Prospective randomized trial of low- versus high-dose radiation therapy in adults with supratentorial low-grade glioma: initial report of a North Central Cancer Treatment Group/Radiation Therapy Oncology Group/Eastern Cooperative Oncology Group study

Role of Extent of Resection in the Long-Term Outcome of Low-Grade Hemispheric Gliomas

Purpose

The prognostic role of extent of resection (EOR) of low-grade gliomas (LGGs) is a major controversy. We designed a retrospective study to assess the influence of EOR on long-term outcomes of LGGs.

Patients and Methods

The study population (N = 216) included adults undergoing initial resection of hemispheric LGG. Region-of-interest analysis was performed to measure tumor volumes based on fluid-attenuated inversion-recovery (FLAIR) imaging.

Results

Median preoperative and postoperative tumor volumes and EOR were 36.6 cm3 (range, 0.7 to 246.1 cm3), 3.7 cm3 (range, 0 to 197.8 cm3) and 88.0% (range, 5% to 100%), respectively. There was no operative mortality. New postoperative deficits were noted in 36 patients (17%); however, all but four had complete recovery. There were 34 deaths (16%; median follow-up, 4.4 years). Progression and malignant progression were identified in 95 (44%) and 44 (20%) cases, respectively. Patients with at least 90% EOR had 5- and 8-year overall survival (OS) rates of 97% and 91%, respectively, whereas patients with less than 90% EOR had 5- and 8-year OS rates of 76% and 60%, respectively. After adjusting each measure of tumor burden for age, Karnofsky performance score (KPS), tumor location, and tumor subtype, OS was predicted by EOR (hazard ratio [HR] = 0.972; 95% CI, 0.960 to 0.983; P < .001), log preoperative tumor volume (HR = 4.442; 95% CI, 1.601 to 12.320; P = .004), and postoperative tumor volume (HR = 1.010; 95% CI, 1.001 to 1.019; P = .03), progression-free survival was predicted by log preoperative tumor volume (HR = 2.711; 95% CI, 1.590 to 4.623; P ≤ .001) and postoperative tumor volume (HR = 1.007; 95% CI, 1.001 to 1.014; P = .035), and malignant progression-free survival was predicted by EOR (HR = 0.983; 95% CI, 0.972 to 0.995; P = .005) and log preoperative tumor volume (HR = 3.826; 95% CI, 1.632 to 8.969; P = .002).

Conclusion

Improved outcome among adult patients with hemispheric LGG is predicted by greater EOR.

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.

Advances in radiation therapy for brain tumors

Radiation therapy is used postoperatively as adjunctive therapy to decrease local failure; to delay tumor progression and prolong survival; as a curative treatment; as a therapy that halts further tumor growth; to alter function; and for palliation. Registration of MRI scan data sets with the treatment-planning CT scan is essential for accurate definition of the tumor and surrounding organs at risk. Integrating additional imaging studies that reflect the biologic characteristics of central nervous system tumors is an area of active research. Conformal treatment delivery is used to spare adjacent normal tissue from receiving unnecessary dose. In the dose range used when treating these tumors, the probability of causing serious late toxicity is relatively low and secondary malignancies are rare.

Surgery Insight: the role of surgery in the management of low-grade gliomas

The benefits of surgery for the management of low-grade gliomas have been difficult to determine from the literature. This difficulty might be explained by the inconsistency of the published data, and also by advances in both neuroimaging and neurosurgical techniques, which have made surgical intervention a safer and more viable option than it has been in the past, making the earlier studies less applicable to modern care. In this article, we critically analyze the utility of surgery in the management of low-grade gliomas, including the value of observation without surgical intervention, the relative risks and benefits of biopsy versus craniotomy and resection, and recent advances that have made surgery safer and gross total resection a more realistic proposition. As we will discuss, the literature provides modest evidence that surgery leads to improved outcomes through a reduction in tumor burden. As a result of advances in surgical techniques, the time might now be right to effectively and accurately assess the influence of aggressive surgical resection on the prognosis of low-grade gliomas.

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.

Radiotherapeutic alternatives for previously irradiated recurrent gliomas

Re-irradiation for recurrent gliomas has been discussed controversially in the past. This was mainly due to only marginal palliation while being associated with a high risk for side effects using conventional radiotherapy.

With modern high-precision radiotherapy re-irradiation has become a more wide-spread, effective and well-tolerated treatment option. Besides external beam radiotherapy, a number of invasive and/or intraoperative radiation techniques have been evaluated in patients with recurrent gliomas.

The present article is a review on the available methods in radiation oncology and summarizes results with respect to outcome and side effects in comparison to clinical results after neurosurgical resection or different chemotherapeutic approaches.

Adding 11C-methionine PET to the EORTC prognostic factors in grade 2 gliomas

PURPOSE

The management of adult patients with grade 2 gliomas remains a challenge for the clinical neuro-oncologist. Several clinical prognostic factors appear to be as important as treatment factors in determining outcome. From the European Organisation for Research and Treatment of Cancer (EORTC) trials 22844 and 22845, a prognostic scoring system has been proposed based on the presence of unfavourable prognostic factors. The aim of the present study was to assess the additional prognostic value of (11)C-methionine (MET) measured by positron emission tomography (PET) in the setting of the EORTC prognostic scoring system.

METHODS

In this retrospective review, 129 patients with supratentorial grade 2 gliomas were subjected to a PET study as part of the pre-treatment tumour investigation. One hundred and three cases were classified as low-risk patients (0-2 unfavourable factors) and 26 cases as high-risk patients (3-5 unfavourable factors) according to the EORTC criteria. MET PET was evaluated as an extra prognostic factor in both groups.

RESULTS

In the high-risk group, patients with high MET uptake had a worse outcome than patients with low MET uptake. A similar trend was found for the low-risk group in patients with oligodendrocytic tumours.

CONCLUSIONS

Our findings further strengthen the role of MET PET as an important prognostic tool in the management of this group of patients.

Prognostic factors for survival in adult patients with recurrent glioma enrolled onto the new approaches to brain tumor therapy CNS consortium phase I and II clinical trials

PURPOSE

Prognostic factor analyses have proven useful in predicting outcome in patients with newly diagnosed malignant glioma. Similar analyses in patients with recurrent glioma could affect the design and conduct of clinical trials substantially.

PATIENTS AND METHODS

Between 1995 and 2002, 333 adults with recurrent gliomas were enrolled onto 10 phase I or II trials of systemic or local therapy. The studies had similar inclusion criteria and were conducted within the New Approaches to Brain Tumor Therapy CNS Consortium. Ninety-three percent of the patients have died. Cox proportional hazards (PH) regression and recursive partitioning analysis (RPA) were performed to identify prognostic factors.

RESULTS

Factors associated with an increased risk of death were increased age, lower Karnofsky performance score (KPS), initial and on-study histologies of glioblastoma multiforme (GBM), corticosteroid use, shorter time from original diagnosis to recurrence, and tumor outside frontal lobe. The final PH model included initial histology of GBM (relative risk [RR] = 2.01), 10-year increase in age (RR = 1.23), KPS less than 80 (RR = 1.54), and corticosteroid use (RR = 1.49). RPA resulted in seven classes. Median survival time was poorest in non-GBM patients with KPS less than 80 or GBM patients, age 50 years, corticosteroid use (4.4 months; 95% CI, 3.6 to 5.4 months); median survival was best in patients with initial histology other than GBM with KPS 80 and tumor confined to the frontal lobe (25.7 months; 95% CI, 18.7 to 52.5), and was 7.0 months (95% CI, 6.2 to 8.0 months) for all patients.

CONCLUSION

Initial histology, age, KPS, and corticosteroid use are prognostic for survival in recurrent glioma patients. To allow comparisons across phase II trials, enrollment criteria may need to be restricted.

Phosphatase and tensin homologue deficiency in glioblastoma confers resistance to radiation and temozolomide that is reversed by the protease inhibitor nelfinavir

Glioblastomas are malignant brain tumors that are very difficult to cure, even with aggressive therapy consisting of surgery, chemotherapy, and radiation. Glioblastomas frequently have loss of the phosphatase and tensin homologue (PTEN), leading to the activation of the phosphoinositide-3-kinase (PI3K)/Akt pathway. We examined whether PTEN deficiency leads to radioresistance and whether this can be reversed by nelfinavir, a protease inhibitor that decreases Akt signaling. Nelfinavir decreased Akt phosphorylation and enhanced radiosensitization in U251MG and U87MG glioblastoma cells, both of which are PTEN deficient. In the derivative line U251MG-PTEN, induction of wild-type PTEN with doxycycline decreased P-Akt expression and increased radiosensitivity to a similar extent as nelfinavir. Combining these two approaches had no greater effect on radiosensitivity than either alone. This epistasis-type analysis suggests that the nelfinavir acts along the Akt pathway to radiosensitize cells. However, nelfinavir neither decreased Akt phosphorylation in immortalized human astrocytes nor radiosensitized them. Radiosensitization was also assessed in vivo using a tumor regrowth delay assay in nude mice implanted with U87MG xenografts. The mean time to reach 1,000 mm(3) in the radiation + nelfinavir group was 71 days, as compared with 41, 34, or 45 days for control, nelfinavir alone, or radiation alone groups, respectively. A significant synergistic effect on tumor regrowth was detected between radiation and nelfinavir. (P = 0.01). Nelfinavir also increased the sensitivity of U251MG cells to temozolomide. These results support the clinical investigation of nelfinavir in combination with radiation and temozolomide in future clinical trials for patients with glioblastomas.

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.

Optimising Radiation Therapy Techniques for Tumours of the Central Nervous System

Introduction: This study aims to assess the early tumour outcome and morbidity associated with radiation therapy (RT) in tumours of the central nervous system (CNS). Materials and Methods: Patients receiving RT with radical intent were entered on a prospective database. Tumour types were categorised into glioma, base of skull, pituitary, germ cell or primitive neuroectodermal tumour (PNET) and other malignant CNS tumours. Study endpoints were overall survival and progression free survival. Acute and late toxicity endpoints included Common Terminology Criteria version 3.0 (CTC) grade 3 or 4 events, need for admission during RT and change in performance status at 12 months. Results: One hundred and fifty-two patients with CNS tumours were managed with radical intent over the 4-year period. The median age was 49 years and 68.4% were Eastern Co-operative Group (ECOG) 0-1 performance status. The major pathology groups were glioma (59.9%) and base of skull tumours (17.1%). Gross total resection was performed in 28.3% only and RT was delayed after diagnosis until time of progression in 19.7%. For the 91 patients with glioma, the median survival and 2-year survival rate was 19.1 months and 44.1%, respectively. The 2-year survival rates for the subgroups of WHO Grade I or II, III and IV were 100%, 52% and 35%, respectively. For the non-glioma tumour groups, the relapse varied with pathology. Toxicity was minimal with only 3 acute and 3 late CTC grade 3 or 4 events occurring. Overall, 47 or 31% of patients required some inpatient hospitalisation during RT, although this was determined to have some causative relationship to RT in only 12 or 8% of patients. In the 12 months post-RT, performance status was stable or improved in 76.2% of patients, and most deterioration was associated with tumour relapse. Conclusions: RT for CNS tumours using modern techniques was well-tolerated with good tumour outcome and minimal morbidity. Key words: Brain, Glioma, Radiotherapy, Toxicity

Primary central nervous system lymphoma: biological aspects and controversies in management

INTRODUCTION

This review was produced from the workshop on primary central nervous system lymphoma (PCNSL) at the European Cancer Conference (ECCO 13) in Paris in 2005. It covers the presentation and biological features of the disease (Professor Khe Hoang-Xuan). The role of chemotherapy, including the management of intraocular lymphoma and the use of high dose chemotherapy followed by autologous stem cell transplantation for PCNSL, is discussed (Dr. Andres Ferreri) as well as controversies in the use of whole brain radiotherapy (WBRT) after chemotherapy (Dr. Michele Reni). The topics covered with discussants at the workshop are also summarised.

CONCLUSION

The imaging of the brain and the histopathology including detailed immunohistochemistry is of vital importance in making an accurate diagnosis of the disease and understanding the extent of spread of the disease in the CNS. The importance of high dose methotrexate (HDMTX; dose > or = 1g/m(2)), as the most active drug in the treatment of PCNSL, is stressed. The authors recommend that HDMTX alone or in combination with other active chemotherapy agents should be used to treat PCNSL followed by whole brain radiotherapy (WBRT) unless contraindicated because of the advanced age of the patient and existing cognitive impairment. Only published protocols should be used unless the patient is to be offered a trial that has either national or international support. Baseline neuropsychological tests should be carried out before treatment and repeated during and after treatment. The risks of cognitive impairment associated with the disease, with methotrexate - containing chemotherapy and with whole brain radiotherapy should be explained to patients and relatives when obtaining informed consent. Long-term survival, with current treatment regimes, is possible with PCNSL but this appears limited to patients less than 60 years of age at presentation (mostly patients less than 50 years of age).

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.

The dose–volume interaction in adult supratentorial low-grade glioma: higher radiation dose is beneficial among patients with partial resection

PURPOSE

To evaluate the hypothesis that adults with partially resected (PR<50% resection) supratentorial low-grade glioma (LGG) benefit from higher doses of radiation.

METHODS

Patients receiving post-operative radiation for WHO grade I-II LGG at the University of Western Ontario between 1979 and 2001 were studied. Patient characteristics evaluated included: age, gender, symptom duration>30 days, seizures at presentation, Karnofsky performance status (KPS)<70, astrocytoma pathology (AS), and radiation dose. A Cox proportional hazard regression model was constructed to test the influence of radiation dose.

RESULTS

One hundred and seven patients were analyzed. Patients who had PR were not significantly different from those with STR (subtotal/total resection) in terms of patient characteristics. Median survival (MST) of PR patients who received<or=50 Gy was 16.5 months while those who received>50 Gy had a MST of 109.2 months. The interaction of radiation dose and extent of resection was tested after controlling for other patient factors by Cox regression model. The interaction was highly significant for both OS and PFS (P=0.013 and P=0.003, respectively). This model remained significant after excluding six patients receiving doses<42 Gy (OS, P=0.024, and PFS, P=0.001).

CONCLUSIONS

The outcome for patients with LGG is dependent on extent of tumor resection and radiation dose. Patients with PR should be considered for higher radiation dose schedules (>50 Gy). Future trials on therapeutic strategies for LGG should consider stratification of patients by extent of tumor resection. Our data suggests that one dose does not fit all.

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.

Are gliomas preventable?

Gliomas are a family of primary central nervous system tumors of variable malignancy that are derived from supporting glia (astrocytes, oligodendrocytes, ependymal cells) or their progenitors/stem cells. There are two potential strategies to prevention: preventing gliomas from forming and preventing lower-grade gliomas from developing into higher-grade gliomas. Each would lower time-dependent mortality. Each also depends on an understanding of what causes gliomas so that these factors can be modulated. In this presentation, I will discuss primary prevention, chemoprevention, and screening. I will first focus on the known chromosomal, genetic, and protein changes associated with the different histologic varieties of glioma and the environmental, hereditary, and infectious/viral factors that may promote glioma development and malignant progression. I will discuss a number of clinical scenarios that eventuate from the known genetic patterns of these tumors and the changes in genetic patterns that reflect malignant progression. The basic thinking is that if one could prevent specific gene mutations and/or deletions or gains of specific chromosomes that lead to the development of low-grade (WHO 2) gliomas, then theoretically this would reduce the occurrence of high-grade (WHO 3 and 4) gliomas and hence the almost certain death that now is the fate of most patients with these tumors. In the case of de novo WHO 3 and 4 tumors, being able to prevent or counter specific gene mutations and/or the deletion of specific chromosomes would in itself reduce the occurrence of these gliomas and increase survival. Alternatively, a curative treatment for low-grade glioma that prevents these chromosomal/gene changes would prevent some glioblastomas (WHO 4) from forming and would have the same desired effect on survival. Obviously, for the latter to be achieved, we must also be able to diagnose and treat low-grade gliomas earlier.

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.

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.

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.

Low‐Grade Gliomas in Adults

Low-grade gliomas are a heterogeneous group of neoplasms usually encountered in younger patient populations. These tumors represent a unique challenge because most patients will survive a decade or more and may be at a higher risk for treatment-related complications. Clinical observations over the years have identified a subset of low-grade gliomas that tends to manifest more aggressive clinical behavior and require earlier, more aggressive intervention. Clinical and molecular parameters may allow better assessment of prognosis and application of risk-adjusted management strategies that may include resection, radiation, or chemotherapy. Improved methods of long-term cognitive and functional assessment are desperately needed in this patient population.

Radiation induced adult medulloblastoma: a case report

Adult medulloblastoma is a rare intracranial tumor. Our patient is a 61 year old woman treated with cranial irradiation 15 years previously for a low grade astrocytoma in the left posterior temporal lobe that was recently diagnosed with medulloblastoma in the right cerebellum. This is the first reported case of radiation induced adult medulloblastoma.

Interstitial 125I radiosurgery of supratentorial de novo WHO Grade 2 astrocytoma and oligoastrocytoma in adults: long-term results and prognostic factors

BACKGROUND

Detailed long-term outcome data are not available for adult patients with World Health Organization (WHO) Grade 2 astrocytoma or oligoastrocytoma.

METHODS

A previously published short-term data set of 239 adult patients with circumscribed de novo supratentorial astrocytoma (187 patients) and oligoastrocytoma (52 patients) treated with interstitial iodine-125 ((125)I) radiosurgery as primary treatment (1979-1992) was revisited. Survival, progression-free survival, functionally independent survival, postrecurrence survival, and time to malignant transformation were estimated with the Kaplan-Meier method. Prognostic factors were obtained from the Cox multivariate proportional hazards model.

RESULTS

Five-, 10-, and 15-year survival was 56%, 37%, and 26%, respectively (median follow-up, 10.3 yrs). Progression-free survival was 45%, 21%, and 14%, respectively. The corresponding malignant transformation rates were 33%, 54%, and 67%. No leveling off of the Kaplan-Meier curves could be observed for any of the chosen endpoints. Age > 50 years, a tumor volume > 20 mL, and/or a Karnofsky score < or = 80 were associated with decreased survival or progression-free survival. Age > 35 years and/or a tumor volume > 20 mL increased risk of malignant transformation. Prognostic factors determined subsets of patients with 10-year survival ranging from as low as 6% to as high as 55% and progression-free survival ranging 1-31%.

CONCLUSIONS

Long-term tumor stabilization is rare. As outcome is mainly determined by treatment-independent factors, minimization of any treatment-related risk must be considered essential.

Recent advances in the treatment of oligodendrogliomas

The optimal treatment for patients with oligodendrogliomas is unknown, and current management strategies remain controversial. This past year, further exploration of the molecular genetics of the tumors and its prognostic implications for outcome, evaluation of the utility of positron emission tomography imaging, and the role of radiation and chemotherapy in the treatment of oligodendrogliomas have been reported. It is becoming increasingly apparent that oligodendrogliomas are several distinct diseases on a molecular level, and that key genetic derangements can signify a response to treatment and favorable outcome. The added contributions of recent publications consolidates these emerging impressions. Ultimately, the combination of improved imaging techniques, molecular profiling, and new therapies should result in improved outcome with reduced treatment-related toxicity for patients with newly diagnosed, progressive, and recurrent oligodendrogliomas.

Surgery for low-grade gliomas: current evidence and controversies

Despite decades of studies, the surgical management of cerebral low-grade gliomas remains quite controversial. Recommendations range from observation with biopsy to radical resection. This controversy arises from several factors, chief of which is the lack of prospective, randomized studies specifically addressing the issue of resection. Nevertheless, the available data, with its inherent inadequacies, must be used to help guide the care of these patients. This article reviews the current literature on the role of surgery for these tumors and attempts to put forward reasonable treatment options in an area where even the American Association of Neurological Surgeons can find no standard management to recommend aside from biopsy prior to the onset of therapy.

New concepts in surgery of WHO grade II gliomas: functional brain mapping, connectionism and plasticity – a review

Despite a recent literature supporting the impact of surgery on the natural history of low-grade glioma (LGG), the indications of resection still remain a matter of debate, especially because of the frequent location of these tumors within eloquent brain areas - thus with a risk to induce a permanent postoperative deficit. Therefore, since the antagonist nature of this surgery is to perform the most extensive glioma removal possible, while preserving the function and the quality of life, new concepts were recently applied to LGG resection in order to optimize the benefit/risk ratio of the surgery.First, due to the development of functional mapping methods, namely perioperative neurofunctional imaging and intrasurgical direct electrical stimulation, the study of cortical functional organization is currently possible for each patient - in addition to an extensive neuropsychological assessment. Such knowledge is essential because of the inter-individual anatomo-functional variability, increased in tumors due to cerebral plasticity phenomena. Thus, brain mapping enables to envision and perform a resection according to individual functional boundaries.Second, since LGG invades not only cortical but also subcortical structures, and shows an infiltrative progression along the white matter tracts, new techniques of anatomical tracking and functional mapping of the subcortical white matter pathways were also used with the goal to study the individual effective connectivity - which needs imperatively to be preserved during the resection.Third, the better understanding of brain plasticity mechanisms, induced both by the slow-growing LGG and by the surgery itself, were equally studied in each patient and applied to the surgical strategy by incorporating individual dynamic potential of reorganization into the operative planning. The integration of these new concepts of individual functional mapping, connectivity and plastic potential to the surgery of LGG has allowed an extent of surgical indications, an optimization of the quality of resection (neuro-oncological benefit), and a minimization of the risk of sequelae (benefit on the quality of life). In addition, such a strategy has also fundamental applications, since it represents a new door to the connectionism and cerebral plasticity.

Hypofractionated stereotactic radiotherapy for low grade glioma at McGill University: long-term follow-up

Small, well-defined, unresectable low-grade gliomas are attractive targets for stereotactic irradiation. Fractionated stereotactic irradiation of these targets has the theoretical benefit of increased normal tissue sparing beyond that provided by the physical characteristics of stereotactic radiosurgery. From July 1987 to November 1992, 21 patients were treated for low-grade glioma at our institution using a hypofractionated regimen of stereotactic radiotherapy. All patients had well-circumscribed, < 40 mm tumors. No patient had had prior radiotherapy. All lesions were histologically proven WHO grade I or II glial tumors. Lesions involved sensitive brain structures and were deemed unresectable. A typical dose of 42 Gy was delivered in 6 fractions over a two-week period using rigid immobilization and a linac-based dynamic stereotactic radiosurgical technique. Patients had a median age of 23 years (9-74) and were predominantly female (60%). Median tumor diameter was 20 mm. With a median follow-up for living patients of 13.3 years, the actuarial 5, 10, and 15-year overall survival rates are 76%, 71%, and 63%, respectively. Treatment was acutely well tolerated although three patients experienced late post-therapy complications. Our results and those of 241 patients treated in nine other institutional series are reviewed. Despite some examples of favorable short-term outcomes, all reported series are highly selected and thus likely biased. The data regarding the use of SRS is limited and, in our opinion, insufficient to claim a clear therapeutic advantage to SRS in the initial management of low-grade glioma. Our own results with hypofractionated stereotactic radiotherapy are similar to those expected with standard therapy.

Diffusely infiltrative low-grade gliomas in adults

Diffusely infiltrating low-grade gliomas (LGGs) include astrocytomas, oligodendrogliomas, and mixed oligoastrocytomas (WHO grade 2). Due to the routine use of magnetic resonance imaging, there is an increasing need to formulate treatment guidelines for patients with LGGs. However, there is little consensus about the optimal treatment strategy for diffusely infiltrative LGGs, and the clinical management of LGGs is one of the most controversial areas in neurooncology. Although the standard of care has not been established, several randomized trials are beginning to provide some answers. Furthermore, laboratory correlative studies are defining subsets of LGG that may identify patients with better prognoses and increased chance of responding to therapy. This article reviews the most recent data regarding the treatment of LGG, emphasizing evidenced based approaches from current clinical trials.

Current Strategies in Treatment of Oligodendroglioma: Evolution of Molecular Signatures of Response

Oligodendroglioma frequently (≥ 70%) responds to radiation and chemotherapy, and is the first CNS neoplasm in which a genetic signature (1p and 19q deletion) has been associated with outcome within the context of large clinical trials. Current translational investigations focus on deletions or mutations of potential tumor suppressor genes, epigenetic alterations, amplification or mutation of growth factor and regulatory genes, and characterization of signaling events and regulatory protein expression. The most compelling data has involved 1p and 19q loss, which is observed in over 50% of anaplastic oligodendrogliomas. In two randomized phase III trials (Radiation Therapy Oncology Group 9402 and European Organisation for Research and Treatment of Cancer 26951), the addition of neoadjuvant or adjuvant procarbazine, lomustine, and vincristine (PCV; respectively) to radiotherapy did not produce superior survival as compared with radiotherapy alone. A modest increase in progression-free survival was observed with the addition of PCV, but at the cost of increased toxicity. Combined 1p and 19q loss identified a favorable prognostic group in both studies, which appeared to be independent of treatment arms. However, it is unclear whether these deletions represent surrogate markers of a favorable biologic tumor behavior, or are predictive of outcome after specific treatment. Currently, there is insufficient data to allow therapeutic decisions to be made solely on the basis of 1p and 19q gene deletion status. Future phase III trials are evaluating other chemotherapeutic and targeted agents, including temozolomide, and include correlative investigations of aberrant molecular events in these neoplasms, which may lead to future therapeutic strategies that are based on specific molecular signatures.

Cerebral radiation necrosis: incidence, outcomes, and risk factors with emphasis on radiation parameters and chemotherapy

PURPOSE

To investigate radiation necrosis in patients treated for glioma in terms of incidence, outcomes, predictive and prognostic factors.

METHODS AND MATERIALS

Records were reviewed for 426 patients followed up until death or for at least 3 years. Logistic regression analysis was performed to identify predictive and prognostic factors. Multivariate survival analysis was conducted using Cox proportional hazards regression. Separate analyses were performed for the subset of 352 patients who received a biologically effective dose (BED) > or =85.5 Gy2 (> or =45 Gy/25 fractions) who were at highest risk for radionecrosis.

RESULTS

Twenty-one patients developed radionecrosis (4.9%). Actuarial incidence plateaued at 13.3% after 3 years. In the high-risk subset, radiation parameters confirmed as risk factors included total dose (p < 0.001), BED (p < 0.005), neuret (p < 0.001), fraction size (p = 0.028), and the product of total dose and fraction size (p = 0.001). No patient receiving a BED <96 Gy2 developed radionecrosis. Subsequent chemotherapy significantly increased the risk of cerebral necrosis (p = 0.001) even when adjusted for BED (odds ratio [OR], 5.8; 95% confidence interval [CI], 1.6-20.3) or length of follow-up (OR, 5.4; 95% CI, 1.5-19.3). Concurrent use of valproate appeared to delay the onset of necrosis (p = 0.013). The development of radionecrosis did not affect survival (p = 0.09).

CONCLUSIONS

Cerebral necrosis is unlikely at doses below 50 Gy in 25 fractions. The risk increases significantly with increasing radiation dose, fraction size, and the subsequent administration of chemotherapy.

An update on oligodendroglial neoplasms

PURPOSE OF REVIEW

The most widely accepted brain tumor classification system remains morphology-based but the increasing knowledge of the molecular pathogenesis of oligodendroglial tumors has spurred translational research yielding new diagnostic and therapeutic paradigms. These data have accumulated rapidly and, in combination with exciting new insights in the cellular origin of these tumors, necessitate a review.

RECENT FINDINGS

'Cancer stem cells' have been identified in gliomas. Further study of these cells will not only provide information on the cellular origin and pathogenesis of these tumors but may also give rise to new treatments that target a cell pool not amenable to current therapeutic strategies. Molecular tumor characteristics have been correlated with imaging findings, treatment response and prognosis. This has enabled neuro-oncologists to take a risk-stratified approach to patients with oligodendrogliomas that optimizes treatment efficacy and minimizes toxicity. Furthermore, more accurate epidemiological data have become available from population-based studies.

SUMMARY

In spite of remarkable progress over the last 15 years, these tumors remain incurable. The search for a cure has to go on, while currently available multidisciplinary treatments are refined.

Changing Paradigms—An Update on the Multidisciplinary Management of Malignant Glioma

Treatment of malignant glioma requires a multidisciplinary team. Treatment includes surgery, radiotherapy, and chemotherapy. Recently developed agents have demonstrated activity against recurrent malignant glioma and efficacy if given concurrently with radiotherapy in the upfront setting. Oligodendroglioma with 1p/19q deletions has been recognized as a distinct pathologic entity with particular sensitivity to radiotherapy and chemotherapy. Randomized trials have shown that early neoadjuvant or adjuvant administration of procarbazine, lomustine, and vincristine chemotherapy prolongs disease-free survival; however, it has no impact on overall survival. Temozolomide, a novel alkylating agent, has shown modest activity against recurrent glioma. In combination with radiotherapy in newly diagnosed patients with glioblastoma, temozolomide significantly prolongs survival. Molecular studies have demonstrated that the benefit is mainly observed in patients whose tumors have a methylated methylguanine methyltransferase gene promoter and are thus unable to repair some of the chemotherapy-induced DNA damage. For lower-grade glioma, the use of chemotherapy remains limited to recurrent disease, and first-line administration is the subject of ongoing clinical trials. Irinotecan and agents like gefitinib, erlotinib, and imatinib targeting the epidermal growth factor receptor and platelet-derived growth factor receptor have shown some promise in recurrent malignant glioma. This review summarizes recent developments, focusing on the clinical management of patients in daily neuro-oncology practice.

Low-grade gliomas: The debate continues

Low-grade gliomas (LGG) are a heterogeneous group of tumors that tend to occur primarily in young adults and children. They are indolent, progressive, and often undergo anaplastic transformation. The prognosis of these tumors is primarily affected by age and pathologic type. Many questions remain in the management of LGGs, including the role of surgical resection (ie, maximal tumor resection), the optimal timing of radiation (ie, postoperative vs at the time of tumor progression), and the role of chemotherapy (ie, salvage after radiotherapy, primary treatment after surgery, concurrent with radiotherapy). Further complicating treatment decisions are concerns about toxicity with any intervention because LGG patients can often lead a relatively normal existence for years with no intervention. In this article we review the pertinent LGG literature published over the past few years and its impact on the management of LGGs.

[Results of the Sainte-Anne - Lyons series of 318 oligodendroglioma in adults]

INTRODUCTION

Incidence of cerebral oligodendrogliomas is increasing because of better recognition made possible by improved classifications. We studied a homogeneous series using the Sainte-Anne grading scale in order to better understanding the history of these tumors with or without treatment and to assess prognosis and associated factors.

PATIENTS AND METHODS

A retrospective series of 318 adult patients with oligodendroglioma (OLG) treated at Hôpital Sainte-Anne, Paris (SA) and Hôpital Neurologique, Lyons (L) between 1984 and 2003 was analyzed: 182 grade A OLG (SA + L), 136 grade B among which a homogenous series of 98 (SA) were included. For grade A: age at diagnosis ranged from 21 to 70 (mean: 41), sex ratio was 1.28. For grade B: age at diagnosis ranged from 12 to 75 (mean: 45.5), sex-ratio was 1.58. The main first symptoms were: epilepsy (A: 91.5%; B: 76%), intracranial hypertension (A: 7.9%; B: 14.6%), neurological deficit (A: 5.1%; B: 17.7%). The most frequent locations were: frontal, insular and central for both A and B. Mean size was 55 mm for grade A, 62 mm for B. Calcifications were found in 20% of A, 48.5% of B. No tumor was enhanced on imaging (CT/MRI) in grade A, all but 7 in grade B. All patients underwent surgery either for biopsy (A: 47.2%; B: 53%), or removal which was partial (A: 26.4% vs B: 19.4%) or extended (A: 36.3% vs B: 37.8%). Fifty-six patients underwent 2 procedures and 12 three procedures. Radiotherapy was performed in 76.9% of grade A, and 91% of B patients, in the immediate postoperative period for 71% A and 82.7% B. Chemotherapy was delivered for 36% of grade A (in the event of transformation to grade B or failure of radiotherapy) and 67.5% of B patients. Among grade A tumors, 38% transformed into grade B within a mean delay of 51 months with a mean follow-up of 78 months.

RESULTS

Median survival was 136 months for grade A and 52 for grade B. Survival at 5, 10 and 15 was 75.5%, 51% and 22.4% for grade A vs 45.2%, 31.3% and 0% for grade B respectively. In univariate and multivariate analysis, grade A survival was associated with age at diagnosis, tumor size, large removal and response to radiotherapy. Grade B survival was associated with age at diagnosis, wide removal and sharply defined limits of the tumor on imaging.

CONCLUSIONS

Analysis of both published data and this series underlines many prognostic parameters. It shows that OLG are heterogeneous tumors even in each grade (A and B). Treatment should consequently progress towards more targeted procedures for patients mainly with postoperative radiotherapy and chemotherapy.

Low-grade gliomas: an update on pathology and therapy

Low-grade gliomas (LGG) are not benign neoplasms. Patients with LGG eventually die as a consequence of this disease. Although the survival of patients with LGG is better than that of patients with higher-grade tumours, many of the treatments can produce or contribute to chronic impairment, particularly radiotherapy. Chemotherapy has emerged as a promising therapy, although definitive findings are awaited. Breakthroughs in molecular biology have improved our understanding of tumours and have led to the development of novel treatments and better prognoses. Ongoing clinical trials will help to elucidate the optimum management of patients with LGG.

Chromosome 1p loss: a favorable prognostic factor in low-grade gliomas

Search for loss of heterozygosity on chromosomes 1p, 9p, 10q, and 19q, epidermal growth factor receptor (EGFR) gene amplification, and p53 expression was performed in a series of 131 low-grade gliomas. The profile of molecular changes, clinical findings, and histology were subsequently correlated with the course of the disease, mainly progression-free survival. When these parameters were considered as candidate variables in a multivariate analysis, only loss of heterozygosity on chromosome 1p was associated with increased progression-free survival (hazard ratio, 0.521), indicating a major favorable prognostic role of this genetic alteration in low-grade gliomas.

Brachytherapy for brain tumors

Over the past several decades neurooncologists have attempted to find an adjuvant treatment that prolongs survival for patients with malignant brain tumors. Brachytherapy, radiotherapy delivered by placing radioactive sources directly into the tumor, was initially thought to be the solution to this problem. Initial single institution studies showed very promising results; however, this technique has failed to show a significant survival advantage in two randomized studies. Despite this, brachytherapy continues to be used in a number of centers throughout the world for the treatment of various types of brain tumors including low-grade gliomas, anaplastic astrocytomas, glioblastomas, meningiomas and metastases. This article reviews brachytherapy's rationale, radiobiology, complications, indications, and results from numerous studies that have focused on its application for brain tumors with emphasis on its application for glial tumors.

Baseline 11C-methionine PET reflects the natural course of grade 2 oligodendrogliomas

OBJECTIVES

The aim of the present study was to assess the usefulness of positron emission tomography (PET) with the amino acid tracer 11C-methionine (MET) as a predictor of time to progression (TTP) in patients with supratentorial grade 2 gliomas.

METHODS

Twenty-seven patients with glioma grade 2 subjected to a baseline PET scan received no anti-tumour treatment except for a diagnostic operation, and were followed until tumour progression. The prognostic impact of the MET uptake and of other prognostic factors was studied.

RESULTS

Twenty-five of the patients (93%) experienced tumour progression after a median of 103 weeks. Low uptake of MET was a predictor for long TTP in patients with oligodendrogliomas (p = 0.04) but not in astrocytomas/oligoastrocytomas. Other predictors for long TTP were oligodendroglioma histology (p = 0.009) and seizures as presenting symptom (p = 0.03). Favourable prognostic factors for overall survival were oligodendroglioma histology (p = 0.002) and good performance status (p = 0.03).

CONCLUSIONS

PET MET has a definite role in the therapeutic management of grade 2 gliomas. However, for the optimal use of PET MET in the clinical management of these patients, histological subclassification of the tumour is required.

Long-term efficacy of early versus delayed radiotherapy for low-grade astrocytoma and oligodendroglioma in adults: the EORTC 22845 randomised trial

BACKGROUND

Postoperative policies of "wait-and-see" and radiotherapy for low-grade glioma are poorly defined. A trial in the mid 1980s established the radiation dose. In 1986 the EORTC Radiotherapy and Brain Tumor Groups initiated a prospective trial to compare early radiotherapy with delayed radiotherapy. An interim analysis has been reported. We now present the long-term results.

METHODS

After surgery, patients from 24 centres across Europe were randomly assigned to either early radiotherapy of 54 Gy in fractions of 1.8 Gy or deferred radiotherapy until the time of progression (control group). Patients with low-grade astrocytoma, oligodendroglioma, mixed oligoastrocytoma, and incompletely resected pilocytic astrocytoma, with a WHO performance status 0-2 were eligible. Analysis was by intention to treat, and primary endpoints were overall and progression-free survival.

FINDINGS

157 patients were assigned early radiotherapy, and 157 control. Median progression-free survival was 5.3 years in the early radiotherapy group and 3.4 years in the control group (hazard ratio 0.59, 95% CI 0.45-0.77; p<0.0001). However, overall survival was similar between groups: median survival in the radiotherapy group was 7.4 years compared with 7.2 years in the control group (hazard ratio 0.97, 95% CI 0.71-1.34; p=0.872). In the control group, 65% of patients received radiotherapy at progression. At 1 year, seizures were better controlled in the early radiotherapy group.

INTERPRETATION

Early radiotherapy after surgery lengthens the period without progression but does not affect overall survival. Because quality of life was not studied, it is not known whether time to progression reflects clinical deterioration. Radiotherapy could be deferred for patients with low-grade glioma who are in a good condition, provided they are carefully monitored.

Follow-up gliomas after radiotherapy: 1H MR spectroscopic imaging for increasing diagnostic accuracy

We evaluated the value of magnetic resonance imaging (MRI) and the additional benefit of proton MR spectroscopic imaging (1H SI) in patients with a new suspicious lesion after fractionated stereotactic radiotherapy (FSRT) of a glioma. Thirty-four patients with histologically proven astrocytoma WHO II-IV after treatment by FSRT and a new suspect lesion in the follow-up were included in this study. Data were analysed by three independent radiologists with different experience in 1H SI: Data were verified by clinical follow-up (PT, progressive tumour; nPT, non-progressive tumour) and a kappa analysis was performed. Sensitivity and specificity of T1 weighted (w) and T2w MRI was compared (imaging at radiotherapy and follow-up) using further follow-up controls as gold standard and the additional benefit of 1H SI (imaging at follow-up) was calculated. Mean interval between last irradiation and detection of a suspicious lesion was 37 +/- 32 months. Time to clinical evaluation was 13 +/- 8 months. Interobserver agreement was significantly high in all analyses (kappa always >0.8, P < 0.05). T2w imaging proved to be superior to contrast enhanced T1w imaging in sensitivity (87.5 vs 81.25%) and specificity (85.7 vs 57.1%). Solitary 1H SI had similar results as T2w (sensitivity 87.5%, specificity 71.4%). Taking all techniques into account, all PT were correctly diagnosed. Radiologists' experience had no significant influence on correct interpretation of a suspicious lesion. We conclude that 1H SI is helpful in characterising new suspicious lesions in irradiated gliomas, particularly if pre-MRI is not available for evaluating follow-up.

Place de la chimiothérapie et de la radiothérapie dans le traitement des oligodendrogliomes

Twenty years ago, the discovery of the chemosensitivity of anaplastic oligodendrogliomas considerably boosted interest for these tumors. In spite of difficulties for histological diagnosis, numerous studies on radiotherapy and chemotherapy for oligodendrogliomas appeared these last years. They allowed to detail the appropriate role for these therapeutics. For low grade oligodendrogliomas, radiotherapy delays the anaplastic transformation, but does not modify the overall survival; its indication has to be discussed particularly in the absence of clinical symptoms. Chemotherapy seems to be effective for low grade oligodendrogliomas as well as anaplastic tumors. However, phase III studies are necessary to clarify the contribution of chemotherapy for the treatment of low grade oligodendrogliomas, mainly in relation to radiotherapy. In anaplastic oligodendrogliomas, in spite of the lack of phase III studies, radiotherapy seems to be effective. Chemotherapy is clearly effective, but the most appropriate timing (neoadjuvant, adjuvant, at recurrence) is unknown. Results of current prospective studies are awaited. Recently, molecular genetic analysis, particularly the loss of 1p and 19q chromosomes appears to demonstrate a genetic influence on both prognosis and response to treatment.

The efficacy of radiation therapy in the management of grade I astrocytomas

INTRODUCTION

The purpose of this study was to analyze the outcome of patients with grade I astrocytomas treated with radiation therapy, specifically looking at the prognostic significance of age, timing of radiation therapy (immediately after surgery or delayed until progression) and tumor location.

MATERIALS AND METHODS

The records of patients with grade I astrocytomas treated at Washington University Medical Center between 1982 and 2002 were reviewed. Twenty patients with grade I pilocytic astrocytoma (n=19) or subependymal giant cell astrocytoma (n=1) were treated with radiation therapy with curative intent.

RESULTS

The median follow-up was 6.4 years. The 5-year overall survival for all patients was 100%. The 5-year progression-free survival (PFS) following radiation therapy for all patients was 68%. Patients who received radiation therapy immediately after biopsy or surgery had a 5-year PFS of 77% versus 50% for patients who received radiation therapy after initial disease progression (P=0.013). Patients with infratentorial tumors had an improved outcome with a 5-year PFS of 80% versus 59% for those with supratentorial tumors (P=0.0076). Patient age did not significantly influence outcome. All tumor recurrences were local.

CONCLUSIONS

While this study reports an excellent overall survival, approximately one third of patients with grade I astrocytomas had progressive disease following radiation therapy. In particular, patients with supratentorial tumors and delayed radiation therapy had a worse PFS. Additional investigation is needed to improve the outcome in these patients.

Oligodendroglioma

Surgery, radiotherapy, and chemotherapy are the standard treatment modalities for all primary brain tumors. Oligodendroglial tumors are uncommon primary brain tumors that typically are classified as low-grade or anaplastic based on their histologic appearance. A great deal of controversy has surrounded the diagnosis of an oligodendroglioma because no unique immunohistochemical marker exists to diagnose this tumor, forcing pathologists to render a diagnosis based on subjective microscopic features. Although once considered relatively rare, oligodendroglial tumors have been increasing in incidence because pathologists have become less rigorous about this diagnosis. However, recent advances in our understanding of the molecular genetic changes associated with brain tumors have identified loss of heterozygosity of chromosomes 1p and 19q as a unique genetic signature of most oligodendroglial tumors, an advance that has paved the way for pathologists to use molecular diagnostics to identify these tumors with improved reliability. These genetic derangements have significant clinical and therapeutic implications because they have been associated with a predictable and durable response to treatment, particularly chemotherapy, and an improved prognosis. The unique chemosensitivity of oligodendroglial tumors has been recognized by neurooncologists for at least 15 years, and various chemotherapeutic agents have been used to manage these diseases. However, the appropriate timing of chemotherapy, and the drugs of choice remain controversial. Increasingly, neurooncologists are reluctant to use radiotherapy as initial management for these diseases because of concerns surrounding the late neurocognitive sequelae of cranial irradiation. These toxicities are particularly important for patients with low-grade oligodendrogliomas in whom the prognosis often exceeds 10 years. Consequently, with the accumulating evidence supporting the chemosensitivity of low-grade and anaplastic oligodendrogliomas and the recent ability to use molecular diagnostics to identify a chemosensitive subset of oligodendrogliomas, neurooncologists are increasingly administering chemotherapy as the initial intervention for all oligodendroglial tumors that harbor favorable genetic derangements. Additionally, although immediate postoperative treatment is uniformly administered to patients with anaplastic oligodendrogliomas, there has been an increasing tendency to defer definitive therapy for those with low-grade oligodendrogliomas until evidence of progression. The development of temozolomide, an oral and well-tolerated alkylating agent that has activity against oligodendroglial tumors, has accelerated this trend to the extent that currently many patients with newly diagnosed low-grade and anaplastic oligodendrogliomas are offered this drug as initial treatment. This paper reviews the current management of oligodendrogliomas, with an emphasis on the expanding role of chemotherapy for these neoplasms.