Survival of patients with well-differentiated astrocytomas diagnosed in the era of computed tomography

The role of extent of resection on the prognosis of low-grade astrocytoma: a systematic review and meta-analysis

Purpose

To investigate the predictor factors of mortality describing the prognosis of primary surgical resection of low-grade astrocytoma.

Materials and methods

A systemic search was conducted from electronic databases (PubMed/Medline, Cochrane Library, and Google Scholar) from inception to November 14, 2021. All statistical analysis was conducted in Review Manager 5.4.1. Studies meeting inclusion criteria were selected. A random-effect model was used when heterogeneity was seen to pool the studies, and the result were reported in the hazards ratio (HR) and corresponding 95% confidence interval.

Result

Five cohort studies were selected for meta-analysis. There was statistically significant effect of total resection on increase mortality after surgery in low-grade astrocytoma patients (HR = 0.70 [0.52, 0.94]; p = 0.02; I2 = Not applicable). On the other hand, there was statistically nonsignificant effect of patient’s age (HR = 1.27 [0.95, 1.68]; p = 0.11; I2 = 83%), tumor size (HR = 1.13 [0.94, 1.35]; p = 0.19; I2 = 73%), and increasing KPS (HR = 0.59 [0.20, 1.77]; p = 0.35; I2 = 86%) on prognosis of low-grade astrocytoma after surgery.

Conclusion

The results of meta-analysis showed significant relationship of extent of resection and mortality, while factors such age, KPS score, and tumor size were nonsignificant to determine mortality in patient diagnosed with low-grade astrocytoma. The gross total resection surgery should be preferred over subtotal resection since the incidence of malignant formation is low in gross total resection.

Pediatric Low-Grade Gliomas

Brain tumors constitute the largest source of oncologic mortality in children and low-grade gliomas are among most common pediatric central nervous system tumors. Pediatric low-grade gliomas differ from their counterparts in the adult population in their histopathology, genetics, and standard of care. Over the past decade, an increasingly detailed understanding of the molecular and genetic characteristics of pediatric brain tumors led to tailored therapy directed by integrated phenotypic and genotypic parameters and the availability of an increasing array of molecular-directed therapies. Advances in neuroimaging, conformal radiation therapy, and conventional chemotherapy further improved treatment outcomes. This article reviews the current classification of pediatric low-grade gliomas, their histopathologic and radiographic features, state-of-the-art surgical and adjuvant therapies, and emerging therapies currently under study in clinical trials.

The fence post depth electrode technique to control both brain tumors and epileptic seizures in patients with brain tumor-related epilepsy

Background:

To control brain tumor-related epilepsy (BTRE), both epileptological and neuro-oncological approaches are required. We hypothesized that using depth electrodes (DEs) as fence post catheters, we could detect the area of epileptic seizure onset and achieve both brain tumor removal and epileptic seizure control.

Methods:

Between August 2009 and April 2018, we performed brain tumor removal for 27 patients with BTRE. Patients who underwent lesionectomy without DEs were classified into Group 1 (13 patients) and patients who underwent the fence post DE technique were classified into Group 2 (14 patients).

Results:

The patients were 15 women and 12 men (mean age, 28.1 years; median age 21 years; range, 5–68 years). The brain tumor was resected to a greater extent in Group 2 than Group 1 (P < 0.001). Shallower contacts showed more epileptogenicity than deeper contacts (P < 0.001). Group 2 showed better epilepsy surgical outcomes than Group 1 (P = 0.041).

Conclusion:

Using DEs as fence post catheters, we detected the area of epileptic seizure onset and controlled epileptic seizures. Simultaneously, we removed the brain tumor to a greater extent with fence post DEs than without.

Evaluation of Mobile Phone and Cordless Phone Use and Glioma Risk Using the Bradford Hill Viewpoints from 1965 on Association or Causation

Objective. Bradford Hill's viewpoints from 1965 on association or causation were used on glioma risk and use of mobile or cordless phones. Methods. All nine viewpoints were evaluated based on epidemiology and laboratory studies. Results. Strength: meta-analysis of case-control studies gave odds ratio (OR) = 1.90, 95% confidence interval (CI) = 1.31-2.76 with highest cumulative exposure. Consistency: the risk increased with latency, meta-analysis gave in the 10+ years' latency group OR = 1.62, 95% CI = 1.20-2.19. Specificity: increased risk for glioma was in the temporal lobe. Using meningioma cases as comparison group still increased the risk. Temporality: highest risk was in the 20+ years' latency group, OR = 2.01, 95% CI =1.41-2.88, for wireless phones. Biological gradient: cumulative use of wireless phones increased the risk. Plausibility: animal studies showed an increased incidence of glioma and malignant schwannoma in rats exposed to radiofrequency (RF) radiation. There is increased production of reactive oxygen species (ROS) from RF radiation. Coherence: there is a change in the natural history of glioma and increasing incidence. Experiment: antioxidants reduced ROS production from RF radiation. Analogy: there is an increased risk in subjects exposed to extremely low-frequency electromagnetic fields. Conclusion. RF radiation should be regarded as a human carcinogen causing glioma.

World Health Organization grade II-III astrocytomas consist of genetically distinct tumor lineages

Recent investigations revealed genetic analysis provides important information in management of gliomas, and we previously reported grade II-III gliomas could be classified into clinically relevant subgroups based on the DNA copy number aberrations (CNAs). To develop more precise genetic subgrouping, we investigated the correlation between CNAs and mutational status of the gene encoding isocitrate dehydrogenase (IDH) of those tumors. We analyzed the IDH status and CNAs of 174 adult supratentorial gliomas of astrocytic or oligodendroglial origin by PCR-based direct sequencing and comparative genomic hybridization, respectively. We analyzed the relationship between genetic subclassification and clinical features. We found the most frequent aberrations in IDH mutant tumors were the combined whole arm-loss of 1p and 19q (1p/19q codeletion) followed by gain on chromosome arm 7q (+7q). The gain of whole chromosome 7 (+7) and loss of 10q (-10q) were detected in IDH wild-type tumors. Kaplan-Meier estimates for progression-free survival showed that the tumors with mutant IDH, -1p/19q, or +7q (in the absence of +7p) survived longer than tumors with wild-type IDH, +7, or -10q. As tumors with +7 (IDH wild-type) showed a more aggressive clinical nature, they are probably not a subtype that developed from the slowly progressive tumors with +7q (IDH mutant). Thus, tumors with a gain on chromosome 7 (mostly astrocytic) comprise multiple lineages, and such differences in their biological nature should be taken into consideration during their clinical management.

Perillyl alcohol: Dynamic interactions with the lipid bilayer and implications for long-term inhalational chemotherapy for gliomas

Background:

Gliomas display a high degree of intratumor heterogeneity, including changes in physiological parameters and lipid composition of the plasma membrane, which may contribute to the development of drug resistance. Biophysical interactions between therapeutic agents and the lipid components at the outer plasma membrane interface are critical for effective drug uptake. Amphipathic molecules such as perillyl alcohol (POH) have a high partition coefficient and generally lead to altered lipid acyl tail dynamics near the lipid-water interface, impacting the lipid bilayer structure and transport dynamics. We therefore hypothesized that glioma cells may display enhanced sensitivity to POH-induced apoptosis due to plasma membrane alterations, while in non-transformed cells, POH may be expelled through thermal agitation.

Methods:

Interactions between POH and the plasma membrane was studied using molecular dynamics simulations. In this phase I/II trial, we set up to evaluate the clinical effectiveness of long-term (up to 5 years) daily intranasal administration of POH in a cohort of 19 patients with low-grade glioma (LGG). Importantly, in a series of clinical studies previously published by our group, we have successfully established that intranasal delivery of POH to patients with malignant gliomas is a viable and effective therapeutic strategy.

Results:

POH altered the plasma membrane potential of the lipid bilayer of gliomas and prolonged intranasal administration of POH in a cohort of patients with LGG halted disease progression with virtually no toxicity.

Conclusion:

Altogether, the results suggest that POH-induced alterations of the plasma membrane might be contributing to its therapeutic efficacy in preventing LGG progression.

Stereotactic interstitial brachytherapy for the treatment of oligodendroglial brain tumors

PURPOSE

We evaluated the treatment of oligodendroglial brain tumors with interstitial brachytherapy (IBT) using (125)iodine seeds ((125)I) and analyzed prognostic factors.

PATIENTS AND METHODS

Between January 1991 and December 2010, 63 patients (median age 43.3 years, range 20.8-63.4 years) suffering from oligodendroglial brain tumors were treated with (125)I IBT either as primary, adjuvantly after incomplete resection, or as salvage therapy after tumor recurrence. Possible prognostic factors influencing disease progression and survival were retrospectively investigated.

RESULTS

The actuarial 2-, 5-, and 10-year overall and progression-free survival rates after IBT for WHO II tumors were 96.9, 96.9, 89.8 % and 96.9, 93.8, 47.3 %; for WHO III tumors 90.3, 77, 54.9 % and 80.6, 58.4, 45.9 %, respectively. Magnetic resonance imaging demonstrated complete remission in 2 patients, partial remission in 13 patients, stable disease in 17 patients and tumor progression in 31 patients. Median time to progression for WHO II tumors was 87.6 months and for WHO III tumors 27.8 months. Neurological status improved in 10 patients and remained stable in 20 patients, while 9 patients deteriorated. There was no treatment-related mortality. Treatment-related morbidity was transient in 11 patients. WHO II, KPS ≥ 90 %, frontal location, and tumor surface dose > 50 Gy were associated with increased overall survival (p ≤ 0.05). Oligodendroglioma and frontal location were associated with a prolonged progression-free survival (p ≤ 0.05).

CONCLUSION

Our study indicates that IBT achieves local control rates comparable to surgery and radio-/chemotherapy treatment, is minimally invasive, and safe. Due to the low rate of side effects, IBT may represent an attractive option as part of a multimodal treatment schedule, being supplementary to microsurgery or as a salvage therapy after chemotherapy and conventional irradiation.

Increasing rates of brain tumours in the Swedish national inpatient register and the causes of death register

Radiofrequency emissions in the frequency range 30 kHz-300 GHz were evaluated to be Group 2B, i.e., "possibly", carcinogenic to humans by the International Agency for Research on Cancer (IARC) at WHO in May 2011. The Swedish Cancer Register has not shown increasing incidence of brain tumours in recent years and has been used to dismiss epidemiological evidence on a risk. In this study we used the Swedish National Inpatient Register (IPR) and Causes of Death Register (CDR) to further study the incidence comparing with the Cancer Register data for the time period 1998-2013 using joinpoint regression analysis. In the IPR we found a joinpoint in 2007 with Annual Percentage Change (APC) +4.25%, 95% CI +1.98, +6.57% during 2007-2013 for tumours of unknown type in the brain or CNS. In the CDR joinpoint regression found one joinpoint in 2008 with APC during 2008-2013 +22.60%, 95% CI +9.68, +37.03%. These tumour diagnoses would be based on clinical examination, mainly CT and/or MRI, but without histopathology or cytology. No statistically significant increasing incidence was found in the Swedish Cancer Register during these years. We postulate that a large part of brain tumours of unknown type are never reported to the Cancer Register. Furthermore, the frequency of diagnosis based on autopsy has declined substantially due to a general decline of autopsies in Sweden adding further to missing cases. We conclude that the Swedish Cancer Register is not reliable to be used to dismiss results in epidemiological studies on the use of wireless phones and brain tumour risk.

Decreased survival of glioma patients with astrocytoma grade IV (glioblastoma multiforme) associated with long-term use of mobile and cordless phones

On 31 May 2011 the WHO International Agency for Research on Cancer (IARC) categorised radiofrequency electromagnetic fields (RF-EMFs) from mobile phones, and from other devices that emit similar non-ionising electromagnetic fields, as a Group 2B, i.e., a "possible", human carcinogen. A causal association would be strengthened if it could be shown that the use of wireless phones has an impact on the survival of glioma patients. We analysed survival of 1678 glioma patients in our 1997-2003 and 2007-2009 case-control studies. Use of wireless phones in the >20 years latency group (time since first use) yielded an increased hazard ratio (HR) = 1.7, 95% confidence interval (CI) = 1.2-2.3 for glioma. For astrocytoma grade IV (glioblastoma multiforme; n = 926) mobile phone use yielded HR = 2.0, 95% CI = 1.4-2.9 and cordless phone use HR = 3.4, 95% CI = 1.04-11 in the same latency category. The hazard ratio for astrocytoma grade IV increased statistically significant per year of latency for wireless phones, HR = 1.020, 95% CI = 1.007-1.033, but not per 100 h cumulative use, HR = 1.002, 95% CI = 0.999-1.005. HR was not statistically significant increased for other types of glioma. Due to the relationship with survival the classification of IARC is strengthened and RF-EMF should be regarded as human carcinogen requiring urgent revision of current exposure guidelines.

Long-Term Results of stereotactic Brachytherapy (Temporary 125Iodine Seeds) for the Treatment of Low-Grade Astrocytoma (Grade II)

Background

Treatment of low-grade astrocytoma (WHO grade II) (LGA II) remains a challenge. There is limited information regarding the long-term effects of stereotactic brachytherapy (SBT) (temporary ¹²⁵Iodine seeds) on patients with LGA II.

Objectives

The purpose of this study was to evaluate disease control and survival after stereotactic brachytherapy in patients with circumscribed and relatively small size tumors.

Materials and Methods

A retrospective review of 29 patients, treated between 1991 and 2011, was conducted to evaluate survival, complications, and local disease control after stereotactic brachytherapy. They belonged to a larger group of 48 cases with low-grade gliomas, treated with stereotactic brachytherapy. The demographic and clinical characteristics in patients including age, sex, and survival time were extracted from records.

Results

Thirteen patients were male and 16 were female, with the median age of 29 years (range, 2.5 – 64 years). The median follow-up was 95 (range, 6 – 240) months. Based on Pignatti classification, 10 patients were at low- and 19 patients at high-risk. The median overall as well as progression-free survivals for patients were 135 months (95% confidence interval: 76 – 194) and 96 months (95% confidence interval: 1 – 199), respectively. Five- and 10-year progression-free survivals were 41.4 % and 34.5 %, respectively, and the 5- and 10-year overall survivals were 65.5 % and 44.8%, respectively. Progression-free survival was not significantly higher in smaller size tumors (P = 0.224), nor for spherical versus non-spherical tumors (P = 0.307). There was no treatment-related morbidity after stereotactic brachytherapy, and no radiogenic complications occurred during the follow-up period. Mortality due to tumor progression occurred in 4 patients (14%), and 11 patients were alive at the last follow-up.

Conclusions

The stereotactic brachytherapy for patients with circumscribed and relatively small size tumors appears to be a safe, feasible, and minimally-invasive treatment.

Pharmacotherapeutic management of pediatric gliomas : current and upcoming strategies

Primary glial brain tumors account for the majority of primary brain tumors in children. They are classified as low-grade gliomas (LGG) or high-grade gliomas (HGG), based on specific pathologic characteristics of the tumor, resulting in disparate clinical prognoses. Surgery is a mainstay of treatment for HGG, although it is not curative, and adjuvant therapy is required. Temozolomide, an oral imidazotetrazine prodrug, while considered standard of care for adult HGG, has not shown the same degree of benefit in the treatment of pediatric HGG. There are significant biologic differences that exist between adult and pediatric HGG, and targets specifically aimed at the biology in the pediatric population are required. Novel and specific therapies currently being investigated for pediatric HGG include small molecule inhibitors of epidermal growth factor receptor, platelet-derived growth factor receptor, histone deacetylase, the RAS/AKT pathway, telomerase, integrin, insulin-like growth factor receptor, and γ-secretase. Surgery is also the mainstay for LGG. There are defined front-line, multiagent chemotherapy regimens, but there are few proven second-line chemotherapy options for refractory patients. Approaches such as the inhibition of the mammalian target of rapamycin pathway, inhibition of MEK1 and 2, as well as BRAF, are discussed. Further research is required to understand the biology of pediatric gliomas as well as the use of molecularly targeted agents, especially in patients with surgically unresectable tumors.

Malignant transformation in pediatric spinal intramedullary tumors: case-based update

BACKGROUND

In children, intramedullary spinal cord neoplasms are rare. These are typically low-grade neuroepithelial tumors, most commonly astrocytomas, ependymomas, and gangliogliomas. Malignant transformation, while common in recurrent adult low-grade gliomas, is an unusual event in pediatric low-grade neoplasms, specifically in intramedullary spinal cord tumors.

ILLUSTRATIVE CASES

We report two cases of malignant transformation in low-grade neuroepithelial tumors of the pediatric intramedullary spinal cord. Two children with intramedullary tumors, one with a WHO grade I ganglioglioma and one with a low-grade astrocytoma, were treated surgically, diagnosed histologically, and followed through the course of their disease. Both patients' tumors transformed to higher grades without prior irradiation or chemotherapy, and without a genetic predisposition to tumorigenesis.

DISCUSSION

Malignant transformation can occur in low-grade intramedullary neoplasms in children. This is a novel documented event for pediatric intramedullary spinal cord tumors and a rare event for all pediatric low-grade neuroepithelial tumors without induction by irradiation. A survey of the relevant literature reveals an underwhelming number of studies focusing on malignant transformation in children's CNS tumors relative to adults. Further investigation into molecular mechanisms of pediatric low-grade neoplasms may reveal more aggressive tumor sub-variants predisposed to malignant degeneration.

Human glioma cells induce hyperexcitability in cortical networks

PURPOSE

Patients with gliomas frequently present with seizures, but the factors associated with seizure development are still poorly understood. In this study, we assessed peritumoral synaptic network activity in a glioma animal model and tested the contribution of aberrant glutamate release from gliomas on glioma-associated epileptic network activity.

METHODS

In vitro brain slices were made from glioma-implanted mice. Using extracellular field recordings, we analyzed peritumoral epileptiform activity induced by Mg(2+)-free medium in slices from tumor-bearing animals and sham-operated controls. We assessed the effect of sulfasalazine (SAS), a blocker of system and glutamate release, on spontaneous and evoked activity in tumor-associated slices.

KEY FINDINGS

Tumor-associated cortical networks were hyperexcitable. The onset latency of Mg(2+)-free-induced epileptiform activity was significantly shorter in tumor-bearing slices, and the incidence of Mg(2+)-free-induced ictal-like events was higher. Block of glutamate release from system decreased the response area of evoked activity and completely blocked Mg(2+)-free-induced ictal-like, but not interictal-like events.

SIGNIFICANCE

Control of seizures in patients with gliomas is an essential component of clinical management; therefore, understanding the origin of seizures is vital. This work provides evidence that peritumoral synaptic network activity is disrupted by tumor masses resulting in network excitability. We show that blocking glutamate release via system with SAS, a drug already approved by the U.S. Food and Drug Administration (FDA), can inhibit Mg(2+)-free-induced ictal-like epileptiform events similar to other chemicals used to decrease seizure activity. We, therefore, suggest that further studies should consider SAS a promising agent to aid in the treatment of seizures associated with gliomas.

Unique gene expression profile associated with an early-onset multiple endocrine neoplasia (MEN1)-associated pituitary adenoma

CONTEXT

Multiple endocrine neoplasia type 1 (MEN1) is caused by mutations in the menin (MEN1) gene. The mechanism(s) by which MEN1 mutations lead to pituitary tumor formation remain(s) unknown.

OBJECTIVE

The aim of the study was to identify the pediatric MEN1-associated pituitary tumor transcriptome.

PATIENTS AND METHODS

A patient harboring a MEN1 mutation (c.525C>G; p.H139D) who presented with an early-onset mammosomatotroph pituitary adenoma was studied. Microarray analysis was performed in the tumor sample and compared with the profile observed in normal pituitaries and in a sporadic mammosomatotropinoma. Validation of the microarray results was performed using quantitative real-time PCR and immunohistochemical analysis for selected genes.

RESULTS

In the MEN1-associated pituitary adenoma, 59 and 24 genes were found to be significantly up- and down-regulated, respectively. The up-regulated genes included those involved in cell growth and maintenance, apoptosis, growth arrest, and tumorigenesis. Moreover, we observed decreased expression in genes neuroendocrine in nature and related to growth or apoptosis. Only 21 of the 59 genes differentially expressed in the MEN1-associated adenoma showed a similar expression profile to that seen in the sporadic mammosomatotropinoma; for some genes an opposite expression profile was observed.

CONCLUSIONS

We identified changes in the transcriptome that occur in pituitary GH- and PRL-producing cells after the loss of menin expression; some of the gene changes are necessary for tumor evolution, and others may be tertiary. Nevertheless, the rare overlap between the expression profiles of the MEN1 tumor vs. that of its sporadic counterpart suggests that these tumors evolve along different molecular pathways.

Clinical Analysis for Brain Tumor-Related Epilepsy during Chemotherapy for Systemic Cancer with Single Brain Metastasis

PURPOSE

The purpose of this prospective observational study was to determine the incidence, patterns, and predisposing factors for brain tumor-related epilepsy (BTRE) during chemotherapy for systemic cancer with single brain metastasis (BM).

MATERIALS AND METHODS

Between February 2006 and June 2010, 103 patients who underwent chemotherapy for systemic cancer with single BM were enrolled. We compared the clinical factors of patients and BM between patients with and without BTRE. We determined the number of patients with BTRE attacks, and seizure-free survival according to the following comparative groups: presence vs. absence of a history of BTRE; high-risk vs. low-risk groups; and presence vs. absence of disease-progression of BM.

RESULTS

Ninety-three of 103 patients (90.3%) remained seizure-free during chemotherapy. The seizure-free rates were 88.9% and 91.0% among patients with or without a history of BTRE, respectively (p=0.694), 87.8% and 92.6% among high- and low-risk patients (p=0.427), respectively, and 62.5% and 98.7% among patients with or without disease-progression of BM (p=0.001), retrospectively. Based on multivariate analysis, the significance of abnormal findings on electroencephalogram (EEG) (p=0.017), and the absence of disease-progression of BM (p=0.001) had an association with seizure-free survival.

CONCLUSION

The significance of abnormal findings on EEG, and disease-progression of BM play important roles in the development of BTRE during chemotherapy for systemic cancer with BM.

Differential kinetics of α-[¹¹C]methyl-L-tryptophan on PET in low-grade brain tumors

Increased tryptophan metabolism via the kynurenine pathway is a major mechanism of tumor immuno-resistance. α-[(11)C]Methyl-L: -tryptophan (AMT) is a positron emission tomography (PET) tracer for tryptophan catabolism, and increased AMT uptake has been demonstrated in brain tumors. In this study we evaluated the use of AMT PET for detection of low-grade gliomas and glioneuronal tumors, and determined if kinetic parameters of AMT uptake can differentiate among tumor types. AMT PET images were obtained in 23 patients with newly diagnosed low-grade brain tumors (WHO grade II gliomas and WHO grade I dysembryoplastic neuroepithelial tumors [DNETs]). Kinetic variables, including the unidirectional uptake rate (K-complex) and volume of distribution (VD; which characterizes tracer transport), were measured using a graphical approach from tumor dynamic PET and blood-input data, and metabolic rates ([Formula: see text]) were also calculated. These values as well as tumor/cortex ratios were compared across tumor types. AMT PET showed increased tumor/cortex K-complex (n = 16) and/or VD ratios (n = 15) in 21/23 patients (91%), including 11/13 tumors with no gadolinium enhancement on MRI. No increases in AMT were seen in an oligodendroglioma and a DNET. Astrocytomas and oligoastrocytomas showed higher [Formula: see text] tumor/cortex ratios (1.66 ± 0.46) than oligodendrogliomas (0.96 ± 0.21; P = 0.001) and DNETs (0.75 ± 0.39; P < 0.001). These results demonstrate that AMT PET identifies most low-grade gliomas and DNETs by high uptake, even if these tumors are not contrast-enhancing on MRI. Kinetic analysis of AMT uptake shows significantly higher tumor/cortex tryptophan metabolic ratios in astrocytomas and oligoastrocytomas in comparison with oligodendrogliomas and DNETs.

Morphological characteristics of brain tumors causing seizures

OBJECTIVE

To quantify size and localization differences between tumors presenting with seizures vs nonseizure neurological symptoms.

DESIGN

Retrospective imaging survey. We performed magnetic resonance imaging-based morphometric analysis and nonparametric mapping in patients with brain tumors.

SETTING

University-affiliated teaching hospital.

PATIENTS OR OTHER PARTICIPANTS

One hundred twenty-four patients with newly diagnosed supratentorial glial tumors.

MAIN OUTCOME MEASURES

Volumetric and mapping methods were used to evaluate differences in size and location of the tumors in patients who presented with seizures as compared with patients who presented with other symptoms.

RESULTS

In high-grade gliomas, tumors presenting with seizures were smaller than tumors presenting with other neurological symptoms, whereas in low-grade gliomas, tumors presenting with seizures were larger. Tumor location maps revealed that in high-grade gliomas, deep-seated tumors in the pericallosal regions were more likely to present with nonseizure neurological symptoms. In low-grade gliomas, tumors of the temporal lobe as well as the insular region were more likely to present with seizures.

CONCLUSIONS

The influence of size and location of the tumors on their propensity to cause seizures varies with the grade of the tumor. In high-grade gliomas, rapidly growing tumors, particularly those situated in deeper structures, present with non-seizure-related symptoms. In low-grade gliomas, lesions in the temporal lobe or the insula grow large without other symptoms and eventually cause seizures. Quantitative image analysis allows for the mapping of regions in each group that are more or less susceptible to seizures.

Analysis of 11C-methionine uptake in low-grade gliomas and correlation with proliferative activity

BACKGROUND AND PURPOSE

The relationship of (11)C-methionine (MET) uptake and tumor activity in low-grade gliomas (those meeting the criteria for World Health Organization [WHO] grade II gliomas) remains uncertain. The aim of this study was to compare MET uptake in low-grade gliomas and to analyze whether MET positron-emission tomography (PET) can estimate tumor viability and provide evidence of malignant transformation.

MATERIALS AND METHODS

We studied glioma metabolic activity in 49 consecutive patients with newly diagnosed grade II gliomas by using MET PET before surgical resection. On MET PET, we measured tumor/normal brain uptake ratio (T/N ratio) in 21 diffuse astrocytomas (DAs), 12 oligodendrogliomas (ODs), and 16 oligoastrocytomas (OAs). We compared MET T/N ratio among these 3 tumors and investigated possible correlation with proliferative activity, as measured by Mib-1 labeling index (LI).

RESULTS

MET T/N ratios of DA, OD, and OA were 2.11 +/- 0.87, 3.75 +/- 1.43, and 2.76 +/- 1.27, respectively. The MET T/N ratio of OD was significantly higher than that of DA (P < .005). In comparison of MET T/N ratios with the Mib-1 LI, a significant correlation was shown in DA (r = 0.63; P < .005) but not in OD and OA.

CONCLUSION

MET uptake in DAs may be closely associated with tumor viability, which depends on increased amino acid transport by an activated carrier-mediated system. DAs with lower MET uptake were considered more quiescent lesions, whereas DA with higher MET uptake may act more aggressively.

Cerebral granular cell tumor

Intracerebral granular cell tumors (GCTs) are a rare finding. We report here on a case of cerebral GCT in a 47-year-old man who suffered with severe headache. The tumor appeared as a relatively well-defined, enhancing mass at the periventricular white matter of the left occipital lobe of the brain. Histologically, the tumor was entirely composed of granular cells. Some of the tumor cells showed peripherally accentuated cytoplasmic granules with central clearing, which produced a unique "targetoid" appearance. The granular cells of the current case were positive for neuron-specific enolase (NSE), S-100 protein, GFAP, vimentin, CD 68, lysozyme, and alpha-1-antitrypsin. These wide immunoexpressions were not observed for the previously reported cerebral GCTs. Interestingly, this case showed "targetoid" or "reversed targetoid" immunoreactive patterns in NSE, CD68, GFAP, and vimentin. Despite these wide immunoexpressions and the lack of any association with astrocytoma, the histogenesis of cerebral GCTs is still suggested to be of a glial origin, based on the tumor location, the GFAP positivity and the ultrastructural findings, of which the latter showed intermediate filaments, and these are reminiscent of neoplastic astrocytes.

[Natural history of supratentorial low-grade astrocytoma: case report]

Low-grade astrocytomas comprise a group of primary brain neoplasms with relatively low anaplastic potential, although through time they tend to behave more aggressively. They have a very heterogeneous natural course and clinical behavior. This report presents a natural history of a patient with low grade astrocytoma. A 32-year-old male sustained head injury after grand mal seizure. On admission, he was conscious and without neurological deficit. Initial computerized tomography and magnetic resonance of brain revealed oval, 4 cm in diameter, lesion in the left parietal region that was considered as low-grade glioma. The patient refused surgery. Eight years and four months later, he was readmitted. This time, he was subcomatose with right hemiplegia. Repeated computerized tomography showed huge tumor in the left frontoparietal region at the site of previous lesion. Urgent left frontoparietal craniotomy and reduction of tumor were performed. The patient recovered after surgery. Right hemiparesis remained. The described patient with low-grade astrocytoma lived without any oncological treatment eight years and four months from the time when diagnosis was made until intracranial herniation. The natural history of disease in presented patient indicated that rational therapeutic strategy, for low-grade astrocytoma with epilepsy only, would be deferral of surgery until the time of manifestation of neurological or radiological deterioration.

Prognostic factors for anaplastic astrocytomas

Anaplastic astrocytomas (WHO grade III) constitute about 10% of all gliomas. Definitive data on predictive and prognostic factors are lacking for these neoplasms that are considered the most enigmatic entity among the whole spectrum of astrocytic tumors because of their unclear biologic behavior and variable clinical outcome. Currently, only few factors have been identified as useful for prognosis of anaplastic astrocytoma: age and Karnofsky Performance Status. Attempts have been made to identify biological prognostic factors for response to therapy and clinical outcome, as well as potential targets for new therapies. Potential prognostic biomarkers concern tumor suppressor genes on chromosome 9q that are involved in the RB1 pathway; PTEN, the PI3k/Akt/p70s6k cascade, survivin gene, Formylpeptide receptor, minichromosome maintenance protein 3 and genes on chromosome 7. Furthermore, some angiogenic factors (e.g. hypoxia-inducible factor-1alpha, vascular endothelial growth factor and scatter factor/hepatocyte growth factor) and the methylation status of O6-methylguanine-DNA methyltransferase gene (one of the main effectors of DNA repair system) are emerging novel putative determinants of prognosis. Moreover, recent studies on magnetic resonance imaging characteristics give prognostic significance to the presence of necrosis and enhancement. The state of the art pictured here underlie the recent interest on gene expression profile to identify aberrations useful to understand the biologic behavior of astrocytic tumors. Our knowledge in this field is still limited, and remains an issue of great concern.

Temozolomide Treatment of Refractory Epilepsy in a Patient with an Oligodendroglioma

A 40-year-old man with a left frontotemporal grade II oligodendroglioma developed seizures that were refractory to 14 antiepileptic medications, the ketogenic diet, and epilepsy surgery. With temozolomide therapy, his seizure frequency gradually changed from 30 partial seizures per day to a single simple partial seizure in 6 months. No additional therapeutic measures were introduced during this time. This reduction in seizure frequency appears attributable solely to temozolomide therapy.

Surgical resection for patients with benign primary brain tumors and low grade gliomas

'Benign' brain tumors are a heterogeneous group of primary neoplasms representing 40% of primary brain tumors. Amongst neuroepithelial tumors, astrocytic neoplasms predominate, followed by oligodendroglial and mixed glial and glial-neuronal neoplasms. Less common are tumors of the ependyma, choroid plexus and neuroepithelial tumors of unknown origin such as chordoid glioma of the third ventricle. Neurosurgical intervention is indicated in order to establish a diagnosis, alleviate symptoms of mass effect, hydrocephalus, or hemorrhage, remove a seizure focus and decrease the cell pool at risk of malignant degeneration. As the majority of patients survive their tumor for years after initial diagnosis, the benefits of therapy must be carefully weighed against adverse treatment effects. This article, with a particular focus on surgical management, reflects the authors approach to the treatment of low-grade tumors of the brain parenchyma in the adult and reviews the pertinent literature published on this controversial issue.

Malignant progression in meningioma: documentation of a series and analysis of cytogenetic findings

Object. The malignant progression of benign tumors is well documented in gliomas and other systemic lesions. It is also well known that some meningiomas become progressively aggressive despite their original benign status. The theory of clonal evolution is widely believed to explain malignant progression in meningioma; however, the data used to explain stepwise progression have typically been derived from the cytogenetic analysis of different types of tumors of different grades and in different patients. In this study, the authors examined the data obtained in a group of patients with meningiomas that showed clear histopathological progression toward a higher grade of malignancy and then analyzed the underlying cytogenetic findings.

Methods. Among 175 patients with recurrent meningiomas, 11 tumors showed a histopathological progression toward a higher grade that was associated with an aggressive clinical course. Six tumors progressed to malignancy and five to the atypical category over a period averaging 112 months. Tests for MIB-1 and p53 and cytogenetic studies with the fluorescence in situ hybridization (FISH) method were performed in successive specimens obtained in four patients.

The MIB-1 value increased in subsequent samples of tumors. Cytogenetic analysis with FISH showed deletions of 22, 1p, and 14q. In all but one case, these aberrations were also present in the previous specimen despite its lower hispathological grade.

Conclusions. The authors documented the progression of meningiomas from benign to a higher histological grade. These tumors were associated with a complex karyotype that was present ab initio in a histologically lower-grade tumor, contradicting the stepwise clonal evolution model. Although it was limited to the tested probes, the FISH method appears to be more accurate than the standard cytogenetic one in detecting these alterations. Tumors that present with complex genetic alterations, even those with a benign histological grade, are potentially aggressive and require closer follow up.

Progress in long-term survival in adult patients with supratentorial low-grade gliomas: a population-based study of 993 patients in whom tumors were diagnosed between 1970 and 1993

Object. The goal of this study was to document and compare long-term survival during the periods 1970 through 1981 and 1982 through 1993 in all adult patients in Norway with histologically verified supratentorial low-grade gliomas (LGGs).

Methods. Nine hundred ninety-three patients 15 to 69 years of age were found to have a primary supratentorial diffuse astrocytoma, oligodendroglioma, oligoastrocytoma, or pilocytic astrocytoma. Survival time was analyzed in all patients and, in a subset of 451 patients, the influence of new imaging methods on the time from symptom onset to imaging diagnosis was estimated.

Overall median survival was 6.4 years (95% confidence interval [CI] 5.7–7.1 years). Survival times for patients in whom a diagnosis was made between 1970 and 1981 (397 patients) and between 1982 and 1993 (596 patients) were 4.1 years (95% CI 3.3–4.9 years) and 9.2 years (95% CI 7.9–10.6 years), respectively (p < 0.0001). Survival also improved in the later period within each histological subgroup. In patients in whom a biopsy was performed the median length of survival was 6.4 years (95% CI 3.1–9.7 years); in patients treated with subtotal tumor resection it was 6.8 years (95% CI 5.8–7.7 years); and in those treated with gross-total tumor resection it was 7.6 years (95% CI 5.5–9.7 years), a nonsignificant difference (p = 0.59). A considerable age-dependent variation in overall survival was demonstrated. The availability of computerized tomography (CT) scanning and/or magnetic resonance (MR) imaging as a diagnostic tool reduced the median period of symptoms prior to diagnosis by 6 months.

Conclusions. Long-term overall survival significantly improved, but age-related differences in prognosis persisted. The increased sensitivity of the diagnostic method due to the availability of CT scanning and/or MR imaging may partly, but not entirely, account for the observed magnitude of improvement in overall survival. Thus local tumor treatment improved during the study period.

Characterization of gene expression profiles associated with glioma progression using oligonucleotide-based microarray analysis and real-time reverse transcription-polymerase chain reaction

Diffuse astrocytoma of World Health Organization (WHO) grade II has an inherent tendency to spontaneously progress to anaplastic astrocytoma (WHO grade III) and/or glioblastoma (WHO grade IV). The molecular basis of astrocytoma progression is still poorly understood, in particular with respect to the progression-associated changes at the mRNA level. Therefore, we compared the transcriptional profile of approximately 6800 genes in primary WHO grade II gliomas and corresponding recurrent high-grade (WHO grade III or IV) gliomas from eight patients using oligonucleotide-based microarray analysis. We identified 66 genes whose mRNA levels differed significantly (P < 0.01, > or =2-fold change) between the primary and recurrent tumors. The microarray data were corroborated by real-time reverse transcription-polymerase chain reaction analysis of 12 selected genes, including 7 genes with increased expression and 5 genes with reduced expression on progression. In addition, the expression of these 12 genes was determined in an independent series of 43 astrocytic gliomas (9 diffuse astrocytomas, 10 anaplastic astrocytomas, 17 primary, and 7 secondary glioblastomas). These analyses confirmed that the transcript levels of nine of the selected genes (COL4A2, FOXM1, MGP, TOP2A, CENPF, IGFBP4, VEGFA, ADD3, and CAMK2G) differed significantly in WHO grade II astrocytomas as compared to anaplastic astrocytomas and/or glioblastomas. Thus, we identified and validated a set of interesting candidate genes whose differential expression likely plays a role in astrocytoma progression.

Repeated operations for infiltrative low-grade gliomas without intervening therapy

OBJECT

Progression of infiltrative low-grade gliomas (LGGs) has been reported previously. The limitations of such studies include diverse histological grading systems, intervening therapy, and the lack of histological confirmation of malignant tumor progression. The aim of this study was to determine tumor progression in adult patients with an initial diagnosis of infiltrative LGG who subsequently underwent a repeated operation, but no other intervening therapy. The authors examined factors that may be associated with tumor progression.

METHODS

The authors retrospectively reviewed a database of 300 patients with the initial diagnosis of LGG and who had been treated at their institution between 1990 and 2000. One hundred four of these patients had undergone a second surgery. Patients with infiltrative LOGs who had undergone two surgical procedures at least 3 months apart without intervening therapy were selected; the authors identified 40 patients who fit these criteria. Clinical, neuroimaging, and pathological data were centrally reviewed. There were 29 men and 11 women in the study, whose median age was 35.5 years (range 23-48 years). At the time of the second surgery, 50% of patients had experienced tumor progression. Patients whose tumors had progressed had a longer median time to repeated operation (49 compared with 22.5 months). Patients who had undergone gross-total resection, as demonstrated on postoperative magnetic resonance images, had a median time to repeated operation of 49 compared with 25 and 24 months in patients who underwent subtotal resection and biopsy, respectively (p = 0.02). The extent of resection did not influence the likelihood of tumor progression (p > 0.3).

CONCLUSIONS

Fifty percent of patients with initially diagnosed infiltrative LGOs had tumor progression at the time of a repeated operation. A gross-total resection was associated with an increased time to repeated surgery. There was no statistically significant effect of gross-total resection as a predictor of tumor progression.

Treatment of low-grade diffuse astrocytomas by surgery and human fibroblast interferon without radiation therapy

Low-grade diffuse astrocytomas are slowly growing tumors with a relatively long overall survival. However, a substantial proportion undergoes dedifferentiation to a more malignant phenotype. Considerable controversy exists as to the best therapeutic management for patients with such tumors. Over the past decade, we have applied human fibroblast interferon (HFIF) therapy without radiation therapy to low-grade astrocytomas. We investigated 28 patients with WHO grade II astrocytomas of the cerebral hemispheres treated by surgery plus HFIF therapy. The overall response rate to the HFIF therapy was 36%. All side-effects of HFIF were transient, tolerable and manageable. The 5-year progression free survival and overall survival probabilities were 65% and 96%, respectively. Although our data from small cohort of patients may have modest value, our results suggest that HFIF may be useful in treating low-grade diffuse astrocytomas.

Evaluation of molecular markers in low-grade diffuse astrocytomas: loss of p16 and retinoblastoma protein expression is associated with short survival

Diffuse astrocytomas have a median survival of 6-8 years. However, in a minority of cases that are histologically low grade, progression is rapid, leading to death within 2 years. Loss of p16, retinoblastoma protein, and deleted-in-colon-carcinoma protein expression, and monosomy of chromosome 10 have been shown to occur in malignant astrocytic tumors. We have investigated the prognostic value of expression of these markers, using techniques applicable in many histopathology laboratories, in diffuse astrocytomas that are histologically low grade. Paraffin sections from 71 diffuse, supratentorial, low-grade astrocytomas, from patients with at least 8-year survival data, were immunostained with antibodies to p16, deleted-in-colon-carcinoma protein, p53, Ki67, and retinoblastoma protein. In situ hybridization with a digoxigenin-labeled probe to chromosome 10 was used to assess chromosomal loss. In most cases there was immunostaining of virtually all tumor cell nuclei with antibodies to p16 and retinoblastoma protein. Three of the 68 tumors in which assessment of p16 was possible included discrete foci with lack of detectable immunoreactivity in tumor cells. The three patients concerned had a significantly shortened median survival (1.1 years vs 4.4 years in those without loss of p16; p <0.01). In six of the 61 cases where assessment of retinoblastoma protein was possible, <70% of tumor cell nuclei showed immunoreactivity. These six patients had a shorter survival (4.0 years) than had the remaining patients (5.4 years), although this difference was not statistically significant. The tumor from one of these patients included areas where only 36% of tumor cells showed retinoblastoma protein immunoreactivity, and this patient survived only 1.5 years. Tumors showing loss of both p16 and retinoblastoma were not seen. p53 and deleted-in-colon-carcinoma protein expression was highly variable and did not correlate with survival. Tumors with monosomy for chromosome 10 were not identified. Both polyploidy and the Ki67 labeling index were significantly associated with the p53 labeling index but not with survival. Focal loss of p16 or retinoblastoma protein is demonstrable in approximately 5% and 10% of diffuse low-grade diffuse astrocytomas, respectively. Tumors with focal loss of immunoreactivity for these proteins are associated with shorter survival than those without, suggesting that immunohistochemistry for p16 and retinoblastoma protein may be a useful adjunct to other methods for assessing the prognosis of astrocytomas.

Low-grade central nervous system tumors

Low-grade tumors of the central nervous system constitute 15 to 35% of primary brain tumors. Although this category of tumors encompasses a number of different well-characterized entities, low-grade tumors constitute every tumor not obviously malignant at initial diagnosis. In this brief review, the authors discuss the pathological classification, diagnostic procedures, treatment, and possible pathogenic mechanisms of these tumors. Emphasis is given in the neu-roradiological and pathological features of the several entities.

Radiation therapy for incompletely resected supratentorial low-grade glioma in adults

In this review on current concepts in radiation therapy in the treatment of incompletely resected supratentorial low-grade glioma, a number of important issues are discussed. They include indication for radiation therapy, timing (early vs delayed), dose response issue, impact of modern neuroimaging, 'optimal' treatment fields, impact of histology, new and promising approaches as well as quality of life in this disease are also discussed. This disease remains a focus of investigations in neuro-oncology owing to the fact that a number of questions discussed in the text are still far from being optimally addressed and answers are, therefore, lacking. New studies and more patients are needed to get more insight into this disease.

Low-grade hemispheric gliomas in adults: a critical review of extent of resection as a factor influencing outcome

OBJECT

The goal of this study was to perform a critical review of literature pertinent to low-grade gliomas of the cerebral hemisphere in adults and, on the basis of this review, to evaluate systematically the prognostic effect of extent of resection on survival and to determine if treatment-related guidelines could be established for patients in whom these tumors have been newly diagnosed. Quality of evidence for current treatment options, guidelines, and standards as well as methodological limitations were evaluated.

METHODS

Several prognostic factors thought to affect outcome in patients with low-grade gliomas include the patient's age and neurological status, tumor volume and histological characteristics, and treatment-related variables such as timing of surgical intervention, extent of resection, postoperative tumor volume, and radiation therapy. Patient age and the histological characteristics of the lesion are generally accepted prognostic factors. Among treatment-related factors, timing and extent of resection are controversial because of the lack of randomized controlled trials addressing these issues and the difficulty in obtaining information from available studies that have methodological limitations. All English-language studies on low-grade gliomas published between January 1970 and April 2000 were reviewed. Thirty studies that included statistical analyses were further evaluated with regard to the prognostic effect of extent of resection. Of these 30 studies, those that included pediatric patients, unless adults were analyzed separately, were excluded from further study because of the favorable outcome associated with the pediatric age group. Also excluded were studies including pilocytic and gemistocytic astrocytomas, because the natural histories of these histological subtypes are significantly different from that of low-grade gliomas. Series in which there were small numbers of patients (< 75) were also excluded. Results for oligodendrogliomas are reported separately. Currently, for patients with low-grade glial tumors located in the cerebral hemisphere, the only management standard based on high-quality evidence is tissue diagnosis. All other treatment methods are practice options supported by evidence that is inconclusive or conflicting. The majority of published series that the authors identified had design-related limitations including a small study size, a small number of events (that is, deaths for survival studies), inclusion of pediatric patients, and/or inclusion of various histological types of tumors with different natural histories. Of the 30 series addressing the issue of timing and extent of surgery, almost all had additional design limitations. Methods used to determine the extent of resection were subjective and qualitative in almost all studies. Only five of the 30 series met the authors' criteria, and these studies are discussed in detail.

CONCLUSIONS

Management of low-grade gliomas is controversial and practice parameters are ill defined. This is caused by limited knowledge regarding the natural history of these tumors and the lack of high-quality evidence supporting various treatment options. Although a prospective randomized study seems unlikely, both retrospective matched studies and prospective observational trials will improve the clinician's ability to understand the importance of various prognostic factors.

Multi-agent cytostatic treatment of 'low-grade' gliomas

The rationale and current supporting evidence for a complementary, multi-agent, low-toxicity, chronic, cytostatic therapeutic approach to treating patients with gliomas is presented in detail. This strategy would involve the simultaneous treatment of patients with DNA/chromosomal stabilizing agent(s), anti-angiogenesis agent(s), and anti- invasion agent(s), with or without the addition of a low-toxicity antiproliferation agent. Oral agents would be the ideal for this chronic, potentially life-long, therapeutic approach. The most logical target group would be patients with newly diagnosed "low-grade" gliomas rather than those with more malignant (usually recurrent) gliomas.

Low grade gliomas treated with adjuvant radiation therapy in the modern imaging era

The purpose of this study is to evaluate tumor control and failure patterns in patients with low grade gliomas treated with surgery and conventional adjuvant radiation therapy. Twenty-eight patients with low grade gliomas (7 grade I, 21 grade II) were retrospectively evaluated. Extent of resection was gross total (3), subtotal (17), and biopsy alone (8). All grade I tumors underwent subtotal resection. Median radiation therapy dose was 54 Gy delivered to localized fields. Tumor control and patterns of failure were determined from follow-up computed tomography and/or magnetic resonance scans. Median follow-up was 86 months (range, 2.4-177 months). Thirteen patients (46%) (four grade I, nine grade II) developed tumor progression. The 5-year actuarial progression-free survival rates for grade I and grade II patients were 86% and 51%, respectively. Corresponding 5-year actuarial survival rates were 100% and 70%. All recurrences were within the treated volume. Our results reveal that conventional adjuvant radiation therapy is associated with high rates of local tumor progression in both grade II and incompletely resected grade I low grade gliomas. Alternative strategies need to be explored in these patients in an effort to improve tumor control and outcome.

Vascular endothelial growth factor (VEGF) in astrocytic gliomas--a prognostic factor?

Survival in astrocytic gliomas is closely related to WHO tumor grade. Within one tumor grade, especially in grade II and III tumors, the clinical course is variable and can hardly be predicted by histological criteria. Neovascularization is a neuropathological hallmark in high grade gliomas and angiogenic factors may play an important role in malignant tumor progression. Therefore, 162 primary astrocytic gliomas (57 astrocytomas WHO grade II, 27 astrocytomas WHO grade III and 78 glioblastomas WHO grade IV) were investigated immunohistochemically for expression of vascular endothelial growth factor (VEGF), which is considered to represent the main angiogenic factor in astrocytic gliomas. Clinical data known to influence prognosis were documented. VEGF expression was found in 21 of 57 astrocytomas WHO grade II (36.8%), in 18 of 27 astrocytomas WHO grade III (66.7%) and in 50 of 78 glioblastomas (64.1%). A strong correlation between VEGF expression and survival was found within the whole study group, however, within one tumor grade no such correlation was obvious. In a multifactorial analysis VEGF expression was not found to be an independent prognostic factor in astrocytic gliomas.

The role of surgery in low grade gliomas

Several prognostic factors appear to be more important than treatment factors in determining the outcome of patients with low grade glioma. The role of surgery in establishing a histological diagnosis or in relieving neurological deficit is well established. The role of surgery in prolonging survival of patients with low grade glioma however, remains controversial, largely because studies in the literature on the management of this disease have been predominantly descriptive and observational, which precludes the setting of standards for the management of these patients. Several viable management options are discussed.

Age-dependent rate of anaplastic transformation in low-grade astrocytoma

Age and histologic grade are interrelated characteristics of diffuse fibrillary astrocytomas, because the peak age incidence rises with increasing grade. The relationship between age and grade may be explained if age determines the rate of anaplastic progression in astrocytomas. The authors tested this hypothesis by determining the interval between diagnosis of low-grade astrocytoma and progression to high-grade astrocytoma in patients of various ages. A two-way scatterplot of age at initial diagnosis versus interval to anaplastic progression demonstrated a strong negative correlation (n = 24; Pearson correlation coefficient = -0.83; Spearman correlation coefficient = -0.79; p < 0.001 for both values). It was concluded that the rate of anaplastic progression in low-grade astrocytoma is directly correlated with patient age.

Prognostic significance of CT contrast enhancement within histological subgroups of intracranial glioma

We report the prognostic significance of tumor CT contrast enhancement within histological subgroups in 831 consecutive adult glioma patients of high-grade (n = 516) and low-grade (n = 315) histology. In the present report, a negative prognostic factor is associated with shortened survival.

METHODS

Survival analysis including Kaplan-Meier plots, log-rank tests, Cox analysis, and Aalen's linear model as implemented in SPSS and S-PLUS.

RESULTS

Sensitivity and specificity of contrast enhancement as a test for high-grade glioma was 0.87 and 0.79, respectively. Enhancement was a strong negative prognostic factor comparable to high-grade histology in the total patient population. Enhancement was also a negative prognostic factor within the subgroups adult high-grade (Grade 3-4), anaplastic (Grade 3), and low-grade (Grade 1-2) gliomas (p < 0.001). The prognostic implications of initial enhancement declined in high-grade patients surviving beyond 36 months. Tumor contrast enhancement or calcifications (in parentheses) were present in 96% (3.6%) of glioblastomas, in 87% (7.4%) of high-grade gliomas, in 56.5% of anaplastic gliomas, and in 21% (16.2%) of low-grade gliomas. Calcification was a positive prognostic factor within the high-grade group of patients (p < 0.0001).

CONCLUSION

Enhancement was a major prognostic factor comparable to high-grade histology in this glioma patient population. Enhancement was a negative prognostic factor within each of the adult subgroups high-grade, anaplastic (grade 3), and low-grade gliomas. Enhancement was strongly associated with but not pathognomonic for high-grade histology.

Practice parameters in adults with suspected or known supratentorial nonoptic pathway low-grade glioma

Gene therapy has many potential applications in neurosurgery. One application involves bone morphogenetic protein-2 (BMP-2), a low-molecular-weight glycoprotein that induces bone formation in vivo. Numerous studies have demonstrated that the BMP-2 protein can enhance spinal fusion. This study was undertaken to determine whether direct injection of an adenoviral construct containing the BMP-2 gene can be used for spinal fusion. Twelve athymic nude rats were used in this study. Recombinant, replication-defective type-5 adenovirus with a universal promoter and BMP-2 gene (Ad-BMP-2) was used. A second adenovirus constructed with a universal promoter and beta-galactosidase (beta-gal) gene (Ad-beta-gal) was used as a control. Seven and one-half microliters of virus was injected percutaneously and paraspinally at the lumbosacral junction in three groups (four animals each): 1) Ad-BMP-2 bilaterally, 2) Ad-BMP-2 on the right, Ad-beta-gal on the left, and 3) Ad-beta-gal bilaterally. Computerized tomography (CT) scans of the lumbosacral spine were obtained at 3, 5, and 12 weeks. At 12 weeks, the animals were killed for histological inspection. Ectopic bone formation was seen both on three-dimensional CT reconstruction and histologically in all rats at sites treated with Ad-BMP-2. Histological analysis revealed bone at different stages of maturity adjacent to the spinous processes, laminae, and transverse processes. This study clearly demonstrated that it is possible to produce in vivo endochondral bone formation by using direct adenoviral construct injection into the paraspinal musculature, which suggests that gene therapy may be useful for spinal fusion in the future.

Supratentorial low grade astrocytoma: prognostic factors, dedifferentiation, and the issue of early versus late surgery

BACKGROUND

A retrospective study of patients with low grade astrocytoma was carried out because the best management of such patients remains controversial. Prognostic factors were identified by multivariate analysis. Special attention was paid to the effect of extent and timing of surgery.

METHODS

Ninety patients with low grade astrocytoma were studied. Seventy two patients had resective surgery, 15 had a diagnostic biopsy only, and three patients had resective surgery after initial biopsy.

RESULTS

Significant prognostic factors for survival were age, preoperative neurological condition, epilepsy as the single sign, extent of surgery, and histology. The extent of surgery was highly significant on univariate analysis (p=0.002); however, after correction for age and preoperative symptoms this was considerably reduced (p=0.04). A subgroup of 30 patients with epilepsy as their single presenting symptom was identified. Thirteen of these patients were treated immediately after diagnosis, whereas the other 17 patients were initially followed up and treated only after clinical or radiological progression. Survival in both groups was identical (63% survival rate after five years) and much better than survival for the whole group (27% survival rate after five years). Malignant dedifferentiation was observed in 25 (70%) of 36 patients who were reoperated, after a median period of 37 months. This period was 41 months for the subgroup of patients with epilepsy only and 28 months for the remaining patients.

CONCLUSIONS

Due to the retrospective nature of the study only restricted conclusions can be drawn. Low grade glioma with epilepsy as the single symptom has a much better prognosis than if accompanied by other symptoms. This prognosis is not influenced by the timing of surgery. It seems, therefore, safe to defer surgery until clinical or radiological progression in low grade glioma with epilepsy only.

Neurosurgical considerations in supratentorial low-grade gliomas: experience with 175 patients

The authors reviewed 175 low-grade hemispheric gliomas surgically treated by one surgeon (P.B.) between 1987 and 1996: 74 astrocytomas (42%), 35 oligodendrogliomas (20%), 52 mixed gliomas (30%), 12 gangliogliomas (7%), and two ependymomas (1%). Patient age ranged from 7.5 to 81.9 years (mean 39.2 years); 84 patients (48%) were males and 91 (52%) females. Postsurgical follow-up review ranged from 0.1 to 225.2 months (mean 36.2 months, median 24.9 months). Either T2-weighted or contrast-enhanced T1-weighted magnetic resonance (MR) images were used to evaluate the percentage of resection achieved and volume of residual disease postoperatively. The majority of patients (55%) had seizures as the presenting symptom, and 45% experienced preoperative symptoms for more than 12 months. Tumor enhancement was present in 21% of cases. In 66% of surgical procedures at least one of the following technical adjuncts was used: monitored local anesthesia, real-time MR imaging, stereotactic guidance with computerized tomography, three dimensional reconstruction, cortical mapping with cortical stimulation, somatosensory or visual evoked potential recording, corticography, or intraoperative ultrasound. Intraoperative MR imaging was used for 40 (22.9%) of the craniotomies and nine (5.14%) biopsies. There were no surgery-related deaths. Complications appeared in 6% of the patients. Progression to a higher-grade tumor occurred in 9.2% of patients within the 3-year follow-up period.

Malignant gliomas of the cerebellum: an analytic review

Using an analytical review, the demographic data on malignant cerebellar gliomas such as length of survival, and those factors associated with prolonged survival were examined. Seventy-one cases of malignant cerebellar glioma reported since 1975 were combined and reviewed with the seven cases treated at our institution since that time. Thirty-seven patients (47%) had grade III tumors and 41 (53%) had grade IV tumors. Fifty-nine percent of the tumors were located in the hemispheres and 41% were found in the vermis. Median survival for patients with grade III anaplastic astrocytomas was 32 months compared to 11 months for those with grade IV glioblastomas multiforme (P = 0.0257). For the entire cohort, patients with grade III tumors, those who had a surgical resection, and those that had received radiation therapy for treatment of their tumor had prolonged survival on multivariable analysis. Radiation therapy was associated with extended survival for patients with grade III tumors by uni- and multivariate analysis. For grade IV tumors, univariate analysis revealed prolonged survival for those patients who had surgical resection compared to those who had biopsy alone (P = 0.0036) and for those who received external beam radiation therapy (P = 0.0001). Patients with malignant gliomas of the cerebellum had length of survival comparable to their supratentorial counterparts. Prompt diagnosis and treatment may explain the similarity in survival found between supra- and infratentorial malignant gliomas despite an expected shorter survival because of treatment limitations. Surgical resection followed by radiation therapy is recommended for patients with malignant gliomas of the cerebellum.

Proliferative activity and prognosis of low-grade astrocytomas

Well-differentiated astrocytomas may transform into malignant astrocytomas in time. In surgical specimens, when the histological picture strictly corresponds to that of grade II glioma, the transformation is unpredictable. Clinically, the bad outcome of a quota of astrocytomas is a well known phenomenon. The use of proliferation markers, and recently of MIB-1 LI, for detecting the proliferation potential comes out to be a useful tool for prognosis. A survival analysis of fifty astrocytomas grade II according to the WHO classification was performed with univariate and multivariate analysis of a series of clinical and histological parameters. MIB-1 LI was calculated and compared with all the other parameters. A cut-off of 8% of MIB-1 LI divided the astrocytomas in two groups with significantly different survival (p = 0.0066): median survival time of 1062 versus 1686 days. According to multivariate analysis MIB-1 LI resulted to be an independent factor (p = 0.002) along with extension of surgical removal (partial versus total), postoperative Karnofsky status (> or = 70 versus < 70) and age (< or = 30 versus > 30). The interpretation of well-differentiated astrocytomas with high MIB-1 LI is that the increasing number of cycling cells precedes phenotypic transformation. MIB-1 LI can be used as a prognostic factor.

Low-grade gliomas: introduction and overview

This issue of the Journal of Neuro-Oncology is devoted to recent investigations of low-grade gliomas. The purpose of this issue is not to debate the relative merits and liabilities of different management strategies for low-grade gliomas, but to present new data concerning novel and innovative approaches to evaluating these lesions. The common theme of many of these reports represents a departure from grading systems that primarily depend on a morphology-based analysis from light microscopy to classify these tumors. The purpose of this review is to present the reasoning behind the selection of authors for this issue of the Journal of Neuro-Oncology and to provide a format for presentation of new ideas concerning these interesting tumors. It is clear that standard classification systems that address only the morphological characteristics of tumor cells can not adequately represent the wide variation in biological activity that is found with these lesions. It is hoped that these articles will stimulate further interest and research into low-grade gliomas that will one day lead to more effective therapy.

Low grade gliomas: functional mapping resection strategies, extent of resection, and outcome

The impact of surgery on outcome of adult patients with low-grade gliomas is controversial. Without prospective randomized treatment trials, one is primarily dependent on retrospective studies to address this issue. This paper reviews the recent clinical series of low-grade gliomas in which the association between extent of resection (EOR) and outcome could be analyzed. Functional stimulation mapping methods will be described to point out their critical role in maximizing the extent of resection while minimizing the risk associated with radical resection of low-grade gliomas. Studies from the CT-era analyzed with multivariate statistical methods were emphasized. The analysis of these studies points out that, for astrocytomas, there is no clear consensus that a greater EOR improves survival, but in most series under review, greater EOR significantly extended the survival of patients with oligodendroglioma. Unfortunately, there is little data which specifically analyzes and stratifies the outcome for other end-points such as time to progression, malignant degeneration, mortality and morbidity, and duration of high quality survival by EOR.

Early vs. delayed radiotherapy in a small cohort of patients with supratentorial low grade glioma

In a cohort of 25 patients with supratentorial low grade glioma, the timing of radiotherapy made no significance difference for 10 year survival. Patients who received early radiotherapy had a 55% 10 year survival and those receiving delayed radiotherapy had a 53% 10 year survival. Radiotherapy was delayed a median of 4.8 years in those receiving delayed radiotherapy.

Low-grade gliomas of chronic epilepsy: a distinct clinical and pathological entity

The authors present a summary of their recent experience regarding the management of patients with a variety of low-grade gliomas found during the evaluation for chronic epilepsy. These tumors are notable because the long-term patient outcome in this population is significantly better than the anticipated results of patients with the same tumors who do not have chronic epilepsy. Based on the long history of preoperative seizures (median 14 years), the frequent cortical location, and the absence of tumor recurrence or anaplastic transformation and the lack of mortality in this population, low-grade gliomas of chronic epilepsy appear to define a specific pathological entity that separates them from other histologically similar low-grade gliomas. Low-grade gliomas of chronic epilepsy also are notable for the absence of morphological features that characterize with dysembryoplastic neuroepithelial tumors (DNTs). Our evidence suggests that low-grade gliomas of chronic epilepsy should be recognized as a distinct pathological entity.