Temozolomide as initial treatment for adults with low-grade oligodendrogliomas or oligoastrocytomas and correlation with chromosome 1p deletions

Correlation of chromosomes 1p and 19q status and expressions of O6-methylguanine DNA methyltransferase (MGMT), p53 and Ki-67 in diffuse gliomas of World Health Organization (WHO) grades II and III: a clinicopathological study

AIMS

The objective of the present study was to verify the correlation of chromosomes 1p and 19q status and expressions of O(6)-methylguanine DNA methyltransferase (MGMT), p53 and Ki-67 in diffuse gliomas of World Health Organization grades II and III.

METHODS

A series of 146 diffuse gliomas, including 45 oligodendrogliomas, 42 oligoastrocytomas and 59 astrocytomas, were analysed by denaturing high-performance liquid chromatography for 1p and 19q status and by immunohistochemistry for MGMT, p53 and Ki-67 expression patterns. The molecular alterations were then correlated with clinicopathological characteristics and with each other.

RESULTS

Loss of heterozygosity (LOH) on 1p, combined LOH on 1p and 19q, low MGMT expression and high Ki-67 expression were associated with oligodendroglial tumours, whereas high p53 expression was associated with astrocytic and mixed tumours. LOH on 1p and low MGMT expression were associated with grade II oligodendroglial tumours, whereas high expressions of p53 and Ki-67 were associated with grade III oligodendroglial tumours. In addition, high Ki-67 expression was associated with grade III astrocytomas. LOH on 1p and LOH on 19q were associated with nontemporal oligodendroglial tumours. Nonrandom associations were found between LOH on 1p and LOH on 19q, MGMT expression and p53 expression, and MGMT expression and Ki-67 expression, whereas mutual exclusions were found between LOH on 1p and 19q and p53 expression, and LOH on 1p and Ki-67 expression.

CONCLUSIONS

The present study revealed significant interrelationships of the investigated molecular alterations and clinicopathological characteristics in diffuse gliomas of World Health Organization grades II and III, which support a promising role of molecular markers in the diagnostic assessment of these neoplasms.

Intracranial low-grade gliomas in adults: 30-year experience with long-term follow-up at Mayo Clinic

The purpose of this study was to evaluate long-term survival in patients with nonpilocytic low-grade gliomas (LGGs). Records of 314 adult patients with nonpilocytic LGGs diagnosed between 1960 and 1992 at the Mayo Clinic, Rochester, Minnesota, were retrospectively reviewed. The Kaplan-Meier method estimated progression-free survival (PFS) and overall survival (OS). Median age at diagnosis was 36 years. Median follow-up was 13.6 years. Operative pathology revealed pure astrocytoma in 181 patients (58%), oligoastrocytoma in 99 (31%), and oligodendroglioma in 34 (11%). Gross total resection (GTR) was achieved in 41 patients (13%), radical subtotal resection (rSTR) in 33 (11%), subtotal resection in 130 (41%), and biopsy only in 110 (35%). Median OS was 6.9 years (range, 1 month-38.5 years). Adverse prognostic factors for OS identified by multivariate analysis were tumor size 5 cm or larger, pure astrocytoma histology, Kernohan grade 2, undergoing less than rSTR, and presentation with sensory motor symptoms. Statistically significant adverse prognostic factors for PFS by multivariate analysis were only tumor size 5 cm or larger and undergoing less than rSTR. In patients who underwent less than rSTR, radiotherapy (RT) was associated with improved OS and PFS. A substantial proportion of patients have a good long-term prognosis after GTR and rSTR, with nearly half of patients free of recurrence 10 years after diagnosis. Postoperative RT was associated with improved OS and PFS and is recommended for patients after subtotal resection or biopsy.

Long-term brain plasticity allowing a multistage surgical approach to World Health Organization Grade II gliomas in eloquent areas

Although the goal of surgery for World Health Organization Grade II gliomas is maximal extent of resection, complete tumor removal is not always possible when the glioma involves eloquent areas. The authors propose a multistage surgical approach to highly crucial areas that are classically considered inoperable, enabling optimization of the extent of resection while avoiding permanent cognitive deficits due to induced functional reshaping in the interim between the 2 consecutive operations. To demonstrate such plasticity, the authors used a combination of sequential functional MR imaging and intraoperative electrical stimulation mapping before and during surgeries spaced by several years in 2 patients who each underwent 2 separate resections of Grade II gliomas located in the left dominant premotor area. During several years of follow-up after the first procedure, both patients had unremarkable examination results and normal socioprofessional lives. There was no malignant transformation. Based on their experience with these cases, the authors suggest that in cases of incomplete glioma removal, a second operation before anaplasia should be considered, made possible by brain reorganization after the first operation.

Pharmacogenomics of brain cancer and personalized medicine in malignant gliomas

The pharmacogenetics of cancer treatment has been aimed at identifying genetic components of interindividual variability in patients' response to cancer chemotherapy and toxicity. This, in turn, will establish an individually based treatment, and also elucidate the molecular basis of the treatment regimen for further improvements. Brain cancer is an instructive example for the potential contributions of pharmacogenomics to improved treatment in the 21st century. Patients with oligodendrogliomas have benefited from phamacogenomics, as there is a clear relationship between response to chemotherapy and chromosomal profile. Drug efficacy, safety and response could be improved by using pharmacogenomics to identify genetic markers that differentiate responder from nonresponder patient groups, as well as identifying patients likely to develop adverse drug reactions. This review will focus on how pharmacogenomics by microarray studies may lead to much more accurate tumor classification, drug and biomarker discovery, and drug efficacy testing. We will discuss relevant scientific advances in pharmacogenetics for more personalized chemotherapy.

Correlations between molecular profile and tumor location in Chinese patients with oligodendroglial tumors

OBJECTIVE

To investigate possible correlations between molecular alterations and tumor location in Chinese patients with oligodendroglial tumors.

METHODS

A series of 105 gliomas, including 42 oligoastrocytomas, and two control groups of 28 oligodendrogliomas and 35 astrocytomas, were retrospectively reviewed. In each case, the radiologic picture and loss of heterozygosity (LOH) on chromosome 1p and 19q detected by denaturing high-performance liquid chromatography (DHPLC) were analyzed. Correlations between molecular profile and tumor location were made by chi-square and Fisher's exact tests.

RESULTS

Oligodendroglial tumors located in the nontemporal lobes were significantly more likely to have combination of LOH 1p and LOH 19q than tumors arising in the insula, temporal lobe, and temporal with another lobe (p=0.001). Subgroup analysis confirmed this finding in oligodendrogliomas (p=0.006), but the difference did not reach significance in the oligoastrocytoma group, although the trend was similar (p=0.067). In contrast to the oligodendroglial tumors, we detected no association between molecular alterations and location for diffuse astrocytomas.

CONCLUSION

We conclude that molecular subsets of oligodendroglial tumors may arise preferentially in certain lobes of the brain, with tumors having LOH 1p and LOH 19q occurring most frequently in the nontemporal lobes. These findings suggest that molecular subsets of oligodendroglial tumors may arise from site-specific precursor cells, which has provided some information for the current management of these neoplasms in China.

Bone marrow transplantation for severe aplastic anemia secondary to temozolomide

Radiotherapy (RT) and concomitant/adjuvant therapy with temozolomide (Temodar) is a common treatment regimen for children and adults with glioma. Although temozolomide is generally well tolerated with temporary myelosuppression as the primary dose-limiting toxicity, irreversible bone-marrow aplasia after treatment with temozolomide has been reported. We report the case of an adolescent patient with a high-grade glioma who, after >2 years of event-free survival, underwent successful bone marrow transplantation for treatment of temozolomide-induced severe aplastic anemia (SAA).

Quality of life in low-grade glioma patients receiving temozolomide

The purpose of this study was to describe the quality of life (QOL) of low-grade glioma (LGG) patients at baseline prior to chemotherapy and through 12 cycles of temozolomide (TMZ) chemotherapy. Patients with histologically confirmed LGG with only prior surgery were given TMZ for 12 cycles. QOL assessments by the Functional Assessment of Cancer Therapy-Brain (FACT-Br) were obtained at baseline prior to chemotherapy and at 2-month intervals while receiving TMZ. Patients with LGG at baseline prior to chemotherapy had higher reported social well-being scores (mean difference = 5.0; p < 0.01) but had lower reported emotional well-being scores (mean difference = 2.2; p < 0.01) compared to a normal population. Compared to patients with left hemisphere tumors, patients with right hemisphere tumors reported higher physical well-being scores (p = 0.01): 44% could not drive, 26% did not feel independent, and 26% were afraid of having a seizure. Difficulty with work was noted in 24%. Mean change scores at each chemotherapy cycle compared to baseline for all QOL subscales showed either no significant change or were significantly positive (p < 0.01). Patients with LGG on TMZ at baseline prior to chemotherapy reported QOL comparable to a normal population with the exception of social and emotional well-being, and those with right hemisphere tumors reported higher physical well-being scores compared to those with left hemisphere tumors. While remaining on therapy, LGG patients were able to maintain their QOL in all realms. LGG patients' QOL may be further improved by addressing their emotional well-being and their loss of independence in terms of driving or working.

[Diagnostic and prognostic values of 1p and 19q deletions in adult gliomas: critical review of the literature and implications in daily clinical practice]

Losses of chromosomes 1p and 19q are deemed correlated with diagnosis of oligodendroglioma, higher chemosensitivity and better prognosis. We reviewed the literature to evaluate the usefulness of these correlations in daily clinical practice. The rates of deletions relative to histology (WHO classifications) were extracted from 33 studies, including 2666 patients. The 1p deletions and 1p19q codeletion mean rates were respectively 65.4 and 63.3% in oligodendrogliomas, 28.7 and 21.6% in oligoastrocytomas, 13.2 and 7.5% in astrocytomas, 11.6 and 2.9% in glioblastomas. The presence of 1p deletion and 1p19q codeletion were strongly correlated with the histological diagnosis corresponding to oligodendroglioma. Calculation of specificity, sensitivity, predictive positive values and false negative rates suggests that presence of deletion 1p or codeletion represents a strong argument in favor of the diagnosis of oligodendroglioma. However, considering the high false negative rate, absence of such deletions does not rule out the diagnosis. In grade 3 oligodendroglial tumors, the probability of responding to chemotherapy, and the duration of response, were higher when codeletions were present. This suggests that, in these tumors, the presence of codeletion is a strong argument in favor of adjuvant chemotherapy. However, chemotherapy should not be systematically excluded when codeletions are absent, as the chances of response are about 33% in this situation. Data concerning low-grade gliomas were more controversial. Oligodendroglial tumors with 1p deletion or 1p19q codeletion seemed to have a better prognosis, as five-year survival rates were 50% higher than in tumors without deletion. This might be explained by the correlation between 1p deletion and other identified prognosis factors: (1) higher chemosensitivity, (2) tumor location more frequently in the frontal lobe, leading to better resection and lower risk of neurological deficit, (3) slower growth rate, (4) higher risk of epilepsy, leading to an early detection.

Chromosomal alterations in oligodendroglial tumours over multiple surgeries: is tumour progression associated with change in 1p/19q status?

BACKGROUND

Oligodendroglial neoplasms have morphologic and genotypic heterogeneity. Loss of heterozygosity (LOH) of 1p and/or 19q is associated with increased treatment responsiveness and overall survival. However, the pathogenesis of treatment-resistance is unknown. We sought to determine if tumour progression is due to a proliferating sub-population of tumour cells with intact 1p, or if recurrent tumours retain 1p/19q LOH.

METHODS

24 patients with oligodendroglial neoplasms, possessing biopsy samples taken at diagnosis and at progression, were identified. 53 tumour specimens were available for LOH analysis of 1p and 19q, using PCR amplification of multiple microsatellite markers. 40 were also tested for 9p and 10q.

RESULTS

At diagnosis, the median age was 34 (24-66) years, 14 were male. 19 tumours were WHO Grade II, and 5 were high grade. The most common genomic status was 19q LOH (70%). 13 (54%) tumours were 1p LOH at diagnosis: of these, 12 were 19q LOH, and 1 was 19q uninformative. All 12 patients with 1p/19q LOH primary tumours had persistent co-deletion at progression. 9 (38%) tumours were 1p intact at diagnosis, and 8 remained 1p intact in the progressed tumours. There was little heterogeneity of 9p and 10q between tumours at diagnosis and progression.

CONCLUSION

100% of oligodendroglial tumours with 1p/19q LOH, demonstrated persistent 1p/19q LOH in the progressed tumour. Therefore, progression of these tumours is not due to a proliferating sub-population of treatment-resistant, 1p intact tumour cells. We propose that additional mutations contribute to this aggressive phenotype, however, 9p LOH or 10q LOH are unlikely to be involved.

Temozolomide three weeks on and one week off as first line therapy for patients with recurrent or progressive low grade gliomas

BACKGROUND

Patients with recurrent or progressive low grade gliomas survive for a decade or more following diagnosis, and may be at a higher risk for treatment-related complications, such as cognitive impairment from radiotherapy.

PURPOSE

The aim of the present study was to determine in patients with progressive or recurrent low grade gliomas, the response rate and toxicity incurred by a continued schedule of temozolomide chemotherapy administered before radiation therapy, and to explore correlations between response and survival with 1p/19q deletions and MGMT promoter methylation status.

METHODS

Progressive radio and chemotherapy naïve low grade glioma patients with O(6)-methyl-guanine-DNA-methyl-tranferase (MGMT) promoter status evaluation were considered eligible. Chemotherapy cycles consisted of temozolomide 75 mg/m(2)/daily for 21 days every 28 days for 12 cycles.

RESULTS

A total of 30 patients (median age 45 [range: 24.2-68.6] years) with a median KPS of 90 (range 60-90) were accrued. The overall response rate was 30% (9 partial responses); 17 patients (56.7%) had disease stabilization.

CONCLUSION

The prolonged temozolomide schedule considered in the present study is followed by a high response rate; toxicity is acceptable. Further randomized trials should therefore be conducted to confirm the efficacy of this regimen as first-line therapy in patients with progressive low grade glioma.

Adjuvant treatment of anaplastic oligodendrogliomas and oligoastrocytomas

BACKGROUND

AO and AOA are known to be chemosensitive tumors. However, the impact of adding chemotherapy to surgery and radiotherapy has not been studied. Also, the value of chromosome 1p and 19q deletions as prognostic and predictive markers is only beginning to be defined.

OBJECTIVES

After surgery, to compare radiotherapy (RT) plus chemotherapy versus RT alone (standard of care) in adults with newly diagnosed AO or mixed AOA. To investigate the prognostic and predictive value of loss of heterozygosity of chromosomes 1p and 19q. Outcomes analyzed include overall survival (OS), progression-free survival (PFS), and treatment toxicity greater than or equal to grade 3.

SEARCH STRATEGY

Cochrane Central Register for Controlled Trials (CENTRAL, Issue 4,2006), MEDLINE (1966 to 2006) and EMBASE (1988 to 2006) were searched. Reference lists from relevant studies were scanned for any additional relevant articles.

SELECTION CRITERIA

RCTs of adults with AO or mixed AOA comparing surgery plus RT versus surgery plus RT plus chemotherapy were included. No specific chemotherapy regimens were excluded.

DATA COLLECTION AND ANALYSIS

Relevant studies were critically appraised and data was extracted. Based on the differences in patient selection with respect to the definition of AO (2 versus 3 high risk anaplastic features) and sequence of treatment (RT and chemotherapy), the results from the two RCTs were not able to be considered for meta-analysis.

MAIN RESULTS

Two RCTs have tested surgery plus RT plus early procarbazine, lomustine, and vincristine (PCV) chemotherapy versus surgery plus RT alone. Neither study observed a survival benefit with the addition of early PCV chemotherapy. However, both studies found a statistically significant increase in PFS associated with the administration of PCV chemotherapy before surgery or after surgery and RT, with the benefit ranging from 10 to 11 months. Co-deletion of chromosomes 1p and 19q identifies a favorable subgroup of tumors with better overall survival outcomes. The predictive value of 1p and 19q co-deletions is less clear with one study observing a longer PFS with chemotherapy, while the other study did not.

AUTHORS' CONCLUSIONS

Early PCV chemotherapy in addition to standard treatment of surgery and RT does not improve OS in patients with AO or AOA. However, it does improve PFS. It also is associated with significant toxicities. Tumors with 1p and 19q co-deletions are associated with better OS and may indicate a more chemo-responsive tumor.

Molecular diagnostic testing in malignant gliomas: a practical update on predictive markers

Advances in understanding the molecular underpinnings of cancer and in molecular diagnostic technologies have changed the clinical practice of oncologic pathology. The development of targeted therapies against specific molecular alterations in cancer further portends changes in the role of the pathology laboratory to guide such custom therapies. To reconcile the flood of scientific discoveries in this area, the promises of highly touted novel therapeutics, and the practicality of applying this knowledge to the day-to-day practice of clinical neuropathology, the present review highlights the operative differences between diagnostic, predictive, and prognostic markers, and discusses issues surrounding the transition of prospective biomarkers to routine laboratory implementation. This review focuses on 3 predictive molecular markers that are either in clinical use or are contemplated for use in the evaluation of malignant gliomas: assessment of 1p/19q loss in oligodendroglial tumors, examination of O6-methylguanine DNA methyltransferase promoter methylation status in glioblastomas, and molecular dissection of the epidermal growth factor receptor-phosphatidylinositol 3-kinase pathway in glioblastomas. Implementation of such predictive markers is not straightforward and requires critical review of the available literature and attention to practical laboratory, compliance, financial, and clinical management issues.

Predictive and prognostic markers in neuro-oncology

Over the past few years molecular assays have been introduced to aid in typing and grading of gliomas. This is the result of improved understanding of these tumors at the molecular level. In particular, the presence or absence of combined 1p/19 loss in oligodendroglial tumors, epidermal growth factor receptor amplification, epidermal growth factor receptor vIII mutations in grade III tumors and glioblastoma multiforme, and MGMT promoter gene methylation in glioblastoma multiforme are now being used to tailor treatment decisions in patients. However, the application of these tests is far from straightforward, and certain standards are required before any test can be introduced in the daily management of patients. Some of these requirements concern inter- and intratest variability, including whether a test gives the same results if repeated in the same or in another laboratory or when different methodologies are used (e.g. loss of heterozygosity vs fluorescence in situ hybridization and a polymerase chain reaction-based test vs immunohistochemistry). The sensitivity and specificity of a test (or negative and positive predictive value) indicate the likelihood that the test results are positive if the disease is present and the likelihood that the disease is present if the test results are positive. Studies on these test characteristics usually require the presence of a gold standard to which new tests should be compared. Last but not least there is the question of what added value the test has; this criterion determines the clinical usefulness of the assay and why some recently introduced molecular assays need to be scrutinized.

Management of patients with low-grade gliomas

The accurate diagnosis and management of patients who have infiltrating low-grade gliomas is increasing in importance. Recent advances in molecular characterization, imaging, and treatment of these tumors underscore this current focus of investigations.

Molecular pathology of malignant gliomas

Malignant gliomas, the most common type of primary brain tumor, are a spectrum of tumors of varying differentiation and malignancy grades. These tumors may arise from neural stem cells and appear to contain tumor stem cells. Early genetic events differ between astrocytic and oligodendroglial tumors, but all tumors have an initially invasive phenotype, which complicates therapy. Progression-associated genetic alterations are common to different tumor types, targeting growth-promoting and cell cycle control pathways and resulting in focal hypoxia, necrosis, and angiogenesis. Knowledge of malignant glioma genetics has already impacted clinical management of these tumors, and researchers hope that further knowledge of the molecular pathology of malignant gliomas will result in novel therapies.

Temozolomide in pediatric low-grade glioma

BACKGROUND

We describe a retrospective series of children with low-grade glioma who received temozolomide.

PROCEDURE

Eligible patients had had a diagnosis of low-grade glioma with or without histological confirmation. Temozolomide was administered at a dose of 200 mg/m(2) daily for 5 days, in a 4-week cycle. Therapy was stopped on completion of the targeted 12 cycles of chemotherapy or on evidence of tumor progression.

RESULTS

Thirteen eligible patients were identified, eight male and five female. Median age at diagnosis was 5.5 years (range 2.6-15.0 years) and at commencement of temozolomide treatment was 9.0 years (range 3.8-15.2 years). Nine patients had a histological diagnosis of pilocytic astrocytoma. Twelve patients had received carboplatin prior to temozolomide, including three in combination with vincristine. A total of 111 cycles of therapy have been administered. Hematological toxicity and nausea were the most common adverse effects. Median time to progression was 6.7 months (range 1.5-41.8 months). Event-free survival rate at 3 years was 57%. Twelve of 13 patients remain alive at the time of report. Eleven have stable disease (SD).

CONCLUSION

Temozolomide appears to be active in pediatric low-grade glioma, with the advantage of oral administration and excellent tolerability.

Temozolomide and radiation in low-grade and anaplastic gliomas: temoradiation

Recently completed trials suggest the addition of nitrosourea-based chemotherapy to radiotherapy increases the progression-free but not overall survival of grade II and III gliomas. Temozolomide has proven benefit in grade II/III gliomas progressive following standard therapy and when added to radiation for glioblastoma. Newly launched and planned phase III trials will explore whether the addition of temozolomide to radiotherapy improves overall survival in grade II/III as well as the prognostic and predictive value of 1p/19q analyses and MGMT promotor methylation status. Additionally, they will measure cognition and quality of life to determine if improvements in time to progression translate into better functional status and patient satisfaction.

Central nervous system tumors

Central nervous system tumors are relatively common in the United States, with more than 40,000 cases annually. Although more than half of these tumors are benign, they can cause substantial morbidity. Malignant primary brain tumors are the leading cause of death from solid tumors in children and the third leading cause of death from cancer in adolescents and adults aged 15 to 34 years. Common presenting symptoms include headache, seizures, and altered mental status. Whereas magnetic resonance imaging helps define the anatomic extent of tumor, biopsy is often required to confirm the diagnosis. Treatment depends on the histologic diagnosis. Benign tumors are usually curable with surgical resection or radiation therapy including stereotactic radiation; however, most patients with malignant brain tumors benefit from chemotherapy either at the time of initial diagnosis or at tumor recurrence. Metastases to the brain remain a frequent and morbid complication of solid tumors but are frequently controlled with surgery or radiation therapy. Unfortunately, the mortality rate from malignant brain tumors remains high, despite initial disease control. This article provides an overview of current diagnostic and treatment approaches for patients with primary and metastatic brain tumors.

Prise en charge des gliomes de bas grade: série rétrospective de 201 patients

BACKGROUND AND PURPOSE

Optimal treatment for low-grade glioma remains controversial. Moreover, though surgery is recommended for disease management, evidence is lacking concerning the appropriate extent of surgery and the use of adjunctive therapy. Available data is basically retrospective, coming from series with substantial limitations. We reviewed our institution's series in order to evaluate the efficiency of surgical management and the influence of the extent of surgical removal for patients with low-grade glioma.

METHODS

Data were collected from a series of 201 patients who underwent first-intention therapy for low-grade glioma, the standard practice in our institution between 1994 and 2005. After applying certain exclusion criteria, we retained for analysis 123 patients with grade II glioma (WHO classification). We compared progression-free survival curves for the three surgical treatment groups defined as biopsy, partial removal, or total removal.

RESULTS

Statistical evaluation of the progression free survival shows a benefit in total surgery as a first intention treatment. No statistical significance was demonstrated between partial surgery and stereotactic biopsy.

CONCLUSION

For patients with low-grade glioma we recommend total surgical removal as first intention management.

Dynamic history of low-grade gliomas before and after temozolomide treatment

OBJECTIVE

To evaluate the natural progression and the impact of temozolomide in low-grade gliomas and to correlate these changes with the profile of genetic alterations.

METHODS

The mean tumor diameter (MTD) of low-grade gliomas was evaluated on serial magnetic resonance images before (n = 39), during, and after (n = 107) treatment with neoadjuvant temozolomide. MTD growth curves were correlated with chromosomes 1p-19q loss and p53 overexpression in the tumors.

RESULTS

Before temozolomide onset, MTD increased linearly over time, indicating a continuous growth that was significantly slower in 1p-19q deleted tumors (3.4 vs 5.9mm/year; p = 0.0016) and in tumors that did not overexpress p53 (4.2 vs 6.3mm/year; p = 0.05). During temozolomide treatment, almost all patients (92%) experienced initial decrease of MTD. Subsequently, some tumors started to resume growth despite continuous administration of temozolomide, with a lower rate of relapse in 1p-19q deleted tumors (16.6 vs 58%; p = 0.0004) and in tumors that did not overexpress p53 (26 vs 68%; p = 0.003). When temozolomide was discontinued in the absence of tumor progression, a majority of tumors resumed their progressive growth within a year.

INTERPRETATION

Untreated low-grade gliomas grow continuously at a rate that is influenced by the genetic alterations of the tumors. Temozolomide reverses this pattern at the onset, but this effect is often brief in patients whose tumors overexpress p53 and do not harbor the 1p-19q codeletion, suggesting acquired chemoresistance. A majority of tumors will resume their growth when treatment is discontinued, raising the issue of the optimal duration of treatment in continuously responding patients.

Role of exclusive chemotherapy as first line treatment in oligodendroglioma

PURPOSE

The optimal therapy of oligodendrogliomas remains uncertain. Although chemosensitive, these tumors are not chemocurable. We investigated whether chemotherapy delays the need for radiation therapy (RT) without decreasing length and quality of survival.

METHODS AND MATERIALS

Among 89 patients treated for oligodendrogliomas at the Centre Léon Bérard of Lyon from 1982 to 1999, 59 patients fitted inclusion criteria, having had centrally reviewed pure oligodendroglioma requiring treatment. According to the WHO's classification 35 patients had Grade III and 24, Grade II oligodendrogliomas.

RESULTS

According to the intent to treat, patients were retrospectively classified in three groups as exclusive RT (Group 1), radio-chemotherapy (Group 2), or exclusive chemotherapy (Group 3). Median progression-free survival (PFS): was 47 months [95% confidence interval (CI) 39-56], and median overall survival (OS) was 109 months (95% CI 83-134). In univariate analysis, PFS was correlated with frontal location and WHO classification; OS was correlated with frontal location and Post-operative Karnosky performans status both appearing as independent prognostic factors for OS in multivariate analysis. There was no significant difference between the treatment groups with regard to PFS (P = 0.82) and OS (P = 0.64). In the group of patients treated with exclusive chemotherapy the 5-year PFS and OS rates were 44 and 71%, respectively.

CONCLUSION

Front-line exclusive chemotherapy results in prolonged OS in patients with confirmed pure oligodendroglioma. Whether this strategy improves quality of life remains debatable.

Treatment of newly diagnosed symptomatic pure low-grade oligodendrogliomas with PCV chemotherapy

Based on studies relating to anaplastic oligodendroglioma (OG) chemosensitivity and benefit of time to progression or overall survival, chemotherapy for pure OG has been proposed. Several studies have reported the efficacy of various chemotherapeutic agents in a small number of patients with low-grade gliomas, e.g. pure astrocytomas, OG or mixed histologies. The 5-year survival rate varies from 61% to 89% with a mean time to progression of 5 years. We report the outcome of 33 consecutive patients with pure low-grade OG diagnosed between 1990 and 2006 systematically treated for residual or non-removable tumor with PCV chemotherapy regimen as the front-line treatment after surgery. All the tumors were low grade (grade II) pure OG according to the WHO classification. All patients were symptomatic at presentation and underwent neurosurgical procedure for histological diagnosis. Response was evaluated by clinical assessment and brain magnetic resonance imaging. Twenty-one men and 12 women with a mean age at pathological diagnosis of 46.5 years were studied. The most common first symptom was partial epileptic seizure (73.7%). Six patients (18%) had initial gadolinium enhancement, associated with methoxyisobutyl (MIBI) hypermetabolism (P < 0.001). The resection was partial in seven cases (21%), and 26 patients (79%) had biopsy only. Eleven patients (36%) had a malignant transformation during the follow-up with a median time to progression of 19 months. Favorable prognostic factors were lack of contrast enhancement (P < 0.0001), and age <40 years (P < 0.0003); 90% of patients were progression-free at 1 year. Survival rates at 2, 5 and 10 years were 85%, 75% and 50%, respectively. Up-front chemotherapy with PCV regimen is a good treatment for symptomatic pure low-grade OG, as it increases the number of progression-free patients and time to progression. These results suggest that radiotherapy could be postponed until the malignant transformation occurs to delay cognitive side effects of irradiation.

Temozolomide in children with progressive low-grade glioma

We conducted a phase II study to assess the efficacy of oral temozolomide (TMZ) in children with progressive low-grade glioma. Thirty eligible patients were enrolled on this study. Median age at enrollment was 10 years (range, 4-18 years). Eligible patients received TMZ (200 mg/m(2) per day) by mouth for five days every four weeks. Patients received a median of nine cycles (range, 2-12 cycles) of treatment. Best responses in the 26 patients (86%) with optic pathway glioma (OPG)/pilocytic astrocytoma (PA) included partial response in 3 patients (11%), minor response in 1 (4%), stable disease in 10 (38%), and progressive disease in 12 (46%). Only one of four patients with fibrillary astrocytoma had stable disease for 29 months after TMZ. The overall disease stabilization rate in patients with OPG/PA was 54%, and disease control was maintained for a median interval of 34 months. Seventeen of 26 patients had progressive disease either on or off therapy, and three have died of disease. The two-year progression-free and overall survivals in patients with OPG/PA were 49% (95% CI, 30%-67%) and 96% (95% CI, 89%-100%), respectively. Worst toxicity related to TMZ in all 30 patients included grade 2-4 thrombocytopenia in seven patients, grade 2-4 neutropenia in seven, grade 2 skin rash in one, and intratumor hemorrhage in one. TMZ given in this schedule was successful in stabilizing disease in a significant proportion of the patients with OPG/PA, with manageable toxicity.

Clinicopathologic aspects of 1p/19q loss and the diagnosis of oligodendroglioma

CONTEXT

Significant interobserver variability exists with respect to the diagnosis of oligodendroglial neoplasms, especially their distinction from astrocytoma and mixed oligoastrocytoma. Combined loss of the short arm of chromosome 1 and the long arm of chromosome 19 has been shown to be both relatively specific to oligodendroglioma and, when present, a marker of improved prognosis in patients with these tumors. In addition, 1p/19q loss has been shown to be a marker of "classic" oligodendroglial histology. These findings raise questions as to the role of 1p/19q testing in clinical practice, both as a prognostic marker and as a potential diagnostic marker among infiltrating glial neoplasms.

OBJECTIVE

This review discusses the issues raised above and tries to clarify the current status of 1p/19q evaluation in the diagnosis of oligodendroglioma.

DATA SOURCES

Sources for this review include recent literature as well as the experience of 3 practicing neuropathologists.

CONCLUSIONS

1p/19q status is an important marker in oligodendroglioma. Loss of 1p/19q is associated with classic oligodendroglioma histology as well as improved prognosis. The combined 1p/19q marker will continue to be a clinically useful marker of prognosis and could potentially be incorporated into diagnostic criteria in the future.

MGMT methylation: a marker of response to temozolomide in low-grade gliomas

The methylation status of the O6-methylguanine-methyltransferase promoter (MGMTP) was evaluated in 68 low-grade gliomas treated by neoadjuvant temozolomide. Methylated MGMTP was detected in 63 of 68 (92.6 %) patients and was a favorable predictor of progression-free survival as compared with unmethylated MGMTP tumors (p < 0.0001). Assessment of MGMTP status could help identifying low-grade gliomas patients more likely to respond to chemotherapy or to benefit from MGMT depletion strategies.

Glioma therapy in adults

BACKGROUND

Gliomas are the most common type of primary brain tumor. Nearly two-thirds of gliomas are highly malignant lesions that account for a disproportionate share of brain tumor-related morbidity and mortality. Despite recent advances, two-year survival for glioblastoma with optimal therapy is less than 30%. Even among patients with low-grade gliomas that confer a relatively good prognosis, treatment is almost never curative.

REVIEW SUMMARY

Surgery and radiation have been the mainstays of therapy for most glioma patients, but temozolomide chemotherapy has recently been proven to prolong overall survival in patients with glioblastoma. Intriguing data suggests that activity of O6-methylguanine-DNA methyltransferase (MGMT), in tumor cells may predict responsiveness to temozolomide and other alkylating agents. Novel treatment approaches, especially targeted molecular therapies against critical components of glioma signaling pathways, appear promising in preliminary studies. Optimal treatment for patients with low-grade gliomas has yet to be determined. Advances in oligodendroglioma biology have identified loss of chromosomes 1p and 19q as powerful indicators of a favorable prognosis. These same changes may predict response to chemotherapy.

CONCLUSIONS

Though the prognosis for many patients with gliomas is poor, the last decade produced a number of important advances, some of which have translated directly into survival benefits. Rapid progress in the field of glioma molecular biology continues to identify therapeutic targets and provide hope for the future of this challenging disease.

Chromosome 1p and 19q status and p53 and p16 expression patterns as prognostic indicators of oligodendroglial tumors: A clinicopathological study using fluorescence in situ hybridization

To verify the prognostic implications of the statuses of chromosome 1p and 19q and the expressions of p53, p16 and GFAP in oligodendrogliomas, we investigated these parameters and correlated the results with patient outcome. Twenty-seven cases of low-grade oligodendroglioma (LO) and 29 cases of anaplastic oligodendroglioma (AO) were analyzed by FISH for 1p and 19q status and by immunohistochemistry for p53, p16, and GFAP expression using a tissue microarray. Direct sequencing of the p53 gene was also performed. 1p deletion was observed in 39 of 56 patients (69.9%), and 19q deletion in 41 of 56 (73.2%). Combined loss of 1p and 19q was found in 38 of 56 (67.9%) and exhibited distinct concomitant deletion (P = 0.000). p53 overexpression was observed in 17 cases (30.3%), GFAP expression in 18 cases (32.1%), and p16 loss in 40 cases (74%) of oligodendrogliomas. The expressions of p53 and GFAP were more frequent in AO than in LO (P= 0.015 and 0.001). In contrast, p53 expression was more common in oligodendrogliomas with an intact 19q (P= 0.029), or an intact 1p (P= 0.071). Only five of 14 patients with p53 expression showed TP53 mutation, which was inversely correlated with 1p deletion (P= 0.036). Patients with combined loss of 1p and 19q exhibited better overall survival (P = 0.045). Patients with p53 expression without combined 1p and 19q loss showed poor overall survival (P < 0.000). However, TP53 mutation along with 1p and 19q status could not predict patient outcome. Patients with p16 loss without combined 1p and 9q loss showed poor overall survival (P = 0.011). Therefore, in oligodendrogliomas, the absence of the combined deletion of 1p and 19q and the aberrant expression of p53 or loss of p16 could be used as poor prognostic markers.

The changing management of low-grade astrocytomas and oligodendrogliomas

Low-grade gliomas are uncommon primary brain tumors that preferentially affect young to middle-aged adults. Although they are indolent tumors, low-grade gliomas cause considerable and progressive morbidity and are ultimately fatal. Surgery and radiotherapy are the primary therapeutic options for patients with these diseases. Chemotherapy is playing a larger role in the management of patients with low-grade gliomas. Patients with oligodendrogliomas or other low-grade gliomas that harbor a distinct genetic derangement characterized by allelic loss of chromosomes 1p and 19q appear to have a superior prognosis that is due in part to a more predictable and durable response to treatment. For this subset of patients with low-grade gliomas, treatment with initial chemotherapy and deferred radiotherapy is an increasingly attractive therapeutic approach.

Chemotherapeutic options for primary brain tumors

Malignant gliomas are the most common primary brain tumors. Despite intensive clinical investigation and many novel therapeutic approaches, treatment for most primary brain tumors remains inadequate. Most are associated with a high rate of recurrence after primary therapy and a dismal outcome following recurrence. Surgery and radiation remain the primary modalities of therapy for malignant brain tumors. The role of chemotherapy in malignant gliomas, especially glioblastoma multiforme, has been inconclusive. However, a recent trial by the European Organisation for Research and Treatment of Cancer and the National Cancer Institute of Canada combining radiation therapy with temozolomide for newly diagnosed glioblastoma patients showed a significantly improved survival benefit over radiation therapy alone. In addition to this encouraging progress, recent experience has shown that selected malignant brain tumors--for example, anaplastic oligodendrogliomas, primary central nervous system lymphomas, medulloblastomas, and intracranial germ cell tumors--are often highly responsive to chemotherapy. Molecular genetic studies are becoming indispensable aids in the diagnosis and treatment of the malignant gliomas. For example, we have learned that allelic loss of chromosome 1p is a significant predictor of chemosensitivity, whereas combined loss of chromosomes 1p and 19q is a strong predictor of chemosensitivity, progression-free survival, and overall survival in patients with anaplastic oligodendroglioma. Similarly, MGMT promoter methylation is associated with more frequent responses and longer survival in patients with glioblastoma multiforme receiving temozolomide-based therapy. These and other recent advances have led to the development and testing of several novel chemotherapeutic and molecular-targeted agents. Several different approaches and modalities to improve the efficacy of chemotherapy (eg, MGMT promoter methylation) are currently under way. Clinical trials implementing angiogenesis inhibitors, biologic modifiers, or molecular-targeted therapies are also actively being investigated.

Cerebral Blood Volume Measurements and Proton MR Spectroscopy in Grading of Oligodendroglial Tumors

OBJECTIVE

The purpose of this study was to determine whether perfusion-weighted imaging (PWI) and proton MR spectroscopy (MRS) are useful in differentiating high- and low-grade oligodendroglial tumors.

MATERIALS AND METHODS

PWI and MRS studies of 22 patients with histologically proven oligodendroglioma or oligoastrocytoma (13 low-grade and nine anaplastic tumors) were retrospectively reviewed. PWI of 14 subjects was performed with a dynamic contrast-enhanced susceptibility-weighted echo-planar technique. Intratumoral relative cerebral blood volume ratio was calculated and normalized to the same value in contralateral normal-appearing white matter. Multivoxel MRS was performed with a point-resolved spectroscopy sequence at a TE of 135 milliseconds in 20 patients and with the addition of a TE of 30 seconds in 17 patients. MRS data were expressed as intratumoral metabolite ratios (choline to creatine [Cho/Cr], choline to N-acetyl aspartate, N-acetyl aspartate to creatine, and myoinositol to creatine).

RESULTS

Relative cerebral blood volume ratios were significantly different (p = 0.004) between low-grade (1.61 +/- 1.20) and high-grade tumors (5.45 +/- 1.96). The optimal relative cerebral blood volume ratio cutoff value in identification of anaplastic oligodendroglial tumors was 2.14. Analysis of MRS data showed significantly higher Cho/Cr ratios (p = 0.002) in high-grade than in low-grade tumors. A Cho/Cr ratio cutoff value of 2.33 had the highest accuracy in identification of high-grade tumors.

CONCLUSION

Relative cerebral blood volume measurement and MRS are helpful in differentiating low-grade from anaplastic oligodendroglial tumors.

A t(1;19)(q10;p10) mediates the combined deletions of 1p and 19q and predicts a better prognosis of patients with oligodendroglioma

Combined deletion of chromosomes 1p and 19q is associated with improved prognosis and responsiveness to therapy in patients with anaplastic oligodendroglioma. The deletions usually involve whole chromosome arms, suggesting a t(1;19)(q10;p10). Using stem cell medium, we cultured a few tumors. Paraffin-embedded tissue was obtained from 21 Mayo Clinic patients and 98 patients enrolled in 2 North Central Cancer Treatment Group (NCCTG) low-grade glioma trials. Interphase fusion of CEP1 and 19p12 probes detected the t(1;19). 1p/19q deletions were evaluated by fluorescence in situ hybridization. Upon culture, one oligodendroglioma contained an unbalanced 45,XX,t(1;19)(q10;p10). CEP1/19p12 fusion was observed in all metaphases and 74% of interphase nuclei. Among Mayo Clinic oligodendrogliomas, the prevalence of fusion was 81%. Among NCCTG patients, CEP1/19p12 fusion prevalence was 55%, 47%, and 0% among the oligodendrogliomas, mixed oligoastrocytomas, and astrocytomas, respectively. Ninety-one percent of NCCTG gliomas with 1p/19q deletion and 12% without 1p/19q deletion had CEP1/19p12 fusion (P < 0.001, chi(2) test). The median overall survival (OS) for all patients was 8.1 years without fusion and 11.9 years with fusion (P = 0.003). The median OS for patients with low-grade oligodendroglioma was 9.1 years without fusion and 13.0 years with fusion (P = 0.01). Similar significant median OS differences were observed for patients with combined 1p/19q deletions. The absence of alterations was associated with a significantly shorter OS for patients who received higher doses of radiotherapy. Our results strongly suggest that a t(1;19)(q10;p10) mediates the combined 1p/19q deletion in human gliomas. Like combined 1p/19q deletion, the 1;19 translocation is associated with superior OS and progression-free survival in low-grade glioma patients.

Toxicity and efficacy of protracted low dose temozolomide for the treatment of low grade gliomas

Protracted low dose temozolomide (75 mg/m(2)/day on days 1-21 of 28 days) offers potential advantages over standard temozolomide schedules (200 mg/m(2)/day on days 1-5 of 28 days) including greater cumulative drug exposure and depletion of O(6)-alkylguanine DNA alkyltransferase levels, theoretically overcoming intrinsic chemoresistance. We retrospectively review our experience in 25 patients with pathologically proven low grade gliomas (LGG) treated with protracted low dose temozolomide to primarily quantify its toxicity and secondarily to assess efficacy. None had previously received radiation. Tumor response was graded based on changes in tumor size, steroid requirements, and clinical exam. About 243 cycles of protracted low dose temozolomide were administered. Three patients (12%) were changed to standard temozolomide dosing due to side effects, including intractable nausea (n = 2) and multiple cytopenias (n = 1). The most frequent toxicities were fatigue (76%), lymphopenia (72% [48% high grade]), constipation (56%), and nausea (52%). High grade toxicities (other than lymphopenia) included secondary malignancy, pruritus, hyponatremia, neutropenia, leukopenia, and cognitive decline (n = 1 for each). Tumor response rate was 52% and and disease control rate was 84%. Six month PFS was 92% and 12 month PFS was 72%. Response rates and PFS were independent of pathological subtype, deletion status, and indication for chemotherapy. Protracted low dose temozolomide has a distinct spectrum of toxicities compared to standard dosing but is well tolerated in most patients and may provide improved response rates compared to standard dosing. The results of larger randomized trials are needed to assess its potential advantages over other management schemes.

Effets à long terme de la chimiothérapie chez 7 patients présentant un gliome de bas grade symptomatique

INTRODUCTION

Whether aggressive treatment or no treatment is the optimal management for low-grade gliomas is controversial. However, symptomatic low-grade gliomas require prompt therapeutic intervention because of neurological impairment, uncontrolled seizures, and deterioration of life quality.

METHODS

We report the long-term follow-up, 71 months, of seven patients treated by procarbazine, lomustine and vincristine (PCV) therapy for a symptomatic low-grade oligodendrogliomatous tumor. The mean age at diagnosis was 47 years, the mean time from first symptoms to initiation of PCV therapy was 62 months (range 15-147).

RESULTS

All patients initially responded favorably, with improvement of the neurological symptoms and radiological response. Chemotherapy was clinically well tolerated, the main side effect being low hematological toxicity. During the follow-up, no progression was observed in two patients. For the five remaining patients, the time to progression after the PCV induction was 56+/-12 months (range 38 to 73). Four of these patients showed favorable response to a second line of treatment.

CONCLUSION

PCV therapy is an interesting therapeutic option for progressively symptomatic low-grade gliomas, even in cases with large tumoral volume. This treatment, of moderate toxicity, improves the quality of life and can result in long-term tumor stabilization.

Molecular changes in brain tumors: prognostic and therapeutic impact

PURPOSE OF REVIEW

This review focuses on recent advances in the molecular biology of the main primary brain tumors (gliomas, medulloblastomas, and ependymomas), with particular emphasis on prognostic markers and potential therapeutic targets.

RECENT FINDINGS

Current biologic markers are useful for predicting prognosis (e.g. 1p/19q codeletion in grade 2 and 3 gliomas, nuclear beta-catenin expression in medulloblastoma) or response to the treatment (e.g. the methyl guanyl methyl transferase promoter methylation status). Recent gene profiling studies have identified specific molecular signatures that permit a molecular classification and that also provide new, potentially useful prognostic markers. The studies have also shown a striking parallel between central nervous system ontogenesis and the oncogenesis of brain tumors. By elucidating the underlying activated molecular pathways, these approaches provide the basis for a biologic therapy to target the critically activated pathways.

SUMMARY

Important advances have been made in the biologic understanding, molecular subclassification, and identification of prognostic markers in brain tumors, thereby improving the current classifications. Such data provide a rational basis for current and future targeted biologically based strategies.

Genetic and metabolic predictors of chemosensitivity in oligodendroglial neoplasms

The −1p/−19q genotype predicts chemosensitivity in oligodendroglial neoplasms, but some with intact 1p/19q also respond and not all with 1p/19q loss derive durable benefit from chemotherapy. We have evaluated the predictive and prognostic significance of pretherapy ²⁰¹Tl and ¹⁸F-FDG SPECT and genotype in 38 primary and 10 recurrent oligodendroglial neoplasms following PCV chemotherapy. 1p/19q loss was seen in 8/15 OII, 6/15 OAII, 7/7 OIII, 3/11 OAIII and was associated with response (Fisher-Exact: P=0.000) and prolonged progression-free (log-rank: P=0.002) and overall survival (OS) (log-rank: P=0.0048). Response was unrelated to metabolism, with tumours with high or low metabolism showing response. Increased ¹⁸F-FDG or ²⁰¹Tl uptake predicted shorter progression-free survival (PFS) in the series (log-rank: ²⁰¹Tl P=0.0097, ¹⁸F-FDG P=0.0170) and in cases with or without the −1p/−19q genotype. Elevated metabolism was associated with shorter OS in cases with intact 1p/19q (log-rank: ¹⁸F-FDG P=0.0077; ²⁰¹Tl P=0.0004) and shorter PFS in responders (log-rank: ¹⁸F-FDG P=0.005; ²⁰¹Tl P=0.0132). ²⁰¹Tl uptake and 1p/19q loss were independent predictors of survival in multivariate analysis. In this initial study, ²⁰¹Tl and ¹⁸F-FDG uptake did not predict response to PCV, but may be associated with poor survival following therapy irrespective of genotype. This may be clinically useful warranting further study.

1p/19q loss within oligodendroglioma is predictive for response to first line temozolomide but not to salvage treatment

BACKGROUND

Combined loss of 1p/19q predicts an almost 100% response rate to first line procarbazine, CCNU and vincristine chemotherapy (PCV) chemotherapy in oligodendroglial tumours. We assessed the impact of 1p and 19q loss on the outcome to first line temozolomide (TMZ) chemotherapy and to second line PCV or TMZ in progressive oligodendroglial tumours.

MATERIALS AND METHODS

Tumour samples from patients included in two prospective EORTC studies on first line and second line TMZ chemotherapy in recurrent oligodendroglioma were used for this study. Most patients in the first line TMZ trial received PCV at further progression. Loss of 1p and 19q was assessed on paraffin embedded tumour samples by fluorescent in situ hybridisation with locus specific probes for 1p36 and 19q13.

RESULTS

Losses of 1p and 19q were mainly observed in morphologically classical oligodendrogliomas (OD). Thirteen out of 18 patients with 1p loss (72%) responded to first line temozolomide (p<0.01). Both response to second line salvage PCV or to second line temozolomide was limited, even in patients with combined 1p/19q loss. Patients with tumours with 1p loss treated with salvage PCV had improved PFS (p<0.05). More patients with 1p loss were alive at 60 and 120 months after initial surgery (p<0.001).

CONCLUSION

Combined 1p/19q loss is mainly observed in classical OD. Responses to first line temozolomide are strongly correlated to loss of 1p. Response to second line alkylating treatment is modest even in tumours with 1p/19q loss. For further improvement of outcome in OD novel treatments are needed.

Temozolomide: a milestone in neuro-oncology and beyond?

Temozolomide (Temodal, Temodar), an imidazol derivative, is a second-generation alkylating agent. The orally available prodrug with the capacity of crossing the blood-brain barrier received accelerated US FDA approval in 1999. Three pivotal Phase II trials showed modest activity in the treatment of recurrent anaplastic astrocytoma glioblastoma. In 2005, the FDA and the European Agency for the Evaluation of Medicinal Products approved temozolomide for use in newly diagnosed glioblastoma, in conjunction with radiotherapy, based on an European Organisation for Research and Treatment of Cancer/National Cancer Institute of Canada Phase III trial. The adverse events associated with temozolomide are mild-to-moderate and generally predictable; the most serious are noncumulative and reversible myelosuppression and, in particular, thrombocytopenia, which occurs in less than 5% of patients. Continuous temozolomide administration is associated with profound CD4-selective lymphocytopenia. Molecular studies have suggested that the benefit of temozolomide chemotherapy is restricted to patients whose tumors have a methylated methylguanine methyltransferase gene promotor and are thus unable to repair some of the chemotherapy-induced DNA damage. Temozolomide is under investigation for other disease entities, in particular lower-grade glioma, brain metastases and melanoma.

Current role of radiation therapy in the management of malignant brain tumors

The objective of this article is to explain how the current management of malignant brain tumors has evolved, using the foundation of evidence-based literature. Radiotherapy plays a central role in the multidisciplinary management of primary brain tumors and brain metastases. The techniques of radiotherapy continue to be refined to optimize local control while minimizing potential treatment-related neurocognitive toxicities.

Glioma test array for use with formalin-fixed, paraffin-embedded tissue: array comparative genomic hybridization correlates with loss of heterozygosity and fluorescence in situ hybridization

Array-based comparative genomic hybridization (aCGH) is a powerful, high-throughput tool for whole genome analysis. Until recently, aCGH could only be reproducibly performed on frozen tissue samples and with significant tissue amounts. For brain tumors however, paraffin-embedded tissue blocks from small stereotactic biopsies may be the only tissue routinely available. The development of methods to analyze formalin-fixed, paraffin-embedded (FFPE) material therefore has the potential to impact molecular diagnosis in a significant way. To this end, we constructed a BAC array representing chromosomes 1, 7, 19, and X because 1p/19q deletion and EGFR gene amplification provide clinically relevant information for glioma diagnosis. We also optimized a two-step labeling procedure using an amine-modified nucleotide for generating aCGH probes. Using this approach, we analyzed a series of 28 FFPE oligodendroglial tumors for alterations of chromosomes 1, 7, and 19. We also independently assayed these tumors for 1p/19q deletion by fluorescence in situ hybridization and by loss of heterozygosity analyses. The concordance between aCGH, standard loss of heterozygosity and fluorescence in situ hybridization was nearly 100% for the chromosomes analyzed. These results suggest that aCGH could offer an improved molecular diagnostic approach for gliomas because of its ability to detect clinically relevant molecular alterations in small FFPE specimens.

Oligodendroglial tumors

Oligodendroglial tumors represent approximately 4-7% of all gliomas; however, in some series the incidence has been reported to be as high as 10-20% because of improved histological appreciation and recently recognized molecular signatures. Oligodendroglial tumors are classified as being low-grade oligodendroglial tumors, high-grade anaplastic oligodendroglial tumors or mixed oligo-astrocytic tumors. The mixed tumors can again be low-grade or high-grade. The recent European Organization for Research and Treatment of Cancer and Radiation Therapy Oncology Group randomized trials have provided level 1 evidence regarding the best management of these tumors. This review provides an overview of oligodendroglial tumors and discusses contemporary and evolving treatment strategies.

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.