Thromboembolism in brain tumors

Decoding the Nexus: Cellular and Molecular Mechanisms Linking Stroke and Neurotoxic Microenvironments in Brain Cancer Patients

Stroke is an often underrecognized albeit significant complication in patients with brain cancer, arising from the intricate interplay between cancer biology and cerebrovascular health. This review delves into the multifactorial pathophysiological framework linking brain cancer to elevated stroke risk, with particular emphasis on the crucial role of the neurotoxic microenvironment (NTME). The NTME, characterized by oxidative stress, neuroinflammation, and blood-brain barrier (BBB) disruption, creates a milieu that promotes and sustains vascular and neuronal injury. Key pathogenic factors driving brain cancer-related stroke include cancer-related hypercoagulability, inflammatory and immunological mechanisms, and other tumor-associated processes, including direct tumor compression, infection-related sequelae, and treatment-related complications. Recent advances in genomic and proteomic profiling present promising opportunities for personalized medicine, enabling the identification of biomarkers-such as oncogenes and tumor suppressor genes-that predict stroke susceptibility and inform individualized therapeutic strategies. Targeting the NTME through antioxidants to alleviate oxidative stress, anti-inflammatory agents to mitigate neuroinflammation, and therapies aimed at reinforcing the BBB could pave the way for more effective stroke prevention and management strategies. This integrative approach holds the potential to reduce both the incidence and severity of stroke, ultimately improving clinical outcomes and quality of life for brain cancer patients. Further research and well-designed clinical trials are essential to validate these strategies and integrate them into routine clinical practice, thereby redefining the management of stroke risk in brain cancer patients.

Venous Thromboembolism in Patients with Glioblastoma: Molecular Mechanisms and Clinical Implications

Patients with glioblastoma are among the cancer patients with the highest risk of developing venous thromboembolism (VTE). Long-term thromboprophylaxis is not generally prescribed because of the increased susceptibility of glioblastoma patients to intracranial hemorrhage. This review provides an overview of the current clinical standard for glioblastoma patients, as well as the molecular and genetic background which underlies the high incidence of VTE. The two main procoagulant proteins involved in glioblastoma-related VTE, podoplanin and tissue factor, are described, in addition to the genetic aberrations that can be linked to a hypercoagulable state in glioblastoma. Furthermore, possible novel biomarkers and future treatment strategies are discussed, along with the potential of sequencing approaches toward personalized risk prediction for VTE. A glioblastoma-specific VTE risk stratification model may help identifying those patients in which the increased risk of bleeding due to extended anticoagulation is outweighed by the decreased risk of VTE.

Incidence and determinants of thrombotic and bleeding complications in patients with glioblastoma

BACKGROUND

Glioblastoma patients are considered to be at high risk of venous thromboembolism (VTE) and major bleeding (MB), although reliable incidence estimates are lacking. Moreover, the risk of arterial thromboembolism (ATE) in these patients is largely unknown. Our aim was to assess the cumulative incidence, predictors, and prognostic impact of VTE, ATE, and MB on subsequent complications and mortality.

METHODS

Cohort study of 967 consecutive patients diagnosed with glioblastoma between 2004-2020 in two hospitals. Patients were followed from 6 months before date of histopathological glioblastoma diagnosis up to 2 years after, or until an outcome of interest (VTE, ATE, and MB) or death occurred, depending on the analysis. Cumulative incidences were estimated with death as competing risk. Cox regression was used to identify predictors and the prognostic impact.

RESULTS

A total of 101 patients were diagnosed with VTE, 50 with ATE, and 126 with MB during a median follow-up of 15 months (interquartile range 9.0-22). The adjusted 1-year cumulative incidence of VTE was 7.5% (95% confidence interval [CI] 5.9-9.3), of ATE 4.1% (95% CI 3.0-5.6), and of MB 12% (95% CI 9.6-14). Older age, type of surgery, and performance status were predictors of VTE. Incident VTE during follow-up was associated with MB (adjusted HR 4.7, 95% CI 2.5-9.0). MB and VTE were associated with mortality (adjusted HR 1.7, 95% CI 1.3-2.1 and 1.3, 95% CI 1.0-1.7, respectively).

CONCLUSION

We found considerable incidences of VTE and MB in glioblastoma patients, with both complications associated with poorer prognosis. Our observations emphasize the need for prospective studies to determine optimal thromboprophylaxis and VTE treatment strategy in these patients.

Venous Thromboembolism Risk and Thromboprophylaxis in Pediatric Neurosurgery and Spinal Injury: Current Trends and Literature Review

Although the entities of venous thromboembolism (VTE), deep venous thrombosis, pulmonary embolus, and thromboprophylaxis in adult patients undergoing brain tumor and spine surgery, traumatic brain injury and elective neurosurgical procedures are widely elucidated, the same is not valid when pediatric patients are under consideration. An attempt to review the peculiarities of these patients through a comprehensive bibliographic review is undertaken. We performed a narrative summary of the relevant literature dedicated to pediatric patients, centered on traumatic brain injury, the general incidence of thromboembolic disease in this patient population, the role of low molecular weight heparin (LMWH) in the treatment and prophylaxis of VTE, and its role in elective neurosurgical procedures, including spinal operations. Additionally, the risk of deep venous thrombosis in elective neurosurgical procedures is reviewed. Due to inherent limitations of the current studies, particularly a restricted number of patients, our data are underpowered to give a definitive protocol and guidelines for all the affected patients. Our current conclusions, based only on pediatric patients, argue that there is limited risk of VTE in pediatric patients suffering from brain tumors and that the possibility of VTE is very low in children undergoing elective neurosurgical procedures. There is no consensus regarding the exact incidence of VTE in traumatic brain injury patients. LMWH seems to be a safe and effective choice for the "at risk" pediatric patient population defined as being older than 15 years, venous catheterization, nonaccidental trauma, increased length of hospital stays, orthopaedic (including spinal) surgery, and cranial surgery.

IDH mutation status and the development of venous thromboembolism in astrocytoma patients

BACKGROUND

Venous thromboembolism (VTE) is a very common adverse event for astrocytoma patients, but validation of proposed risk biomarkers has been elusive. We examine whether the status of the isocitrate dehydrogenase (IDH) gene is a risk factor for the development of venous thromboembolism (VTE) in astrocytoma patients.

METHODS

We conducted a retrospective chart review of 282 astrocytoma patients enrolled in the PROACTIVE (Prospective Assessment of Correlative Biomarker) study at MD Anderson Cancer Center (MDACC) from 9/1/2000 until 12/31/2013.

RESULTS

We identified 282 astrocytoma patients consisting of 49 IDH mutant astrocytomas and 233 IDH wildtype astrocytomas. Glioblastoma was the initial histopathologic diagnosis in 30 (61.2%) of the IDH mutated astrocytomas compared to 227(97.4%) of the IDH wild type astrocytomas. VTE was identified in 52 (18.4%) of patients. VTE was diagnosed in 7 (14.3%) of the IDH mutated astrocytomas compared to 45(19.3%) of the IDH wild type astrocytoma s (p = 0.4094). Median time to VTE from diagnosis was 2.71 months. Median time to VTE from diagnosis was 2.6 months for IDH mutated astrocytomas compared to 3.06 months for the IDH wild type astrocytomas (p = 0.8663).

CONCLUSIONS

IDH gene status did not appear as a significant risk factor for the development of venous thromboembolism (VTE) in our cohort of astrocytoma patients. Further research into potential biomarkers for VTE may be warranted.

Plasma levels of extracellular vesicles and the risk of post-operative pulmonary embolism in patients with primary brain tumors: a prospective study

Primary brain tumors are associated with an increased risk of pulmonary embolism (PE), particularly in the early post-operative period. The pathophysiological mechanisms of PE are poorly understood. This study aims to describe prospectively extracellular vesicles (EVs) levels and investigate whether or not their variations allow to identify patients at increased risk of post-operative PE. Consecutive meningioma or glioma patients candidate to tumor resection were included in the study if a pulmonary perfusion scan (Q-scan) performed before surgery ruled out PE. EVs derived from platelets (CD41⁺) or endothelial cells (CD144⁺), tissue factor-bearing EVs (CD142⁺) and their procoagulant subtype (annexin V⁺) were analyzed by flow cytometry before surgery (T0), within 24 h (T1), two (T2) and seven days (T7) after surgery. Q-scan was repeated at T2. Ninety-three patients with meningioma, 59 with glioma and 76 healthy controls were included in the study. CD142⁺ and annexin V⁺/CD142⁺ EVs were increased at T0 in meningioma and glioma patients compared to healthy controls. Twenty-nine meningioma (32%) and 16 glioma patients (27%) developed PE at T2. EVs levels were similar in meningioma patients with or without PE, whereas annexin V⁺ and annexin V⁺/CD142⁺ EVs were significantly higher at T1 and T2 in glioma patients with PE than in those without. Procoagulant EVs, particularly annexin V⁺/CD142⁺, increase after surgery and are more prevalent in glioma patients who developed PE after surgery than in those who did not.

Venous thromboembolism in primary central nervous system lymphoma during frontline chemoimmunotherapy

BACKGROUND

In primary central nervous system lymphoma (PCNSL), venous thromboembolism (VTE) can cause significant morbidity and hinder chemotherapy delivery.

OBJECTIVES

To assess VTE incidence, timing and adequacy of inpatient and outpatient VTE prophylaxis in patients with PCNSL receiving chemoimmunotherapy with curative intent.

PATIENTS/METHODS

We reviewed patients diagnosed with PCNSL between 1997 and 2018 who received methotrexate, procarbazine, and vincristine ± Rituximab. Patient demographics, VTE prophylaxis and incidence, adverse events of anticoagulation, and survival outcomes were collected.

RESULTS

Fifty-one PCNSL patients were included (median 67 years [range, 32-87], 30 males [59%]). Thirteen patients (25%, 95% confidence interval [CI], 14-40) developed VTE at a median of 1.6 months from diagnosis (range, 0-4). Patients with Khorana Risk Score ≥2 were more likely to have VTE than those with a KRS < 2 (60% vs 15%; P = .01). Eighty-five percent had deviations from inpatient VTE prophylaxis guidelines, and outpatient prophylaxis was not routinely administered. Three patients required inferior vena cava filters. Hemorrhagic complications of anticoagulation included an intracranial hemorrhage from therapeutic anticoagulation and three cases of major bleeding from prophylactic anticoagulation. No patients died from VTE or its treatment.

CONCLUSIONS

Patients with newly diagnosed PCNSL are at high risk of VTE. Further research is required into optimal VTE prophylaxis in PCNSL.

Defects in Processes of Care for Pharmacologic Prophylaxis Are Common Among Neurosurgery Patients Who Develop In-Hospital Postoperative Venous Thromboembolism

BACKGROUND

Venous thromboembolism (VTE) is a cause of considerable morbidity and mortality in hospitalized patients. An evidence-based algorithm was developed and implemented at our institution to guide perioperative VTE prophylaxis management.

OBJECTIVE

We evaluated compliance with prescription of risk-appropriate VTE prophylaxis and administration of prescribed VTE prophylaxis in neurosurgery patients.

METHODS

This was a retrospective analysis of postoperative neurosurgery patients at a single institution with subsequent diagnosis of acute VTE during their inpatient stay. Descriptive statistics were used to characterize pharmacologic VTE prophylaxis and prescribing patterns.

RESULTS

The incidence of VTE in our neurosurgery population was 248/13,913 (1.8%). Of the 123 patients, the median time to VTE diagnosis was 96 hours after surgery (interquartile range [IQR], 58-188 hours). A total of 108 patients (87.8%) were prescribed risk-appropriate VTE prophylaxis, among whom 61 (56.5%) received all doses as prescribed. Fifty-three patients (43.1%) missed ≥1 dose of prescribed prophylaxis and the median missed doses was 3 (IQR, 0-3). The median time to first dose of pharmacologic VTE prophylaxis was 42 hours (IQR, 28-51). More than half (n = 63, 51.2%) of the VTE risk assessments contained ≥1 error, of which 15 (23.8%) would have resulted in a change in recommendation.

CONCLUSIONS

Our evidence-based VTE prophylaxis algorithm was not accurately completed in more than half of patients. Many patients who developed VTE had a defect in their VTE prophylaxis management during their inpatient stay. Research to improve optimal VTE prevention practice in neurosurgery patients is needed.

The intertwined fates of inflammation and coagulation in glioma

Inflammation and coagulation are two intertwined pathways with evolutionary ties being traced back to the hemocyte, a single cell type in invertebrates that has functions in both the inflammatory and coagulation pathways. These systems have functioned together throughout evolution to provide a solid defence against infection, damaged cells and irritants. While these systems work in harmony the majority of the time, they can also become dysregulated or corrupted by tumours, enhancing tumour proliferation, invasion, dissemination and survival. This review aims to give a brief overview of how these systems work in harmony and how dysregulation of these systems aids in the development and progression of cancer, using glioma as an example.

Platelet activation parameters and platelet-leucocyte-conjugate formation in glioblastoma multiforme patients

Patients with glioblastoma multiforme (GBM) suffer from an increased incidence of vascular thrombotic events. However, key influencing factors of the primary hemostasis have not been characterized in GBM patients to date. Thus, the present study determines the activation level of circulating platelets in GBM patients, in-vitro reactivity to agonist-induced platelet stimulation and the formation of circulating platelet-leucocyte conjugates as well as the plasma levels of the proinflammatory lipid mediator sphingosine-1-phosphate (S1P). The endogenous thrombin potential (ETP) was determined as global marker for hemostasis. The 21 GBM patients and 21 gender and age matched healthy individuals enrolled in this study did not differ in mean total platelet count. Basal surface expression of platelet CD63 determined by flow cytometry was significantly increased in GBM patients compared to controls as was observed for the concentration of soluble P-selectin in the plasma of GBM patients. While the ETP was not affected, the immunomodulatory lipid S1P was significantly decreased in peripheral blood in GBM. Interestingly, monocyte expression of PSGL-1 (CD162) was decreased in GBM patient blood, possibly explaining the rather decreased formation of platelet-monocyte conjugates. Our study reveals an increased CD63 expression and P-selectin expression/ secretion of circulating platelets in GBM patients. In parallel a down-modulated PSGL-1 expression in circulating monocytes and a trend towards a decreased formation of heterotypic platelet-monocyte conjugates in GBM patients was seen. Whether this and the observed decreased plasma level of the immunomodulatory S1P reflects a systemic anti-inflammatory status needs to be addressed in future studies.

Recommendations for the management of malignant gliomas in the elderly

According to epidemiological estimations, the elderly are going to constitute an increasing proportion of patients with gliomas in the near future. Predominantly glioblastoma histology with invariably fatal outcome, disabling comorbidities and presumed low tolerability of radiochemotherapeutic treatments are the main reasons why elderly patients have been under-represented in the majority of neuro-oncological clinical trials conducted so far. Some small retrospective studies have reported that patients with good performance status receiving surgery plus radiotherapy, and sometimes chemotherapy, may achieve a survival comparable with that of younger patients, however, in the absence of randomized studies, the balance of benefits and adverse effects of aggressive treatments remains controversial. Multidisciplinary evaluation of prognostic factors, such as performance status, cognitive functions, tumor operability and burden of comorbidities, appears to be mandatory in order to choose which patients must not be deprived of an integrated treatment with surgery, full-dose radiotherapy and chemotherapy, and which patients may reasonably be given a shorter radiotherapy plan, or even no treatment at all due to the rapidly fatal course of their disease. Peculiar features of malignant gliomas in the elderly and some practical recommendations of management will be presented and discussed in this review.

Current advances in understanding and managing secondary brain metastasis

Metastatic brain tumors are the number one cause of intracranial neoplasms in adults and are associated with higher morbidity and mortality. The frequency of metastatic brain tumors is increasing because of improved survival in cancer patients. The molecular mechanism of brain metastasis is complex and not completely known. Vasogenic edema produced by tumor-derived VEGF is responsible for clinical symptoms. Dexamethasone remains the mainstay of medical management with not completely known mechanisms of action. Surgery and radiation are the main treatment modalities for metastatic brain tumors. Systemic chemotherapy has a very limited role in treatment of these tumors. Leptomeningeal metastasis is associated with extremely poor outcome.

Microscopic thrombi in anaplastic astrocytoma predict worse survival?

The purpose of this study is to determine whether anaplastic astrocytoma patients with intratumoral vascular thrombi have a worse survival than anaplastic astrocytoma patients without thrombi. A retrospective review of 101 patients (60 males; mean age, 53.3 years) with anaplastic astrocytoma (World Health Organization grade III) was conducted. Thrombi were counted relative to the number of involved blood vessels in the initially resected tumor (69 biopsies, 32 subtotal resections) and were correlated with survival and development of postoperative deep venous thrombosis (DVT). Of tumors with thrombi (n = 17), the percentage of blood vessels with thrombi ranged from 1.5% to 20% (mean, 5.6%). Of these patients, 16 died of tumor (mean survival, 15.4 months), and 1 patient was alive with tumor at 180 months. Eighty-four patients with anaplastic astrocytoma had no intravascular tumor thrombi; 75 of these patients died of tumor (mean survival, 26.5 months), 4 patients were alive, and 5 patients were lost to follow-up. Evidence of DVT was found in 2 (18.2%) of 11 tested patients with thrombi vs 10 (18.5%) of 54 patients without thrombi. Patients with microscopic intratumoral thrombi (17% of anaplastic astrocytoma) had a worse survival compared with patients without thrombi; the difference did not reach statistical significance. There was no correlation between the presence of intratumoral thrombi and the development of DVT.

Medical management of patients with brain tumors

OPINION STATEMENT

Patients with brain tumors require meticulous attention to medical issues resulting from their disease or its therapy. The following specific issues are the ones most frequently arising in the purview of neurologists: (1) Vasogenic edema: Corticosteroids should be used in divided doses in the minimum amount required to control symptoms and should be tapered as quickly as possible. Some patients may require long-term steroid supplementation, and symptoms of adrenal insufficiency should be investigated with 8 AM: cortisol measurement and treated with appropriate repletion. (2) Seizures: Patients with brain tumors should receive antiepileptic drugs only if they have had seizures, and the drugs should be chosen to minimize cognitive effects and interactions with concurrently administered chemotherapy. Levetiracetam is an excellent choice for patients with partial seizures and is available both orally and parenterally. Lamotrigine is another reasonable choice but requires slow titration. (3) Venous thromboembolism: All brain tumor patients should receive perioperative venous thrombosis prophylaxis with compression boots and enoxaparin or dalteparin. Lifelong treatment with low molecular weight heparinoids or warfarin is required for those developing venous thromboembolism. (4) Other problems: Long-term survivors of brain tumors should be monitored indefinitely for cognitive problems, endocrine dysfunction, and development of secondary neoplasms. Modafinil can improve mood and attention impairments.

Prothrombotic state in glioblastoma multiforme: an evaluation of the procoagulant activity of circulating microparticles

The relationship between venous thromboembolism (VTE) and cancer is supported by several pathogenetic factors, including circulating microparticles (MP) originating from different cells and often bearing tissue factor. Since VTE often complicates the clinical course of patients with glioblastoma multiforme (GBM; WHO grade IV astrocytoma) and the role of MPs in these patients population is still not clear, this prospective study was conducted to evaluate the procoagulant activity of circulating MP (MP activity) in GBM patients. We enrolled 61 GBM patients undergoing gross-total or subtotal surgical resection followed by combined radio-chemotherapy; 20 healthy volunteers were tested as controls. Blood samples for MP activity and hemostatic profiles were obtained before and then 1 week and 1, 4, and 7 months after surgery. GBM patients had significantly higher mean MP activity levels than healthy controls before and 7 days after surgery. During the follow-up, MP activity levels became significantly lower 1 and 4 months after surgery (P = 0.007 and P = 0.018, respectively) than prior to surgery, but this decrease was only seen in the subgroup achieving complete tumor resection. MP activity levels increased in 7 (63.6%) of 11 patients who developed VTE. The different incidence of the increase in MP activity levels between patients with and without VTE was statistically significant (χ (2) = 4.93, P = 0.026; relative risk 1.38, 95% CI 1.03-1.86). GBM patients may have an increase in MP-associated procoagulant activity that could contribute to any prothrombotic states and increases the likelihood of VTE complications; this procoagulant activity drops during control of disease.

Venous thromboembolism in malignant gliomas

Malignant gliomas are associated with a very high risk of venous thromboembolism (VTE). While many clinical risk factors have previously been described in brain tumor patients, the risk of VTE associated with newer anti-angiogenic therapies such as bevacizumab in these patients remains unclear. When VTE occurs in this patient population, concern regarding the potential for intracranial hemorrhage complicates management decisions regarding anticoagulation, and these patients have a worse prognosis than their VTE-free counterparts. Risk stratification models identifying patients at high risk of developing VTE along with predictive plasma biomarkers may guide the selection of eligible patients for primary prevention with pharmacologic thromboprophylaxis. Recent studies exploring disordered coagulation, such as increased expression of tissue factor (TF), and tumorigenic molecular signaling may help to explain the increased risk of VTE in patients with malignant gliomas.

Microscopic thrombi in glioblastoma multiforme do not predict the development of deep venous thrombosis

Patients with glioblastoma multiforme (GBM) are known to be at risk for hypercoagulable events. Tumoral intravascular thrombi likely contribute to the development of hypoxia and necrosis. The purpose of this study was to assess whether there is a relationship between the number of thrombi identified microscopically at the time of tumor resection and the subsequent development of extremity deep venous thrombosis (DVT). A retrospective review of 96 patients (53 men and 43 women; age range, 21-92 years; mean age, 60.2 years) with GBM (World Health Organization grade IV) was carried out. Thrombi were counted (number of thrombi/blood vessels evaluated/10 high-power fields) in nonnecrotic areas of the resected tumor and correlated with a variety of clinical and pathological parameters, including the development of postoperative DVT, as detected by extremity ultrasound. Thrombi were identified in the resected GBM in 66 (69%) patients. Of the tumors with thrombi, the percentage of blood vessels with thrombi ranged from 1.1% to 42.9% (mean, 10.7%). Deep venous thrombosis was discovered in 30 (31.3%) patients. There was no correlation between the number of microscopic thrombi and the development of DVT. Eighty-one patients died of tumor (survival, 1-66 months; mean, 11.0 months), 12 patients were alive at last known follow-up (mean, 23 months), and 3 patients were lost to follow-up. Of patients with DVT, 27 patients died of tumor (survival, 1-47 months; mean, 11.0 months), 3 patients were alive (18, 20, and 21 months), and 1 patient was lost to follow-up. There was no correlation between the number of microscopic thrombi and the percentage of resected tumor that was necrotic (range, <5%-90%), presence of palisaded necrosis (36.8% of tumors), presurgical (mean, 78.3) or postsurgical (mean, 75.5) Karnofsky performance scores, or survival (mean, 8.9 months in patients with no microscopic thrombi vs 11.5 months in patients with thrombi). Microscopic thrombi were identified in about two thirds (69%) of patients with GBM, and DVT developed in about one third (31.3%) of patients with GBM. There was no correlation between the number of microscopic thrombi and the subsequent development of DVT in patients with GBM. Patients who developed DVT did not appear to have a worse survival.

Intravascular thrombosis in central nervous system malignancies: a potential role in astrocytoma progression to glioblastoma

The presence of necrosis within a diffuse glioma is a powerful predictor of poor prognosis, yet little is known of its origins. Intravascular thrombosis is a frequent finding in glioblastoma [GBM; World Health Organization (WHO) grade IV] specimens and could potentially be involved in astrocytoma progression to GBM or represent a surrogate marker of GBM histology. We investigated whether intravascular thrombosis was more frequent or prominent in GBM than other central nervous system (CNS) malignancies and considered its prognostic significance in anaplastic astrocytoma (AA; WHO grade III), which lacks necrosis. Histologic sections were examined for thrombosis, necrosis and microvascular hyperplasia from each of 297 CNS tumors, including 103 GBMs, 46 AAs, 20 diffuse astrocytoma (DAs; WHO grade II), eight anaplastic oligodendrogliomas (AOs; WHO grade III), 20 oligodendrogliomas (ODs; WHO grade II), 49 metastatic carcinomas (METs), 31 primary central nervous system lymphomas (PCNSLs) and 20 medulloblastomas (MBs). Among newly diagnosed tumors, thrombosis was present in 92% of GBM resections, significantly greater than other types of CNS malignancies. Of tumors with thrombosis, GBMs had a higher frequency of affected vessels than AAs, DAs, AOs, ODs and MBs, but had a frequency similar to METs and PCNSLs. The sensitivity of thrombosis for the diagnosis of GBM in this set of tumors was 92% and the specificity was 91%. Intravascular thrombosis was uncommon in AAs and was only noted in stereotactic biopsies. This subset of patients had shorter survivals than those AAs without thrombosis. Thus, intravascular thrombosis is more frequent in GBM than other CNS malignancies. When present in AAs, it appears to indicate aggressive clinical behavior.

Medical management of brain tumor patients

Brain tumors can present challenging medical problems. Seizures, peritumoral edema, venous thromboembolism, fatigue, and cognitive dysfunction can complicate the treatment of patients who have primary or metastatic brain tumors. Effective medical management results in decreased morbidity and mortality and improved quality of life for affected patients.

Supportive management of patients with brain tumors

Management issues for patients with brain tumors include peritumoral edema, symptomatic seizures, venous thromboembolism, headache, pain, fatigue and neuropsychological complaints. Vasogenic edema is typically ameliorated with the lowest dose possible of corticosteroid. Seizures are managed with attention to additional or complicated side effects of antiepileptic drugs and their interactions with chemotherapy, and primary prevention with antiepileptic medications is not recommended. Appropriate treatments for headache, pain, fatigue and neuropsychological complaints are important, but are not yet well standardized. Above all, patients' personal goals regarding their priorities at the end of life have the most importance.

Vascular endothelial growth factor in astroglioma stem cell biology and response to therapy

Malignant astrogliomas are among the most aggressive, highly vascular and infiltrating tumours bearing a dismal prognosis, mainly due to their resistance to current radiation treatment and chemotherapy. Efforts to identify and target the mechanisms that underlie astroglioma resistance have recently focused on candidate cancer stem cells, their biological properties, interplay with their local microenvironment or 'niche', and their role in tumour progression and recurrence. Both paracrine and autocrine regulation of astroglioma cell behaviour by locally produced cytokines such as the vascular endothelial growth factor (VEGF) are emerging as key factors that determine astroglioma cell fate. Here, we review these recent rapid advances in astroglioma research, with emphasis on the significance of VEGF in astroglioma stem-like cell biology. Furthermore, we highlight the unique DNA damage checkpoint properties of the CD133-marker-positive astroglioma stem-like cells, discuss their potential involvement in astroglioma radioresistance, and consider the implications of this new knowledge for designing combinatorial, more efficient therapeutic strategies.

Common critical pathways in embryogenesis and cancer

Cancer may arise because the developmental programs that create the dramatic alterations in form and structure in embryonic development are potentially corrupted. The cells in our bodies retain memories of these processes and cancer can occur later in life if imperfections occur in the fidelity of these pathways. This article is particularly interested in the phenomenon of epithelial to mesenchymal transition, which occurs in embryogenesis. Also reviewed are the small molecules and pathways that are involved both in homeostasis in adult epithelium and embryogenesis in utero. There are five such pathways in particular selected for review in this article: the Wnt pathway, Hedgehog, Notch, PAR and Bone morphogenetic peptide/TGF beta. These are usually conserved throughout mammalian evolution. Though they have been arbitrarily separated in this article they are not exclusive from one another. Their pathologically altered expression is found especially frequently in childhood tumours where they may recapitulate their developmental role, and in tumours that resemble primitive precursor cells. These pathways are important for selecting cell fates, cellular rearrangements, cytological context and morphologic design in embryology as well as participating in epithelial function in adults.

Therapeutic advances in the treatment of glioblastoma: rationale and potential role of targeted agents

Despite advances in standard therapy, including surgical resection followed by radiation and chemotherapy, the prognosis for patients with glioblastoma multiforme (GBM) remains poor. Unfortunately, most patients die within 2 years of diagnosis of their disease. Molecular abnormalities vary among individual patients and also within each tumor. Indeed, one of the distinguishing features of GBM is its marked genetic heterogeneity. Nonetheless, recent developments in the field of tumor biology have elucidated signaling pathways and genes involved in the development of GBM, and several novel agents that target these signaling pathways are being developed. As new details on the genetic characteristics of this disease become available, innovative treatment regimens, including a variety of traditional treatment modalities such as surgery, radiation, and cytotoxic chemotherapy, will be combined with newer targeted therapies. This review introduces these new targeted therapies in the context of current treatment options for patients with GBM. It is hoped that this combined approach will overcome the current limitations in the treatment of patients with GBM and result in a better prognosis for these patients.

Medical management of patients with brain tumors

The most common medical problems in brain tumor patients include the management of seizures, peritumoral edema, medication side effects, venous thromboembolism (VTE), fatigue and cognitive dysfunction. Despite their importance, there are relatively few studies specifically addressing these issues. There is increasing evidence that brain tumor patients who have not had a seizure do not benefit from prophylactic antiepileptic medications. Patients on corticosteroids are at greater risk of Pneumocystis jerovecii pneumonia and may benefit from prophylactic therapy. There is also growing evidence suggesting that anticoagulation may be more effective than inferior vena cava IVC) filtration devices for treating VTE in brain tumor patients and the risk of hemorrhage with anticoagulation is relatively small. Low-molecular weight heparin may be more effective than coumadin. Medications such as modafinil and methylphenidate have assumed an increasing role in the treatment of fatigue, while donepezil and memantine may be helpful with memory loss.

‘Pseudopalisading’ Necrosis in Glioblastoma: A Familiar Morphologic Feature That Links Vascular Pathology, Hypoxia, and Angiogenesis

Glioblastoma (GBM) is a highly malignant, rapidly progressive astrocytoma that is distinguished pathologically from lower grade tumors by necrosis and microvascular hyperplasia. Necrotic foci are typically surrounded by "pseudopalisading" cells-a configuration that is relatively unique to malignant gliomas and has long been recognized as an ominous prognostic feature. Precise mechanisms that relate morphology to biologic behavior have not been described. Recent investigations have demonstrated that pseudopalisades are severely hypoxic, overexpress hypoxia-inducible factor (HIF-1), and secrete proangiogenic factors such as VEGF and IL-8. Thus, the microvascular hyperplasia in GBM that provides a new vasculature and promotes peripheral tumor expansion is tightly linked with the emergence of pseudopalisades. Both pathologic observations and experimental evidence have indicated that the development of hypoxia and necrosis within astrocytomas could arise secondary to vaso-occlusion and intravascular thrombosis. This emerging model suggests that pseudopalisades represent a wave of tumor cells actively migrating away from central hypoxia that arises after a vascular insult. Experimental glioma models have shown that endothelial apoptosis, perhaps resulting from angiopoetin-2, initiates vascular pathology, whereas observations in human tumors have clearly demonstrated that intravascular thrombosis develops with high frequency in the transition to GBM. Tissue factor, the main cellular initiator of thrombosis, is dramatically upregulated in response to PTEN loss and hypoxia in human GBM and could promote a prothrombotic environment that precipitates these events. A prothrombotic environment also activates the family of protease activated receptors (PARs) on tumor cells, which are G-protein-coupled and enhance invasive and proangiogenic properties. Vaso-occlusive and prothrombotic mechanisms in GBM could readily explain the presence of pseudopalisading necrosis in tissue sections, the rapid peripheral expansion on neuroimaging, and the dramatic shift to an accelerated rate of clinical progression resulting from hypoxia-induced angiogenesis.

Management of venous thromboembolism in patients with primary and metastatic brain tumors

Venous thromboembolism occurs commonly throughout the clinical course of patients with brain tumors. A number of hemostatic and clinical factors contribute to this hypercoagulable state. Concern over the possibility of intracranial bleeding has limited the use of anticoagulation in this population. However, mechanical approaches such as vena cava filters have high complication and treatment failure rates in patients with intracranial malignancies. In addition, the available data suggest that anticoagulation can be used safely and effectively in most of these patients. Patients with thrombocytopenia, recent neurosurgery, and tumor types prone to bleeding require special consideration. When intracranial hemorrhage does occur, it is often due to overanticoagulation, requiring prompt anticoagulation reversal and neurosurgical consultation.

Thromboprophylaxie en neurochirurgie et en neurotraumatologie intracrânienne

The incidence of deep vein thrombosis (DVT) is between 20 and 35% using contrast venography, with a rate of symptomatic DVT between 2.3 and 6% in neurosurgery without any prophylaxis. The risk of DVT is poorly evaluated in head injured patients but is around 5%. Specific risk factors in neurosurgery are: a motor deficit, a meningioma or malignant tumour, a large tumour, age over 60 years, surgery lasting more than 4 hours, a chemotherapy. The benefit of mechanical methods or low molecular weight heparin (LMWH) for the prevention of DVP in neurosurgery is demonstrated (grade A). Each method decreases the risk by about 50%. A postoperative prophylaxis with a LMWH does not seem to increase the risk of intracranial bleeding (grade C). There is no demonstrated benefit to begin a prophylaxis with LMWH before the intervention. The duration of the prophylaxis is 7 to 10 days but this has not been scientifically determined.

Treatment of medical complications in patients with brain tumors

Patients with primary brain tumors and those with cerebral metastases are at risk throughout their illness for several major medical problems, including vasogenic edema, seizures, and symptomatic venous thrombosis. In turn, the corticosteroids, anti-epileptic drugs, and anticoagulants used to treat these problems may produce significant adverse effects and result in important drug-drug interactions that may complicate chemotherapy. Although few Class I studies address any of these issues, guidelines can be offered to maximize quality of life and minimize hospital readmissions. Optimal management of brain edema involves minimizing corticosteroid use and tapering the steroid dose slowly to avoid steroid withdrawal symptoms. Prophylaxis of Pneumocystis pneumonia is necessary for patients requiring corticosteroids for more than 1 month. Anti-epileptic drugs (AEDs) should be avoided unless patients experience seizures. If possible, non-CTY (P450) enzyme-inducing drugs should be chosen. AED levels should be obtained frequently during corticosteroid taper. Multimodality venous thrombosis prophylaxis should begin at the time of the original surgery with external leg compression and unfractionated subcutaneous heparin or a low molecular weight heparin (LMWH). Brain tumor patients with symptomatic venous thrombosis or pulmonary embolism can be anticoagulated safely with warfarin or with LMWH, and LMWHs are preferable from the standpoints of efficacy, safety, and convenience for long-term outpatient treatment of venous thrombosis. Clinicians should be aware of potential drug-drug interactions between prescribed AEDs and chemotherapy and possible interactions with complementary and alternative therapies chosen by their patients. They also should be aware of interventions to minimize late sequelae of brain tumors and their treatment, including cognitive decline, depression, and increased stroke risk.

Prophylaxis for Deep Venous Thrombosis in Craniotomy Patients: A Decision Analysis

OBJECTIVE:

We sought to determine the most efficient perioperative prophylactic strategy for deep venous thrombosis (DVT) in craniotomy patients by use of a decision analysis model.

METHODS:

We conducted a structured review of the relevant literature and compiled the reported incidences of DVT, pulmonary embolism, and postoperative intracranial hemorrhage (ICH) in craniotomy patients. We also obtained from the literature estimates of the likelihood and the impact of various outcomes of these complications. Data from 810 craniotomies performed at our own institution were also examined. The decision analytic model was then used to compare the effectiveness of pneumatic compression boots with pneumatic compression boots combined with either unfractionated or low-molecular-weight heparin. The model dealt with variability by using both sensitivity analysis and Monte Carlo simulation.

RESULTS:

As expected, the addition of heparin lowered the incidence of both DVT and pulmonary embolism, but at the cost of increasing ICH. Because the deleterious effects of ICH were so much greater than the benefits from heparinization, overall outcomes were best with mechanical prophylaxis alone. This was especially true for low-molecular-weight heparin, which is associated with a relatively high risk of ICH. Our own institutional data support the findings in the literature. Although the differences are modest, they reach statistical significance in the case of low-molecular-weight heparin.

CONCLUSION:

Using decision analytic modeling, we have shown that mechanical prophylaxis yields outcomes in craniotomy patients superior to those of either unfractionated or low-molecular-weight heparin.

PTEN and hypoxia regulate tissue factor expression and plasma coagulation by glioblastoma

We have previously proposed that intravascular thrombosis and subsequent vasoocclusion contribute to the development of pseudopalisading necrosis, a pathologic hallmark that distinguishes glioblastoma (WHO grade 4) from lower grade astrocytomas. To better understand the potential prothrombotic mechanisms underlying the formation of these structures that drive tumor angiogenesis, we investigated tissue factor (TF), a potent procoagulant protein known to be overexpressed in astrocytomas. We hypothesized that PTEN loss and tumor hypoxia, which characterize glioblastoma but not lower grade astrocytomas, could up-regulate TF expression and cause intravascular thrombotic occlusion. We examined the effect of PTEN restoration and hypoxia on TF expression and plasma coagulation using a human glioma cell line containing an inducible wt-PTEN cDNA. Cell exposure to hypoxia (1% O(2)) markedly increased TF expression, whereas restoration of wt-PTEN caused decreased cellular TF. The latter effect was at least partially dependent on PTEN's protein phosphatase activity. Hypoxic cells accelerated plasma clotting in tilt tube assays and this effect was prevented by both inhibitory antibodies to TF and plasma lacking factor VII, implicating TF-dependent mechanisms. To further examine the genetic events leading to TF up-regulation during progression of astrocytomas, we investigated its expression in a series of human astrocytes sequentially infected with E6/E7/human telomerase, Ras, and Akt. Cells transformed with Akt showed the greatest incremental increase in hypoxia-induced TF expression and secretion. Together, our results show that PTEN loss and hypoxia up-regulate TF expression and promote plasma clotting by glioma cells, suggesting that these mechanisms may underlie intravascular thrombosis and pseudopalisading necrosis in glioblastoma.

The management of thromboembolic disease in patients with central nervous system malignancies

Venous thromboembolic disease (VTE) is a common complication of malignancies affecting the central nervous system (CNS), both in the perioperative period and throughout the disease course. Until recently, the perceived risk of intracranial hemorrhage in patients with CNS malignancies was felt to be a relative contraindication to systemic anticoagulation, and most patients were managed with nonpharmacologic methods in both the prophylactic and treatment setting. However, several studies of the safety and efficacy of anticoagulation in both neurosurgical and cancer patients have challenged the previous dogma, and routine use of unfractionated heparin or low molecular weight heparin (LMWH) for VTE prophylaxis in patients undergoing craniotomy for CNS malignancy is recommended. Likewise, treatment of established VTE in this population with heparins is recommended, at least initially, followed by long-term treatment either with heparin or oral warfarin. Complications of inferior vena cava (IVC) filters, used as an alternative to systemic anticoagulation, appear to be more common in brain tumor patients with VTE, lending further support to treatment with systemic anticoagulation when possible. 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, LMWH is recommended in brain tumor patients with newly diagnosed VTE, followed by long-term warfarin or LMWH.

Current management of glioblastoma multiforme

Glioblastoma multiforme is the most common primary brain tumor in adults. Despite major research efforts and progress in neuroimaging, neurosurgery, and radiation and medical oncology, the overall survival of patients with this disease has changed little over the past 30 years. Surgery and radiation therapy remain critical components in the care of patients with glioblastoma multiforme. Treatment with chemotherapy has been hampered by the apparent resistance of these tumor cells to available agents and challenges in delivering agents to the tumor cells. The blood-brain barrier can restrict entry of some agents and the effect of antiepileptic drugs inducing hepatic P450 can significantly affect the pharmacology of a wide range of antineoplastic agents. As a result, new agents and novel approaches are required. Translational research efforts should: (1) pursue a broad research agenda until productive avenues are identified; (2) quantify the delivery of novel agents to the malignant brain tumor cells; (3) determine the maximum tolerated dose (MTD) and preliminary efficacy data on novel agents before initiating combination therapies; (4) optimize trial designs; and (5) improve psychosocial and supportive care for patients with this devastating illness.

Risk of venous thromboembolism in pediatric patients with brain tumors

BACKGROUND

Venous thromboembolism (VTE) is a common event in adults with malignant brain tumors approaching 24% throughout the course of the disease. The high morbidity and mortality of this complication yielded several protocols for prevention of the disease in adults undergoing neurosurgery for brain tumors and possible primary prevention afterwards. We investigated the incidence and complications of VTE in pediatric neuro-oncology patients.

PROCEDURE

We analyzed, retrospectively, the files of all consecutive patients under the age of 18 years who were hospitalized for the treatment of brain tumors between the years 1990 and 2003 in two leading, closely related, Israeli neuro-oncology centers.

RESULTS

A total of 462 children were analyzed. Three hundred eighty-four patients underwent surgery and 78 were treated medically. Only three (0.64%) of the patients developed clinical episodes of VTE that were treated conservatively. Two of these patients developed intracranial bleeding while on secondary prevention for the disease.

CONCLUSIONS

Although this study has considerable limitations in terms of retrospective design, heterogeneous group of patients and diagnoses, the changing awareness for thrombosis over the last 14 years and the inclusion of symptomatic VTE events only, our surprising data suggest that, as opposed to adults, the risk of clinically significant VTE in children with brain tumors may be exceedingly low. These findings set the stage for future forthcoming evaluations in view of the prospective studies that were done in adults and the possible significant implications for the prevention and possible etiologies of the disease.

Prevention of venous thromboembolism: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy

This article discusses the prevention of venous thromboembolism (VTE) and is part of the Seventh American College of Chest Physicians Conference on Antithrombotic and Thrombolytic Therapy: Evidence-Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs. Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading see Guyatt et al, CHEST 2004; 126:179S-187S). Among the key recommendations in this chapter are the following. We recommend against the use of aspirin alone as thromboprophylaxis for any patient group (Grade 1A). For moderate-risk general surgery patients, we recommend prophylaxis with low-dose unfractionated heparin (LDUH) (5,000 U bid) or low-molecular-weight heparin (LMWH) [< or = 3,400 U once daily] (both Grade 1A). For higher risk general surgery patients, we recommend thromboprophylaxis with LDUH (5,000 U tid) or LMWH (> 3,400 U daily) [both Grade 1A]. For high-risk general surgery patients with multiple risk factors, we recommend combining pharmacologic methods (LDUH three times daily or LMWH, > 3,400 U daily) with the use of graduated compression stockings and/or intermittent pneumatic compression devices (Grade 1C+). We recommend that thromboprophylaxis be used in all patients undergoing major gynecologic surgery (Grade 1A) or major, open urologic procedures, and we recommend prophylaxis with LDUH two times or three times daily (Grade 1A). For patients undergoing elective total hip or knee arthroplasty, we recommend one of the following three anticoagulant agents: LMWH, fondaparinux, or adjusted-dose vitamin K antagonist (VKA) [international normalized ratio (INR) target, 2.5; range, 2.0 to 3.0] (all Grade 1A). For patients undergoing hip fracture surgery (HFS), we recommend the routine use of fondaparinux (Grade 1A), LMWH (Grade 1C+), VKA (target INR, 2.5; range, 2.0 to 3.0) [Grade 2B], or LDUH (Grade 1B). We recommend that patients undergoing hip or knee arthroplasty, or HFS receive thromboprophylaxis for at least 10 days (Grade 1A). We recommend that all trauma patients with at least one risk factor for VTE receive thromboprophylaxis (Grade 1A). In acutely ill medical patients who have been admitted to the hospital with congestive heart failure or severe respiratory disease, or who are confined to bed and have one or more additional risk factors, we recommend prophylaxis with LDUH (Grade 1A) or LMWH (Grade 1A). We recommend, on admission to the intensive care unit, all patients be assessed for their risk of VTE. Accordingly, most patients should receive thromboprophylaxis (Grade 1A).

Prophylaxis for deep venous thrombosis in patients with craniotomies: a review

Deep venous thrombosis (DVT) remains a source of significant morbidity and mortality in patients who undergo craniotomy procedures. Despite several studies in which the safety and efficacy of various prophylactic strategies were examined, there is still no consensus among clinicians. In this paper the authors review the literature with regard to epidemiological and pathophysiological features, screening methods, and prophylactic measures for DVT.