Prognostic parameters in benign astrocytomas

The role of radiotherapy in the management of patients with diffuse low grade glioma: A systematic review and evidence-based clinical practice guideline

QUESTIONS

(1) What is the optimal role of external beam radiotherapy in the management of adult patients with newly diagnosed low-grade glioma (LGG) in terms of improving outcome (i.e., survival, complications, seizure control or other reported outcomes of interest)? (2) Which radiation strategies (dose, timing, fractionation, stereotactic radiation, brachytherapy, chemotherapy) improve outcomes compared to standard external beam radiation therapy in the initial management of low grade gliomas in adults? (3) Do specific factors (e.g., age, volume, extent of resection, genetic subtype) identify subgroups with better outcomes following radiation therapy than the general population of adults with newly diagnosed low-grade gliomas?

TARGET POPULATION

These recommendations apply to adults with newly diagnosed diffuse LGG.

RECOMMENDATIONS

OUTCOMES IN ADULT PATIENTS WITH NEWLY DIAGNOSED LOW GRADE GLIOMA TREATED WITH RADIOTHERAPY: Level I Radiotherapy is recommended in the management of newly diagnosed low-grade glioma in adults to prolong progression free survival, irrespective of extent of resection. Level II Radiotherapy is recommended in the management of newly diagnosed low grade glioma in adults as an equivalent alternative to observation in preserving cognitive function, irrespective of extent of resection. Level III Radiotherapy is recommended in the management of newly diagnosed low grade glioma in adults to improve seizure control in patients with epilepsy and subtotal resection. Level III Radiotherapy is recommended in the management of newly diagnosed low-grade glioma in adults to prolong overall survival in patients with subtotal resection. Level III Consideration of the risk of radiation induced morbidity, including cognitive decline, imaging abnormalities, metabolic dysfunction and malignant transformation, is recommended when the delivery of radiotherapy is selected in the management of newly diagnosed low-grade glioma in adults. STRATEGIES OF RADIOTHERAPY IN ADULT PATIENTS WITH NEWLY DIAGNOSED LOW GRADE GLIOMA: Level I Lower dose radiotherapy is recommended as an equivalent alternative to higher dose immediate postoperative radiotherapy (45-50.4 vs. 59.4-64.8 Gy) in the management of newly diagnosed low-grade glioma in adults with reduced toxicity. Level III Delaying radiotherapy until recurrence or progression is recommended as an equivalent alternative to immediate postoperative radiotherapy in the management of newly diagnosed low-grade glioma in adults but may result in shorter time to progression. Level III The addition of chemotherapy to radiotherapy is not recommended over whole brain radiotherapy alone in the management of low-grade glioma, as it provides no additional survival benefit. Level III Limited-field radiotherapy is recommended over whole brain radiotherapy in the management of low-grade glioma. Level III Either stereotactic radiosurgery or brachytherapy are recommended as acceptable alternatives to external radiotherapy in selected patients. PROGNOSTIC FACTORS IN ADULT PATIENTS WITH NEWLY DIAGNOSED LOW GRADE GLIOMA TREATED WITH RADIOTHERAPY: Level II It is recommended that age greater than 40 years, astrocytic pathology, diameter greater than 6 cm, tumor crossing the midline and preoperative neurological deficit be considered as negative prognostic indicators when predicting overall survival in adult low grade glioma patients treated with radiotherapy. Level II It is recommended that smaller tumor size, extent of surgical resection and higher mini-mental status exam be considered as positive prognostic indicators when predicting overall survival and progression free survival in patients in adult low grade glioma patients treated with radiotherapy. Level III It is recommended that seizures at presentation, presence of oligodendroglial histological component and 1p19q deletion (along with additional relevant factors-see Table 1) be considered as positive prognostic indicators when predicting response to radiotherapy in adults with low grade gliomas. Level III It is recommended that increasing age, decreasing performance status, decreasing cognition, presence of astrocytic histological component (along with additional relevant factors (see Tables 1, 2) be considered as negative prognostic indicators when predicting response to radiotherapy.

Low-grade gliomas in older patients: long-term follow-up from Mayo Clinic

BACKGROUND

Low-grade gliomas (LGGs) are uncommon in older patients, and long-term clinical behavior and prognostic factors are not well defined in this group.

METHODS

The authors retrospectively searched their tumor registry for the records of adult patients (> or =18 years) diagnosed as having nonpilocytic LGG between 1960 and 1992 at Mayo Clinic. The Kaplan-Meier method was used to estimate progression-free survival and overall survival (OS) in patients aged 55 years and older.

RESULTS

Of 314 patients initially identified, 32 were aged at least 55 years, with a median age at diagnosis of 61 years (range, 55-74 years). Median follow-up was 17.3 years for survivors. Operative pathologic diagnoses comprised astrocytoma (n = 22, 69%), mixed oligoastrocytoma (n = 7, 22%), and oligodendroglioma (n = 3, 9%). Gross total resection was achieved in 1 patient, radical subtotal resection in 1, and subtotal resection in 14; 16 patients had biopsy only. Postoperative radiotherapy or chemotherapy was given to 23 (72%) patients and 1 (3%) patient, respectively. Median OS was 2.7 years for all patients: 3 years with resection and 2.2 years with biopsy only (P = .58). The 5- and 10-year OS rates were 31% and 18%, respectively. Factors adversely affecting OS on univariate analysis were enhancement on computed tomography (P < .001) and supratentorial location (P = .03).

CONCLUSIONS

This retrospective series of older patients suggests that intracranial LGG in this age group behaves aggressively. Pathologic sampling error failing to recognize higher-grade tumors does not seem to account for these poor outcomes. Aggressive management with maximally safe resection followed by adjuvant therapy should be strongly considered.

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.

Definition and diagnostic implications of gemistocytic astrocytomas: a pathological perspective

Gemistocytic astrocytoma still continues to be enigmatic; both in terms of definition and prognostic implications. The major issue of contention has been the clinical relevance of this pathological entity. The currently accepted definition of gemistocytic astrocytoma requires 20% or more gemistocytes, and considers the neoplasm as a diffuse astrocytoma, which is a WHO grade II tumor. Some suggest that gemistocytic morphology should be considered as evidence of a higher grade astrocytoma. However, there is no consensus on the percentage of gemistocytes associated with a worse prognosis than otherwise expected. Given the reported cases and series, it is not clear that this morphology portends a more aggressive biology when all else is equal. There is still a need for studies with sufficient numbers of well-matched gemistocytic and non-gemistocytic astrocytic neoplasms to decide whether upgrading a tumor with 'significant' number of gemistocytes is justifiable. This article presents a critical review of the existing studies and a brief mention of our experience from a pathological perspective.

Cognitive function after radiotherapy for supratentorial low-grade glioma: a North Central Cancer Treatment Group prospective study

PURPOSE

To evaluate the effects of cranial radiotherapy (RT) on cognitive function in patients with supratentorial low-grade glioma.

METHODS AND MATERIALS

Twenty adult patients with supratentorial low-grade glioma were treated with 50.4 Gy (10 patients) or 64.8 Gy (10 patients) localized RT. The patients then were evaluated with an extensive battery of psychometric tests at baseline (before RT) and at approximately 18-month intervals for as long as 5 years after completing RT. To allow patients to serve as their own controls, cognitive performance was evaluated as change in scores over time. All patients underwent at least two evaluations.

RESULTS

Baseline test scores were below average compared with age-specific norms. At the second evaluation, the groups' mean test scores were higher than their initial performances on all psychometric measures, although the improvement was not statistically significant. No changes in cognitive performance were seen during the evaluation period when test scores were analyzed by age, treatment, tumor location, tumor type, or extent of resection.

CONCLUSIONS

Cognitive function was stable after RT in these patients evaluated prospectively during 3 years of follow-up. Slight improvements in some cognitive areas are consistent with practice effects attributable to increased familiarity with test procedures and content.

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

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

Cognitive sequelae of brain radiation in adults

Radiotherapy (RT) is a proven curative and palliative therapeutic tool in the treatment of a wide variety of primary and metastatic brain tumors in adults. Recent advances in multimodality therapy have led to improvement in survival for many cancer patients. As survival has improved, more attention has been directed toward long-term treatment-related morbidity. Specifically, the effect of RT on the long-term cognitive performance of these patients is a major concern. This article reviews the neurocognitive effects of cranial RT on adult patients with brain tumors. Analyses of neurocognitive function are confounded by factors such as surgery, chemotherapy, tumor characteristics, tumor progression, concurrent medical illnesses, neurologic comorbidity, and medications that can contribute to neurocognitive deficits. Risk of deficits after cranial RT is associated with high RT dose, large fraction size, larger field size, and extremes of age at time of treatment. Using modern techniques with moderate total doses (50 to 54 Gy), conformal RT, conventional fractionation, and advanced planning imaging and software, the risks of neurocognitive deficits are quite small and greatly overshadowed by deficits caused by the tumor itself. Further studies need to be undertaken to elucidate the degree and cause of cognitive decline in adult patients undergoing multimodality therapy for cranial tumors.

Importance of baseline mini-mental state examination as a prognostic factor for patients with low-grade glioma

PURPOSE

The outcome and cognitive performance data collected in a prospective, intergroup clinical trial were analyzed to assess the prognostic importance of the baseline (before radiotherapy) Mini-Mental State Examination (MMSE) score in patients with low-grade glioma.

METHODS AND MATERIALS

The patients studied were 203 adults with a supratentorial low-grade glioma randomly assigned to low-dose (50.4 Gy in 28 fractions) or high-dose (64.8 Gy in 36 fractions) localized radiotherapy. Folstein MMSE scores and neurologic function scores at baseline in combination with multiple other baseline variables were analyzed. The median follow-up was 7.4 years for the 101 patients still alive.

RESULTS

Patients (n = 36) with an abnormal baseline MMSE score (< or =26) had a worse 5-year progression-free survival rate (27% vs. 60%; p <0.001) and overall survival rate (31% vs. 76%; p <0.001) compared with those with a normal score. On multivariate analysis, the baseline MMSE score was a statistically significant predictor of survival. Other factors associated with overall survival were age, tumor size, and tumor histologic type.

CONCLUSION

The presence of an abnormal baseline MMSE score was a strong predictor of poorer progression-free and overall survival for patients with a low-grade glioma. The baseline MMSE should be considered in future prognostic scoring systems.

The neurocognitive effects of radiation in adult low-grade glioma patients

Radiotherapy is a component of the treatment regimen for the majority of patients with low-grade gliomas. Therefore, the effect of radiotherapy on the long-term cognitive performance of these patients is a major concern. This article reviews the neurocognitive effects of radiotherapy on patients with low-grade gliomas. The weight of evidence suggests only sporadic, limited neurocognitive damage from focal radiotherapy at the doses usually prescribed for low-grade gliomas.

Effects of radiotherapy on cognitive function in patients with low-grade glioma measured by the folstein mini-mental state examination

PURPOSE

To assess the neurocognitive effects of cranial radiotherapy on patients with low-grade gliomas, we analyzed cognitive performance data collected in a prospective, intergroup clinical trial.

METHODS

Patients included 203 adults with supratentorial low-grade gliomas randomly assigned to a lower dose (50.4 Gy in 28 fractions) or a higher dose (64.8 Gy in 36 fractions) of localized radiotherapy. Folstein Mini-Mental State Examination (MMSE) scores and neurologic function scores (NFS) at baseline and key evaluations were analyzed. Median follow-up was 7.4 years in 101 patients still alive. A change of more than three MMSE points was considered clinically significant.

RESULTS

In patients without tumor progression, significant deterioration from baseline occurred at years 1, 2, and 5 in 8.2%, 4.6%, and 5.3% of patients, respectively. Most patients with an abnormal baseline MMSE score (< 27) experienced significant increases. Baseline variables such as radiation dose, conformal versus conventional radiotherapy, number of radiation fields, age, sex, tumor size, NFS, seizures, and seizure medications did not predict cognitive function changes.

CONCLUSION

In this population, most low-grade glioma patients maintained a stable neurocognitive status after focal radiotherapy as measured by the MMSE. Patients with an abnormal baseline MMSE were more likely to have an improvement in cognitive abilities than deterioration after receiving radiotherapy. Only a small percentage of patients had cognitive deterioration after radiotherapy. However, more discriminating neurocognitive assessment tools may identify cognitive decline not apparent with the use of the MMSE.

Effect of surgery on tumor progression and malignant degeneration in hemispheric diffuse low-grade astrocytomas

The aim of this study is to determine the impact of surgery on tumor progression and malignant degeneration in hemispheric diffuse astrocytoma WHO grade II. Twenty-eight patients who were operated or underwent stereotactic biopsy for hemispheric diffuse astrocytoma WHO grade II at Marmara University between January 1987 and January 1996, were prospectively reviewed for the presence of recurrence and histopathological dedifferentiation at their fourth years after the initial treatment. Twenty-two patients underwent surgical resection. Of this group, 7 patients had a total, 11 had a subtotal and 4 patients had a partial resection. Six patients underwent stereotactic biopsy. All patients, except for the ones in whom a radiological total surgical removal could be achieved, received postoperative radiotherapy. In the total surgical-removal group only one patient had recurrence, while no upgrade was noted. All of the patients in the partial resection and stereotactic biopsy groups recurred at a higher grade. Our results indicate that both tumor progression and histopathological dedifferentiation were less commonly seen when a total or subtotal resection could be achieved. So, surgery, as radical as possible, should be the choice of treatment in low-grade hemispheric astrocytomas.

Randomized trials of radiation therapy in adult low-grade gliomas

There are two central questions in the radiotherapeutic management of the adult patient with a supratentorial low-grade (WHO grade II) astrocytoma, oligo-astrocytoma, or oligodendroglioma. The first question is one of timing. Following tissue diagnosis with or without maximum surgical resection, should immediate postoperative radiation therapy (RT) be given, or should RT be deferred to the time of local recurrence? The second question is one of dose. Assuming RT is given, should lower doses (ie, approximately 45-50 Gray (Gy)) or higher doses (ie, approximately 60-65 Gy) be administered? One Phase III prospective randomized clinical trial addressing the first question and two addressing the second question have been performed. Their results suggest that delayed (versus immediate) RT and low-dose (versus high-dose) RT are both acceptable treatment strategies despite the bias amongst radiation oncologists (primarily based on retrospective data) that immediate and high-dose RT would result in better outcome. The schema of the ongoing Radiation Therapy Oncology Group study is presented.

Oligodendroglioma: an appraisal of recent data pertaining to diagnosis and treatment

OBJECTIVE

This article reviews and summarizes recent data on the diagnosis, prognosis, and treatment of oligodendroglial tumors.

METHODS

Histological criteria for optimized diagnosis and grading of oligodendroglial tumors are described and discussed. The therapeutic approaches are analyzed in light of the results of recent series.

RESULTS

Oligodendroglial tumors may be more common than is generally thought. Perinuclear halo and "chicken-wire" pattern, although considered classic histological features of oligodendrogliomas, are unreliable as sole criteria for diagnosis. Nuclear regularity and roundness and an eccentric rim of eosinophilic cytoplasm lacking obvious cell processes are more constant features. Grading should be accomplished using a composite of radiological and histopathological relevant features. The allelic loss of chromosome arms 1p and 19q might be a marker for both chemosensitivity and longer survival after chemotherapy. Oligodendrogliomas are notably chemosensitive when compared with other gliomas. For aggressive lesions, chemotherapy should be used upfront, after surgery.

CONCLUSION

Oligodendrogliomas are underdiagnosed. One unfortunate implication is that a large number of patients may be receiving suboptimal care. A simplification in grading of oligodendroglioma to two grades would reduce the confusion surrounding the classification and better define prognosis and response to treatment modalities. A better definition of the so-called mixed tumor should also allow a better classification of these lesions in an intermediate prognostic class between astrocytic and oligodendroglial lesions. Loss of 1p and 19q could be used as a cytogenetic marker in assisting grading. New concepts emerging in the recent literature should help optimize the diagnosis of these lesions and reduce interobserver variability.

The role of surgery in low grade gliomas

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

Dysembryoplastic neuroepithelial tumors: nonspecific histological forms -- a study of 40 cases

OBJECTIVE

To demonstrate that DNTs include a large morphological spectrum of tumors that cannot be histologically distinguished from conventional categories of gliomas.

METHODS

All tumors from patients who underwent epilepsy surgery in Sainte-Anne hospital (Paris) that histologically resembled gliomas and did not conform to current histological criteria for DNTs or gangliogliomas were entered in the study.

RESULTS

According to the WHO histological classification, the 40 tumors resembled: pilocytic astrocytomas (4 cases), astrocytomas (16 cases), anaplastic astrocytoma (1 case), oligodendrogliomas (10 cases), oligo-astrocytomas (8 cases) or anaplastic oligo-astrocytomas (1 case). However foci of cortical dysplasia could be observed in 47% of the cases. Clinical presentation and imaging features were strikingly similar to that observed in typical DNTs. Although surgical removal was incomplete in 28% of the cases and none of the patients underwent chemo or radiotherapy, none of the tumors recurred (mean follow-up: 7 years). Moreover, serial preoperative imaging in 26 patients (mean follow-up: 4.5 years) demonstrated that these lesions were perfectly stable.

CONCLUSIONS

Whatever the histological appearance of a glial tumor, the diagnosis of DNT must be considered when all the following criteria are associated: (1) partial seizures, with or without secondary generalization, beginning before the age 20 years, (2) no neurological deficit or stable congenital deficit, (3) cortical topography of the lesion as better demonstrated by MRI and (4) no mass effect on imaging.

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

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

METHODS

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

RESULTS

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

CONCLUSION

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

Prevalence and prognostic significance of epilepsy in patients with gliomas

The aim of this study was to evaluate the prevalence and prognostic significance of epilepsy in 1028 patients diagnosed in the computer tomography (CT) era with histological low- or high-grade intracranial gliomas. Survival analysis included Kaplan-Meier plots, log-rank tests, logistic regression and Cox's analysis as implemented in the SPSS statistical package. Epilepsy was a positive univariate (P < 0.0001) and multivariate, (P < 0.03) prognostic factor for survival in the total patient group (n = 1028, relative risk of death 0.83, 95% confidence interval (CI) 0.70-0.98) as well as in the high-grade patient group (n = 649, relative risk of death 0.80, 95% CI 0.66-0.96), but not in the group of low-grade glioma patients (P > 0.2). The prevalence of epilepsy in glioblastoma patients was 251/512 (49%), 95/137 (69%) in anaplastic gliomas, and 322/379 (85%) in patients with low-grade gliomas, with 97 of the 102 T1 low-grade subgroup (95%) having epilepsy, indicating that the presence of epilepsy may select patients for early radiological diagnosis. The frequency of epilepsy at presentation decreased with age in high-grade glioma patients, and increased with age in low-grade glioma patients to a plateau in the fourth decade of life (P < 0.01). The prevalence of epilepsy in patients with histological intracranial gliomas varied with patient age and tumour histology, with low-grade patients having the highest prevalence. Epilepsy was a significant positive prognostic factor except in patients with low-grade gliomas, and may select low-grade patients for early diagnosis.

Low-grade gliomas: introduction and overview

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

Prognostic factors in low grade (WHO grade II) gliomas of the cerebral hemispheres: the role of surgery

OBJECTIVE

To assess the role of surgery on survival of patients with grade II gliomas of the cerebral hemispheres.

METHODS

One hundred and thirty one low grade hemispheric gliomas surgically treated (biopsied patients excluded) between 1978 and 1989 were retrospectively reviewed. Thalamic, basal ganglia, callosal, or ventricular location were not considered. All tumours were World Health Organisation (WHO) grade II gliomas: 42 fibrillary and 11 gemistocytic astrocytomas, 49 oligodendrogliomas, and 29 oligoastrocytomas. Patients' ages ranged from 14 to 63 (mean 32.9, median 34) years, Karnofsky performance from 0.50 to 0.90 (mean 80.7, median 80), and postsurgical follow up of the living patients from 24 to 190 (mean 97.02, median 93) months. Postoperative external radiotherapy was performed in 49 cases.

RESULTS

The overall survival probability at five years was 97.1%, at eight years 76.1%, and at 10 years 62.7% (median survival time 144 months). The impact on survival of the following variables was analysed: age (< 20, 21-40, and > 40 years), Karnofsky score (80-100, 70 < or = 70), histology, tumour extension (T1 < 3 cm, T2 3-5 cm, T3 > 5 cm maximum diameter), extent of surgical resection (S1 radical, S2 subtotal < 10% residual tumour, S3 partial-10%-50% residual tumour), and radiotherapy (either performed or not). A significant positive association with survival at univariate analysis was found for the age group < 20 years (P = 0.003), for total and subtotal surgical resections (S1 and S2; P < 0.001) and for the non-irradiated patients (P = 0.0049), whereas a shorter survival probability was noticed for gemistocytic astrocytomas (P < 0.001) and for tumour extension > 5 cm (T3; P = 0.0193). Karnofsky performance did not show any significant association with survival. The most relevant factor affecting survival at the multivariate analysis was the extent of surgical resection, which resulted as the only variable retaining a significant value (P = 0.001, risk factor = 2.20).

CONCLUSIONS

The data strongly support the role of a surgical removal as extensive as possible in the treatment of these tumours.

Current treatment of thalamic gliomas in children

Historically, the outcome of children with thalamic gliomas has been poor. Because of the potential for severe perioperative mortality, conservative approaches toward these lesions have been commonly instituted. However, recent improvements in therapeutic approaches have been numerous. These refinements have most importantly centered on improving the neurosurgical technique of tumor resection by integrating computer-assisted, stereotactic approaches. In so doing, perioperative mortality has dropped from as high as 40% to as low as 0-1%. Gross total resection confirmed with postoperative imaging is becoming an expectation. However, because of anatomical limitations or malignant histology, incomplete resections will undoubtedly occur in an effort to preserve neurological function. At the same time, not all residual disease implies a poor outcome. Indolent, low-grade gliomas of childhood are not limited to the cerebellum or optic/hypothalamic regions, and histologically similar lesions in the region of the thalamus occur with some frequency. In this case scenario, incompletely resected low-grade lesions should be followed sequentially with routine imaging; further therapy, be it surgical or adjuvant, is instituted only if disease progression is documented. Children found to have malignant gliomas of the thalamus should undergo surgical resection in an effort to relieve them of any existing mass effect. Subsequently, adjuvant therapy is utilized depending on the exact histopathology and the child's age. Thus, what evolves from recent data and current surgical techniques is an aggressively directed therapy based upon anatomical considerations and tumor type.

Low-grade astrocytomas: prognosis factors and elements of management

BACKGROUND

The literature provides information concerning prognosis of low-grade astrocytomas, but the series are quite heterogeneous in terms of clinical material, neuropathological evaluation, and statistical methods of analysis. Therapeutical indications are poorly defined. The last World Health Organization (WHO) histological classification provided a very precise definition of low-grade gliomas.

METHODS

Taking into account a recent study of our own and literature data, management guidelines of these tumors were proposed.

RESULTS

Grade I (pilocytic and subependymal giant cell astrocytomas) are surgically curable lesions. No adjuvant treatment is mandatory. Management of grade II astrocytomas is less clear-cut. Conservative management is probably possible in young patients without functional threat. The role of surgery on duration of survival has been properly established in very few series and was negative in many others. The role of radiotherapy has been demonstrated in a few subgroups of patients. In our study of ordinary astrocytomas, considering decades of age at diagnosis, survival curve analysis established three prognostic classes of age (before 50, between 50 and 60, and after 60 years of age). Based on our results and on recently published data, a branch decisional approach was proposed for management of grade II astrocytomas. Other grade II gliomas exhibit more favorable prognoses but could be managed in the same manner.

CONCLUSIONS

Ordinary grade II astrocytomas constitute a paradigm of difficult differential management. Further pertinent information on these tumors could come from the field of tumor biology, or be provided by very large and homogeneous groups of patients.