Stereotactic Radiosurgery and Interstitial Brachytherapy for Glial Neoplasms

Long-term outcome of stereotactic brachytherapy with temporary Iodine-125 seeds in patients with WHO grade II gliomas

BACKGROUND

This long-term retrospective analysis aimed to investigate the outcome and toxicity profile of stereotactic brachytherapy (SBT) in selected low-grade gliomas WHO grade II (LGGII) in a large patient series.

METHODS

This analysis comprised 106 consecutive patients who received SBT with temporary Iodine-125 seeds for histologically verified LGGII at the University of Munich between March 1997 and July 2011. Investigation included clinical characteristics, technical aspects of SBT, the application of other treatments, outcome analyses including malignization rates, and prognostic factors with special focus on molecular biomarkers.

RESULTS

For the entire study population, the 5- and 10-years overall survival (OS) rates were 79% and 62%, respectively, with a median follow-up of 115.9 months. No prognostic factors could be identified. Interstitial radiotherapy was applied in 51 cases as first-line treatment with a median number of two seeds (range 1-5), and a median total implanted activity of 21.8 mCi (range 4.2-43.4). The reference dose average was 54.0 Gy. Five- and ten-years OS and progression-free survival rates after SBT were 72% and 43%, and 40% and 23%, respectively, with a median follow-up of 86.7 months. The procedure-related mortality rate was zero, although an overall complication rate of 16% was registered. Patients with complications had a significantly larger tumor volume (p = 0.029).

CONCLUSION

SBT is a minimally invasive treatment modality with a favorable outcome and toxicity profile. It is both an alternative primary treatment method as well as an adjunct to open tumor resection in selected low-grade gliomas.

Outcome of salvage treatment for recurrent glioblastoma

Most glioblastoma (GBM) cases recur within a year and almost all cases recur at some point. Standard treatment for recurrent GBM has not yet been established. We investigated the outcome of various salvage treatments for recurrent GBM. Retrospective analysis was undertaken in 144 patients who received salvage treatment at the time of first progression after maximum debulking surgery followed by concomitant chemoradiotherapy and adjuvant temozolomide (TMZ) chemotherapy. The median follow-up period was 18.2 months. We grouped these patients into five groups according to the salvage modalities: Gamma Knife radiosurgery (GKS) group (n=29), TMZ group (n=31), GKS+TMZ group (n=28), reoperation group (n=38) and "other treatment" group (n=18). The median time to first progression from initial diagnosis was 8.8 months. The median overall survival (OS) of the five different treatment groups; GKS, TMZ, GKS+TMZ, reoperation, and "other treatment", was 9.2, 5.6, 15.5, 13.2, and 8.0 months, respectively. Median progression-free survival (PFS) was 3.6, 2.3, 6.0, 4.3, and 2.6 months, respectively. Pairwise comparison of OS of the GKS+TMZ group with the other groups showed that the OS of the GKS+TMZ group was significantly better than all others except the reoperation group. Statistically significant prolongation of PFS was observed in the GKS+TMZ group compared with the TMZ group and the "other treatment" group. GKS followed by TMZ salvage treatment was a good prognostic factor for both PFS and OS in multivariate analysis. Retrospectively, GKS+TMZ as a salvage treatment, tended to provide a superior survival benefit at the time of recurrence.

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

Background

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

Objectives

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

Materials and Methods

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

Results

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

Conclusions

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

Metallofullerene-nanoplatform-delivered interstitial brachytherapy improved survival in a murine model of glioblastoma multiforme

Fullerenes are used across scientific disciplines because of their diverse properties gained by altering encapsulated or surface-bound components. In this study, the recently developed theranostic agent based on a radiolabeled functionalized metallofullerene ((177)Lu-DOTA-f-Gd(3)N@C(80)) was synthesized with high radiochemical yield and purity. The efficacy of this agent was demonstrated in two orthotopic xenograft brain tumor models of glioblastoma multiforme (GBM). A dose-dependent improvement in survival was also shown. The in vivo stability of the agent was verified through dual label measurements of biological elimination from the tumor. Overall, these results provide evidence that nanomaterial platforms can be used to deliver effective interstitial brachytherapy.

Efficacy of gamma knife radiosurgery for small-volume recurrent malignant gliomas after initial radical resection

OBJECTIVE

To review the authors' experience with Gamma Knife radiosurgery (GKR) for small recurrent high-grade gliomas (HGGs) following prior radical resection, external-beam radiation therapy (EBRT), and chemotherapy with temozolomide (TMZ).

METHODS

The authors retrospectively analyzed 26 consecutive adults (9 women and 17 men; median age 60.4 years; Karnofsky Performance Status [KPS]≥70) who underwent GKR for recurrent HGGs from 2004-2009. Median lesion volume was 1.22 cc, and median treatment dose was 15 Gy. Pathology included glioblastoma multiforme (GBM; n=16), anaplastic astrocytoma (AA; n=5), and anaplastic mixed oligoastrocytoma (AMOA; n=5). Two patients lost to follow-up were excluded from radiographic outcome analyses.

RESULTS

Median overall survival (OS) for the entire cohort from the time of GKR was 13.5 months. Values for 12-month actuarial survival from time of GKR for GBM, AMOA, and AA were 37%, 20% and 80%. Local failure occurred in 9 patients (37.5%) at a median time of 5.8 months, and 18 patients (75%) experienced distant progression at a median of 4.8 months. Complications included radiation necrosis in two patients and transient worsening of hemiparesis in one patient. Multivariate hazard ratio (HR) analysis showed KPS 90 or greater, smaller tumor volumes, and increased time to recurrence after resection to be associated with longer OS following GKR.

CONCLUSIONS

GKR provided good local tumor control in this group of clinically stable and predominantly high-functioning patients with small recurrent HGGs after radical resection. Meaningful survival times after GKR were seen. GKR can be considered for selected patients with recurrent HGGs.

A Phase II study of anti-epidermal growth factor receptor radioimmunotherapy in the treatment of glioblastoma multiforme

OBJECT

This single-institution Phase II study tests the efficacy of adjuvant radioimmunotherapy with (125)I-labeled anti-epidermal growth factor receptor 425 murine monoclonal antibody ((125)I-mAb 425) in patients with newly diagnosed glioblastoma multiforme (GBM).

METHODS

A total of 192 patients with GBM were treated with (125)I-mAb 425 over a course of 3 weekly intravenous injections of 1.8 GBq following surgery and radiation therapy. The primary end point was overall survival, and the secondary end point was toxicity. Additional subgroup analyses were performed comparing treatment with (125)I-mAb 425 (RIT, 132 patients), (125)I-mAb 425 and temozolomide (TMZ+RIT, 60 patients), and a historical control group (CTL, 81 patients).

RESULTS

The median age was 53 years (range 19-78 years), and the median Karnofsky Performance Scale score was 80 (range 60-100). The percentage of patients who underwent debulking surgery was 77.6% and that of those receiving temozolomide was 31.3%. The overall median survival was 15.7 months (95% CI 13.6-17.8 months). The 1- and 2-year survivals were 62.5 and 25.5%, respectively. For subgroups RIT and TMZ+RIT, the median survivals were 14.5 and 20.2 months, respectively. No Grade 3 or 4 toxicity was seen with the administration of (125)I-mAb 425. The CTL patients lacked Karnofsky Performance Scale scores, had poorer survival, were older, and were less likely to receive radiation therapy. On multivariate analysis, the hazard ratios for RIT versus CTL, TMZ+RIT versus CTL, and TMZ+RIT versus RIT were 0.49 (p < 0.001), 0.30 (p < 0.001), and 0.62 (p = 0.008), respectively.

CONCLUSIONS

In this large Phase II study of 192 patients with GBM treated with anti-epidermal growth factor receptor (125)I-mAb 425 radioimmunotherapy, survival was 15.7 months, and treatment was safe and well tolerated.

[Local therapy of primary brain tumors]

In recent years further forms of local treatment for primary brain tumors have been developed in addition to resection and radiation. There are basically three principles for local therapy, intralesional therapy for primary or recurrent non-resectable tumors as well as intracavitary and pericavitary therapy following microscopic surgical complete resection. Local therapy procedures are complex and suffer from special difficulties in the evaluation of their effectiveness by imaging techniques, because they are inevitably accompanied by alterations in the imaging, barrier disturbances and contrast medium uptake.

Controversies concerning the application of brachytherapy in central nervous system tumors

INTRODUCTION

Brachytherapy (BRT) is defined as a therapy technique where a radioactive source is placed a short distance from or within the tumor being treated. Much expectation has been placed on its efficacy to improve the outcome for patients with central nervous system (CNS) tumors due to the initial promising results from single institution retrospective studies. However, these optimistic findings have been highly debated since the selection criteria itself is preferable to other therapeutic modalities. The fact that BRT demonstrated no significant survival advantage in two prospective studies, together with the emerging role of stereotactic convergence therapy as a promising alternative, has further decreased the enthusiasm for BRT. Despite all the negative aspects, BRT continues to be conducted for the management of CNS tumors including gliomas, meningiomas and brain metastases.

MATERIAL AND METHODS

As many controversies have been aroused concerning the experience and future application of BRT, this article reviews the existing heterogeneities in terms of implants choice, optimal dose rate, targeting volume, timing of BRT, patients selection, substantial efficacy, BRT in comparison with stereotactic convergence therapy techniques and BRT in combination with other treatment modalities (data were identified by Pubmed searches).

RESULTS AND CONCLUSION

Though it is inconvincible to argue for the routine use of BRT, BRT may provide a choice for patients with large recurrent or inoperable deep-seated tumors, especially with the Glia-site technique. Radiotherapies including BRT may hold more promise if biologic mechanisms of radiation could be better understand and biologic modifications could be added in clinical trials.

Intralesional lymphokine-activated killer cells as adjuvant therapy for primary glioblastoma

Despite recent advances, median survival for patients with resectable glioblastoma multiforme (GBM) is only 12 to 15 months. We previously observed minimal toxicity and a 9.0-month median survival after treatment with intralesional autologous lymphokine-activated killer (LAK) cells in 40 patients with recurrent GBM. In this study, GBM patients were treated with adjuvant intralesional LAK cells. Eligible patients had completed primary therapy for GBM without disease progression. LAK cells were produced by incubating autologous peripheral blood mononuclear cells with interleukin-2 for 3 to 7 days and then placed into the surgically exposed tumor cavity by a neurosurgeon. The 19 men and 14 women had a median age of 57 years. Prior therapy included surgical resection (97%), partial brain irradiation (97%), gamma knife radiosurgery (97%), and temozolomide chemotherapy (70%). Median time from diagnosis to LAK cell therapy was 5.3 months (range: 3.0 to 11.1 mo). LAK cell treatment was well tolerated; average length of hospitalization was 3 days. At the time of this analysis, 27 patients have died; the median survival from the date of original diagnosis is 20.5 months with a 1-year survival rate of 75%. In subset analyses, superior survival was observed for patients who received higher numbers of CD3+/CD16+/CD56+ (T-LAK) cells in the cell products, which was associated with not taking corticosteroids in the month before leukopheresis. Intralesional LAK cell therapy is safe and the survival sufficiently encouraging to warrant further evaluation in a randomized phase 2 trial of intralesional therapies with LAK or carmustine-impregnated wafers.

Survival following stereotactic radiosurgery for newly diagnosed and recurrent glioblastoma multiforme: a multicenter experience

Despite decades of clinical trials investigating new treatment modalities for glioblastoma multiforme (GBM), there have been no significant treatment advances since the 1980s. Reported median survival times for patients with GBM treated with current modalities generally range from 9 to 19 months. The purpose of the current study is to retrospectively review the ability of CyberKnife (Accuray Incorporated, Sunnyvale, CA, USA) radiosurgery to provide local tumor control of newly diagnosed or recurrent GBM. Twenty patients (43.5%) underwent CyberKnife treatment at the time of the initial diagnosis and/or during the first 3 months of their initial clinical management. Twenty-six patients (56.5%) were treated at the time of tumor recurrence or progression. CyberKnife was performed in addition to the traditional therapy. The median survival from diagnosis for the patients treated with CyberKnife as an initial clinical therapy was 11.5 months (range, 2-33) compared to 21 months (range, 8-96) for the patients treated at the time of tumor recurrence/progression. This difference was statistically significant (Kaplan-Meier analysis, P = 0.0004). The median survival from the CyberKnife treatment was 9.5 months (range, 0.25-31 months) and 7 months (range, 1-34 months) for patients in the newly diagnosed and recurrent GBM groups (Kaplan-Meier analysis, P = 0.79), respectively. Cox proportional hazards survival regression analysis demonstrated that survival time did not correlate significantly with treatment parameters (Dmax, Dmin, number of fractions) or target volume. Survival time and recursive partitioning analysis class were not correlated (P = 0.07). Patients with more extensive surgical interventions survived longer (P = 0.008), especially those who underwent total tumor resection vs. biopsy (P = 0.004). There is no apparent survival advantage in using CyberKnife in initial management of glioblastoma patients, and it should be reserved for patients whose tumors recur or progress after conventional therapy.

Racial, ethnic and socioeconomic disparities in the treatment of brain tumors

Disparities in American health care based on socially-defined patient characteristics such as race, ethnicity, and socioeconomic position are well-documented. We review differences and disparities in incidence, pathobiology, processes and outcomes of care, and survival based on social factors for brain tumors of all histologies. In the US, black patients have lower incidences of most brain tumor types and lower-income patients have lower incidences of low grade glioma, meningioma and acoustic neuroma; ascertainment bias may contribute to these findings. Pathogenetic differences between malignant gliomas in patients of different races have been demonstrated, but their clinical significance is unclear. Patients in disadvantaged groups are less often treated by high-volume providers. Mortality and morbidity of initial treatment are higher for brain tumor patients in disadvantaged groups, and they present with markers of more severe disease. Long term survival differences between malignant glioma patients of different races have not yet been shown. Clinical trial enrollment appears to be lower among brain tumor patients from disadvantaged groups. We propose future research both to better define disparities and to alleviate them.

Effects of Gamma Knife surgery on C6 glioma in combination with adenoviral p53 in vitro and in vivo

OBJECT

The authors sought to study the combined potential of wild-type p53 gene transfer and Gamma Knife surgery (GKS) for the treatment of glioblastomas multiforme. Modification of the radiation response in C6 glioma cells in vitro and in vivo by the wild-type p53 gene was investigated.

METHODS

Stable expression of wild-type p53 in C6 cells was achieved by transduction of the cells with adenoviral p53. Two days later, some cells were treated with GKS. Forty-eight hours after irradiation, the comparative survival rate was assessed by monotetrazolium (MTT) assays. Treated and control C6 glioma cells (4 x 10(3) per well) were plated into a 96-well plate in octuplicate and tested every 24 hours. Meanwhile, immunohistopathological examination of proliferating cell nuclear antigen (PCNA) and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (TUNEL) assays were performed. The MTT assays indicated the p53, GKS, and combined treated cells proliferated at a significantly lower rate than those of the control group (p < 0.01, Days 2-6) and the positive fraction of PCNA in p53-treated group and GKS-treated group was 70.18 +/- 3.61 and 50.71 +/- 2.61, respectively, whereas the percentage in the combined group was 30.68 +/- 1.49 (p < 0.01). Fifty-six male Sprague-Dawley rats were anesthetized and inoculated with 10(6) cultured C6 glioma cells into the cerebrum. Forty-eight hours after transduction with adenoviral p53, some rats underwent GKS. A margin dose of 15 Gy was delivered to the 50% isodose line. Two days later, six rats in each group were killed. Their brains were removed and paraffin-embedded section were prepared for immunohistopathological examination and TUNEL assays. The remaining rats were observed for the duration of the survival period. The survival curve indicated that a modest but significant enhancement of survival duration was seen in the p53-treated or GKS alone groups, whereas a more marked and highly significant enhancement of survival duration was achieved when these two treatment modalities were combined. When PCNA expression was downregulated, apoptotic cells become obvious after TUNEL staining.

CONCLUSIONS

The findings of this study suggest that p53-based gene therapy in combination with GKS may be superior to single-modality treatment of C6 glioma.

Efficacy of stereotactic radiosurgery as a salvage treatment for recurrent malignant gliomas

BACKGROUND

The objective of this prospective cohort study was to determine the efficacy of stereotactic radiosurgery (SRS) as a salvage treatment in patients with recurrent malignant gliomas.

METHODS

Between January 2000 and December 2006, 114 consecutive patients were treated with SRS as a salvage treatment for recurrent malignant gliomas at a single institution. Clinical outcome and its prognostic factors were analyzed and compared with the historical control group who were treated at the same institution between 1995 and 1999.

RESULTS

The median overall survival from the time of diagnosis was 37.5 months (95% confidence interval [95% CI], 11.7-63.2 months) for patients with grade 3 gliomas (according to World Health Organization criteria) and was 23 months (95% CI, 16.2-29.3 months) for patients with glioblastomas. The median progression-free survival after SRS was 8.6 months (95% CI, 1.1-16.2 months) for patients with grade 3 gliomas and 4.6 months for patients with glioblastomas (95% CI, 4.0-5.2 months). With regard to treatment-related complications, radiation-induced necrosis was observed in 22 of 114 patients (24.4%). Compared with this historic control group, SRS significantly prolonged survival as a salvage treatment in patients with recurrent glioblastomas (23 months vs 12 months; P < .0001), but it was not found to provide a significant surgical benefit in patients with recurrent grade 3 gliomas (37.5 months vs 26 months; P = .789). On univariate analysis of prognostic factors, tumor volume (<10 mL) and low histologic grade were found to significantly influence better survival (P = .009 and P = .041, respectively).

CONCLUSIONS

SRS is a safe and effective modality in selected patients with recurrent small-sized glioblastomas. However, the efficacy of SRS for recurrent grade 3 gliomas needs to be further evaluated in well-designed clinical studies.

Potential value of MR spectroscopic imaging for the radiosurgical management of patients with recurrent high-grade gliomas

Previous studies have shown that metabolic information provided by 3D Magnetic Resonance Spectroscopy Imaging (MRSI) could affect the definition of target volumes for radiation treatments (RT). This study aimed to (i) investigate the effect of incorporating spectroscopic volumes as determined by MRSI on target volume definition, patient selection eligibility, and dose prescription for stereotactic radiosurgery treatment planning; (ii) correlate the spatial extent of pre-SRS spectroscopic abnormality and treatment volumes with areas of focal recurrence as defined by changes in contrast enhancement; and (iii) examine the metabolic changes following SRS to assess treatment response. Twenty-six patients treated with Gamma Knife radiosurgery for recurrent glioblastoma multiforme (GBM) were retrospectively evaluated. All patients underwent both MRI and MRSI studies prior to SRS. Follow-up MRI exams were available for all 26 patients, with MRI/MRSI available in only 15/26 patients. We observed that the initial CNI 2 contours extended beyond the pre-SRS CE in 25/26 patients ranging in volume from 0.8 cc to 18.8 cc (median 5.6 cc). The inclusion of the volume of CNI 2 extending beyond the CE would have increased the SRS target volume by 5-165% (median 23.4%). This would have necessitated decreasing the SRS prescription dose in 19/26 patients to avoid increased toxicity; the resultant treatment volume would have exceeded 20cc in five patients, thus possibly excluding those from RS treatment per our institutional practice. MRSI follow-up studies showed a decrease in Choline, stable Creatine, and increased NAA indicative of response to SRS in the majority of patients. When combined with patient survival data, metabolic information obtained during follow-up MRSI studies seemed to indicate the potential to help to distinguish necrosis from new/recurrent tumor; however, this should be further verified by biopsy studies.

Photodynamic effects of SIM01, a new sensitizer, on experimental brain tumors in rats

BACKGROUND

Glioblastomas are the third most common cause of cancer death in patients between 15 and 35 years old. Literature suggests that PDT could represent a promising treatment, providing that sensitizers could accumulate within the cancer tissues despite the blood-brain barrier.

METHODS

Distribution and PDT effect of SIM01, a promising photosensitizer, have been evaluated on orthotopic C6 tumor model in rats by comparison with HPD and m-THPC. Pharmacokinetics had been analyzed with fluorescence and ROS. Photodynamic treatment was done using a 630-nm light with an energy density of 100 J cm(-2) for HPD and a 652-nm light with an energy density of 20 J cm(-2) for m-THPC and SIM01.

RESULTS

The correlation between fluorescence and ROS dosimetry was found to be excellent. An optimal concentration was found after 12 hours for SIM01 (4 mg/kg), 24 hours for HPD (10 mg/kg), and 48 hours for m-THPC (4 mg/kg). The best normal tissue/cancer ratio of concentration had been found after 12 hours for SIM01 and 48 hours for HPD and m-THPC. Pathological examinations after PDT showed that the criteria for histology of glioblastic origin were absent in SIM01-treated rats 12 hours after injection but were present in 50% of rats treated 24 hours after injection and in all after a 48-hour delay. Mean survival of rats treated 12 or 24 hours after SIM01 injection was significantly improved compared with controls, HPD-, or m-THPC-treated groups. Survival of rats treated 12 or 24 hours after SIM01 injection reached 20 days but decreased for longer delays. On the contrary, survival reached 18 days at the maximum for rats treated 48 hours after m-THPC or HPD injection.

CONCLUSIONS

Our results confirm that PDT is a promising treatment for glioblastomas. SIM01 efficacy is as efficient as m-THPC but with much more favorable pharmacokinetics.

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.

Current treatment approaches to surgery for brain metastases

The role for surgical treatment of brain metastases continues to evolve. Data have demonstrated survival and quality-of-life benefits for surgical treatment of appropriate lesions in selected patients. With improvements in surgical technique, along with therapeutic improvements in the management of systemic cancers, more patients are now eligible for surgical resection. Selection of patients for surgical treatment depends on performance status, size, location, and number of brain lesions, as well as the status of systemic disease. Although surgery has traditionally been performed for patients with a single brain metastasis, an increasing number of patients with multiple brain metastases may also be treated surgically. Surgical techniques, such as image guidance, intraoperative ultrasound, functional neuronavigation, cortical mapping, and awake craniotomies, have expanded the scope of lesions that can be removed safely to optimize outcomes. Seizures, peritumoral edema, and venous thromboembolic disease all contribute significantly to surgical morbidity and mortality and thus require aggressive treatment around the time of the surgical procedure to improve the quality of life and maximize survival time.

Optimization of semi-quantification in metabolic PET studies with 18F-fluorodeoxyglucose and 11C-methionine in the determination of malignancy of gliomas

The treatment of the glioma patient depends on the nature of the lesion and on the aggressiveness of the tumor. The management of gliomas continues to be a challenging task, because morphological neuroimaging techniques do not always differentiate them from nontumoral lesions or high grade tumors from low grade lesions. Positron Emission Tomography (PET) offers the possibility of the in vivo quantitative characterization of brain tumors. Despite decades of useful application of PET in the clinical monitoring of gliomas, no consensus has been reached on the most effective image analysis approach for providing the best diagnostic performance under heavy-duty clinical diagnostic circumstances. The main objective of the present study was to find and validate optimal semi-quantitative search strategies for metabolic PET studies on gliomas, with special regard to the optimization of those metabolic tracer uptake ratios most sensitive in predicting histologic grade and prognosis. 11C-Methionine (11C-Met, n = 50) and/or 18F-Fluorodeoxyglucose (18F-FDG, n = 33) PET measurements were performed in 59 patients with primary and recurrent brain gliomas (22 high grade and 37 low grade tumors) in order to correlate the biological behavior and 11C-Met/18F-FDG uptake of tumors. Data were analyzed by region-of-interests (ROI) methods using standard uptake value calculation. Different ROI defining strategies were then compared with each other for two of the most commonly used metabolic radiotracers, 18F-FDG and 11C-Met, in order to determine their usefulness in grading gliomas. The results were compared to histological data in all patients. Both ANOVA and receiver operating characteristic (ROC) analysis indicated that the performance of 18F-FDG was superior to that of 11C-Met for most of the ratios. 18F-FDG is therefore suggested as the tracer of choice for noninvasive semi-quantitative indicator of histologic grade of gliomas. 11C-Methionine has been suggested as a complimentary tracer, useful in delineating the extent of the tumor. The best diagnostic performance was obtained by calculating the ratio of the peak 18F-FDG uptake of the tumor to that of white matter (p < 0.001; ANOVA). This metabolic tracer uptake ratio is therefore suggested as an easily obtained semi-quantitative PET indicator of malignancy and histological grade in gliomas.

Efficacy of Fractionated Stereotactic Reirradiation in Recurrent Gliomas: Long-Term Results in 172 Patients Treated in a Single Institution

Purpose

To evaluate the efficacy of fractionated stereotactic radiotherapy (FSRT) performed as reirradiation in 172 patients with recurrent low- and high-grade gliomas.

Patients and Methods

Between 1990 and 2004, 172 patients with recurrent gliomas were treated with FSRT as reirradiation in a single institution. Seventy-one patients suffered from WHO grade 2 gliomas. WHO grade 3 gliomas were diagnosed in 42 patients, and 59 patients were diagnosed with glioblastoma multiforme (GBM). The median time between primary radiotherapy and reirradiation was 10 months for GBM, 32 months for WHO grade 3 tumors, and 48 months for grade 2 astrocytomas. FSRT was performed with a median dose of 36 Gy in a median fractionation of 5 × 2 Gy/wk.

Results

Median overall survival after primary diagnosis was 21 months for patients with GBM, 50 months for patients with WHO grade 3 gliomas, and 111 months for patients with WHO grade 2 gliomas. Histologic grading was the strongest predictor for overall survival, together with the extent of neurosurgical resection and age at primary diagnosis. Median survival after reirradiation was 8 months for patients with GBM, 16 months for patients with grade 3 tumors, and 22 months for patients with low-grade gliomas. Only time to progression and histology were significant in influencing survival after reirradiation. Progression-free survival after FSRT was 5 months for GBM, 8 months for WHO grade 3 tumors, and 12 months for low-grade gliomas.

Conclusion

FSRT is well tolerated and may be effective in patients with recurrent gliomas. Prospective studies are warranted for further evaluation.

New frontiers in radiosurgery for the brain and body

Radiosurgery is defined as the use of highly focused beams of radiation to ablate a pathologic target, thus achieving a surgical objective by noninvasive means. Recent advances have allowed a wide variety of intracranial lesions to be effectively treated with radiosurgery, and radiosurgical treatment has been accepted as a standard part of the neurosurgical armamentarium. The advent of frameless radiosurgery now permits radiosurgical treatment to all parts of the body and is being actively explored by many centers. This article reviews some of the modern tools for radiosurgical treatment and discusses the current clinical practice of radiosurgery.