Low-grade pure and mixed cerebral astrocytomas treated in the CT scan era

Management of low-grade glioma: a systematic review and meta-analysis

Background

Optimum management of low-grade gliomas remains controversial, and widespread practice variation exists. This evidence-based meta-analysis evaluates the association of extent of resection, radiation, and chemotherapy with mortality and progression-free survival at 2, 5, and 10 years in patients with low-grade glioma.

Methods

A quantitative systematic review was performed. Inclusion criteria included controlled trials of newly diagnosed low-grade (World Health Organization Grades I and II) gliomas in adults. Eligible studies were identified, assigned a level of evidence for every endpoint considered, and analyzed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The relative risk of mortality and of progression at 2, 5, and 10 years was calculated for patients undergoing resection (gross total, subtotal, or biopsy), radiation, or chemotherapy.

Results

Gross total resection was significantly associated with decreased mortality and likelihood of progression at all time points compared to subtotal resection. Early radiation was not associated with decreased mortality; however, progression-free survival was better at 5 years compared to patients receiving delayed or no radiation. Chemotherapy was associated with decreased mortality at 5 and 10 years in the high-quality literature. Progression-free survival was better at 5 and 10 years compared to patients who did not receive chemotherapy. In patients with isocitrate dehydrogenase 1 gene (IDH1) R132H mutations receiving chemotherapy, progression-free survival was better at 2 and 5 years than in patients with IDH1 wild-type gliomas.

Conclusions

Results from this review, the first to quantify differences in outcome associated with surgery, radiation, and chemotherapy in patients with low-grade gliomas, can be used to inform evidence-based management and future clinical trials.

Rotating Gamma System Irradiation: A Promising Treatment for Low-grade Brainstem Gliomas

AIM

To evaluate the role of rotating gamma system (RGS) radiosurgery for low-grade brainstem gliomas.

PATIENTS AND METHODS

Thirty-seven patients undergoing RGS radiosurgery at the Bach Mai Hospital Hanoi for low-grade brainstem glioma were included in this prospective interventional study. The median RGS dose was 12 Gy (range=8-16 Gy). Endpoints included response to RGS radiosurgery given as change in glioma size (maximum diameter), survival and adverse events. Follow-up was performed for 36 months. Three dose-groups (<13, 13-14 and >14 Gy) were compared for survival.

RESULTS

Mean glioma size decreased from 1.87 cm before RGS irradiation to 1.15 cm at 36 months. Mean survival was 39.5 months. Mean survival after <13, 13-14 and >14 Gy were 22.7, 66.7 and 49 months, respectively (p<0.05). Adverse events, mainly reduced appetite, sleep disturbances, headache and edema, were not associated with RGS dose and were easily managed.

CONCLUSION

RGS radiosurgery led to promising results with acceptable toxicity in patients with low-grade brainstem gliomas.

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.

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

QUESTION

Should patients with imaging suggestive of low grade glioma (LGG) undergo observation versus treatment involving a surgical procedure?

TARGET POPULATION

These recommendations apply to adults with imaging suggestive of a WHO grade 2 glioma (oligodendroglioma, astrocytoma, or oligo-astrocytoma).

RECOMMENDATIONS

Surgical resection is recommended over observation to improve overall survival for patients with diffuse low-grade glioma (Level III) although observation has no negative impact on cognitive performance and quality of life (Level II).

QUESTION

What is the impact of extent of resection on progression free survival (PFS) or overall survival (OS) in LGG patients?

TARGET POPULATION

These recommendations apply to adults with imaging suggestive of a WHO grade 2 glioma (oligodendroglioma, astrocytoma, or oligo-astrocytoma).

RECOMMENDATIONS

IMPACT OF EXTENT OF RESECTION ON PFS:

LEVEL II

It is recommended that GTR or STR be accomplished instead of biopsy alone when safe and feasible so as to decrease the frequency of tumor progression recognizing that the rate of progression after GTR is fairly high.

IMPACT OF EXTENT OF RESECTION ON OS

LEVEL III

Greater extent of resection can improve OS in LGG patients.

QUESTION

What tools are available to increase extent of resection in LGG patients?

TARGET POPULATION

These recommendations apply to adults with imaging suggestive of a WHO grade 2 glioma (oligodendroglioma, astrocytoma, or oligo-astrocytoma).

RECOMMENDATIONS

INTRAOPERATIVE MRI DURING SURGERY:

LEVEL III

The use of intraoperative MRI should be considered as a method of increasing the extent of resection of LGGs.

QUESTION

What is the impact of surgical resection on seizure control and accuracy of pathology in low grade glioma patients?

TARGET POPULATION

These recommendations apply to adults with imaging suggestive of a WHO grade 2 glioma (oligodendroglioma, astrocytoma, or oligo-astrocytoma).

RECOMMENDATIONS

SURGICAL RESECTION AND SEIZURE CONTROL:

LEVEL III

After taking into account the patient's clinical status and tumor location, gross total resection is recommended for patients with diffuse LGG as a way to achieve more favorable seizure control.

ACCURACY OF DIAGNOSIS

LEVEL III

Taking into account the patient's clinical status and tumor location, surgical resection should be carried out to maximize the chance of accurate diagnosis.

QUESTION

What tools can improve the safety of surgery for LGGs in eloquent locations?

TARGET POPULATION

These recommendations apply to adults with imaging suggestive of a WHO grade 2 glioma (oligodendroglioma, astrocytoma, or oligo-astrocytoma).

RECOMMENDATIONS

PREOPERATIVE IMAGING:

LEVEL III

It is recommended that preoperative functional MRI and diffusion tensor imaging be utilized in the appropriate clinical setting to improve functional outcome after surgery for LGG.

INTRAOPERATIVE MAPPING OF TUMORS IN ELOQUENT AREAS

LEVEL III

Intraoperative mapping is recommended for patients with diffuse LGGs in eloquent locations compared to patients with non-eloquently located diffuse LGGs as a way of preserving function.

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.

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.

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.

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.

Treatment outcomes and prognostic factors in patients with supratentorial low-grade gliomas

Low-grade gliomas account for 10-15% of all adult primary intracranial tumours. Currently, there is no consensus on the treatment strategy for low-grade gliomas. This study was designed to evaluate the treatment outcomes, prognostic factors and radiation-related late complications, as well as to assess whether or not post-operative radiotherapy has benefit on local control and overall survival in this population. We retrospectively reviewed 93 consecutive adult patients with supratentorial low-grade gliomas diagnosed at our institution from July 1985 to December 1997. All patients underwent surgical intervention and 60 of them received post-operative radiotherapy. With a median follow-up of 110 months for surviving patients, the 5-year overall and progression-free survival rates were 57% and 47%, respectively. 46 patients experienced local progression of disease during the follow-up period. In multivariate analysis, age at diagnosis, extent of surgery and post-operative Karnofsky performance status showed independent prognostic significance for progression-free and overall survival rates. Post-operative radiotherapy had independent prognostic value for progression-free survival. This analysis has changed our practice and we suggest that aggressive surgical resection and post-operative radiotherapy might be considered for patients with low-grade gliomas. Further efforts should be made to optimize radiotherapy techniques and to integrate new therapeutic modalities.

Survival rates in patients with low-grade glioma after intraoperative magnetic resonance image guidance

BACKGROUND

No age-adjusted or histologic-adjusted assessments of the association between extent of resection and risk of either recurrence or death exist for neurosurgical patients who undergo resection of low-grade glioma using intraoperative magnetic resonance image (MRI) guidance.

METHODS

The current data included 156 patients who underwent surgical resection of a unifocal, supratentorial, low-grade glioma in the MRI suite at Brigham and Women's Hospital between January 1, 1997, and January 31, 2003. Estimates of disease-free and overall survival probabilities were calculated using Kaplan-Meier methodology. The association between extent of resection and these probabilities was measured using a Cox proportional hazards model. Observed death rates were compared with the expected death rate using age-specific and histologic-specific survival rates obtained from the Surveillance, Epidemiology, and End Results Registry.

RESULTS

Patients who underwent subtotal resection were at 1.4 times the risk of disease recurrence (95% confidence interval [95% CI], 0.7-3.1) and at 4.9 times the risk of death (95% CI, 0.61-40.0) relative to patients who underwent gross total resection. The 1-year, 2-year, and 5-year age-adjusted and histologic-adjusted death rates for patients who underwent surgical resection using intraoperative MRI guidance were 1.9% (95% CI, 0.3-4.2%), 3.6% (95% CI, 0.4-6.7%), and 17.6% (95% CI, 5.9-29.3%), respectively: significantly lower than the rates reported using national data bases.

CONCLUSIONS

The data from the current study suggested a possible association between surgical resection and survival for neurosurgical patients who underwent surgery for low-grade glioma under intraoperative MRI guidance. Further study within the context of a large, prospective, population-based project will be needed to confirm these findings.

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.

Prognostic factors for low-grade gliomas

Low-grade gliomas are a heterogenous group of diseases characterized by relatively slow-growing primary brain tumors of astrocytic and/or oligodendroglial origin. Many patients present with easily controlled seizures and remain stable for years, whereas others progress rapidly to higher-grade tumors. Several studies have retrospectively investigated tumor-, patient-, and treatment-related prognostic factors in this patient population. Tumor histology, grade, location, contrast enhancement, and molecular markers have been identified as prognostic factors for survival. Likewise, patient age, performance status, and seizure history are patient-dependent prognostic factors. However, although patients who undergo surgical resection and receive adjuvant radiotherapy tend to have improved survival, treatment-dependent prognostic factors have yet to be definitively identified. Recursive partitioning and multivariant analyses have identified a class of patients with good prognosis. Younger patients with good performance status, non-contrast-enhancing tumors (<5 cm), and tumors of oligodendroglial or mixed-oligoastrocytic subtype have improved survival. The European Organisation for Research and Treatment of Cancer has recently developed a prognostic score based on identified prognostic factors to assist in the management of low-grade gliomas. For patients with a favorable (low-risk) score, treatment with radiotherapy or chemotherapy treatment should be withheld until tumor progression. For patients with a high-risk score, treatment at diagnosis may be indicated. However, other than surgery, the optimal types and sequence of therapies are not yet established. Improvements in defining prognostic factors will assist in low-grade glioma management.

Radiotherapy in low-grade gliomas: cons

Although postoperative radiotherapy (RT) is widely used in patients with low-grade gliomas (LGGs), its clinical benefit remains unproven. Because LGGs include diseases with many different histologies, cytogenetic patterns, and natural histories, evaluating the effect of any treatment for LGGs is difficult. Analysis of prognostic subgroups has shown median survival rates ranging from 1 to 10 years. The clinical benefit of postoperative RT in LGGs in retrospective studies is confounded by the heterogeneity of LGGs and treatment-related variables. These studies report conflicting results, most likely because of differences in patient populations. The only prospective, randomized trial comparing postoperative RT with observation failed to show a survival benefit but showed a modest, although statistically significant, improvement in time to progression. Given that two thirds of patients in the observation group received RT at progression, the absence of a survival benefit suggests that RT is active in LGGs, but that delayed RT may provide the same survival advantage as postoperative RT. Moreover, high-dose or whole-brain RT can cause cognitive deficits. Our opinion is that postoperative RT should not be administered routinely to patients with LGGs. If RT is deemed necessary, such as in progressive or inoperable disease causing neurologic symptoms, a total dose of </=50 Gy with a fractional dose of </=1.8 to 2 Gy should be administered using modern, highly conformal techniques. Ideally, RT should be used only within the context of clinical research protocols.

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.

Supratentorial grade II astrocytoma: biological features and clinical course

Because of its unpredictable clinical course, treatment strategies for low-grade (grade II) astrocytoma vary from "wait and see" to gross tumour resection followed by immediate radiotherapy. Clinical studies on grade II astrocytoma show that 5-year-survival ranges from 27% to 85% of patients with very few consistent prognostic variables besides the patient's age and the presence of neurological deficit. There is no universally recognised choice of therapy for patients with astrocytoma grade II, partly because of the shortcomings of histological classification systems. Routine microscopy tends to underestimate malignancy grading of astrocytomas and in most cases cannot distinguish between indolent and progressive subtypes. Recent studies suggest that proliferation and genetic markers can be used to identify subgroups of astrocytoma grade II with a rapid progressive clinical course. Therefore these markers should be included in ongoing and future clinical studies of patients with astrocytoma grade II.

Oligodendroglioma: does deferring treatment compromise outcome?

This study reports the University of Florida experience treating oligodendrogliomas with the goal of identifying the factors that predict favorable outcome. Between 1958 and June 1998, 51 patients (aged 5-75 years) were diagnosed with pure oligodendroglioma at the University of Florida. Histologic grade was anaplastic in 19 patients, low-grade in 30 patients, and unknown in one patient. Twelve patients were treated with surgery alone (10 with low-grade tumors). Thirty-nine patients underwent postoperative radiotherapy after surgery (plus chemotherapy in four patients). A biopsy was performed in 10 patients, 40 underwent subtotal or gross total resection, and one had surgery of unknown extent. Thirteen patients with a radiographic abnormality consistent with a low-grade glioma had the initiation of definitive treatment (i.e., surgery with or without radiotherapy) deferred for a median of 4.5 years before undergoing treatment for worsening symptoms or radiographic progression. Absolute survival for the entire group (51 patients) at 5, 10, and 20 years from the date of initial treatment was 61%, 37%, and 31%, respectively, and at 5, 10, and 20 years from the date of initial diagnosis was 65%, 43%, and 34%, respectively. No patient died of intercurrent disease. Multivariate analysis for absolute survival from the time of initial treatment demonstrated young age (young patients fared better than older patients) and size (<5 cm better than > or =5 cm) to be significant variables. No patient under the age of 21 years (n = 8) at the time of diagnosis has died in this series. Deferring aggressive treatment did not alter survival. Multivariate analysis for favorable absolute survival based on the time from initial diagnosis demonstrated young age and presentation with seizures alone to be statistically significant for favorable outcomes. Approximately one third of patients with oligodendroglioma appear to be cured with aggressive treatment. Age is the most important predictor of long-term progression-free and absolute survival with young patients (especially aged <21 years) doing much better than older patients. Deferring aggressive treatment (surgery and/or radiation) until symptoms clearly indicate tumor progression does not compromise outcome for a select group of patients who are diagnosed at a young age with a nonenhancing mass on MR and seizures as the lone presenting symptom.

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

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

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

OBJECT

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

METHODS

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

CONCLUSIONS

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

Diagnosis and management of astrocytomas, oligodendrogliomas and mixed gliomas: a review

Low-grade gliomas are a diverse group of neoplasms which, as the name implies, are thought to arise from glial cells. Common among this group are astrocytomas (low-grade astrocytoma; LGA), oligodendrogliomas and mixed gliomas. Among these, LGA is the commonest low-grade glioma and, occasionally, although incorrectly, the terms are used interchangeably. Advances in imaging technology have improved the accuracy of preoperative diagnosis. The management of low-grade gliomas is controversial. Recent evidence suggests that previously considered standard therapy (i.e. surgery plus radiotherapy) may not be in the patient's best interests. A review of the available published research concerning low-grade gliomas is therefore timely.

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.

Postoperative radiotherapy of astrocytomas

Astrocytomas account for the majority of primary brain tumors. Low-grade tumors are slowly growing tumors with relatively long overall survival. However, a high percentage of these tumors transform to more malignant, high-grade tumors. High-grade gliomas (anaplastic astrocytomas and glioblastoma multiforme) have a poor prognosis. Treatment options are capable of prolonging the natural history of the disease, but the long-term survival is poor. This review discusses the different postoperative treatment options and the prognostic factors in low- and high-grade astrocytomas.

Pretreatment factors predict overall survival for patients with low-grade glioma: a recursive partitioning analysis

PURPOSE

Three databases were pooled and analyzed to determine which groupings of prognostic factors best predicted overall survival for patients with low-grade gliomas treated with surgery and immediate or delayed radiotherapy.

METHODS AND MATERIALS

Databases of patients with low-grade gliomas compiled at the London Regional Cancer Centre (LRCC), the Norwegian Radium Hospital (NRH), and the University of California, San Francisco (UCSF) were merged. Inclusion criteria for the pooled analysis included: age > or =18 years and histologically confirmed low-grade (World Health Organization Grade II) supratentorial fibrillary astrocytoma, oligodendroglioma or mixed oligoastrocytoma. Factors analyzed for prognostic significance included: age at diagnosis, gender, seizures at presentation, presence of enhancement on computed tomography (CT) or magnetic resonance imaging (MRI), Karnofsky Performance Status (KPS) at diagnosis, histology, extent of surgical resection, timing of radiotherapy, and treating institution. Univariate and multivariate analysis of overall survival for these factors was performed. Recursive partitioning was performed to generate prognostic groups using these factors.

RESULTS

From the combined databases, 401 patients were eligible for analysis. Median survival for the entire group was 95 months/7.9 years. On univariate analysis age 18-40, presence of seizures at presentation, KPS > or =70, treating institution, and absence of contrast enhancement were associated with improved overall survival. On multivariate analysis, these factors remained independent predictors of improved overall survival. Recursive partitioning analysis yielded four prognostic groups with statistically different median survivals (MS): Group I (n = 41: KPS <70, age >40) MS 12 months; Group II (n = 34: KPS > or =70, age >40, enhancement present) MS 46 months; Group III (n = 138: KPS <70, age 18-40 or KPS > or =70 age >40, no enhancement) MS 87 months; Group IV (n = 188: KPS > or =70, age 18-40) MS 128 months.

CONCLUSION

Clusters of pretreatment prognostic factors described subgroups of low-grade glioma patients with divergent overall survivals. Consideration of these prognostic subgroups may be important when considering timing of interventions for these patients and in the stratification of patients for clinical trials.

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.