3.0). A total of 434 treatment weeks with TMZ 7/14 were delivered. The median number of treatment weeks was 7 (range, 1-41 weeks). No grade 4 hematological toxicity and no opportunistic infections occurred. Patients with neutropenia were not observed. Two patients developed grade 3 and 4 patients grade 2 leukocytopenia. Thrombocytopenia grade 3 and grade 2 occurred in 4 patients and 6 patients, respectively. The progression-free survival (PFS) rate at 6 months was 43 %. Median PFS from treatment initiation was 18 weeks (95 % CI, 14-22 weeks) and median overall survival (OS) was 37 weeks (95 % CI, 31-42 weeks). The rates for PFS and OS at 1 year were 24 and 28 %, respectively. Our data suggest that treatment with TMZ 7/14 is safe and effective in patients with recurrent or progressive HGG.

Standards of care for treatment of recurrent glioblastoma--are we there yet?

Newly diagnosed glioblastoma is now commonly treated with surgery, if feasible, or biopsy, followed by radiation plus concomitant and adjuvant temozolomide. The treatment of recurrent glioblastoma continues to be a moving target as new therapeutic principles enrich the standards of care for newly diagnosed disease. We reviewed PubMed and American Society of Clinical Oncology abstracts from January 2006 to January 2012 to identify clinical trials investigating the treatment of recurrent or progressive glioblastoma with nitrosoureas, temozolomide, bevacizumab, and/or combinations of these agents. At recurrence, a minority of patients are eligible for second surgery or reirradiation, based on appropriate patient selection. In temozolomide-pretreated patients, progression-free survival rates at 6 months of 20%-30% may be achieved either with nitrosoureas, temozolomide in various dosing regimens, or bevacizumab. Combination regimens among these agents or with other drugs have not produced evidence for superior activity but commonly produce more toxicity. More research is needed to better define patient profiles that predict benefit from the limited therapeutic options available after the current standard of care has failed.

MGMT methylation analysis of glioblastoma on the Infinium methylation BeadChip identifies two distinct CpG regions associated with gene silencing and outcome, yielding a prediction model for comparisons across datasets, tumor grades, and CIMP-status

The methylation status of the O⁶-methylguanine-DNA methyltransferase (MGMT) gene is an important predictive biomarker for benefit from alkylating agent therapy in glioblastoma. Recent studies in anaplastic glioma suggest a prognostic value for MGMT methylation. Investigation of pathogenetic and epigenetic features of this intriguingly distinct behavior requires accurate MGMT classification to assess high throughput molecular databases. Promoter methylation-mediated gene silencing is strongly dependent on the location of the methylated CpGs, complicating classification. Using the HumanMethylation450 (HM-450K) BeadChip interrogating 176 CpGs annotated for the MGMT gene, with 14 located in the promoter, two distinct regions in the CpG island of the promoter were identified with high importance for gene silencing and outcome prediction. A logistic regression model (MGMT-STP27) comprising probes cg1243587 and cg12981137 provided good classification properties and prognostic value (kappa = 0.85; log-rank p < 0.001) using a training-set of 63 glioblastomas from homogenously treated patients, for whom MGMT methylation was previously shown to be predictive for outcome based on classification by methylation-specific PCR. MGMT-STP27 was successfully validated in an independent cohort of chemo-radiotherapy-treated glioblastoma patients (n = 50; kappa = 0.88; outcome, log-rank p < 0.001). Lower prevalence of MGMT methylation among CpG island methylator phenotype (CIMP) positive tumors was found in glioblastomas from The Cancer Genome Atlas than in low grade and anaplastic glioma cohorts, while in CIMP-negative gliomas MGMT was classified as methylated in approximately 50 % regardless of tumor grade. The proposed MGMT-STP27 prediction model allows mining of datasets derived on the HM-450K or HM-27K BeadChip to explore effects of distinct epigenetic context of MGMT methylation suspected to modulate treatment resistance in different tumor types.

Molecular mechanisms of temozolomide resistance in glioblastoma multiforme

Glioblastoma multiforme (GBM; WHO astrocytoma grade IV) is considered incurable owing to its inherently profound resistance towards current standards of therapy. Considerable effort is being devoted to identifying the molecular basis of temozolomide resistance in GBMs and exploring novel therapeutic regimens that may improve overall survival. Several independent DNA repair mechanisms that normally safeguard genome integrity can facilitate drug resistance and cancer cell survival by removing chemotherapy-induced DNA adducts. Furthermore, subpopulations of cancer stem-like cells have been implicated in the treatment resistance of several malignancies including GBMs. Thus, a growing number of molecular mechanisms contributing to temozolomide resistance are being uncovered in preclinical studies and, consequently, we are being presented with a broad range of potentially novel targets for therapy. A substantial future challenge is to successfully exploit the increasing molecular knowledge contributing to temozolomide resistance in robust clinical trials and to ultimately improve overall survival for GBM patients.

Temozolomide dosing regimens for glioma patients

Even in modern times of high-precision brain surgery and irradiation, malignant gliomas belong to the deadliest types of cancer. Due to a marked primary and presumably also acquired resistance, the beneficial effects of cytotoxic chemotherapy are limited. Only one randomized clinical trial demonstrated a significant impact on overall survival with temozolomide. Ever since, there have been attempts to improve the efficacy of alkylating chemotherapy by modulating the distribution of dose in time aiming at a better treatment success. Apart from higher cumulative doses per cycle, better efficacy by depletion of the anti-alkylating O⁶-methylguanine-DNA methyltransferase (MGMT) protein has been a major goal of these regimens. After promising results of single-arm pilot studies, however, randomized studies have been disappointing so far. In this overview, the different strategies of dose-dense temozolomide regimen are highlighted and results of clinical trials put into perspective.

State of the art and perspectives in the treatment of glioblastoma

Glioblastoma is the most common malignant primary brain tumor. Cures are rare and median survival varies from several to 22 months. Standard treatment for good performance patients consists of maximal safe surgical resection followed by radiotherapy with concurrent temozolomide (TMZ) chemotherapy and six cycles of postradiotherapy TMZ. At recurrence, treatment options include repeat surgery (with or without Gliadel wafer placement), reirradiation or systemic therapy. Most patients with good performance status are treated with cytotoxic chemotherapy or targeted biologic therapy following or in lieu of repeat surgery. Cytotoxic chemotherapy options include nitrosoureas, rechallenge with TMZ, platins, phophoramides and topoisomerase inhibitors, although efficacy is limited. Despite the intense effort of developing biologic agents that target angiogenesis and growth and proliferative pathways, bevacizumab is the only agent that has shown efficacy in clinical trials. It was awarded accelerated approval in the USA after demonstrating an impressive radiographic response in two open-label, prospective Phase II studies. Two randomized, Phase III trials of upfront bevacizumab have completed and may demonstrate survival benefit; however, results are pending at this time. Given the limited treatment options at tumor recurrence, consideration for enrollment on a clinical trial is encouraged.

Lipidized glioblastoma: pathological and molecular characteristics

We report a rare case of a 33-year-old man with a lipidized glioblastoma multiforme (GBM) in the right posterior frontal region. Histologically the tumor had all the typical features of a GBM but with the rare observation of lipidized differentiation. There were multiple mitoses, extensive vascular proliferation, focal necrosis and the tumor cells had abundant xanthomatous cytoplasm and marked nuclear pleomorphism. The tumor showed immunoreactivity with GFAP. The O(6) - methylguanine methyltransferase (MGMT) promoter was methylated and there were no isocitrate dehydrogenase (IDH)1 and IDH2 mutations. To the best of our knowledge, this is the first time MGMT promoter status and IDH mutation assessment have been reported in a case of lipidized GBM.

Primary brain tumours in adults

Important advances have been made in the understanding and management of adult gliomas and primary CNS lymphomas--the two most common primary brain tumours. Progress in imaging has led to a better analysis of the nature and grade of these tumours. Findings from large phase 3 studies have yielded some standard treatments for gliomas, and have confirmed the prognostic value of specific molecular alterations. High-throughput methods that enable genome-wide analysis of tumours have improved the knowledge of tumour biology, which should lead to a better classification of gliomas and pave the way for so-called targeted therapy trials. Primary CNS lymphomas are a group of rare non-Hodgkin lymphomas. High-dose methotrexate-based regimens increase survival, but the standards of care and the place of whole-brain radiotherapy remain unclear, and are likely to depend on the age of the patient. The focus now is on the development of new polychemotherapy regimens to reduce or defer whole-brain radiotherapy and its delayed complications.

Temozolomide chemotherapy alone versus radiotherapy alone for malignant astrocytoma in the elderly: the NOA-08 randomised, phase 3 trial

BACKGROUND

Radiotherapy is the standard care in elderly patients with malignant astrocytoma and the role of primary chemotherapy is poorly defined. We did a randomised trial to compare the efficacy and safety of dose-dense temozolomide alone versus radiotherapy alone in elderly patients with anaplastic astrocytoma or glioblastoma.

METHODS

Between May 15, 2005, and Nov 2, 2009, we enrolled patients with confirmed anaplastic astrocytoma or glioblastoma, age older than 65 years, and a Karnofsky performance score of 60 or higher. Patients were randomly assigned 100 mg/m(2) temozolomide, given on days 1-7 of 1 week on, 1 week off cycles, or radiotherapy of 60·0 Gy, administered over 6-7 weeks in 30 fractions of 1·8-2·0 Gy. The primary endpoint was overall survival. We assessed non-inferiority with a 25% margin, analysed for all patients who received at least one dose of assigned treatment. This trial is registered with ClinicalTrials.gov, number NCT01502241.

FINDINGS

Of 584 patients screened, we enrolled 412. 373 patients (195 randomly allocated to the temozolomide group and 178 to the radiotherapy group) received at least one dose of treatment and were included in efficacy analyses. Median overall survival was 8·6 months (95% CI 7·3-10·2) in the temozolomide group versus 9·6 months (8·2-10·8) in the radiotherapy group (hazard ratio [HR] 1·09, 95% CI 0·84-1·42, p(non-inferiority)=0·033). Median event-free survival (EFS) did not differ significantly between the temozolomide and radiotherapy groups (3·3 months [95% CI 3·2-4·1] vs 4·7 [4·2-5·2]; HR 1·15, 95% CI 0·92-1·43, p(non-inferiority)=0·043). Tumour MGMT promoter methylation was seen in 73 (35%) of 209 patients tested. MGMT promoter methylation was associated with longer overall survival than was unmethylated status (11·9 months [95% CI 9·0 to not reached] vs 8·2 months [7·0-10·0]; HR 0·62, 95% CI 0·42-0·91, p=0·014). EFS was longer in patients with MGMT promoter methylation who received temozolomide than in those who underwent radiotherapy (8·4 months [95e% CI 5·5-11·7] vs 4·6 [4·2-5·0]), whereas the opposite was true for patients with no methylation of the MGMT promoter (3·3 months [3·0-3·5] vs 4·6 months [3·7-6·3]). The most frequent grade 3-4 intervention-related adverse events were neutropenia (16 patients in the temozolomide group vs two in the radiotherapy group), lymphocytopenia (46 vs one), thrombocytopenia (14 vs four), raised liver-enzyme concentrations (30 vs 16), infections (35 vs 23), and thromboembolic events (24 vs eight).

INTERPRETATION

Temozolomide alone is non-inferior to radiotherapy alone in the treatment of elderly patients with malignant astrocytoma. MGMT promoter methylation seems to be a useful biomarker for outcomes by treatment and could aid decision-making.

FUNDING

Merck Sharp & Dohme.

Efficacy of clinically relevant temozolomide dosing schemes in glioblastoma cancer stem cell lines

The effectiveness of temozolomide (TMZ) dosing schemes and the "rechallenge" of recurrent glioblastoma (GBM) with TMZ are controversial. We therefore compared the efficacy of different TMZ dosing schemes against GBM cancer stem cell (CSC) lines in vitro. In O(6)-methyl-guanidine-methyl-transferase (MGMT)-negative CSC lines, all schedules (1 day on/27 days off, 5 days on/23 days off, 7 days on/7 days off, 21 days on/7 days off, continuous low-dose TMZ) depleted clonogenic cells. In TMZ-resistant CSC lines, the 7 days on/7 days off scheme showed higher toxicity as compared with the other schemes. However, clinically feasible concentrations remained ineffective in highly resistant CSC lines. In addition, none of the schedules induced long-term depletion of clonogenic cells even at the highest concentrations (up to 250 μM). After sublethal TMZ treatment for 5 days, TMZ rechallenge of recovering CSC lines remained effective. Our data advocate CSC lines as in vitro model to address clinical questions. Using this model, our data suggest the effectiveness of TMZ in MGMT-negative CSC lines and support the concept of TMZ rechallenge. The 7 days on/7 days off scheme consistently showed the best activity of all schedules in TMZ-resistant CSC lines.

Extended adjuvant temozolomide for treatment of newly diagnosed glioblastoma multiforme

The standard of care for newly diagnosed glioblastoma multiforme (GBM) is temozolomide (TMZ) chemotherapy given concurrently with radiation for 6 weeks followed by 6 months of adjuvant TMZ. Originally, patients in Alberta were treated with only six cycles of adjuvant TMZ regardless of clinical status but institutional policy was amended to allow up to 12 cycles of adjuvant therapy for patients experiencing at least stable disease and minimal toxicity. We conducted a population-based analysis to determine if extended adjuvant TMZ treatment (i.e., more than six cycles) confers a survival advantage as compared to the standard six cycles for newly diagnosed GBM patients. Patient data was collected from the Alberta Cancer Registry and patient charts. Progression free--and overall survival was determined in patients receiving six cycles of adjuvant TMZ and compared with that of patients receiving more than six cycles. Patients in whom adjuvant chemotherapy was stopped at cycle six experienced a median survival of 16.5 months, whereas, those who received more than six cycles survived for 24.6 months (p = 0.031). Extended adjuvant therapy was not associated with increased toxicity. In multivariate analysis, adjuvant monthly Temozolomide for more than six cycles was an independent prognostic factor for both progression free--and overall survival. These data suggest extended adjuvant temozolomide (i.e., more than six cycles) should be considered in patients with newly diagnosed GBM.

Establishing the standard of care for patients with newly diagnosed and recurrent glioblastoma

The current standard of care for patients with newly diagnosed glioblastoma includes maximal safe tumor resection followed by concurrent external-beam radiation with daily low-dose temozolomide followed by 6 to 12 months of adjuvant temozolomide, typically by using a cycle of 5 consecutive days out of 28. Efforts to improve on these results from the European Organisation for Research and Treatment of Cancer (EORTC)/National Cancer Institute of Canada (NCIC) trial using either dose-dense chemotherapy strategies or combinations with signal transduction modulators have, to date, been unsuccessful. Two large international randomized trials examining the efficacy of adding bevacizumab, an antiangiogenic agent, to the standard treatment have been completed, with expectations of results within in the next 2 years. For recurrent glioblastoma, there are no firmly established standards of care. Although intracavitary insertion of carmustine-impregnated polymers has been approved by the U.S. Food and Drug Administration (FDA), this strategy is not widely used. Bevacizumab has been FDA approved for recurrent glioblastoma, but no randomized trial has clearly demonstrated a survival benefit. Alternative dosing schedules of temozolomide (i.e., metronomic) has modest activity even in patients with prior temozolomide exposure. Clinical trials testing small-molecule signal transduction modulators have been disappointing, although most report a small response rate, suggesting that molecularly definable tumor subpopulations may help guide treatment decisions. Successful implementation of marker-based treatment would lead to personalized care and the creation of individualized standards of care.

Future directions in glioblastoma therapy

The standard of care for both newly diagnosed and recurrent glioblastoma (GBM) patients has changed significantly in the past 10 years. Surgery followed by radiation and concurrent and adjuvant temozolomide is now the well-established standard treatment for newly diagnosed GBM. More recently, bevacizumab has become a mainstay of treatment for recurrent GBM. However, despite these advances and significant improvements in patient outcomes, the management and treatment of GBM patients remains a challenging and frustrating endeavor. Difficulties in interpretation of imaging changes after initial treatment, as well as the effects of antiangiogenic agents like bevacizumab on MRI characteristics, can make even the determination of disease progression complicated in multiple situations. Although a high percentage of patients benefit from antiangiogenic therapy in terms of radiographic response and progression-free survival, the effects of bevacizumab on prolonging overall survival remain controversial. Furthermore, tumor progression after treatment with antiangiogenic agents carries a particularly poor prognosis and there is a general lack of effective therapies for this group of patients. These limitations in terms of standard treatments contrast with a relative wealth of new information regarding the molecular underpinnings of GBM. Data from several large-scale efforts to molecularly profile GBM tumors including The Cancer Genome Atlas (TCGA) project have helped define specific molecular subtypes of GBM with distinct biology and clinical outcomes. These findings are helping to refine our understanding of the molecular heterogeneity and pathogenesis of these tumors and provide a basis for the future development of rational and targeted therapies for specific tumor subtypes.

Clinical cancer advances 2011: Annual Report on Progress Against Cancer from the American Society of Clinical Oncology

A message from ASCO'S President. It has been forty years since President Richard Nixon signed the National Cancer Act of 1971, which many view as the nation's declaration of the "War on Cancer." The bill has led to major investments in cancer research and significant increases in cancer survival. Today, two-thirds of patients survive at least five years after being diagnosed with cancer compared with just half of all diagnosed patients surviving five years after diagnosis in 1975. The research advances detailed in this year's Clinical Cancer Advances demonstrate that improvements in cancer screening, treatment, and prevention save and improve lives. But although much progress has been made, cancer remains one of the world's most serious health problems. In the United States, the disease is expected to become the nation's leading cause of death in the years ahead as our population ages. I believe we can accelerate the pace of progress, provided that everyone involved in cancer care works together to achieve this goal. It is this viewpoint that has shaped the theme for my presidential term: Collaborating to Conquer Cancer. In practice, this means that physicians and researchers must learn from every patient's experience, ensure greater collaboration between members of a patient's medical team, and involve more patients in the search for cures through clinical trials. Cancer advocates, insurers, and government agencies also have important roles to play. Today, we have an incredible opportunity to improve the quality of cancer care by drawing lessons from the real-world experiences of patients. The American Society of Clinical Oncology (ASCO) is taking the lead in this area, in part through innovative use of health information technology. In addition to our existing quality initiatives, ASCO is working with partners to develop a comprehensive rapid-learning system for cancer care. When complete, this system will provide physicians with personalized, real-time information that can inform the care of every patient with cancer as well as connect patients with their entire medical teams. The rapid learning system will form a continuous cycle of learning: securely capturing data from every patient at the point of care, drawing on evidence-based guidelines, and evaluating quality of care against those standards and the outcomes of other patients. Clinical trials are another area in which collaboration is critical. Increasing clinical trial participation will require commitment across the cancer community from physicians, patients, insurers, hospitals, and industry. A 2010 report by the Institute of Medicine described challenges to participation in trials by both physicians and patients and provided recommendations for revitalizing clinical trials conducted through the National Cancer Institute's Cooperative Group Program. ASCO has pledged its support for the full implementation of these recommendations. More broadly, ASCO recently outlined a bold vision for translational and clinical cancer research for the next decade and made recommendations to achieve that vision. Accelerating Progress Against Cancer: ASCO's Blueprint for Transforming Clinical and Translational Research, released in November, calls for a research system that takes full advantage of today's scientific and technologic opportunities and sets a high-level agenda for policy makers, regulators, and advocates. Cancer research has transformed cancer care in the past forty years, and this year's Clinical Cancer Advances illustrates how far we have come in the past year alone. We now have a tremendous opportunity to use today's knowledge and collaborate across all facets of cancer care to conquer this deadly disease. Michael P. Link, MD President American Society of Clinical Oncology.

Neuro-oncology: a selected review of ASCO 2011 abstracts

American Society of Clinical Oncology (ASCO), the largest clinical oncology meeting in the USA, meets annually and consistently provides an exciting forum to present new cancer clinical trials and research data. The ASCO 2011 neuro-oncology session, comprising of 3 days of presentations and over 100 abstracts, provided an overview of neuro-oncology, including both metastatic diseases of the CNS and primary brain tumors. This brief article attempts to highlight select abstracts presented at this years meeting in an organizational manner that will hopefully provide a portrait of the large and multifaceted meeting.