Survival following CyberKnife radiosurgery and hypofractionated radiotherapy for newly diagnosed glioblastoma multiforme

Preclinical models of glioblastoma: limitations of current models and the promise of new developments

Glioblastoma (GBM) is the most common and aggressive primary brain tumour, yet little progress has been made towards providing better treatment options for patients diagnosed with this devastating condition over the last few decades. The complex nature of the disease, heterogeneity, highly invasive potential of GBM tumours and until recently, reduced investment in research funding compared with other cancer types, are contributing factors to few advancements in disease management. Survival rates remain low with less than 5% of patients surviving 5 years. Another important contributing factor is the use of preclinical models that fail to fully recapitulate GBM pathophysiology, preventing efficient translation from the lab into successful therapies in the clinic. This review critically evaluates current preclinical GBM models, highlighting advantages and disadvantages of using such models, and outlines several emerging techniques in GBM modelling using animal-free approaches. These novel approaches to a highly complex disease such as GBM show evidence of a more truthful recapitulation of GBM pathobiology with high reproducibility. The resulting advancements in this field will offer new biological insights into GBM and its aetiology with potential to contribute towards the development of much needed improved treatments for GBM in future.

The Stanford stereotactic radiosurgery experience on 7000 patients over 2 decades (1999-2018): looking far beyond the scalpel

OBJECTIVE

The CyberKnife (CK) has emerged as an effective frameless and noninvasive method for treating a myriad of neurosurgical conditions. Here, the authors conducted an extensive retrospective analysis and review of the literature to elucidate the trend for CK use in the management paradigm for common neurosurgical diseases at their institution.

METHODS

A literature review (January 1990-June 2019) and clinical review (January 1999-December 2018) were performed using, respectively, online research databases and the Stanford Research Repository of patients with intracranial and spinal lesions treated with CK at Stanford. For each disease considered, the coefficient of determination (r2) was estimated as a measure of CK utilization over time. A change in treatment modality was assessed using a t-test, with statistical significance assessed at the 0.05 alpha level.

RESULTS

In over 7000 patients treated with CK for various brain and spinal lesions over the past 20 years, a positive linear trend (r2 = 0.80) in the system's use was observed. CK gained prominence in the management of intracranial and spinal arteriovenous malformations (AVMs; r2 = 0.89 and 0.95, respectively); brain and spine metastases (r2 = 0.97 and 0.79, respectively); benign tumors such as meningioma (r2 = 0.85), vestibular schwannoma (r2 = 0.76), and glomus jugulare tumor (r2 = 0.89); glioblastoma (r2 = 0.54); and trigeminal neuralgia (r2 = 0.81). A statistically significant difference in the change in treatment modality to CK was observed in the management of intracranial and spinal AVMs (p < 0.05), and while the treatment of brain and spine metastases, meningioma, and glioblastoma trended toward the use of CK, the change in treatment modality for these lesions was not statistically significant.

CONCLUSIONS

Evidence suggests the robust use of CK for treating a wide range of neurological conditions.

Trends in physician reimbursements and procedural volumes for radiosurgery versus open surgery in brain tumor care: an analysis of Medicare data from 2009 to 2018

OBJECTIVE

Given its minimally invasive nature and effectiveness, stereotactic radiosurgery (SRS) has become a mainstay for the multimodal treatment of intracranial neoplasm. However, no studies have evaluated recent trends in the use of SRS versus those of open resection for the management of brain tumor or trends in the involvement of neurosurgeons in SRS (which is primarily delivered by radiation oncologists). Here, the authors used publicly available Medicare data from 2009 to 2018 to elucidate trends in the treatment of intracranial neoplasm and to compare reimbursements between these approaches.

METHODS

By using CPT Professional 2019, the authors identified 10 open resection and 9 SRS codes (4 for neurosurgery and 5 for radiation oncology) for the treatment of intracranial neoplasm. Medicare payments (inflation adjusted) and allowed services (number of reimbursed procedures) for each code were abstracted from the Centers for Medicare and Medicaid Services Part B National Summary Data File (2009-2018). Payments per procedure and procedures per 100,000 Medicare enrollees were analyzed with linear regression and compared with tests for equality of slopes (α = 0.05). The average payment per procedure over the study period was compared by using the 2-tailed Welsh unequal variances t-test, and more granular comparisons were conducted by using ANOVA with post hoc Tukey honestly significant difference (HSD) tests.

RESULTS

From 2009 to 2018, the number of SRS treatments per 100,000 Medicare enrollees for intracranial neoplasm increased by 3.97 cases/year (R2 = 0.99, p < 0.001), while comparable open resections decreased by 0.34 cases/year (R2 = 0.85, p < 0.001) (t16 = 7.5, p < 0.001). By 2018, 2.6 times more SRS treatments were performed per 100,000 enrollees than open resections (74.9 vs 28.7 procedures). However, neurosurgeon involvement in SRS treatment declined over the study period, from 23.4% to 11.5% of SRS treatments; simultaneously, the number of lesions treated per session increased from 1.46 to 1.84 (R2 = 0.98, p < 0.001). Overall, physician payments from 2013 to 2018 averaged $1816.08 (95% CI $1788.71-$1843.44) per SRS treatment and $1565.59 (95% CI $1535.83-$1595.34) per open resection (t10 = 15.9, p < 0.001). For neurosurgeons specifically, reimbursements averaged $1566 per open resection, but this decreased to $1031-$1198 per SRS session; comparatively, radiation oncologists were reimbursed even less (average $359-$898) per SRS session (p < 0.05 according to the Tukey HSD test for all comparisons).

CONCLUSIONS

Over a decade, the number of open resections for intracranial neoplasm in Medicare enrollees declined slightly, while the number of SRS procedures increased greatly. This latter expansion is largely attributable to radiation oncologists; meanwhile, neurosurgeons have shifted their involvement in SRS toward sessions for the management of multiple lesions.

Concise review of stereotactic irradiation for pediatric glial neoplasms: Current concepts and future directions

Brain tumors, which are among the most common solid tumors in childhood, remain a leading cause of cancer-related mortality in pediatric population. Gliomas, which may be broadly categorized as low grade glioma and high grade glioma, account for the majority of brain tumors in children. Expectant management, surgery, radiation therapy (RT), chemotherapy, targeted therapy or combinations of these modalities may be used for management of pediatric gliomas. Several patient, tumor and treatment-related characteristics including age, lesion size, grade, location, phenotypic and genotypic features, symptomatology, predicted outcomes and toxicity profile of available therapeutic options should be considered in decision making for optimal treatment. Management of pediatric gliomas poses a formidable challenge to the physicians due to concerns about treatment induced toxicity. Adverse effects of therapy may include neurological deficits, hemiparesis, dysphagia, ataxia, spasticity, endocrine sequelae, neurocognitive and communication impairment, deterioration in quality of life, adverse socioeconomic consequences, and secondary cancers. Nevertheless, improved understanding of molecular pathology and technological advancements may pave the way for progress in management of pediatric glial neoplasms. Multidisciplinary management with close collaboration of disciplines including pediatric oncology, surgery, and radiation oncology is warranted to achieve optimal therapeutic outcomes. In the context of RT, stereotactic irradiation is a viable treatment modality for several central nervous system disorders and brain tumors. Considering the importance of minimizing adverse effects of irradiation, radiosurgery has attracted great attention for clinical applications in both adults and children. Radiosurgical applications offer great potential for improving the toxicity profile of radiation delivery by focused and precise targeting of well-defined tumors under stereotactic immobilization and image guidance. Herein, we provide a concise review of stereotactic irradiation for pediatric glial neoplasms in light of the literature.

Spinal Drop Metastasis of Glioblastoma-Two Case Reports, Clinicopathologic Features, Current Modalities of Evaluation, and Treatment with a Review of the Literature

BACKGROUND

Glioblastomas (World Health Organization grade IV) are aggressive primary neoplasms of the central nervous system. Spinal metastasis occurs supposedly in 2%-5% of patients. This percentage may be only the tip of iceberg because most succumb to the disease before clinical detection and few documented cases are reported.

CASE DESCRIPTIONS

A 45-year-old man presented with history of diplopia and gait disturbance. Magnetic resonance imaging showed a left cerebellar space-occupying lesion. The histopathology was consistent with glioblastoma. The patient underwent adjuvant chemoradiation. A year later, he presented with seizures, worsening headache, neck stiffness, and low back pain. Imaging showed metastasis to the S1/S2 region of the spinal canal. A 29-year-old man presented with episodic headaches associated with nausea, vomiting, neck stiffness, and imbalance while walking. Computed tomography of the brain showed a hypodense lesion involving the left midbrain, pons, and left middle cerebellar peduncle, causing fourth ventricular pressure with obstructive hydrocephalus. A navigation-guided biopsy of the brainstem lesion confirmed the diagnosis of glioblastoma World Health Organization grade IV, isocitrate dehydrogenase 1 (R132 H) and H3K27M negative. Isocitrate dehydrogenase gene sequencing was suggested. The patient was referred for chemoradiation. During treatment, he worsened neurologically and developed axial neck and back pain. Neuraxis screening showed disseminated leptomeningeal spread, which was confirmed on dural biopsy.

CONCLUSIONS

Spinal and dural metastasis should always be suspected in patients with glioblastoma with signs and symptoms not explained by primary lesion. A regular protocol with postcontrast magnetic resonance imaging before and after initial surgery is mandatory to detect spinal metastasis before it becomes clinically apparent, thereby improving the prognosis and quality of life in patients.

Survival after hypofractionation in glioblastoma: a systematic review and meta-analysis

BACKGROUND

Glioblastoma multiforme (GBM) has a poor prognosis despite a multi modal treatment that includes normofractionated radiotherapy. So, various hypofractionated alternatives to normofractionated RT have been tested to improve such prognosis. There is need of systematic review and meta-analysis to analyse the literature properly and maybe generalised the use of hypofractionation. The aim of this study was first, to perform a meta-analysis of all controlled trials testing the impact of hypofractionation on survival without age restriction and secondly, to analyse data from all non-comparative trials testing the impact of hypofractionation, radiosurgery and hypofractionated stereotactic RT in first line.

MATERIALS/METHODS

We searched Medline, Embase and Cochrane databases to identify all publications testing the impact of hypofractionation in glioblastoma between 1985 and March 2020. Combined hazard ratio from comparative studies was calculated for overall survival. The impact of study design, age and use of adjuvant temozolomide was explored by stratification. Meta-regressions were performed to determine the impact of prognostic factors.

RESULTS

2283 publications were identified. Eleven comparative trials were included. No impact on overall survival was evidenced (HR: 1.07, 95%CI: 0.89-1.28) without age restriction. The analysis of non-comparative literature revealed heterogeneous outcomes with limited quality of reporting. Concurrent chemotherapy, completion of surgery, immobilization device, isodose of prescription, and prescribed dose (depending on tumour volume) were poorly described. However, results on survival are encouraging and were correlated with the percentage of resected patients and with patients age but not with median dose.

CONCLUSIONS

Because few trials were randomized and because the limited quality of reporting, it is difficult to define the place of hypofactionation in glioblastoma. In first line, hypofractionation resulted in comparable survival outcome with the benefit of a shortened duration. The method used to assess hypofractionation needs to be improved.

Simultaneous release of two drugs from polymer nano-implant inhibits recurrence in glioblastoma spheroids

Local implant-based delivery of rationally selected combination of chemotherapeutics has some major advantages for the treatment of glioblastoma such as: (a) 100 % bio-availability locally in brain can be achieved at the tumor site (b) avoid systemic leakage and associated toxicity, and (c) simultaneous inhibition of multiple, mutually exclusive cancer mechanisms is possible. Here, we report a polymeric brain implant capable of delivering two different drugs in recur-rent glioma cells. We have selected a combination of clinically used DNA alkylating agent, Te-mozolomide, and a DNA mismatch repair protein (Ligase IV) inhibitor, SCR-7, and delivered simultaneously into tumor spheroids formed by rat glioma cells, C6. The dual-drug loaded polymeric wafer, prepared by lyophilization method, could deliver both the drugs in a controlled fashion. To test the efficacy of this system, we have optimized an in vitro recurrent model of glioma spheroids wherein, the implant released both the drugs in a sustained fashion, thereby continuously exposing the cells to DNA methylation while inhibiting the DNA repair pathways. This leads to synergistic toxicity and inhibition of tumor recurrence for extended duration compared to free drug combination.

Stereotactic Radiosurgery and Hypofractionated Radiotherapy for Glioblastoma

Glioblastoma is the most common primary brain tumor in adults. Standard therapy depends on patient age and performance status but principally involves surgical resection followed by a 6-wk course of radiation therapy given concurrently with temozolomide chemotherapy. Despite such treatment, prognosis remains poor, with a median survival of 16 mo. Challenges in achieving local control, maintaining quality of life, and limiting toxicity plague treatment strategies for this disease. Radiotherapy dose intensification through hypofractionation and stereotactic radiosurgery is a promising strategy that has been explored to meet these challenges. We review the use of hypofractionated radiotherapy and stereotactic radiosurgery for patients with newly diagnosed and recurrent glioblastoma.

The radiosurgery fractionation quandary: single fraction or hypofractionation?

Stereotactic radiosurgery (SRS), typically administered in a single session, is widely employed to safely, efficiently, and effectively treat small intracranial lesions. However, for large lesions or those in close proximity to critical structures, it can be difficult to obtain an acceptable balance of tumor control while avoiding damage to normal tissue when single-fraction SRS is utilized. Treating a lesion in 2 to 5 fractions of SRS (termed "hypofractionated SRS" [HF-SRS]) potentially provides the ability to treat a lesion with a total dose of radiation that provides both adequate tumor control and acceptable toxicity. Indeed, studies of HF-SRS in large brain metastases, vestibular schwannomas, meningiomas, and gliomas suggest that a superior balance of tumor control and toxicity is observed compared with single-fraction SRS. Nonetheless, a great deal of effort remains to understand radiobiologic mechanisms for HF-SRS driving the dose-volume response relationship for tumors and normal tissues and to utilize this fundamental knowledge and the results of clinic studies to optimize HF-SRS. In particular, the application of HF-SRS in the setting of immunomodulatory cancer therapies offers special challenges and opportunities.

Improvement in treatment results of glioblastoma over the last three decades and beneficial factors

BACKGROUND

The purpose of this study is to elucidate the trend of glioblastoma outcome and scrutinize the factors contributing to better outcome over three decades.

METHODS

Survival time and the influencing factors were retrospectively analyzed in 223 newly diagnosed primary glioblastoma patients during 1980-2010. Appraised factors included age, sex, tumor site, year of surgery, extent of resections, use of surgery supporting system, Karnofsky Performance Status (KPS), chemotherapy, conventional external beam radiotherapy (EBRT), and CyberKnife stereotactic radiotherapy (CK-SRT) use.

RESULTS

The median survival time (MST) in all patients was 13.6 months. The MSTs for 4 periods were 9.8 (1980-1990), 13.7 (1991-2000), 12.9 (2001-2005), and 15.8 months (2006-2010), respectively (p=0.0047). Total resection, subtotal resection, partial resection, and biopsy had MSTs of 31.8, 13.9, 11.4, and 7.0 months, respectively (p<0.0001). Regarding chemotherapy, MSTs of the temozolomide base group and nimustine hydrochloride (ACNU) base group were 16.9 and 14.6 months, respectively, whereas the MST of patients without chemotherapy was only 9.8 months (p<0.0001). The MSTs for 40-Gy EBRT plus CK-SRT and 60-Gy EBRT were 19.1 and 10.7 months, respectively (p<0.0001). But in sub-selected patients, treated during 2001-2010, whose resection rate was total resection or subtotal resection, EBRT was completed and postoperative KPS was greater than or equal to 70, the MST with and without CK-SRT was 26.6 and 18.3 months, respectively (p=0.1529). According to the Cox proportional hazards model, degree of resection, KPS, ACNU use, temozolomide use, bevacizumab use, EBRT dose, and CK-SRT use were good prognostic factors. Use of neuronavigation and use of intraoperative magnetic resonance imaging were related to higher resection rate, but not determined as prognostic factors.

CONCLUSIONS

We observed a gradual improvement in glioblastoma outcome, presumably because of improvements in therapeutic modalities for surgery, anticancer agents, and radiation, but the efficacy of CK-SRT remains unclear.

The potential role of magnetic resonance spectroscopy in image-guided radiotherapy

Magnetic resonance spectroscopy (MRS) is a non-invasive technique to detect metabolites within the normal and tumoral tissues. The ability of MRS to diagnose areas of high metabolic activity linked to tumor cell proliferation is particularly useful for radiotherapy treatment planning because of better gross tumor volume (GTV) delineation. The GTV may be targeted with higher radiation dose, potentially improving local control without excessive irradiation to the normal adjacent tissues. Prostate cancer and glioblastoma multiforme (GBM) are two tumor models that are associated with a heterogeneous tumor distribution. Preliminary studies suggest that the integration of MRS into radiotherapy planning for these tumors is feasible and safe. Image-guided radiotherapy (IGRT) by virtue of daily tumor imaging and steep dose gradient may allow for tumor dose escalation with the simultaneous integrated boost technique (SIB) and potentially decrease the complications rates in patients with GBM and prostate cancers.

Potential applications of imaging and image-guided radiotherapy for brain metastases and glioblastoma to improve patient quality of life

Treatment of glioblastoma multiforme (GBM) and brain metastasis remains a challenge because of the poor survival and the potential for brain damage following radiation. Despite concurrent chemotherapy and radiation dose escalation, local recurrence remains the predominant pattern of failure in GBM most likely secondary to repopulation of cancer stem cells. Even though radiotherapy is highly effective for local control of radio-resistant tumors such as melanoma and renal cell cancer, systemic disease progression is the cause of death in most patients with brain metastasis. Preservation of quality of life (QOL) of cancer survivors is the main issue for patients with brain metastasis. Image-guided radiotherapy (IGRT) by virtue of precise radiation dose delivery may reduce treatment time of patients with GBM without excessive toxicity and potentially improve neurocognitive function with preservation of local control in patients with brain metastasis. Future prospective trials for primary brain tumors or brain metastasis should include IGRT to assess its efficacy to improve patient QOL.

Chloroquine or chloroquine-PI3K/Akt pathway inhibitor combinations strongly promote γ-irradiation-induced cell death in primary stem-like glioma cells

We asked whether inhibitors of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway, which is highly active in cancer stem cells (CSCs) and upregulated in response to genotoxic treatments, promote γ-irradiationγIR)-induced cell death in highly radioresistant, patient-derived stem-like glioma cells (SLGCs). Surprisingly, in most cases the inhibitors did not promote γIR-induced cell death. In contrast, the strongly cytostatic Ly294002 and PI-103 even tended to reduce it. Since autophagy was induced we examined whether addition of the clinically applicable autophagy inhibitor chloroquine (CQ) would trigger cell death in SLGCs. Triple therapy with CQ at doses as low as 5 to 10 µM indeed caused strong apoptosis. At slightly higher doses, CQ alone strongly promoted γIR-induced apoptosis in all SLGC lines examined. The strong apoptosis in combinations with CQ was invariably associated with strong accumulation of the autophagosomal marker LC3-II, indicating inhibition of late autophagy. Thus, autophagy-promoting effects of PI3K/Akt pathway inhibitors apparently hinder cell death induction in γ-irradiated SLGCs. However, as we show here for the first time, the late autophagy inhibitor CQ strongly promotes γIR-induced cell death in highly radioresistant CSCs, and triple combinations of CQ, γIR and a PI3K/Akt pathway inhibitor permit reduction of the CQ dose required to trigger cell death.

Hypofractionated conformal irradiation of patients with malignant glioma

PURPOSE

The aim of the study is to evaluate the effect of a conformal irradiation in short fractionation scheme of 49.5Gy in 15 fractions in an overall time of 3 weeks, in terms of overall survival (OAS) and progression free survival (PFS) rates in brain glioma patients.

PATIENTS AND METHODS

A prospective study was conducted on 54 brain glioma patients and was carried out in the Radiation Oncology Department, South Egypt Cancer Institute, Assiut University during the period from April 2006 till June 2009. Patients were treated by hypofractionated conformal irradiation (49.5 Gy/15 fractions/3 weeks).

RESULTS

The median follow up was 23 months (range: 9-39 months). Two-year OAS and PFS rates were 68% and 60%, respectively. In univariate analysis, age >50 years, poor performance status [Karnofasky score of ≥40-≤70%], poor neuroperformance status of score III, high-grade tumor [glioblastoma multiforme], and biopsy were all associated with statistically significant reduction in OAS and PFS rates. Multivariate analysis, showed that age >50 years and glioblastoma pathology were the only independent prognostic factors that were associated with poor OAS (p=0.003 and p=0.004, respectively), and PFS (p=0.027 and p=0.011, respectively).

CONCLUSION

Hypofractionated conformal radiotherapy was as effective as the conventional radiotherapy, with time sparing for patients, and for radiation oncology centers. Hypofractionated radiotherapy may be considered the radiotherapy regimen of choice in clinical practice for patients with gliomas.

Delayed cell death associated with mitotic catastrophe in γ-irradiated stem-like glioma cells

Background and Purpose

Stem-like tumor cells are regarded as highly resistant to ionizing radiation (IR). Previous studies have focused on apoptosis early after irradiation, and the apoptosis resistance observed has been attributed to reduced DNA damage or enhanced DNA repair compared to non-stem tumor cells. Here, early and late radioresponse of patient-derived stem-like glioma cells (SLGCs) and differentiated cells directly derived from them were examined for cell death mode and the influence of stem cell-specific growth factors.

Materials and methods

Primary SLGCs were propagated in serum-free medium with the stem-cell mitogens epidermal growth factor (EGF) and fibroblast growth factor-2 (FGF-2). Differentiation was induced by serum-containing medium without EGF and FGF. Radiation sensitivity was evaluated by assessing proliferation, clonogenic survival, apoptosis, and mitotic catastrophe. DNA damage-associated γH2AX as well as p53 and p21 expression were determined by Western blots.

Results

SLGCs failed to apoptose in the first 4 days after irradiation even at high single doses up to 10 Gy, but we observed substantial cell death later than 4 days postirradiation in 3 of 6 SLGC lines treated with 5 or 10 Gy. This delayed cell death was observed in 3 of the 4 SLGC lines with nonfunctional p53, was associated with mitotic catastrophe and occurred via apoptosis. The early apoptosis resistance of the SLGCs was associated with lower γH2AX compared to differentiated cells, but we found that the stem-cell culture cytokines EGF plus FGF-2 strongly reduce γH2AX levels. Nonetheless, in two p53-deficient SLGC lines examined γIR-induced apoptosis even correlated with EGF/FGF-induced proliferation and mitotic catastrophe. In a line containing CD133-positive and -negative stem-like cells, the CD133-positive cells proliferated faster and underwent more γIR-induced mitotic catastrophe.

Conclusions

Our results suggest the importance of delayed apoptosis, associated mitotic catastrophe, and cellular proliferation for γIR-induced death of p53-deficient SLGCs. This may have therapeutic implications. We further show that the stem-cell culture cytokines EGF plus FGF-2 activate DNA repair and thus confound in vitro comparisons of DNA damage repair between stem-like and more differentiated tumor cells.

In vitro effects of Cyberknife-driven intermittent irradiation on glioblastoma cell lines

Radiosurgery is used increasingly upon recurrence of high-grade gliomas to deliver a high dose of focused radiation to a defined target. The purpose of our study was to compare intermittent irradiation (IIR) by using a CyberKnife (CK) with continuous irradiation (CIR) by using a conventional linear accelerator (LINAC). A significant decrease in surviving fraction was observed after IIR irradiation compared with after CIR at a dose of 8 Gy. Three hours after irradiation, most of the DNA damage was repaired in U87. Slightly higher basal levels of Ku70/80 mRNA were found in U87 compared with A172, while radiation treatment induced only minor regulation of Ku70/80 and Rad51 transcription in either cell lines. IIR treatment using CK significantly decreased the survival in U87 and A172 compared with CIR. Although the two cell lines differed in DNA repair capability, the role of Ku70/80 and Rad51 in the cell line radiosensitivity seemed marginal.

CyberKnife Stereotactic Radiosurgery for Intracranial Neoplasms, with a Focus on Malignant Tumors

Stereotactic radiosurgery is well established as a means of managing intracranial tumors, both as an adjuvant to surgical resection, and also as a primary treatment modality for those tumors that are considered unresectable by conventional surgical means. Of particular concern during radiosurgery of brain tumors is the risk of radiation damage to otherwise healthy tissue, potentially resulting in cognitive impairment. The conformality and precise targeting of the CyberKnife radiation beam enables this risk to be minimized to a greater extent than hitherto possible, which may allow treatment to be completed in a small number of fractions, thereby improving the quality of life for patients. The CyberKnife has proven particularly valuable in the treatment of metastases, which represent the great majority of brain tumors, though its role in the management of malignant glial tumors remains a subject of controversy. This article reviews the published studies on the efficacy of CyberKnife radiosurgery for brain tumors of both glial and metastatic origin, and considers its future role in the management of such lesions.

ASSOCIATION OF SURGICALLY ACQUIRED MOTOR AND LANGUAGE DEFICITS ON OVERALL SURVIVAL AFTER RESECTION OF GLIOBLASTOMA MULTIFORME

OBJECTIVE

Balancing the benefits of extensive tumor resection with the consequence of potential postoperative deficits remains a challenge in malignant astrocytoma surgery. Although studies have suggested that increasing extent of resection may benefit survival, the effect of new postoperative deficits on survival remains unclear. We set out to determine whether new-onset postoperative motor or speech deficits were associated with survival in our institutional experience with glioblastoma multiforme (GBM).

METHODS

We retrospectively reviewed records of all patients (age range, 18–70 years; Karnofsky Performance Scale score, 80–100) who had undergone GBM resection between 1996 and 2006 at a single institution. Survival was compared between patients who had experienced surgically acquired motor or language deficits versus those who did not experience these deficits.

RESULTS

Three hundred six consecutive patients (age, 54 ± 11 years; median Karnofsky Performance Scale score, 80) underwent primary GBM resection. Nineteen patients (6%) developed surgically acquired motor deficits and 15 (5%) developed surgically acquired language deficits. Median survival was decreased in patients who acquired language deficits (9.6 months; P &lt; 0.05) or motor deficits (9.0 months; P &lt; 0.05) versus patients without surgically acquired deficits (12.8 months). Two-year survival was 8% and 0% for patients with surgically acquired motor or language deficits, respectively, versus 23% for patients without new-onset deficits.

CONCLUSION

In our experience, the development of new perioperative motor or language deficits was associated with decreased overall survival despite similar extent of resection and adjuvant therapy. Although it is well known that surgically induced neurological deficits affect quality of life, our results suggest that these surgical morbidities may also affect survival. Care should be taken to avoid surgically induced deficits in the management of GBM.

Technological advances in radiation oncology for central nervous system tumors

Advances in computer software technology have led to enormous progress that has enabled increasing levels of complexity to be incorporated into radiotherapy treatment planning systems. Because of these changes, the delivery of radiotherapy evolved from therapy designed primarily on plain 2-dimensional X-ray images and hand calculations to therapy based on 3-dimensional images incorporating increasingly complex computer algorithms in the planning process. In addition, challenges in treatment planning and radiation delivery, such as problems with setup error and organ movement, have begun to be systematically addressed, ushering in an era of so-called 4-dimensional radiotherapy. This review article discusses how these advances have changed the way in which many common neoplasms of the central nervous system are being treated at present.