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

CGCG clinical practice guidelines for the management of adult diffuse gliomas

The Chinese Glioma Cooperative Group (CGCG) Guideline Panel for adult diffuse gliomas provided recommendations for diagnostic and therapeutic procedures. The Panel covered all fields of expertise in neuro-oncology, i.e. neurosurgeons, neurologists, neuropathologists, neuroradiologists, radiation and medical oncologists and clinical trial experts. The task made clearer and more transparent choices about outcomes considered most relevant through searching the references considered most relevant and evaluating their value. The scientific evidence of papers collected from the literature was evaluated and graded based on the Oxford Centre for Evidence-based Medicine Levels of Evidence and recommendations were given accordingly. The recommendations will provide a framework and assurance for the strategy of diagnostic and therapeutic measures to reduce complications from unnecessary treatment and cost. The guideline should serve as an application for all professionals involved in the management of patients with adult diffuse glioma and also as a source of knowledge for insurance companies and other institutions involved in the cost regulation of cancer care in China.

Astrocytic gliomas WHO grades II and III

World Health Organization grades II and III lower-grade astrocytomas are a challenging area in neuro-oncology. One the one hand, for proper diagnosis, the analysis of molecular factors, especially mutation status of isocitrate dehydrogenase and 1p/19q status in the tumor status needs to be done in addition to classical neuropathology. Further, the high clinical and prognostic value of a maximal safe resection requires a profound knowledge of presurgical diagnosis and surgical as well as imaging techniques to ensure optimal outcome for patients. Also medical treatment may be more intensive than previously believed, with randomized trials providing evidence for a benefit in overall survival by combined chemoradiation versus radiation alone. A critical problem concerns the considerable undesirable effects of therapeutic interventions on long-term health-related quality of life, cognitive and functional outcome as well as future developments in this still difficult disease that will need to be addressed in future trials.

Surgical approaches for the gliomas

Neurosurgical intervention remains the first step in effective glioma management. Mounting evidence suggests that cytoreduction for low- and high-grade gliomas is associated with a survival benefit. Beyond conventional neurosurgical principles, an array of techniques have been refined in recent years to maximize the effect of the neurosurgical oncologist and facilitate the impact of subsequent adjuvant therapy. With intraoperative mapping techniques, aggressive microsurgical resection can be safely pursued even when tumors occupy essential functional pathways. Other adjunct techniques, such as intraoperative magnetic resonance imaging, intraoperative ultrasonography, and fluorescence-guided surgery, can be valuable tools to safely reduce the tumor burden of low- and high-grade gliomas. Taken together, this collection of surgical strategies has pushed glioma extent of resection towards the level of cellular resolution.

Innovations in Intraoperative Tumor Visualization

In the surgical management of solid tumors, adequacy of tumor resection has implications for local recurrence and survival. The standard method of intraoperative identification of tumor margin is frozen section pathologic analysis, which is time-consuming with potential for sampling error. Intraoperative tumor visualization has the potential to significantly improve surgical cancer care across disciplines, by guiding accuracy of biopsies, increasing adequacy of resections, directing adjuvant therapy, and even providing diagnostic information. We provide an outline of various methods of intraoperative tumor visualization developed to aid in the real-time assessment of tumor extent and adequacy of resection.

Surgical Ventricular Entry is a Key Risk Factor for Leptomeningeal Metastasis of High Grade Gliomas

Leptomeningeal metastasis (LM) of high grade gliomas (HGG) can lead to devastating disease courses. Understanding of risk factors for LM is important to identify patients at risk. We reviewed patient records and magnetic resonance imaging (MRI) of all patients with a first diagnosis of HGG who underwent surgery in our institution between 2008 and 2012. To assess the influence of potential risk factors for LM and the impact of LM on survival multivariate statistics were performed. 239 patients with a diagnosis of HGG and at least 6 months of MRI and clinical follow-up were included. LM occurred in 27 (11%) patients and was symptomatic in 17 (65%). A strong correlation of surgical entry to the ventricle and LM was found (HR: 8.1). Ventricular entry was documented in 137 patients (57%) and LM ensued in 25 (18%) of these. Only two (2%) of 102 patients without ventricular entry developed LM. Median overall survival of patients after diagnosis of LM (239 days) was significantly shorter compared to patients without LM (626 days). LM is a frequent complication in the course of disease of HGG and is associated with poor survival. Surgical entry to the ventricle is a key risk factor for LM.

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.

Sensitivity analysis aimed at blood vessels detection using interstitial optical tomography during brain needle biopsy procedures

A brain needle biopsy procedure is performed for suspected brain lesions in order to sample tissue that is subsequently analysed using standard histopathology techniques. A common complication resulting from this procedure is brain hemorrhaging from blood vessels clipped off during tissue extraction. Interstitial optical tomography (iOT) has recently been introduced by our group as a mean to assess the presence of blood vessels in the vicinity of the needle. The clinical need to improve safety requires the detection of blood vessels within 2 mm from the outer surface of the needle, since this distance is representative of the volume of tissue that is aspirated durirng tissue extraction. Here, a sensitivity analysis is presented to establish the intrinsic detection limits of iOT based on simulations and experiments using brain tissue phantoms. It is demonstrated that absorbers can be detected with diameters >300 μm located up to >2 mm from the biopsy needle core for bulk optical properties consistent with brain tissue.

Neurosurgical management of adult diffuse low grade gliomas in Canada: a multi-center survey

Adult diffuse low-grade gliomas are slow growing, World Health Organization grade II lesions with insidious onset and ultimate anaplastic transformation. The timing of surgery remains controversial with polarized practices continuing to govern patient management. As a result, the management of these patients is variable. The goal of this questionnaire was to evaluate practice patterns in Canada. An online invitation for a questionnaire including diagnostic, preoperative, perioperative, and postoperative parameters and three cases with magnetic resonance imaging data with questions to various treatment options in these patients was sent to practicing neurosurgeons and trainees. Survey was sent to 356 email addresses with 87 (24.7 %) responses collected. The range of years of practice was less than 10 years 36 % (n = 23), 11–20 years 28 % (n = 18), over 21 years 37 % (n = 24). Twenty-two neurosurgery students of various years of training completed the survey. 94 % (n = 47) of surgeons and trainees (n = 20) believe that we do not know the “right treatment”. 90 % of surgeons do not obtain formal preoperative neurocognitive assessments. 21 % (n = 13) of surgeons and 23 % of trainees (n = 5) perform a biopsy upon first presentation. A gross total resection was believed to increase progression free survival (surgeons: 75 %, n = 46; trainees: 95 %, n = 21) and to increase overall survival (surgeons: 64 %, n = 39, trainees: 68 %, n = 15). Intraoperative MRI was only used by 8 % of surgeons. Awake craniotomy was the procedure of choice for eloquent tumors by 80 % (n = 48) of surgeons and 100 % of trainees. Of those surgeons who perform awake craniotomy 93 % perform cortical stimulation and 38 % performed subcortical stimulation. Using the aid of three hypothetical cases with progressive complexities in tumor eloquence there was a trend for younger surgeons to operate earlier, and use awake craniotomy to obtain greater extent of resection with the aid of cortical stimulation when compared to senior surgeons who still more often preferred a “wait-and-see” approach. Despite the limitations of an online survey study, it has offered insights into the variability in surgeon practice patterns in Canada and the need for a consensus on the workup and surgical management of this disease.

Intraoperative high-field magnetic resonance imaging combined with functional neuronavigation in resection of low-grade temporal lobe tumors

BACKGROUND

The aim of this study is to investigate the role of intraoperative MR imaging in temporal lobe low-grade glioma (LGG) surgery and to report the surgical outcome in our series with regard to seizures, neurological defects, and quality of life.

METHODS

Patients with temporal lobe contrast-nonenhancing gliomas who presented with seizures in the course of their disease were enrolled in our prospective study. We non-randomly assigned patients to undergo intraoperative magnetic resonance imaging (iMRI)-guided surgery or conventional surgery. Extent of resection (EOR) and surgical outcomes were compared between the two groups.

RESULTS

Forty-one patients were allocated in the iMRI group, and 14 were in the conventional group. Comparable EOR was achieved for the two groups (p = 0.634) although preoperative tumor volumes were significantly larger for the iMRI group. Seizure outcome tended to be better for the iMRI group (Engel class I achieved for 89.7% (35/39) vs 75% (9/12)) although this difference was not statistically different. Newly developed neurological deficits were observed in four patients (10.3%) and two patients (16.7%), respectively (p = 0.928). Free of seizures and neurological morbidity led to a return-to-work or return-to-school rate of 84.6% (33/39) vs 75% (9/12), respectively (p = 0.741).

CONCLUSIONS

Our study provided evidence that iMRI was a safe and useful tool in temporal lobe LGG surgery. Optimal extent of resection contributed to favorable seizure outcome in our series with low morbidity rate, which led to a high return-to-work rate.

Survival and low-grade glioma: the emergence of genetic information

Significant gaps exist in our understanding of the causes and clinical management of glioma. One of the biggest gaps is how best to manage low-grade (World Health Organization [WHO] Grade II) glioma. Low-grade glioma (LGG) is a uniformly fatal disease of young adults (mean age 41 years), with survival averaging approximately 7 years. Although LGG patients have better survival than patients with high-grade (WHO Grade III or IV) glioma, all LGGs eventually progress to high-grade glioma and death. Data from the Surveillance, Epidemiology and End Results (SEER) program of the National Cancer Institute suggest that for the majority of LGG patients, overall survival has not significantly improved over the past 3 decades, highlighting the need for intensified study of this tumor. Recently published research suggests that historically used clinical variables are not sufficient (and are likely inferior) prognostic and predictive indicators relative to information provided by recently discovered tumor markers (e.g., 1p/19q deletion and IDH1 or IDH2 mutation status), tumor expression profiles (e.g., the proneural profile) and/or constitutive genotype (e.g., rs55705857 on 8q24.21). Discovery of such tumor and constitutive variation may identify variables needed to improve randomization in clinical trials as well as identify patients more sensitive to current treatments and targets for improved treatment in the future. This article reports on survival trends for patients diagnosed with LGG within the United States from 1973 through 2011 and reviews the emerging role of tumor and constitutive genetics in refining risk stratification, defining targeted therapy, and improving survival for this group of relatively young patients.

Functional preoperative and intraoperative mapping and monitoring: increasing safety and efficacy in glioma surgery

Greater extent of resection (EOR) of low-grade gliomas is associated with improved survival. Proximity to eloquent cortical regions often limits resectability and elevates the risk of surgery-related deficits. Therefore, functional localization of eloquent cortex or subcortical fiber tracts can enhance the EOR and functional outcome. Imaging techniques such as functional MRI and diffusion tensor imaging fiber tracking, and neurophysiological methods like navigated transcranial magnetic stimulation and magnetoencephalography, make it possible to identify eloquent areas prior to resective surgery and to tailor indication and surgical approach but also to assess the surgical risk. Intraoperative monitoring with direct cortical stimulation and subcortical stimulation enables surgeons to preserve essential functional tissue during surgery. Through tailored pre- and intraoperative mapping and monitoring the EOR can be maximized, with reduced rates of surgery-related deficits.

Intraoperative MRI in pediatric brain tumors

Intraoperative magnetic resonance imaging (iMRI) has emerged as an important tool in guiding the surgical management of children with brain tumors. Recent advances have allowed utilization of high field strength systems, including 3-tesla MRI, resulting in diagnostic-quality scans that can be performed while the child is on the operating table. By providing information about the possible presence of residual tumor, it allows the neurosurgeon to both identify and resect any remaining tumor that is thought to be safely accessible. By fusing the newly obtained images with the surgical guidance software, the images have the added value of aiding in navigation to any residual tumor. This is important because parenchyma often shifts during surgery. It also gives the neurosurgeon insight into whether any immediate postoperative complications have occurred. If any complications have occurred, the child is already in the operating room and precious minutes lost in transport and communications are saved. In this article we review the three main approaches to an iMRI system design. We discuss the possible roles for iMRI during intraoperative planning and provide guidance to help radiologists and neurosurgeons alike in the collaborative management of these children.

Awake craniotomy to maximize glioma resection: methods and technical nuances over a 27-year period

OBJECT

Awake craniotomy is currently a useful surgical approach to help identify and preserve functional areas during cortical and subcortical tumor resections. Methodologies have evolved over time to maximize patient safety and minimize morbidity using this technique. The goal of this study is to analyze a single surgeon's experience and the evolving methodology of awake language and sensorimotor mapping for glioma surgery.

METHODS

The authors retrospectively studied patients undergoing awake brain tumor surgery between 1986 and 2014. Operations for the initial 248 patients (1986–1997) were completed at the University of Washington, and the subsequent surgeries in 611 patients (1997–2014) were completed at the University of California, San Francisco. Perioperative risk factors and complications were assessed using the latter 611 cases.

RESULTS

The median patient age was 42 years (range 13–84 years). Sixty percent of patients had Karnofsky Performance Status (KPS) scores of 90–100, and 40% had KPS scores less than 80. Fifty-five percent of patients underwent surgery for high-grade gliomas, 42% for low-grade gliomas, 1% for metastatic lesions, and 2% for other lesions (cortical dysplasia, encephalitis, necrosis, abscess, and hemangioma). The majority of patients were in American Society of Anesthesiologists (ASA) Class 1 or 2 (mild systemic disease); however, patients with severe systemic disease were not excluded from awake brain tumor surgery and represented 15% of study participants. Laryngeal mask airway was used in 8 patients (1%) and was most commonly used for large vascular tumors with more than 2 cm of mass effect. The most common sedation regimen was propofol plus remifentanil (54%); however, 42% of patients required an adjustment to the initial sedation regimen before skin incision due to patient intolerance. Mannitol was used in 54% of cases. Twelve percent of patients were active smokers at the time of surgery, which did not impact completion of the intraoperative mapping procedure. Stimulation-induced seizures occurred in 3% of patients and were rapidly terminated with ice-cold Ringer's solution. Preoperative seizure history and tumor location were associated with an increased incidence of stimulation-induced seizures. Mapping was aborted in 3 cases (0.5%) due to intraoperative seizures (2 cases) and patient emotional intolerance (1 case). The overall perioperative complication rate was 10%.

CONCLUSIONS

Based on the current best practice described here and developed from multiple regimens used over a 27-year period, it is concluded that awake brain tumor surgery can be safely performed with extremely low complication and failure rates regardless of ASA classification; body mass index; smoking status; psychiatric or emotional history; seizure frequency and duration; and tumor site, size, and pathology.

The Value of Pre- and Intraoperative Adjuncts on the Extent of Resection of Hemispheric Low-Grade Gliomas: A Retrospective Analysis

BACKGROUND

To achieve maximal resection with minimal risk of postoperative neurologic morbidity, different neurosurgical adjuncts are being used during low-grade glioma (LGG) surgery.

OBJECTIVES

To investigate the effect of pre- and intraoperative adjuncts on the extent of resection (EOR) of hemispheric LGGs.

METHODS

Medical records were reviewed to identify patients of any sex, ≥ 18 years of age, who underwent LGG surgery at X Hospital between January 2005 and July 2013. Patients were divided into eight subgroups based on the use of various combinations of a neuronavigation system alone (NN), functional MRI-diffusion tensor imaging (fMRI-DTI) guided neuronavigation (FD), intraoperative MRI (MR), and direct electrical stimulation (DES). Initial and residual tumors were measured, and mean EOR was compared between groups.

RESULTS

Of all 128 patients, gross total resection was achieved in 23.4%. Overall mean EOR was 81.3% ± 20.5%. Using DES in combination with fMRI-DTI (mean EOR: 86.7% ± 12.4%) on eloquent tumors improved mean EOR significantly after adjustment for potential confounders when compared with NN alone (mean EOR: 76.4% ± 25.5%; p = 0.001).

CONCLUSIONS

Using DES in combination with fMRI and DTI significantly improves EOR when LGGs are located in eloquent areas compared with craniotomies in which only NN was used.

Glioma

Gliomas are primary brain tumours that are thought to derive from neuroglial stem or progenitor cells. On the basis of their histological appearance, they have been traditionally classified as astrocytic, oligodendroglial or ependymal tumours and assigned WHO grades I-IV, which indicate different degrees of malignancy. Tremendous progress in genomic, transcriptomic and epigenetic profiling has resulted in new concepts of classifying and treating gliomas. Diffusely infiltrating gliomas in adults are now separated into three overarching tumour groups with distinct natural histories, responses to treatment and outcomes: isocitrate dehydrogenase (IDH)-mutant, 1p/19q co-deleted tumours with mostly oligodendroglial morphology that are associated with the best prognosis; IDH-mutant, 1p/19q non-co-deleted tumours with mostly astrocytic histology that are associated with intermediate outcome; and IDH wild-type, mostly higher WHO grade (III or IV) tumours that are associated with poor prognosis. Gliomas in children are molecularly distinct from those in adults, the majority being WHO grade I pilocytic astrocytomas characterized by circumscribed growth, favourable prognosis and frequent BRAF gene fusions or mutations. Ependymal tumours can be molecularly subdivided into distinct epigenetic subgroups according to location and prognosis. Although surgery, radiotherapy and alkylating agent chemotherapy are still the mainstay of treatment, individually tailored strategies based on tumour-intrinsic dominant signalling pathways and antigenic tumour profiles may ultimately improve outcome. For an illustrated summary of this Primer, visit: http://go.nature.com/TXY7Ri.

Low-grade glioma management: a contemporary surgical approach

PURPOSE OF REVIEW

The primary treatment of low-grade gliomas is still claimed to lack robust supporting evidence. Yet, several investigations were performed in the last 2 decades. To critically review these studies could help in further clarifying the role of surgery aimed at maximal resection.

RECENT FINDINGS

Despite the lack of randomized clinical trials hampering the performance of appropriate meta-analyses, the increasing amount of evidence pointed toward an aggressive surgical strategy to low-grade glioma. Low-grade glioma surgery has to be performed with the appropriate armamentarium, which is the availability of intraoperative stimulation mapping, especially for those lesions occurring in cortical and subcortical eloquent sites.

SUMMARY

According to the recently published guidelines, surgical treatment has been increasingly recognized as the initial therapeutic act of choice for patients diagnosed with a presumed low-grade glioma, given that total resection can improve seizure control, progression-free survival and overall survival, while reducing the risk of malignant transformation and preserving patients' functional status.

Intraoperative fiducial-less patient registration using volumetric 3D ultrasound: a prospective series of 32 neurosurgical cases

OBJECT

Fiducial-based registration (FBR) is used widely for patient registration in image-guided neurosurgery. The authors of this study have developed an automatic fiducial-less registration (FLR) technique to find the patient-to-image transformation by directly registering 3D ultrasound (3DUS) with MR images without incorporating prior information. The purpose of the study was to evaluate the performance of the FLR technique when used prospectively in the operating room and to compare it with conventional FBR.

METHODS

In 32 surgical patients who underwent conventional FBR, preoperative T1-weighted MR images (pMR) with attached fiducial markers were acquired prior to surgery. After craniotomy but before dural opening, a set of 3DUS images of the brain volume was acquired. A 2-step registration process was executed immediately after image acquisition: 1) the cortical surfaces from pMR and 3DUS were segmented, and a multistart sum-of-squared-intensity-difference registration was executed to find an initial alignment between down-sampled binary pMR and 3DUS volumes; and 2) the alignment was further refined by a mutual information-based registration between full-resolution grayscale pMR and 3DUS images, and a patient-to-image transformation was subsequently extracted.

RESULTS

To assess the accuracy of the FLR technique, the following were quantified: 1) the fiducial distance error (FDE); and 2) the target registration error (TRE) at anterior commissure and posterior commissure locations; these were compared with conventional FBR. The results showed that although the average FDE (6.42 ± 2.05 mm) was higher than the fiducial registration error (FRE) from FBR (3.42 ± 1.37 mm), the overall TRE of FLR (2.51 ± 0.93 mm) was lower than that of FBR (5.48 ± 1.81 mm). The results agreed with the intent of the 2 registration techniques: FBR is designed to minimize the FRE, whereas FLR is designed to optimize feature alignment and hence minimize TRE. The overall computational cost of FLR was approximately 4-5 minutes and minimal user interaction was required.

CONCLUSIONS

Because the FLR method directly registers 3DUS with MR by matching internal image features, it proved to be more accurate than FBR in terms of TRE in the 32 patients evaluated in this study. The overall efficiency of FLR in terms of the time and personnel involved is also improved relative to FBR in the operating room, and the method does not require additional image scans immediately prior to surgery. The performance of FLR and these results suggest potential for broad clinical application.

Survival trends of grade I, II, and III astrocytoma patients and associated clinical practice patterns between 1999 and 2010: A SEER-based analysis

Background

The survival trends and the patterns of clinical practice pertaining to radiation therapy and surgical resection for WHO grade I, II, and III astrocytoma patients remain poorly characterized.

Methods

Using the Surveillance, Epidemiology and End Results (SEER) database, we identified 2497 grade I, 4113 grade II, and 2755 grade III astrocytomas during the period of 1999-2010. Time-trend analyses were performed for overall survival, radiation treatment (RT), and the extent of surgical resection (EOR).

Results

While overall survival of grade I astrocytoma patients remained unchanged during the study period, we observed improved overall survival for grade II and III astrocytoma patients (Tarone-Ware P < .05). The median survival increased from 44 to 57 months and from 15 to 24 months for grade II and III astrocytoma patients, respectively. The differences in survival remained significant after adjusting for pertinent variables including age, ethnicity, marital status, sex, tumor size, tumor location, EOR, and RT status. The pattern of clinical practice in terms of EOR for grade II and III astrocytoma patients did not change significantly during this study period. However, there was decreased RT utilization as treatment for grade II astrocytoma patients after 2005.

Conclusion

Results from the SEER database indicate that there were improvements in the overall survival of grade II and III astrocytoma patients over the past decade. Analysis of the clinical practice patterns identified potential opportunities for impacting the clinical course of these patients.

Early versus delayed postoperative radiotherapy for treatment of low-grade gliomas

BACKGROUND

In most people with low-grade gliomas (LGG), the primary treatment regimen remains a combination of surgery followed by postoperative radiotherapy. However, the optimal timing of radiotherapy is controversial. It is unclear whether to use radiotherapy in the early postoperative period, or whether radiotherapy should be delayed until tumour progression occurs.

OBJECTIVES

To assess the effects of early postoperative radiotherapy versus radiotherapy delayed until tumour progression for low-grade intracranial gliomas in people who had initial biopsy or surgical resection.

SEARCH METHODS

We searched up to September 2014 the following electronic databases: the Cochrane Register of Controlled Trials (CENTRAL, Issue 8, 2014), MEDLINE (1948 to Aug week 3, 2014), and EMBASE (1980 to Aug week 3, 2014) to identify trials for inclusion in this Cochrane review.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared early versus delayed radiotherapy following biopsy or surgical resection for the treatment of people with newly diagnosed intracranial LGG (astrocytoma, oligodendroglioma, mixed oligoastrocytoma, astroblastoma, xanthoastrocytoma, or ganglioglioma). Radiotherapy may include conformal external beam radiotherapy (EBRT) with linear accelerator or cobalt-60 sources, intensity-modulated radiotherapy (IMRT), or stereotactic radiosurgery (SRS).

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed the trials for inclusion and risk of bias, and extracted study data. We resolved any differences between review authors by discussion. Adverse effects were also extracted from the study report. We performed meta-analyses using a random-effects model with inverse variance weighting.

MAIN RESULTS

We included one large, multi-institutional, prospective RCT, involving 311 participants; the risk of bias in this study was unclear. This study found that early postoperative radiotherapy is associated with an increase in time to progression compared to observation (and delayed radiotherapy upon disease progression) for people with LGG but does not significantly improve overall survival (OS). The median progression-free survival (PFS) was 5.3 years in the early radiotherapy group and 3.4 years in the delayed radiotherapy group (hazard ratio (HR) 0.59, 95% confidence interval (CI) 0.45 to 0.77; P value < 0.0001; 311 participants; 1 trail; low quality evidence). The median OS in the early radiotherapy group was 7.4 years, while the delayed radiotherapy group experienced a median overall survival of 7.2 years (HR 0.97, 95% CI 0.71 to 1.33; P value = 0.872; 311 participants; 1 trail; low quality evidence). The total dose of radiotherapy given was 54 Gy; five fractions of 1.8 Gy per week were given for six weeks. Adverse effects following radiotherapy consisted of skin reactions, otitis media, mild headache, nausea, and vomiting. Rescue therapy was provided to 65% of the participants randomised to delayed radiotherapy. People in both cohorts who were free from tumour progression showed no differences in cognitive deficit, focal deficit, performance status, and headache after one year. However, participants randomised to the early radiotherapy group experienced significantly fewer seizures than participants in the delayed postoperative radiotherapy group at one year (25% versus 41%, P value = 0.0329, respectively).

AUTHORS' CONCLUSIONS

Given the high risk of bias in the included study, the results of this analysis must be interpreted with caution. Early radiation therapy was associated with the following adverse effects: skin reactions, otitis media, mild headache, nausea, and vomiting. People with LGG who undergo early radiotherapy showed an increase in time to progression compared with people who were observed and had radiotherapy at the time of progression. There was no significant difference in overall survival between people who had early versus delayed radiotherapy; however, this finding may be due to the effectiveness of rescue therapy with radiation in the control arm. People who underwent early radiation had better seizure control at one year than people who underwent delayed radiation. There were no cases of radiation-induced malignant transformation of LGG. However, it remains unclear whether there are differences in memory, executive function, cognitive function, or quality of life between the two groups since these measures were not evaluated.

Therapeutic decision making in patients with newly diagnosed low grade glioma

OPINION STATEMENT

Low grade gliomas (LGG) encompass primary brain tumors that are typically well-differentiated and do not exhibit frankly malignant histologic features. These tumors can be further classified by their cellular morphology (eg, oligodendroglioma, pilocytic astrocytoma, etc), which does convey prognostic and therapeutic implications. Typically, low grade gliomas convey an overall better prognosis for patients as opposed to the higher grade primary brain tumors. Surgery for low grade gliomas and timing of such intervention remains controversial. Maximal resection of these tumors appears to prolong progression free survival. Advanced surgical techniques, including language mapping and awake craniotomies, have been shown to decrease morbidity associated with resection of lesions in eloquent areas of the brain. Radiation therapy has been proven effective in increasing time to progression in LGG, and emerging data support a role for combined modality therapy incorporating chemotherapy. Postoperative RT has been shown to have significant benefits with regards to progression free survival. Recent advances in molecular genetic markers, including the combined loss of chromosome arms 1p and 19q, and the mutation of the isocitrate dehydrogenase gene (IDH1/IDH2) have allowed for increased accuracy of predicting susceptibility to chemotherapeutic agents, as well as having some role in determining prognosis. PCV and temozolomide chemotherapy have both been studied when assessing progression free survival for LGG patients. Approaching patients with LGGs can be somewhat daunting given the lack of Class I evidence based protocols. However, significant evidence is now mounting to suggest early, maximal surgical excision; followed by fractionated RT will be the mainstays of treatment. Clearly, additional evidence is also mounting for the addition of chemotherapy in the treatment paradigm for patients with LGGs.

Movable intraoperative magnetic resonance imaging incorporating a seismic system

INTRODUCTION

A high-field ceiling-mounted and movable intraoperative MR imaging (iMRI) can minimize additional risks for MRI and enhance safety by not moving the patient. In this system, hanging the heavy magnet from the ceiling requires structural stability; this stability was confirmed in earlier studies, but not proved during a seismic event.

OBJECTIVE

We have installed a 1.5 T movable iMRI system with an incorporated seismic system in our hospital in Japan, a seismic event-prone region. This arrangement is the first in the world, to our knowledge. The objective of this study was to describe the mechanism of this seismic system and the first clinical experience using this system.

METHODS

The seismic system consists of a stabilizer pad that is mounted directly under the magnet, in addition to the structural stability. The seismic system was tested with using a shaker table testing at a test laboratory.

RESULTS

Ninety-one patients underwent neurosurgical intervention using this iMRI and seismic system at our hospital. In all patients, intra-, pre, and/or postoperative MR images were successfully obtained, and image quality was excellent. The workflow of moving the magnet and scanning were smooth and unproblematic. We had 169 seismic events in our city during this time period, but had no incidental or accidental events related to the seismic events.

CONCLUSION

With the use of the seismic system, a ceiling-mounted, movable iMRI system can be more safely used. This seismic system may contribute to the spread of movable iMRI systems in countries where seismic events occur.

Preliminary experience with an intraoperative MRI-compatible infant headholder: technical note

The development of high-quality intraoperative MRI (iMRI) capability has offered a major advance in the care of patients with complex intracranial disease. To date, this technology has been limited by the need for pin fixation of the calvaria. The authors report their preliminary experience with an MRI-compatible horseshoe headrest that allows for the following: 1) iMRI in patients too young for pin fixation; 2) iMRI in patients with large calvarial defects; 3) the ability to move the head during iMRI surgery; and 4) the use of neuronavigation in such cases. The authors report 2 cases of infants in whom the Visius Surgical Theatre horseshoe headrest (IMRIS Inc.) was used. Image quality was equivalent to that of pin fixation. The infants suffered no skin issues. The use of neuronavigation with the system remained accurate and could be updated with the new iMRI information. The Visius horseshoe headrest offers a technical advance in iMRI technology for infants, for patients with cranial defects or prior craniotomies in whom pin fixation may not be safe, or for patients in whom the need to move the head during surgery is required. The image quality of the system remains excellent, and the ability to merge new images to the neuronavigation system is helpful.

Intraoperative Magnetic Resonance Imaging in Intracranial Glioma Resection: A Single-Center, Retrospective Blinded Volumetric Study

BACKGROUND

Intraoperative magnetic resonance imaging (IoMRI) was devised to overcome brain shifts during craniotomies. Yet, the acceptance of IoMRI is limited.

OBJECTIVE

To evaluate impact of IoMRI on intracranial glioma resection outcome including overall patient survival.

METHODS

A retrospective review of records was performed on a cohort of 164 consecutive patients who underwent resection surgery for newly diagnosed intracranial gliomas either with or without IoMRI technology performed by 2 neurosurgeons in our center. Patient follow-up was at least 5 years. Extent of resection (EOR) was calculated using pre- and postoperative contrast-enhanced and T2-weighted MR-images. Adjusted analysis was performed to compare gross total resection (GTR), EOR, permanent surgery-associated neurologic deficit, and overall survival between the 2 groups.

RESULTS

Overall median EOR was 92.1%, and 97.45% with IoMRI use and 89.9% without IoMRI, with crude (unadjusted) P < 0.005. GTR was achieved in 49.3% of IoMRI cases, versus in only 21.4% of no-IoMRI cases, P < 0.001. GTR achieved was more with the use of IoMRI among gliomas located in both eloquent and noneloquent brain areas, P = 0.017 and <0.001, respectively. Permanent surgery-associated neurologic deficit was not (statistically) more significant with no-IoMRI, P = 0.284 (13.8% vs. 6.7%). In addition, the IoMRI group had better 5-year overall survival, P < 0.001.

CONCLUSION

This study shows that the use of IoMRI was associated with greater rates of EOR and GTR, and better overall 5-year survival in both eloquent brain areas located and non-eloquent brain areas located gliomas, with no increased risk of neurologic complication.

Comparing high-resolution microscopy techniques for potential intraoperative use in guiding low-grade glioma resections

BACKGROUND AND OBJECTIVES

Fluorescence image-guided surgery (FIGS), with contrast provided by 5-ALA-induced PpIX, has been shown to enable a higher extent of resection of high-grade gliomas. However, conventional FIGS with low-power microscopy lacks the sensitivity to aid in low-grade glioma (LGG) resection because PpIX signal is weak and sparse in such tissues. Intraoperative high-resolution microscopy of PpIX fluorescence has been proposed as a method to guide LGG resection, where sub-cellular resolution allows for the visualization of sparse and punctate mitochondrial PpIX production in tumor cells. Here, we assess the performance of three potentially portable high-resolution microscopy techniques that may be used for the intraoperative imaging of human LGG tissue samples with PpIX contrast: high-resolution fiber-optic microscopy (HRFM), high-resolution wide-field microscopy (WFM), and dual-axis confocal (DAC) microscopy.

MATERIALS AND METHODS

Thick unsectioned human LGG tissue samples (n = 7) with 5-ALA-induced PpIX contrast were imaged using three imaging techniques (HRFM, WFM, DAC). The average signal-to-background ratio (SBR) was then calculated for each imaging modality (5 images per tissue, per modality).

RESULTS

HRFM provides the ease of use and portability of a flexible fiber bundle, and is simple and inexpensive to build. However, in most cases (6/7), HRFM is not capable of detecting PpIX signal from LGGs due to high autofluorescence, generated by the fiber bundle under laser illumination at 405 nm, which overwhelms the PpIX signal and impedes its visualization. WFM is a camera-based method possessing high lateral resolution but poor axial resolution, resulting in sub-optimal image contrast.

CONCLUSIONS

Consistent successful detection of PpIX signal throughout our human LGG tissue samples (n = 7), with an acceptable image contrast (SBR >2), was only achieved using DAC microscopy, which offers superior image resolution and contrast that is comparable to histology, but requires a laser-scanning mechanism to achieve optical sectioning.

The status of contemporary image-guided modalities in oncologic surgery

OBJECTIVE

To review the current trends in optical imaging to guide oncologic surgery.

BACKGROUND

Surgical resection remains the cornerstone of therapy for patients with early stage solid malignancies and more than half of all patients with cancer undergo surgery each year. The technical ability of the surgeon to obtain clear surgical margins at the initial resection remains crucial to improve overall survival and long-term morbidity. Current resection techniques are largely based on subjective and subtle changes associated with tissue distortion by invasive cancer. As a result, positive surgical margins occur in a significant portion of tumor resections, which is directly correlated with a poor outcome.

METHODS

A comprehensive review of studies evaluating optical imaging techniques is performed.

RESULTS

A variety of cancer imaging techniques have been adapted or developed for intraoperative surgical guidance that have been shown to improve functional and oncologic outcomes in randomized clinical trials. There are also a large number of novel, cancer-specific contrast agents that are in early stage clinical trials and preclinical development that demonstrate significant promise to improve real-time detection of subclinical cancer in the operative setting.

CONCLUSIONS

There has been an explosion of intraoperative imaging techniques that will become more widespread in the next decade.

Prediction of anaplastic transformation in low-grade oligodendrogliomas based on magnetic resonance spectroscopy and 1p/19q codeletion status

The aim of this study was to assess whether combining multimodal magnetic resonance imaging (MRI) with the determination of the 1p/19q codeletion status could improve the ability to predict anaplastic transformation in low-grade oligodendrogliomas. Twenty patients with grade II oligodendrogliomas were followed-up using multimodal MR [proton MR spectroscopy (MRS), perfusion, and conventional MR imaging]. All patients diagnoses were histologically proven, and 1p/19q codeletion status was analyzed for all patients. Median follow-up was 30.5 ± 11.4 months. Anaplastic transformation was observed in six patients. The only MRI feature that was associated with anaplastic transformation was an elevation of the choline/creatine ratio >2.4 which was observed in 4 out of 6 patients with anaplastic transformation versus 1 out of 14 patients without anaplastic transformation. In patients without 1p/19q codeletion, an elevation of the choline/creatine ratio >2.4 was associated with the occurrence of anaplastic transformation in all cases (4 out of 4 patients), with a mean time of 12 months. In contrast, in patients with a 1p/19q codeletion, no anaplastic transformation was observed in the patient who had an elevation of >2.4 of the choline/creatine ratio and two patients demonstrated an anaplastic transformation without any elevation of this ratio.Prospective validation in a larger series is needed, yet the present study suggests that combining data from in vivo proton MRS and genetic analysis could be a promising strategy to predict time to anaplastic transformation at the individual level in patients with low-grade oligodendrogliomas and may help deciding when chemotherapy and/or radiotherapy should be initiated in these tumors.

"Extraoperative" MRI (eoMRI) for Brain Tumor Surgery: Initial Results at a Single Institution

BACKGROUND

There is accumulating evidence that extent of resection (EOR) in intrinsic brain tumor surgery prolongs overall survival (OS) and progression-free survival (PFS). One of the strategies to increase EOR is the use of intraoperative MRI (ioMRI); however, considerable infrastructure investment is needed to establish and maintain a sophisticated ioMRI. We report the preliminary results of an extraoperative (eoMRI) protocol, with a focus on safety, feasibility, and EOR in intrinsic brain tumor surgery.

METHODS

Ten patients underwent an eoMRI protocol consisting of surgical resection in a conventional operating room followed by an immediate MRI in a clinical MRI scanner while the patient was still under anesthesia. If findings of the MRI suggested residual safely resectable tumor, the patient was returned to the operating room. A retrospective volumetric analysis was undertaken to investigate the percentage of tumor resected after first resection and if applicable, after further resection.

RESULTS

Six of 10 (60%) patients were thought to require no further resection after eoMRI. The EOR in these patients was 97.8% ± 1.8%. In the 4 patients who underwent further resection, the EOR during the original surgery was 88.5% ± 9.5% (P = 0.04). There was an average of 10.1% more tumor removed between the first and second surgery. In 3 of 4 (75%) of patients who returned for further resection, gross total resection of tumor was achieved.

CONCLUSION

An eoMRI protocol appears to be a safe and practical method to ensure maximum safe resections in patients with brain tumors and can be performed readily in all centers with MRI capabilities.

Advances in the Surgical Management of Low-Grade Glioma

Over the past 2 decades, extent of resection has emerged as a significant prognostic factor in patients with low-grade gliomas (LGGs). Greater extent of resection has been shown to improve overall survival, progression-free survival, and time to malignant transformation. The operative goal in most LGG cases is to maximize extent of resection, while avoiding postoperative neurologic deficits. Several advanced surgical techniques have been developed in an attempt to better achieve maximal safe resection. Intraoperative magnetic resonance imaging, fluorescence-guided surgery, intraoperative functional pathway mapping, and neuronavigation are some of the most commonly used techniques with multiple studies to support their efficacy in glioma surgery. By using these techniques either alone or in combination, patients harboring LGGs have a better prognosis with less surgical morbidity following tumor resection.

Near real-time robust non-rigid registration of volumetric ultrasound images for neurosurgery

Ultrasound images are acquired before and after the resection of brain tumors to help the surgeon to localize the tumor and its extent and to minimize the amount of residual tumor after the resection. Because the brain undergoes large deformation between these two acquisitions, deformable image-based registration of these data sets is of substantial clinical importance. In this work, we present an algorithm for non-rigid registration of ultrasound images (RESOUND) that models the deformation with free-form cubic B-splines. We formulate a regularized cost function that uses normalized cross-correlation as the similarity metric. To optimize the cost function, we calculate its analytic derivative and use the stochastic gradient descent technique to achieve near real-time performance. We further propose a robust technique to minimize the effect of non-corresponding regions such as the resected tumor and possible hemorrhage in the post-resection image. Using manually labeled corresponding landmarks in the pre- and post-resection ultrasound volumes, we illustrate that our registration algorithm reduces the mean target registration error from an initial value of 3.7 to 1.5 mm. We also compare RESOUND with the previous work of Mercier et al. (2013) and illustrate that it has three important advantages: (i) it is fully automatic and does not require a manual segmentation of the tumor, (ii) it produces smaller registration errors and (iii) it is about 30 times faster. The clinical data set is available online on the BITE database website.

Surgery for gliomas

Surgical resection, with the goal of maximal tumor removal, is now standard of care for the overwhelming majority of newly diagnosed gliomas. In order to achieve this goal while minimizing the risk of postoperative neurologic deficits, intraoperative brain mapping remains the gold standard. Recent advances in technical aspects of preoperative and intraoperative brain mapping, as well as our understanding of the functional anatomy of the human brain with respect to language, movement, sensation, and cognition, particularly at the subcortical level, have improved our ability to safely perform aggressive resective surgeries in eloquent areas. In this chapter, the functional anatomy of the human brain relevant to intrinsic tumor resection is reviewed. In addition, general principles governing surgical management of patients are highlighted, with a particular emphasis on awake brain mapping.

Use of high-field intraoperative magnetic resonance imaging to enhance the extent of resection of enhancing and nonenhancing gliomas

BACKGROUND

Intraoperative magnetic resonance imaging (IoMRI) is used to improve the extent of resection of brain tumors. Most previous studies evaluating the utility of IoMRI have focused on enhancing tumors.

OBJECTIVE

To report our experience with the use of high-field IoMRI (1.5 T) for both enhancing and nonenhancing gliomas.

METHODS

An institutional review board-approved retrospective review was performed of 102 consecutive glioma patients (104 surgeries, 2010-2012). Pre-, intra-, and postoperative tumor volumes were assessed. Analysis was performed with the use of volumetric T2 images in 43 nonenhancing and 13 minimally enhancing tumors and with postcontrast volumetric magnetization-prepared rapid gradient-echo images in 48 enhancing tumors.

RESULTS

In 58 cases, preoperative imaging showed tumors likely to be amenable to complete resection. Intraoperative electrocorticography was performed in 32 surgeries, and 14 cases resulted in intended subtotal resection of tumors due to involvement of deep functional structures. No further resection (complete resection before IoMRI) was required in 25 surgeries, and IoMRI showed residual tumor in 79 patients. Of these, 25 surgeries did not proceed to further resection (9 due to electrocorticography findings, 14 due to tumor in deep functional areas, and 2 due to surgeon choice). Additional resection that was performed in 54 patients resulted in a final median residual tumor volume of 0.21 mL (0.6%). In 79 patients amenable to complete resection, the intraoperative median residual tumor volume for the T2 group was higher than for the magnetization-prepared rapid gradient-echo group (1.088 mL vs 0.437 mL; P = .049), whereas the postoperative median residual tumor volume was not statistically significantly different between groups.

CONCLUSION

IoMRI enhances the extent of resection, particularly for nonenhancing gliomas.

Preoperative diffusion tensor imaging: improving neurosurgical outcomes in brain tumor patients

Preoperative mapping has revolutionized neurosurgical care for brain tumor patients. Maximizing resections has improved diagnosis, optimized treatment algorithms, and decreased potentially devastating postoperative deficits. Although mapping has multiple steps and complimentary localization sources, diffusion tensor imaging (DTI) excels in its essential role in depicting white matter tracts. A thorough understanding of DTI, data visualization methods, and limitations with mastery of functional and dysfunctional white matter anatomy is necessary to realize the potential of DTI. By establishing spatial relationships between lesion borders and functional networks preoperatively and intraoperatively, DTI is central to high-risk neurosurgical resections and becoming the standard of care.

Application of desorption electrospray ionization mass spectrometry imaging in breast cancer margin analysis

Distinguishing tumor from normal glandular breast tissue is an important step in breast-conserving surgery. Because this distinction can be challenging in the operative setting, up to 40% of patients require an additional operation when traditional approaches are used. Here, we present a proof-of-concept study to determine the feasibility of using desorption electrospray ionization mass spectrometry imaging (DESI-MSI) for identifying and differentiating tumor from normal breast tissue. We show that tumor margins can be identified using the spatial distributions and varying intensities of different lipids. Several fatty acids, including oleic acid, were more abundant in the cancerous tissue than in normal tissues. The cancer margins delineated by the molecular images from DESI-MSI were consistent with those margins obtained from histological staining. Our findings prove the feasibility of classifying cancerous and normal breast tissues using ambient ionization MSI. The results suggest that an MS-based method could be developed for the rapid intraoperative detection of residual cancer tissue during breast-conserving surgery.

Multimodal imaging for improved diagnosis and treatment of cancers

The authors review methods for image-guided diagnosis and therapy that increase precision in the detection, characterization, and localization of many forms of cancer to achieve optimal target definition and complete resection or ablation. A new model of translational, clinical, image-guided therapy research is presented, and the Advanced Multimodality Image-Guided Operating (AMIGO) suite is described. AMIGO was conceived and designed to allow for the full integration of imaging in cancer diagnosis and treatment. Examples are drawn from over 500 procedures performed on brain, neck, spine, thorax (breast, lung), and pelvis (prostate and gynecologic) areas and are used to describe how they address some of the many challenges of treating brain, prostate, and lung tumors. Cancer 2015;121:817-827. © 2014 American Cancer Society.

Time to focus on brain tumor-related epilepsy trials

Brain tumor-related epilepsy (BTRE) is a common complication of cerebral glioma. It has a serious impact on the patient's confidence and quality of life and can be life threatening. There are significant differences in the management of BTRE and nontumoral epilepsy in adults. Surgery is performed early in management, and resection can be curative. Radiotherapy can also improve seizure frequency. Antiepileptic drugs (AEDs) are started after first seizure but are only effective at stopping attacks in 50% of cases. There are no satisfactory randomized controlled clinical trials, or even good prospective series, to support using one AED over another with respect to efficacy. Guidelines are therefore based on poor levels of evidence. In general, the choice of AED may depend on risk of early side effect (rash, biochemical, or hematological effects) and whether drug interactions with chemotherapy are likely. In patients with suspected low-grade glioma, where use of chemotherapy early in the management is not standard practice and survival in measured in many years, the drug interactions are less relevant, and rational seizure management should focus on drugs with the fewest long-term effects on neurocognition, personality, mood, and fatigue. While intriguing and potentially very important, there is no good evidence that any specific AED has a clinical antitumor effect or improves survival. Development of special interest groups in BTRE within countries, or between countries, may be a model for promoting better BTRE trials in the future.

Clinical trials in neurosurgical oncology

Brain tumors such as diffuse infiltrating gliomas continue to represent a major clinical challenge. Overall survival for patients diagnosed with glioblastoma, the most common primary brain tumor, remains less than 2 years despite intensive multimodal therapy with surgery, radiation, and chemotherapy. However, advances have been made in standard therapies and novel treatments that are showing great potential. These advances reflect careful study performed in the context of clinical trials. Neurosurgeons have played and will continue to play key parts in these studies. In this manuscript, we review clinical trials in neuro-oncology from a neurosurgical point of view and discuss potential roles for neurosurgeons in advancing glioma therapy in the future.

New concepts in the management of diffuse low-grade glioma: Proposal of a multistage and individualized therapeutic approach

Diffuse low-grade glioma grows, migrates along white matter tracts, and progresses to high-grade glioma. Rather than a "wait and see" policy, an aggressive attitude is now recommended, with early surgery as the first therapy. Intraoperative mapping, with maximal resection according to functional boundaries, is associated with a longer overall survival (OS) while minimizing morbidity. However, most studies have investigated the role of only one specific treatment (surgery, radiotherapy, chemotherapy) without taking a global view of managing the cumulative time while preserving quality of life (QoL) versus time to anaplastic transformation. Our aim is to switch towards a more holistic concept based upon the anticipation of a personalized and long-term multistage therapeutic approach, with online adaptation of the strategy over the years using feedback from clinical, radiological, and histomolecular monitoring. This dynamic strategy challenges the traditional approach by proposing earlier therapy, by repeating treatments, and by reversing the classical order of therapies (eg, neoadjuvant chemotherapy when maximal resection is impossible, no early radiotherapy) to improve OS and QoL. New individualized management strategies should deal with the interactions between the course of this chronic disease, reaction brain remapping, and oncofunctional modulation elicited by serial treatments. This philosophy supports a personalized, functional, and preventive neuro-oncology.

3T intraoperative MRI for management of pediatric CNS neoplasms

BACKGROUND AND PURPOSE

High-field-strength intraoperative MR imaging has emerged as a powerful adjunct for resection of brain tumors. However, its exact role has not been firmly established. We sought to determine the impact of 3T-intraoperative MRI on the surgical management of childhood CNS tumors.

MATERIALS AND METHODS

We evaluated patient data from a single academic children's hospital during a consecutive 24-month period after installation of a 3T-intraoperative MRI. Tumor location, histology, surgical approach, operating room time, presence and volume of residual tumor, need for tumor and non-tumor-related reoperation, and anesthesia- and MR imaging-related complications were evaluated. Comparison with pre-intraoperative MRI controls was performed.

RESULTS

One hundred ninety-four patients underwent intraoperative MRI-guided surgery. Of these, 168 were 18 years or younger (mean, 8.9 ± 5.0 years; 108 males/60 females). There were 65 posterior fossa tumors. The most common tumors were pilocytic astrocytoma (n = 31, 19%), low-grade glioma (n = 31, 19%), and medulloblastoma (n = 20, 12%). An average of 1.2 scanning sessions was performed per patient (maximum, 3). There were no MR imaging-related safety issues. Additional tumor was resected after scanning in 21% of patients. Among patients with a preoperative goal of gross total resection, 93% achieved this goal. The 30-day reoperation rate was <1% (n = 1), and no patient required additional postoperative MR imaging during the same hospital stay.

CONCLUSIONS

Intraoperative MRI is safe and increases the likelihood of gross total resection, albeit with increased operating room time, and reduces the need for early reoperation or repeat sedation for postoperative scans in children with brain tumors.

Supratentorial low-grade diffuse astrocytoma: medical management

Diffuse astrocytomas (DAs) represent less than 10% of all gliomas. They are diffusely infiltrating World Health Organization (WHO) grade II neoplasms that have a median survival in the range of 5-7 years, generally with a terminal phase in which they undergo malignant transformation to glioblastoma (GBM). The goals of treatment in addition to prolonging survival are therefore to prevent progression and malignant transformation, as well as optimally managing symptoms, primarily tumor-associated epilepsy. Available data suggest that the course of this disease is only minimally impacted by adjuvant therapies and that there does not seem to be much difference in terms of outcome of whether patients are treated in the adjuvant setting with irradiation or chemotherapy. We review the experience with chemotherapy as a treatment modality and offer some guidelines for its usage and discuss medical management of arising symptoms.

Neurosurgical oncology: advances in operative technologies and adjuncts

Modern glioma surgery has evolved around the central tenet of safely maximizing resection. Recent surgical adjuncts have focused on increasing the maximum extent of resection while minimizing risk to functional brain. Technologies such as cortical and subcortical stimulation mapping, intraoperative magnetic resonance imaging, functional neuronavigation, navigable intraoperative ultrasound, neuroendoscopy, and fluorescence-guided resection have been developed to augment the identification of tumor while preserving brain anatomy and function. However, whether these technologies offer additional long-term benefits to glioma patients remains to be determined. Here we review advances over the past decade in operative technologies that have offered the most promising benefits for glioblastoma patients.

Surgical strategies for nonenhancing slow-growing gliomas with special reference to functional reorganization: review with own experience

Nonenhancing intrinsic brain tumors have been empirically treated with a strategy that has been adopted for World Health Organization (WHO) grade II gliomas (low-grade gliomas: LGGs), even though small parts of the tumors might have been diagnosed as WHO grade III gliomas after surgery. However, the best surgical strategy for nonenhancing gliomas, including LGGs, is still debatable. LGGs have the following features: slow growth, high possibility of histologically malignant transformation, and no clear border between the tumor and adjacent normal brain. We retrospectively examined 26 consecutive patients with nonenhancing gliomas who were surgically treated at Kanazawa University Hospital between January 2006 and May 2012, with special reference to functional reorganization, extent of resection (EOR), and functional mapping during awake surgery. These categories are closely related with the features of LGG, i.e. functional reorganization due to slow-growing nature, EOR with related malignant transformation, and functional mapping for delineating the unclear tumor border. Finally, we discuss surgical strategies for slow-growing gliomas that are represented by LGGs and nonenhancing gliomas. In conclusion, slow-growing gliomas tend to undergo functional reorganization, and the functional reorganization affects the presurgical evaluation for resectability based on tumor location related to eloquence. In the clinical setting, to definitely identify the reorganized functional regions, awake surgery is recommended. Therefore, awake surgery could increase the extent of the resection of the tumor without deficits, resulting in the delay of malignant transformation and increase in overall survival.

Low-grade gliomas

Low-grade gliomas (LGGs) are a diverse group of primary brain tumors that often arise in young, otherwise healthy patients and generally have an indolent course with longer-term survival in comparison with high-grade gliomas. Treatment options include observation, surgery, radiation, chemotherapy, or a combined approach, and management is individualized based on tumor location, histology, molecular profile, and patient characteristics. Moreover, in this type of brain tumor with a relatively good prognosis and prolonged survival, the potential benefits of treatment must be carefully weighed against potential treatment-related risks. We review in this article current management strategies for LGG, including surgery, radiotherapy, and chemotherapy. In addition, the importance of profiling the genetic and molecular properties of LGGs in the development of targeted anticancer therapies is also reviewed. Finally, given the prevalence of these tumors in otherwise healthy young patients, the impact of treatment on neurocognitive function and quality of life is also evaluated.

Role of surgical resection in low- and high-grade gliomas

OPINION STATEMENT

Central nervous system tumors are a major cause of morbidity and mortality in the United States. Outside of brain metastasis, low- and high-grade gliomas are the most common intrinsic brain tumors. Low-grade gliomas have a 5- and 10-year survival rate of 97 % and 91 %, respectively, when extent of resection is greater than 90 %. High-grade gliomas are extremely aggressive with the vast majority of patients experiencing recurrence and a median survival of 1 to 3 years. Survival of patients with both low- and high-grade gliomas is enhanced with maximal tumor resection. The pursuit of more aggressive extent of resection must be balanced with preservation of functional pathways. Several innovations in neurosurgical oncology have expanded our understanding of individualized patient neuroanatomy, physiology, and function. Emerging imaging technologies as well as intraoperative techniques have expanded our ability to resect maximal amounts of tumor while preserving essential function. Stimulation mapping of language and motor pathways is well-established for the safe resection of intrinsic brain lesions. Additional techniques including neuro-navigation, fluorescence-guided microsurgery using 5-aminolevulinic acid, intraoperative magnetic resonance imaging, and high-frequency ultrasonography can all be used to improve extent of resection in glioma patients.