Epidemiology of venous thromboembolism in 9489 patients with malignant glioma

Intracranial hemorrhage in setting of glioblastoma with venous thromboembolism

Background

Venous thromboembolism (VTE) is a complication of glioblastoma. Anticoagulating patients with glioblastoma carries a theoretical risk of intracranial hemorrhage (ICH).

Methods

We performed a retrospective cohort study of consecutive glioblastoma patients (2007-2013) diagnosed with VTE.

Results

The study population comprised of 523 glioblastoma patients of whom 173 (33%) had VTE events. Seventeen (10%) had ICH: 6 (35%) subdural hematomas and 11 (65%) intratumoral hemorrhages. In total, 4 patients with ICH required neurosurgical intervention. Enhancement in the area of subsequent intratumoral hemorrhage was noted in 9 of 10 with available pre-ICH scans. Multivariable regression did not show associations between ICH and tumor enhancement diameter or use of vascular-endothelial-growth-factor inhibitor. Fifteen (16%) patients receiving anticoagulation had ICH compared with 2 (2.6%) not receiving anticoagulation (P = .005). The method of anticoagulation was not associated with development of ICH. Median survival times from nondistal VTE diagnosis to death were 8.0 and 3.5 months (P = .05) in patients receiving anticoagulation and those not on anticoagulation, respectively.

Conclusion

Patients with glioblastoma and VTE on anticoagulation have increased incidence of ICH. However, development of ICH was not associated with lower median survival from time of VTE. Intratumoral hemorrhage occurred within the enhancing portion of tumor; however, no relationship was identified between the development of ICH and (i) the median diameter of enhancement or (ii) type of anticoagulant used. However, patients with absence of enhancing tumor did not have intratumoral bleed, suggesting gross total resection may limit this adverse outcome. It is appropriate to initiate anticoagulation in glioblastoma patients with VTEs.

A prospective multicenter study of venous thromboembolism in patients with newly-diagnosed high-grade glioma: hazard rate and risk factors

Venous thromboembolism (VTE) is a common complication in patients with high-grade gliomas. The purpose of this prospective multicenter study was to determine the hazard rate of first symptomatic VTE in newly-diagnosed glioma patients and identify clinical and laboratory risk factors. On enrollment, demographic and clinical information were recorded and a comprehensive coagulation evaluation was performed. Patients were followed until death. The study end point was objectively-documented symptomatic VTE. One hundred seven patients were enrolled with a median age of 57 years (range 29-85) between June 2005 and April 2008. Ninety-one (85 %) had glioblastoma multiforme (GBM). During an average survival of 17.7 months, 26 patients (24 %) (95 % CI 17-34 %) developed VTE (hazard rate 0.15 per person-year) and 94 patients (88 %) died. Median time to VTE was 14.2 weeks post-operation (range 3-126). Patients with an initial tumor biopsy were 3.0 fold more likely to suffer VTE (p = 0.02). Patients with an elevated factor VIII activity (>147 %) were 2.1-fold more likely to develop VTE. ABO blood group, D dimer and thrombin generation were not associated with VTE. No fatal VTE occurred. VTE is a common complication in patients with newly-diagnosed high grade gliomas, particularly in the first six months after diagnosis. Patients with an initial tumor biopsy and elevated factor VIII levels are at increased risk. However, VTE was not judged to be primarily responsible for any patient deaths. Therefore, outpatient primary VTE prophylaxis remains investigational until more effective primary prophylaxis strategies and therapies for glioma are identified.

Bevacizumab-Based Therapy for Patients with Brain Metastases from Non-Small-Cell Lung Cancer: Preliminary Results

BACKGROUND

Bevacizumab is a recombinant humanized monoclonal antibody that obstructs the vascular endothelial growth factor (VEGF) pathway. Despite its extensive employment in the treatment of primary tumors of the brain, experience of brain metastatic disease, a frequent complication in patients with lung cancer, is very limited. On the basis of the strong antiedemigenous effect and no risk of intracranial bleeding, we administered a bevacizumab-based chemotherapy to patients with non-small-cell lung cancer (NSCLC) and symptomatic metastatic brain lesions who were not suitable candidates for a specific local therapy.

METHODS

The patients received bevacizumab 7.5 mg/kg and cisplatin 75 mg/m(2) on day 1, and gemcitabine 1,250 mg/m(2) on days 1 and 8, every 21 days.

RESULTS

We studied 13 patients with clinical and radiological progressive brain metastases; the majority had a treatment-naïve disease. Bevacizumab-based chemotherapy was found to be well tolerated and effective: progression-free survival (PFS) was 9.1 months (range: 0.9-39.2+) and overall survival (OS) was 9.6 months (range 3-41.5+).

CONCLUSIONS

Bevacizumab-based therapy proved to be feasible and safe. The PFS and the OS data are very encouraging as well as the symptomatic benefit due to bevacizumab's high capacity to provide a long-lasting decrease of perilesional edema.

Trends and outcomes in the treatment of gliomas based on data during 2001-2004 from the Brain Tumor Registry of Japan

The committee of Brain Tumor Registry of Japan (BTRJ) was founded in 1973 and conducts surveys and analyses of incidence, therapeutic methods, and treatment outcomes of primary and metastatic brain tumors with the cooperation of the Japan Neurosurgical Society members. Newly diagnosed 3,000-4,000 primary brain tumors and 600-1,000 brain metastases patients were enrolled in each year. This report describes the trends and treatment outcomes of gliomas from BTRJ volume 13, including 13,431 patients with primary brain tumors who newly started treatment from 2001 to 2004. Data from 382 diffuse astrocytomas (DAs), 121 oligodendrogliomas (OLs), 90 oligoastrocytomas (OAs), 513 anaplastic astrocytomas (AAs), 126 anaplastic oligodendrogliomas (AOs), 106 anaplastic oligoastrocytomas (AOAs), and 1,489 glioblastomas (GBMs) were analyzed for overall survival (OS) and progression free survival (PFS) depending on age, symptoms, Karnofsky performance status, location of the tumor, extent of resection (EOR), initial radiotherapy and chemotherapy. The 5-year PFS rates of the patients with DA, OL+OA, AA, AO+AOA, and GBM were 57.0%, 74.6%, 28.7%, 54.0%, and 9.2%, and the 5-year OS rates were 75.0%, 90.0%, 41.1%, 68.2%, and 10.1%, respectively. Higher EOR≥75% in DA and OL+OA and that ≥50% in AA, AO+AOA, and GBM significantly prolonged OS. Complications and cause of death were also reported. BTRJ had been edited for all the patients, researchers, and especially for clinicians at bedside to give useful information about brain tumors and to contribute to the advances in brain tumor treatment. This report revealed various clinical problematic issues pertaining to the diagnosis and treatment of gliomas.

Glioblastoma treatment patterns, survival, and healthcare resource use in real-world clinical practice in the USA

Background:

Glioblastoma (GB) treatment remains challenging because of recurrence and poorly defined treatment options after first-line therapy. To better understand real-world application of treatment paradigms and their impact on outcomes, we describe patterns of treatment, outcomes, and use of cancer-related healthcare resource for glioblastoma in the USA.

Methods:

A retrospective, online chart-abstraction study was conducted; each participating oncologist contributed ≤5 charts. Patients were ≥18 years with biopsy-confirmed primary or secondary newly diagnosed GB on or after 1 January 2010, had received first- and second-line therapies, and had information collected for ≥3 months after initiation of second-line therapy or until death. Assessments were descriptive and included Kaplan– Meier analyses from initiation to end of second-line therapy, disease progression, or death.

Results:

One hundred sixty physicians contributed information on 503 patient charts. During first-line therapy, patients most commonly underwent temozolomide monotherapy (76.5%). During second-line therapy, patients most commonly underwent bevacizumab monotherapy (58.1%). Median duration of second-line therapy was 130 days; median time to disease progression was 113 days. Median survival was 153 days. Use of supportive care was observed to be numerically higher in first- compared with second-line therapy except for anti-depressants, growth factors, and stimulants. Frequently used resources included corticosteroids (78.8% of patients in first-line and 62.6% in second-line therapies), anti-epileptics (45.8% and 41.5%) and narcotic opioids (45.3% and 41.4%).

Conclusions:

Most GB patients received temozolomide during first-line therapy and bevacizumab monotherapy or combination therapy during second-line therapy. Use of supportive care appeared to be higher in first- compared with second-line therapy for some agents.

Vandetanib plus sirolimus in adults with recurrent glioblastoma: results of a phase I and dose expansion cohort study

Targeting specific molecular alterations in glioblastoma (GBM) might more effectively kill tumor cells and increase survival. Vandetanib inhibits epidermal growth factor receptor and vascular endothelial growth factor receptor 2. Sirolimus inhibits mammalian target of rapamycin (mTOR), a member the phosphoinositide 3-Kinase signaling pathway. We sought to determine the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of vandetanib combined with sirolimus. Twenty-two patients (14 men; 8 women) with recurrent GBM enrolled. Median age and KPS were 52.5 years and 90 %, respectively. Patients were naive to anti-VEGF and anti-EGF therapy and mTOR inhibitors, and not on CYP3A4-inducing drugs. Vandetanib and sirolimus were orally administered on a continuous daily dosing schedule in escalating dose cohorts. Ten patients enrolled in the dose escalation phase. Twelve more enrolled at the MTD to explore progression-free survival at 6 months (PFS6) in a single arm, single stage phase II-type design. In total, 19 patients received at least one dose at the MTD, and 15 completed at least 1 cycle at MTD. MTD was 200 mg vandetanib plus 2 mg sirolimus. The DLT was elevated AST/SGOT. The most common toxicities were lymphopenia, fatigue, rash, and hypophosphatemia. For 19 patients who received at least one dose at the MTD, including seven from the phase I group, two had a partial response [10.5 %; 95 % CI (1, 33 %)] and PFS6 was 15.8 % [95 % CI (3.9, 34.9 %)]. Vandetanib and sirolimus can be safely co-administered on a continuous, daily dosing schedule.

Impact of thrombophilic genes mutations on thrombosis risk in Egyptian nonmetastatic cancer patients

Venous thromboembolism (VTE) is a common complication in cancer patients. Several genetic risk factors related to thrombophilia are known; however, their contributions to thrombotic tendency in cancer patients have conflicting results. We aimed to determine the prevalence of factor V Leiden (FVL), prothrombin (PTH) G20210A and methylene tetrahydrofolate reductase (MTHFR) C677T gene polymorphisms in Egyptian nonmetastatic cancer patients and their influence on thrombosis risk in those patients. Factor V Leiden, PTH G20210A and MTHFR C677T polymorphisms were detected in 40 cancer patients with VTE (group 1) and 40 cancer patients with no evidence of VTE (group 2) by PCR-based DNA analysis. Factor V and MTHFR mutations were higher in group 1 than in group 2 (factor V heterozygous mutation: 20 vs. 7.5%, homozygous mutation: 10 vs. 2.5%; MTHFR heterozygous mutation: 40 vs. 25%, homozygous mutation 5 vs. 0%, respectively) (P = 0.03). Mortality rate was higher in group 1 (75%) than in group 2 (25%; P < 0.001). No difference was found between those groups regarding PTH mutation (P = 1). Mortality rate was higher in the presence of homozygous and heterozygous factor V mutation (100 and 82%, respectively) compared to the wild type (41%) (P = 0.0006). Having any of the three studied gene mutations worsened the overall survival (P = 0.0003). Cox regression proved that both thrombosis and presence of factor V mutation are independent factors affecting survival in cancer patients (P < 0.001 and P = 0.01, respectively). In conclusion, there is an association between factor V and MTHFR mutations and risk of VTE in Egyptian cancer patients. Thrombosis and presence of factor V mutation are independent factors that influence survival in those patients.

Practical management of bevacizumab-related toxicities in glioblastoma

Bevacizumab, currently an option for treatment of different types of tumors including glioblastoma, has a peculiar toxicity profile related to its antiangiogenic effect. Because some bevacizumab-related adverse events can be life threatening, it is important to identify risk factors and to establish treatment protocols to minimize treatment-related morbidity and mortality. In glioblastoma patients, the risk of developing certain side effects, such as gastrointestinal perforation, venous thromboembolism, and intracranial hemorrhages, is slightly higher than in patients treated with bevacizumab for other tumor types. We performed a systematic review of the side effects of bevacizumab and their incidence, causal mechanisms, and available treatments. Finally, we identified risk factors and proposed preventive and therapeutic measures for these adverse events.

Coagulation and angiogenic gene expression profiles are defined by molecular subgroups of medulloblastoma: evidence for growth factor-thrombin cross-talk

BACKGROUND

The coagulation system becomes activated during progression and therapy of high-grade brain tumors. Triggering tissue factor (F3/TF) and thrombin receptors (F2R/PAR-1) may influence the vascular tumor microenvironment and angiogenesis irrespective of clinically apparent thrombosis. These processes are poorly understood in medulloblastoma (MB), in which diverse oncogenic pathways define at least four molecular disease subtypes (WNT, SHH, Group 3 and Group 4). We asked whether there is a link between molecular subtype and the network of vascular regulators expressed in MB.

METHODS

Using R2 microarray analysis and visualization platform, we mined MB datasets for differential expression of vascular (coagulation and angiogenesis)-related genes, and explored their link to known oncogenic drivers. We evaluated the functional significance of this link in DAOY cells in vitro following growth factor and thrombin stimulation.

RESULTS

The coagulome and angiome differ across MB subtypes. F3/TF and F2R/PAR-1 mRNA expression are upregulated in SHH tumors and correlate with higher levels of hepatocyte growth factor receptor (MET). Cultured DAOY (MB) cells exhibit an up-regulation of F3/TF and F2R/PAR-1 following combined SHH and MET ligand (HGF) treatment. These factors cooperate with thrombin, impacting the profile of vascular regulators, including interleukin 1β (IL1B) and chondromodulin 1 (LECT1).

CONCLUSIONS

Coagulation pathway sensors (F3/TF, F2R/PAR-1) are expressed in MB in a subtype-specific manner, and may be functionally linked to SHH and MET circuitry. Thus coagulation system perturbations may elicit subtype/context-specific changes in vascular and cellular responses in MB.

Venous thromboembolism in high grade glioma among surgical patients: results from a single center over a 10 year period

Patients with high-grade glioma are at elevated risk of venous thromboembolism (VTE). The relationship between VTE and survival in glioma patients remains unclear, as does the optimal protocol for chemoprophylaxis. The purpose of this study was to assessthe incidence of and risk factors associated with VTE in patients with high-grade glioma, and the correlation between VTE and survival in this population. Furthermore, we sought to define a protocol for perioperative DVT prophylaxis. This was a retrospective review of patients who underwent craniotomy for resection of high-grade glioma (WHO grade III or IV) at Northwestern University between 1999 and 2010. A total of 336 patients met inclusion criteria. 53 patients developed postoperative VTE (15.7 %). Median survival was 12.0 months and was not significantly different between VTE(+) and VTE(-) patients. Demographics and surgical factors were not significantly correlated with VTE development. Prior history of VTE was highly predictive of postoperative VTE (OR 7.1, p < .01), as was seizure (OR 2.4, p = .005). Increased duration of postoperative ICU stay was also a risk factor for VTE (p = .025). 25 patients in our study received prophylactic anticoagulation(pAC) with either heparin or enoxaparin. Early initiation of pAC was associated with decreased incidence of VTE (p = .042). There were no hemorrhagic complications in patients receiving pAC. VTE is a common complication in high-grade glioma patients. Early initiation of anticoagulation is safe and may decrease the risk of VTE. We recommend initiation of chemoprophylaxis on postoperative day 1 in patients without contraindication.

Case-control studies in neurosurgery

OBJECT

Observational studies, such as cohort and case-control studies, are valuable instruments in evidence-based medicine. Case-control studies, in particular, are becoming increasingly popular in the neurosurgical literature due to their low cost and relative ease of execution; however, no one has yet systematically assessed these types of studies for quality in methodology and reporting.

METHODS

The authors performed a literature search using PubMed/MEDLINE to identify all studies that explicitly identified themselves as "case-control" and were published in the JNS Publishing Group journals (Journal of Neurosurgery, Journal of Neurosurgery: Pediatrics, Journal of Neurosurgery: Spine, and Neurosurgical Focus) or Neurosurgery. Each paper was evaluated for 22 descriptive variables and then categorized as having either met or missed the basic definition of a case-control study. All studies that evaluated risk factors for a well-defined outcome were considered true case-control studies. The authors sought to identify key features or phrases that were or were not predictive of a true case-control study. Those papers that satisfied the definition were further evaluated using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist.

RESULTS

The search detected 67 papers that met the inclusion criteria, of which 32 (48%) represented true case-control studies. The frequency of true case-control studies has not changed with time. Use of odds ratios (ORs) and logistic regression (LR) analysis were strong positive predictors of true case-control studies (for odds ratios, OR 15.33 and 95% CI 4.52-51.97; for logistic regression analysis, OR 8.77 and 95% CI 2.69-28.56). Conversely, negative predictors included focus on a procedure/intervention (OR 0.35, 95% CI 0.13-0.998) and use of the word "outcome" in the Results section (OR 0.23, 95% CI 0.082-0.65). After exclusion of nested case-control studies, the negative correlation between focus on a procedure/intervention and true case-control studies was strengthened (OR 0.053, 95% CI 0.0064-0.44). There was a trend toward a negative association between the use of survival analysis or Kaplan-Meier curves and true case-control studies (OR 0.13, 95% CI 0.015-1.12). True case-control studies were no more likely than their counterparts to use a potential study design "expert" (OR 1.50, 95% CI 0.57-3.95). The overall average STROBE score was 72% (range 50-86%). Examples of reporting deficiencies were reporting of bias (28%), missing data (55%), and funding (44%).

CONCLUSIONS

The results of this analysis show that the majority of studies in the neurosurgical literature that identify themselves as "case-control" studies are, in fact, labeled incorrectly. Positive and negative predictors were identified. The authors provide several recommendations that may reverse the incorrect and inappropriate use of the term "case-control" and improve the quality of design and reporting of true case-control studies in neurosurgery.

Brain tumors enhance plasmatic coagulation: the role of hemeoxygenase-1

BACKGROUND

Patients with brain tumors suffer significant thrombotic morbidity and mortality. In addition to increased thrombin generation via tumor release of tissue factor-bearing microparticles and hyperfibrinogenemia, brain tumors and surrounding normal brain likely generate endogenous carbon monoxide (CO) via the hemeoxygenase-1 (HO-1) system. CO has been shown to enhance plasmatic coagulation via formation of carboxyhemefibrinogen (COHF). Thus, our goals in this study were to determine whether patients with brain tumors had increased HO-1 upregulation/CO production, plasmatic hypercoagulability, and formation of COHF.

METHODS

Patients with brain tumors (N = 20) undergoing craniotomy had blood collected for determination of carboxyhemoglobin as a marker of HO-1 activity, plasmatic hypercoagulability (defined as clot strength > 95% confidence interval value of normal subject plasma), and COHF formation (determined with a thrombelastograph-based assay). Plasma obtained from commercially available normal subjects (N = 30) was used for comparison with brain tumor patient samples.

RESULTS

Brain tumor patients had carboxyhemoglobin concentrations of 1.5% ± 0.5% (mean ± SD), indicative of HO-1 upregulation. Compared with normal subject plasma, brain tumor patient plasma had significantly (P < 0.0001) greater clot formation velocity (5.2 ± 1.5 vs 9.5 ± 2.3 dynes/cm/s, respectively) and significantly (P = 0.00016) stronger final clot strength (166 ± 28 vs 230 ± 78 dynes/cm, respectively). Ten of the brain tumor patients had plasma clot strength that exceeded the 95% confidence interval value observed in normal subjects, and 12 of the brain tumor patients had COHF formation. Five of the brain tumor patients in the hypercoagulable subgroup had COHF formation. Last, 5 of the hypercoagulable patients had primary brain tumors, whereas the other 5 patients had metastatic tumors or an inflammatory mass lesion.

CONCLUSIONS

A subset of patients with brain tumors has increased endogenous CO production, plasmatic hypercoagulability, and COHF formation. Future investigation of the role played by HO-1 derived CO in the pathogenesis of brain tumor-associated thrombophilia is warranted.

Outcomes in neurosurgical patients who develop venous thromboembolism: a review of the RIETE registry

OBJECTIVES

Registro Informatizado de Enfermedad TromboEmbólica (RIETE) database was used to investigate whether neurosurgical patients with venous thromboembolism (VTE) were more likely to die of bleeding or VTE and the influence of anticoagulation on these outcomes.

METHODS

Clinical characteristics, treatment details, and 3-month outcomes were assessed in those who developed VTE after neurosurgery.

RESULTS

Of 40 663 patients enrolled, 392 (0.96%) had VTE in less than 60 days after neurosurgery. Most patients in the cohort (89%) received initial therapy with low-molecular-weight heparin, (33% received subtherapeutic doses). In the first week, 10 (2.6%) patients died (8 with pulmonary embolism [PE], no bleeding deaths; P = .005). After the first week, 20 (5.1%) patients died (2 with fatal bleeding, none from PE). Overall, this cohort was more likely to develop a fatal PE than a fatal bleed (8 vs 2 deaths, P = .058).

CONCLUSIONS

Neurosurgical patients developing VTE were more likely to die from PE than from bleeding in the first week, despite anticoagulation.

Venous thromboembolism in neurologic disease

Patients with neurologic disease are at high risk of venous thromboembolism (VTE) because of relative immobility. They are also at increased risk due to the presence of a hypercoagulable state. Patients with spinal cord injuries, brain tumors, and strokes are at particularly high risk and extra vigilance is needed in these patients. Because VTE is very common in hospitalized neurologic and neurosurgical patients, mechanical thromboprophylaxis is indicated in virtually all patients. Pharmacologic prophylaxis with either subcutaneous heparin or low molecular heparinoids should be given to all high-risk neurologic and neurosurgical patients provided there are no major contraindications. The major concern would be a risk of bleeding but in some patients alternate drugs must be considered given the risk of thrombosis (i.e., in the context of heparin-induced thrombocytopenia). The immediate or long-term treatment of full dose anticoagulation for VTE may not be appropriate in all patients as VTE therapy represents a balance between the risks of bleeding related to anticoagulant therapy versus the risk of recurrent events. An inferior vena cava (IVC) filter is another option in these patients but may not necessarily be the best choice for most neurologic patients. Given the high risk of VTE in patients with neurologic diseases, early recognition by clinicians of the signs and symptoms of VTE is essential.

Circulating microparticles of glial origin and tissue factor bearing in high-grade glioma: a potential prothrombotic role

Venous thromboembolism (VTE) may complicate the clinical course of glioblastoma multiforme (GBM). Circulating microparticles (MPs) have been associated with cancer-related VTE. Sixty-one consecutive patients with GBM undergoing gross-total (41) or subtotal (20) surgical resection followed by radio-chemotherapy were prospectively evaluated. MPs numbers according to cellular origin and the procoagulant activity of annexin V positive (AV+) MPs (MP-activity) were measured before surgery and then 1 week and 1, 4, and 7 months after surgery. Glial (GFAP+) and endothelial (CD62E+) derived MPs, AV+ and tissue factor-bearing (TF+) MPs were measured using flow cytometry. Baseline levels of GFAP+/TF-, TF+/GFAP-, and GFAP+/TF+ MPs were significantly higher in GBM patients than in healthy controls, and significantly increased at each time point after surgery; at 7 months, a further significant increase over the level found a week after surgery was only seen in the subtotally resected patients. The number AV+/CD62E- MPs increased in GBM patients and correlated with MP activity. TF+/GFAP- MPs numbers were significantly higher in 11 GBM patients who developed VTE than in those who did not (p 0.04). TF+/GFAP- MPs levels above the 90th percentile (calculated in GBM patients without VTE) were associated with a higher risk of VTE (RR 4.17, 95% CI 1.57-11.03). In conclusion, the numbers of glial-derived and/or TF-bearing MPs were high in GBM patients both before and even more after the neoplasm was treated, especially in patients with subtotal resection likely according to disease progression. A contribution of TF+/GFAP- MPs to the risk of VTE is suggested.

Thromboembolic disease in patients with high-grade glioma

Venous thromboembolism (VTE) is common throughout the course of disease in high-grade glioma (HGG). The interactions between the coagulation cascade, endothelium, and regulation of angiogenesis are complex and drive glioblastoma growth and invasion. We reviewed the incidence of VTE in HGG, the biology of the coagulome as related to glioblastoma progression, prevention and treatment of thrombosis, and the putative role of anticoagulants as anti-cancer therapy. VTE can be significantly reduced during the postoperative period with adherence to the use of mechanical and medical thromboprophylaxis. Activation of the coagulation cascade occurs throughout the course of disease because of a variety of complex interactions, including tumor hypoxia, upregulation of VEGR expression, and increases in both tumor cell-specific tissue factor (TF) expression and inducible TF expression in numerous intrinsic regulatory pathways. Long-term anticoagulation to prevent VTE is an attractive therapy; however, the therapeutic window is narrow and current data do not support its routine use. Most patients with proven symptomatic VTE can be safely anticoagulated, including those receiving anti-VEGF therapy, such as bevacizumab. Initial therapy should include low molecular weight heparin (LMWH), and protracted anticoagulant treatment, perhaps indefinitely, is indicated for patients with HGG because of the ongoing risk of thrombosis. A variety of coagulation- and tumor-related proteins, such as TF and circulating microparticles, may serve as potential disease-specific biomarkers in relation to disease recurrence, monitoring of therapy, and as potential therapeutic targets.

The therapeutic management of bleeding and thrombotic disorders complicating CNS malignancies

OPINION STATEMENT

Patients with central nervous system (CNS) malignancies have a substantial risk for developing both thrombotic and bleeding disorders. The risk of venous thromboembolism (VTE) is substantially higher in these patients, both in the perioperative period and throughout their disease course. Patients with CNS malignancy harbor a latent hypercoagulability, which predisposes to VTE, as do postoperative immobility, hemiparesis, and other factors. The management of VTE in these patients is complex, given the significant morbidity and mortality associated with intratumoral hemorrhage. In the past, the perceived risk of intracranial hemorrhage limited the use of anticoagulation for the management of VTE with many favoring nonpharmacologic methods for prophylaxis and treatment. Inferior vena cava (IVC) filters have since lost favor at many centers given significant complications, which appear to be more frequent in patients with CNS malignancy. Recent studies have demonstrated safe and efficacious use of anticoagulation in these patients with a low incidence of intracranial hemorrhage. Treatment of established VTE is now recommended in this population with many centers favoring low-molecular-weight heparin (LMWH) versus oral warfarin for short- or long-term treatment. We advocate a multimodality approach utilizing compression stockings, intermittent compression devices, and heparin in the perioperative setting as the best proven method to reduce the risk of VTE. In the absence of a strict contraindication to systemic anticoagulation, such as previous intracranial hemorrhage or profound thrombocytopenia, we recommend LMWH in patients with newly diagnosed VTE and a CNS malignancy.

Bevacizumab in high-grade gliomas: a review of its uses, toxicity assessment, and future treatment challenges

High-grade gliomas continue to have dismal prognosis despite advances made in understanding the molecular genetics, signaling pathways, cytoskeletal dynamics, and the role of stem cells in gliomagenesis. Conventional treatment approaches, including surgery, radiotherapy, and cytotoxic chemotherapy, have been used with limited success. Therapeutic advances using molecular targeted therapy, immunotherapy, and others such as dietary treatments have not been able to halt tumor progression and disease-related death. High-grade gliomas (World Health Organization grades III/IV) are histologically characterized by cellular and nuclear atypia, neoangiogenesis, and necrosis. The expression of vascular endothelial growth factor, a molecular mediator, plays a key role in vascular proliferation and tumor survival. Targeting vascular endothelial growth factor has demonstrated promising results, with improved quality of life and progression-free survival. Bevacizumab, a humanized monoclonal antibody to vascular endothelial growth factor, is approved by the Food and Drug Administration as a single agent in recurrent glioblastoma and is associated with manageable toxicity. This review discusses the efficacy, practical aspects, and response assessment challenges with the use of bevacizumab in the treatment of high-grade gliomas.

Drug review: Safety and efficacy of bevacizumab for glioblastoma and other brain tumors

Glioblastoma is a highly vascular tumor that expresses vascular endothelial growth factor, a key regulator of angiogenesis and tumor blood vessel permeability. Bevacizumab is a monoclonal antibody that inhibits vascular endothelial growth factor and the growth of gliomas. Bevacizumab monotherapy has proven effective for recurrent glioblastoma, and it extended progression-free survival and improved patient quality of life in various clinical trials. Some patients who receive bevacizumab experience improvements in neurological symptoms and steroid dose reductions. Bevacizumab induces a dramatic and rapid radiological response, but non-enhancing lesions are often detected on magnetic resonance imaging without enhancing lesions. Rebound phenomena such as rapid tumor regrowth are occasionally observed after the discontinuation of bevacizumab therapy. Therefore, Response Assessment in Neuro-Oncology criteria were recently devised to evaluate the efficacy and radiological response of bevacizumab treatment. Hypertension and proteinuria are characteristic adverse events associated with bevacizumab therapy. In addition, many fatal adverse events such as intracranial hemorrhage and venous thromboembolism are reported in patients treated with bevacizumab. However, these events are also associated with glioma itself, and careful attention needs to be paid to these events. Bevacizumab is used to treat various diseases including radiation necrosis and recurrent brain tumors such as brain metastases, schwannoma and meningioma, but additional clinical trials are necessary. The efficacy and current problems associated with bevacizumab in the treatment of glioblastoma and other brain tumors are reviewed.

Primary venous thromboembolism prophylaxis in ambulatory cancer patients

OBJECTIVE

To summarize and review current medical literature regarding the efficacy and safety of antithrombotic therapy for primary venous thromboembolism (VTE) prophylaxis in various ambulatory cancer populations.

DATA SOURCES

A literature search was conducted in PubMed (1966-September 2012) and International Pharmaceutical Abstracts (1970-September 2012) using the terms venous thromboembolism, primary prophylaxis, anticoagulation, antithrombotic agents, cancer, and ambulatory. The bibliographies of pertinent studies and topic articles were reviewed for additional references.

STUDY SELECTION AND DATA EXTRACTION

All English-language articles were evaluated for inclusion. All randomized trials were included in the review.

DATA SYNTHESIS

Malignancy has been identified as a major independent risk factor for the development of VTE in the surgical, medically ill, and ambulatory populations. Primary VTE prophylaxis has been identified as an area of great impact in cancer patients because of the difficulties associated with the treatment of VTE and the greater risk for its recurrence in this population. Although primary VTE prophylaxis is recommended in all surgical and hospitalized cancer patients without contraindications to anticoagulants, its role in ambulatory cancer patients is less certain because of varying patient, cancer, and treatment-related factors. Fourteen randomized studies have investigated the use of antithrombotic agents for primary VTE prophylaxis in ambulatory cancer patients. Strong evidence for primary prophylaxis exists for several populations with advanced or metastatic cancer considered to be at high risk, including those with pancreatic cancer, lung cancer, or multiple myeloma. Evidence is inconsistent or lacking for lower risk cancer populations, such as those with breast cancer, or for those with malignant glioma, which carries a high risk for VTE and bleeding relative to the general ambulatory cancer population.

CONCLUSIONS

Use of antithrombotic agents has reduced the rate of primary VTE, with minimal increases in bleeding risk in specific ambulatory cancer populations. Further investigation is needed to guide and narrow recommendations for primary VTE prophylaxis in ambulatory cancer patients.

Coagulation and cancer: biological and clinical aspects

Malignancy affects the hemostatic system and the hemostatic system affects malignancy. In cancer patients there are a number of coagulation abnormalities which provide the background for an increased tendency of these patients to both thrombosis and hemorrhage. The causes of this coagulation impairment rely on general risk factors which are common to other categories of patients, and other factors which are specific to cancer, such as tumor type and disease stage. In addition, data from basic research indicate that the hemostatic components and the cancer biology are interconnected in multiple ways. Notably, while cancer cells are able to activate the coagulation system, the hemostatic factors play a role in tumor progression. This opens the way to the development of bifunctional therapeutic approaches that are both capable of attacking the malignant process and resolving the coagulation impairment. On the other hand, the management of thrombosis and hemorrhages in cancer patients can be different. To approach these problems, some guidelines have been released by prominent international scientific societies. Also actively investigated is the issue of identifying new biomarkers to classify the subjects at a higher risk, thus improving the prevention of thrombohemorrhagic events in these patients. Finally, novel prophylactic and therapeutic approaches are currently under development. This review provides an overview of the hemostatic complications in cancer, together with new insights into the interaction between hemostasis and cancer biology. We also review the assessment of the risk of thrombohemorrhagic events in cancer patients, and the prophylaxis and treatment of such manifestations.

Deep venous thrombosis and pulmonary embolisms in adult patients undergoing craniotomy for brain tumors

OBJECTIVE

The development of venothromboembolisms (VTEs), including deep vein thrombosis (DVT) and pulmonary emboli (PE), is common in brain tumor patients. Their development can be catastrophic. Studies evaluating pre-operative clinical factors that predispose patients to the development of VTE are few and limited. An understanding may help risk stratify patients and guide subsequent therapy aimed at reducing the risk of DVTs/PEs.

METHODS

All adult patients who underwent surgery for an intracranial tumor at an academic tertiary care institution between 1998 and 2008 were retrospectively reviewed. Stepwise multivariate logistical regression analysis was used to identify pre-operative factors associated with the development of peri-operative (within 30 days of surgery) DVTs/PEs among patients who underwent surgery of their intracranial tumor.

RESULTS

Of the 4293 patients in this study, 126 (3%) patients developed DVT and/or PE in the peri-operative period. The pre-operative factors independently associated with the development of DVTs/PEs were: poorer Karnofsky performance scale (KPS) [odds ratio (OR), 1·040; 95% confidence interval (CI), 1·026-1·052; P<0·0001], high grade glioma (OR, 1·702; 95% CI, 1·176-2·465; P = 0·005), older age (OR, 1·033; 95% CI, 1·020-1·046; P<0·0001), hypertension (OR, 1·785; 95% CI, 1·180-2·699; P = 0·006), and motor deficit (OR, 1·854; 95% CI, 1·244-2·763; P = 0·002). Eighty six per cent of the patients with DVTs/PEs were treated with either unfractionated or low molecular weight heparin, and 4% of these patients developed intracranial hemorrhage.

DISCUSSION

The present study found that poorer functional status, older age, pre-operative motor deficit, high grade glioma, and hypertension each independently increased the risk of developing peri-operative DVTs/PEs. These findings may provide patients and physicians with prognostic information that may guide therapies aimed at minimizing the development of peri-operative DVTs/PEs.

Tumour and microparticle tissue factor expression and cancer thrombosis

Cancer is frequently complicated by venous thromboembolic events (VTE), which pose a significant health burden due to the associated high morbidity and mortality rates, yet the exact details of the pathophysiological mechanisms underlying their development are yet to be fully elucidated. Tissue factor (TF), the primary initiator of coagulation, is often overexpressed in malignancy and as such is a prime candidate in predicting the hypercoagulable state. Further exploration of this potential role has identified increases in the number of TF-expressing microparticles (MP) in the circulation of cancer patients, in particular in those known to have high incidences of thromboembolic complications. The risk of VTE in cancer is found to be further elevated by chemotherapy. Chemotherapy may, in eliciting cancer cell apoptosis, result in an increase in release of circulating procoagulant MP. We discuss a potential role of elevated tumour TF expression and increased circulating TF-positive MP in predicting VTE risk.

Screening strategy using sequential serum D-dimer assay for the detection and prevention of venous thromboembolism after elective brain tumor surgery

OBJECTIVE

Venous thromboembolism (VTE) is a life-threatening complication in neurosurgical patients. This study retrospectively analyzed the effectiveness and safety of a screening strategy for the detection and prevention of VTE in patients undergoing elective brain tumor surgery.

PATIENTS

A total of 419 consecutive patients who underwent brain tumor surgery during 5 years were enrolled. At the midpoint of the study period, screening for VTE was introduced based on measurement of serum D-dimer level on the day after surgery and then once or twice every week. Anticoagulant therapy was started after the diagnosis of VTE. The two groups with (228 patients) and without (191 patients) screening were compared.

RESULTS

Most of the demographic and clinical characteristics were relatively well balanced in the groups. VTE was diagnosed in 23 (5.5%) patients overall; the rate was higher in the screening group (7.0%) than in the non-screening group (3.7%). Although the rate of VTE-related adverse events was lower in the screening group (1.3% vs. 2.6%), the rate of hemorrhagic complications was higher (2.2% vs. 0.5%). Multivariate analysis indicated that malignant histology and preoperative paresis were independent risk factors for the diagnosis of VTE.

CONCLUSIONS

Many VTE patients may not exhibit signs or symptoms, so screening using surrogate markers for VTE (D-dimer) may be useful in the early detection of asymptomatic VTE. However, most distal, deep venous thrombosis in isolation is not life-threatening, so the added efficacy of anticoagulant agents at this stage has to be weighed against the risks of hemorrhagic complications, especially in the early postoperative period.

A comprehensive analysis of vascular complications in 3,889 glioma patients from the German Glioma Network

Ischemic strokes, intracranial hemorrhages (ICH) and deep venous thromboembolism (DVT) are clinically important events in patients with gliomas. In this multicentre, noninterventional observational study, current data pertaining to frequency, contributing factors and outcomes of vascular events during times of anti-angiogenic therapy with the antibody against vascular endothelial growth factor, bevacizumab (BEV) was collected from the German Glioma Network. Among 3,889 glioma patients, 70 ischemic strokes (1.8 %) and 123 ICH (3.2 %) were recorded. 143 DVT (5.0 %) were recorded in 2,855 patients. Rates of DVT and ICH, but not of ischemic strokes, increased with the World Health Organization (WHO) grade of glioma. In 81 BEV-treated patients, five ischemic strokes (6.2 %), one ICH (1.2 %) and six DVT (7.4 %) were documented. Compared to patients that were not treated with BEV, ischemic stroke rate was significantly higher during treatment with BEV (p < 0.001). The rates of DVT (p = 0.123) or ICH (p = 0.571) in BEV-treated patients did not differ. On cerebral magnetic resonance imaging (MRI), BEV-related ischemic strokes appeared as diffusion-restricted sites next to contrast-enhancing tumor. 67 % of ICH, 61 % of ischemic strokes and 18 % of DVT occurred postoperatively (within 30 days after tumor resection). Outcome after postoperative ICH was significantly worse than after spontaneous ICH (p = 0.008). Ischemic stroke outcomes did not differ between postoperative and spontaneous occurrence (p = 0.401). Rate of pulmonary embolism did not differ significantly between postoperative and spontaneous DVT (p = 0.133). Relatively low rates of ICH and DVT might be partially due to a high proportion of low-grade gliomas in this patient cohort. The finding of a relevant number of symptomatic, therapy-associated intracerebral diffusion restrictions should be controlled in ongoing phase III studies.

Management of treatment-associated toxicites of anti-angiogenic therapy in patients with brain tumors

Anti-angiogenic therapies, including bevacizumab, are being used with increasing frequency in the management of malignant glioma. Common clinically significant toxicities include hypertension and proteinuria, poor wound healing, and the potential for thromboembolic events. Literature related to the use of bevacizumab in malignant glioma, reported toxicities in this patient population, and management of these toxicities was reviewed. Recommendations for assessment and management are provided. Anti-angiogenic therapies will continue to have a role in the treatment of malignant glioma. Further studies of the prevention, assessment, and management of these toxicities are warranted.

Randomized controlled trial of a new portable calf compression device (Venowave) for prevention of venous thrombosis in high-risk neurosurgical patients

BACKGROUND

Patients undergoing neurosurgical procedures are at risk of venous thromboembolism (VTE), but often have contraindications for anticoagulant prophylaxis.

OBJECTIVES

To assess the efficacy and tolerability of a new, lightweight, portable, battery-powered, intermittent calf compression device, Venowave, for the prevention of VTE in neurosurgical inpatients.

PATIENTS/METHODS

We performed an open randomized controlled trial comparing Venowave with control for the prevention of VTE in patients undergoing neurosurgery. The primary outcome was the composite of asymptomatic deep vein thrombosis (DVT) detected by screening venography or compression ultrasound performed on day 9 (± 2 days) and symptomatic VTE.

RESULTS

We randomized 75 patients to receive Venowave devices and 75 to the control group. All patients were prescribed graduated compression stockings and physiotherapy. VTE occurred in three patients randomized to Venowave and in 14 patients randomized to control (4.0% vs. 18.7%, relative risk 0.21; 95% confidence interval 0.05-0.75, P = 0.008). Similar reductions were seen for proximal DVT (2.7% vs. 8.0%) and symptomatic VTE (0% vs. 2.7%), and the results were consistent in all subgroups examined.

CONCLUSIONS

Venowave devices are effective in preventing VTE in high-risk neurosurgical patients.

Risk of venous thromboembolism in patients with cancer: a systematic review and meta-analysis

BACKGROUND

People with cancer are known to be at increased risk of venous thromboembolism (VTE), and this risk is believed to vary according to cancer type, stage of disease, and treatment modality. Our purpose was to summarise the existing literature to determine precisely and accurately the absolute risk of VTE in cancer patients, stratified by malignancy site and background risk of VTE.

METHODS AND FINDINGS

We searched the Medline and Embase databases from 1 January 1966 to 14 July 2011 to identify cohort studies comprising people diagnosed with one of eight specified cancer types or where participants were judged to be representative of all people with cancer. For each included study, the number of patients who developed clinically apparent VTE, and the total person-years of follow-up were extracted. Incidence rates of VTE were pooled across studies using the generic inverse variance method. In total, data from 38 individual studies were included. Among average-risk patients, the overall risk of VTE was estimated to be 13 per 1,000 person-years (95% CI, 7 to 23), with the highest risk among patients with cancers of the pancreas, brain, and lung. Among patients judged to be at high risk (due to metastatic disease or receipt of high-risk treatments), the risk of VTE was 68 per 1,000 person-years (95% CI, 48 to 96), with the highest risk among patients with brain cancer (200 per 1,000 person-years; 95% CI, 162 to 247). Our results need to be considered in light of high levels of heterogeneity, which exist due to differences in study population, outcome definition, and average duration of follow-up between studies.

CONCLUSIONS

VTE occurs in greater than 1% of cancer patients each year, but this varies widely by cancer type and time since diagnosis. The absolute VTE risks obtained from this review can aid in clinical decision-making about which people with cancer should receive anticoagulant prophylaxis and at what times.

The impact of recent data on the optimization of standards of care in newly diagnosed glioblastoma

Glioblastoma is an aggressive form of brain cancer with a poor long-term prognosis. Treatment regimens for newly diagnosed disease range from surgical resection alone to surgery followed by radiotherapy with concurrent and adjuvant chemotherapy. Ongoing investigations are focused on optimization of chemotherapy by improving dosing and duration schedules and utilization of biomarkers for patient selection. Our understanding of glioblastoma tumor biology, the role of molecular signaling pathways, cellular repair mechanisms, and angiogenesis has increased greatly over the past few years, leading to the investigation of a variety of targeted therapies. In addition, advances in radiographic assessment have significantly impacted not only improvement in diagnosis, but interpretation of response to therapy. In order to effectively evaluate the clinical utility of new agents, as well as incorporate advances in radiographic assessment, changes to current clinical trial design need to be considered. This article reviews the care for newly diagnosed glioblastoma, as well as how recent findings might be incorporated into patient care.

Heparin-induced thrombocytopenia in a glioblastoma multiforme patient with inferior vena cava filter placement for deep venous thrombosis

A 58-year-old woman presented with right supplementary motor area glioblastoma multiforme and deep venous thrombosis in her legs. The tumor was resected after temporary inferior vena cava filter placement, considering that increased thrombosis during and after the operation would cause fatal pulmonary embolism. After anticoagulation with unfractionated heparin, thrombocytopenia was aggravated, and computed tomography showed filter catheter-related thrombosis in the inferior vena cava. The diagnosis was heparin-induced thrombocytopenia, and argatroban and urokinase were administered. Thrombolysis with urokinase was completed and the temporary inferior vena cava filter catheter was removed without complication. The present case illustrates the possibility of heparin-induced thrombocytopenia associated with catheter-related thrombosis in neurosurgery.

Risk assessment models for cancer-associated venous thromboembolism

Venous thromboembolism (VTE) is common in cancer patients, and is associated with significant morbidity and mortality. Several factors, including procoagulant agents secreted by tumor cells, immobilization, surgery, indwelling catheters, and systemic treatment (including chemotherapy), contribute to an increased risk of VTE in cancer patients. There is growing interest in instituting primary prophylaxis in high-risk patients to prevent incident (first-time) VTE events. The identification of patients at sufficiently high risk of VTE to warrant primary thromboprophylaxis is essential, as anticoagulation may be associated with a higher risk of bleeding. Current guidelines recommend the use of pharmacological thromboprophylaxis in postoperative and hospitalized cancer patients, as well as ambulatory cancer patients receiving thalidomide or lenalidomide in combination with high-dose dexamethasone or chemotherapy, in the absence of contraindications to anticoagulation. However, the majority of cancer patients are ambulatory, and currently primary thromboprophylaxis is not recommended for these patients, even those considered at very high risk. In this concise review, the authors discuss risk stratification models that have been specifically developed to identify cancer patients at high risk for VTE, and thus might be useful in future studies designed to determine the potential benefit of primary thromboprophylaxis.

Different characteristics and prognostic impact of deep-vein thrombosis / pulmonary embolism and intraabdominal venous thrombosis in colorectal cancer patients

This study was performed to determine the incidence, risk factors, and prognostic implications of venous thromboembolism (VTE) in Asian patients with colorectal cancer (CRC). Differences in clinical characteristics and prognostic impact between extremity venous thrombosis (or deep-vein thrombosis; DVT)/pulmonary embolism (PE) and intra-abdominal venous thrombosis (IVT) were also evaluated. For this study, consecutive CRC patients (N = 2,006) were enrolled and analyses were conducted retrospectively. VTEs were classified into two categories (DVT/PE and IVT). Significant predictors of developing VTEs were advanced stage and an increased number of co-morbidities. The two-year cumulative incidence of DVT/PE was 0.3%, 0.9% and 1.4% in stages 0~1, 2 and 3, respectively; this incidence range of DVT/PE in Asian patients with loco-regional CRC was lower than in Western patients. However, the two-year incidence (6.4%) of DVT/PE in Asian patients with distant metastases was not lower than in Western patients. Although 65.2% of patients with DVT/PE were symptomatic, only 15.7% of patients with IVT were symptomatic. During chemotherapy, DVT/PE developed more frequently than IVT. Only DVT/PE had a negative effect on survival; IVT had no prognostic significance. In conclusion, despite the low incidence of DVT/PE in Asian patients with loco-regional CRC, the protective effect of Asian ethnicity on VTE development disappears as tumour stage increases in patients with distant metastases. Considering different clinical characteristics and prognostic influences between DVT/PE and IVT, the treatment approach should be also different.

Epidemiology, risk and outcomes of venous thromboembolism in cancer

Cancer is associated with a fourfold increased risk of venous thromboembolism (VTE). The risk of VTE varies according to the type of malignancy (i. e. pancreatic cancer, brain cancer, lymphoma) and its disease stage and individual factors (i. e. sex, race, age, previous VTE history, immobilization, obesity). Preventing cancer-associated VTE is important because it represents a significant cause of morbidity and mortality. In order to identify cancer patient at particularly high risk, who need thromboprophylaxis, risk prediction models have become available and are under validation. These models include clinical risk factors, but also begin to incorporate biological markers. The major American and European scientific societies have issued their recommendations to guide the management of VTE in patients with cancer. In this review the principal aspects of epidemiology, risk factors and outcome of cancer-associated VTE are summarized.

Current concepts and management of glioblastoma

Glioblastoma is the most common malignant primary brain tumor in adults. Its often rapid clinical course, with many medical and psychosocial challenges, requires a multidisciplinary management. Modern multimodality treatment and care improve patients' life expectancy and quality of life. This review covers major aspects of care of glioblastoma patients with a focus on the management of common symptoms and complications. We aim to provide a guide for clinicians confronted with glioblastoma patients in their everyday practice.

Antiangiogenic therapy for patients with recurrent and newly diagnosed malignant gliomas

Malignant gliomas have a poor prognosis despite advances in diagnosis and therapy. Although postoperative temozolomide and radiotherapy improve overall survival in glioblastoma patients, most patients experience a recurrence. The prognosis of recurrent malignant gliomas is dismal, and more effective therapeutic strategies are clearly needed. Antiangiogenesis is currently considered an attractive targeting therapy for malignant gliomas due to its important role in tumor growth. Clinical trials using bevacizumab have been performed for recurrent glioblastoma, and these studies have shown promising response rates along with progression-free survival. Based on the encouraging results, bevacizumab was approved by the FDA for the treatment of recurrent glioblastoma. In addition, bevacizumab has shown to be effective for recurrent anaplastic gliomas. Large phase III studies are currently ongoing to demonstrate the efficacy and safety of the addition of bevacizumab to temozolomide and radiotherapy for newly diagnosed glioblastoma. In contrast, several other antiangiogenic drugs have also been used in clinical trials. However, previous studies have not shown whether antiangiogenesis improves the overall survival of malignant gliomas. Specific severe side effects, difficult assessment of response, and lack of rational predictive markers are challenging problems. Further studies are warranted to establish the optimized antiangiogenesis therapy for malignant gliomas.

Bevacizumab for the treatment of recurrent glioblastoma

Despite advances in upfront therapy, the prognosis in the great majority of patients with glioblastoma (GBM) is poor as almost all recur and result in disease-related death. Glioblastoma are highly vascularized cancers with elevated expression levels of vascular endothelial growth factor (VEGF), the dominant mediator of angiogenesis. A compelling biologic rationale, a need for improved therapy, and positive results from studies of bevacizumab in other cancers led to the evaluation of bevacizumab in the treatment of recurrent GBM. Bevacizumab, a humanized monoclonal antibody that targets VEGF, has been shown to improve patient outcomes in combination with chemotherapy (most commonly irinotecan) in recurrent GBM, and on the basis of positive results in two prospective phase 2 studies, bevacizumab was granted accelerated approval by the US Food and Drug Administration (FDA) as a single agent in recurrent GBM. Bevacizumab therapy is associated with manageable, class-specific toxicity as severe treatment-related adverse events are observed in only a minority of patients. With the goal of addressing questions and controversies regarding the optimal use of bevacizumab, the objective of this review is to provide a summary of the clinical efficacy and safety data of bevacizumab in patients with recurrent GBM, the practical issues surrounding the administration of bevacizumab, and ongoing investigations of bevacizumab in managing GBM.