Gamma Knife surgery for subependymal giant cell astrocytomas. Clinical article

Therapeutic Strategies for Gliomas Associated With Cancer Predisposition Syndromes

PURPOSE

The purpose of this article was to provide an overview of syndromic gliomas.

DESIGN

The authors conducted a nonsystematic literature review.

RESULTS

Cancer predisposition syndromes (CPSs) are genetic conditions that increase one's risk for certain types of cancer compared with the general population. Syndromes that can predispose one to developing gliomas include neurofibromatosis, Li-Fraumeni syndrome, Lynch syndrome, and tuberous sclerosis complex. The standard treatment for sporadic glioma may involve resection, radiation therapy, and/or alkylating chemotherapy. However, DNA-damaging approaches, such as radiation and alkylating agents, may increase the risk of secondary malignancies and other complications in patients with CPSs. In some cases, depending on genetic aberrations, targeted therapies or immunotherapeutic approaches may be considered. Data on clinical characteristics, therapeutic strategies, and prognosis of syndromic gliomas remain limited.

CONCLUSION

In this review, we provide an overview of syndromic gliomas with a focus on management for patients with CPSs and the role of novel treatments that can be considered.

A Comparison of Clinical Outcomes for Subependymal Giant Cell Astrocytomas Treated with Laser Interstitial Thermal Therapy, Open Surgical Resection, and mTOR Inhibitors

INTRODUCTION

Subependymal giant cell astrocytoma (SEGA) is the most common CNS tumor in patients with tuberous sclerosis complex (TSC). Although these are benign, their proximity to the foramen of Monroe frequently causes obstructive hydrocephalus, a potentially fatal complication. Open surgical resection has been the mainstay of treatment; however, this can cause significant morbidity. The development of mTOR inhibitors has changed the treatment landscape, but there are limitations to their use. Laser interstitial thermal therapy (LITT) is an emerging treatment modality that has shown promise in treatment of a variety of intracranial lesions, including SEGAs. We present a single institution, retrospective study of patients treated for SEGAs with LITT, open resection, mTOR inhibitors, or a combination of these modalities. The primary study outcome was tumor volume at most recent follow-up compared with volume at treatment initiation. The secondary outcome was clinical complications associated with treatment modality.

METHODS

Retrospective chart review was performed to identify patients with SEGAs treated at our institution from 2010 to 2021. Demographics, treatment information, and complications were collected from the medical record. Tumor volumes were calculated from imaging obtained at initiation of treatment and at most recent follow-up. Kruskal-Wallis nonparametric testing was used to assess differences in tumor volume and follow-up duration between groups.

RESULTS

Four patients underwent LITT (3 with LITT only), three underwent open surgical resection, and four were treated with mTOR inhibitors only. Mean percent tumor volume reduction for each group was 48.6 ± 13.8, 90.7 ± 39.8, and 67.1 ± 17.2%, respectively. No statistically significant difference was identified comparing percent tumor volume reduction between the three groups (p = 0.0513). Additionally, there was no statistically significant difference in follow-up duration between groups (p = 0.223). Only 1 patient in our series required permanent CSF diversion and 4 discontinued or decreased the dose of mTOR inhibitor due to either cost or side effects.

CONCLUSIONS

Our study suggests that LITT could be considered as a treatment option for SEGAs as it was effective in reducing tumor volume with very few complications. This modality is less invasive than open resection and may be an alternative for patients who are not candidates for mTOR inhibitors. We recommend an updated paradigm for SEGA treatment which includes LITT in select cases after consideration of patient-specific factors.

Nervous system (NS) Tumors in Cancer Predisposition Syndromes

Genetic syndromes which develop one or more nervous system (NS) tumors as one of the manifestations can be grouped under the umbrella term of NS tumor predisposition syndromes. Understanding the underlying pathological pathways at the molecular level has led us to many radical discoveries, in understanding the mechanisms of tumorigenesis, tumor progression, interactions with the tumor microenvironment, and development of targeted therapies. Currently, at least 7-10% of all pediatric cancers are now recognized to occur in the setting of genetic predisposition to cancer or cancer predisposition syndromes. Specifically, the cancer predisposition rate in pediatric patients with NS tumors has been reported to be as high as 15%, though it can approach 50% in certain tumor types (i.e., choroid plexus carcinoma associated with Li Fraumeni Syndrome). Cancer predisposition syndromes are caused by pathogenic variation in genes that primarily function as tumor suppressors and proto-oncogenes. These variants are found in the germline or constitutional DNA. Mosaicism, however, can affect only certain tissues, resulting in varied manifestations. Increased understanding of the genetic underpinnings of cancer predisposition syndromes and the ability of clinical laboratories to offer molecular genetic testing allows for improvement in the identification of these patients. The identification of a cancer predisposition syndrome in a CNS tumor patient allows for changes to medical management to be made, including the initiation of cancer surveillance protocols. Finally, the identification of at-risk biologic relatives becomes feasible through cascade (genetic) testing. These fundamental discoveries have also broadened the horizon of novel therapeutic possibilities and have helped to be better predictors of prognosis and survival. The treatment paradigm of specific NS tumors may also vary based on the patient's cancer predisposition syndrome and may be used to guide therapy (i.e., immune checkpoint inhibitors in constitutional mismatch repair deficiency [CMMRD] predisposition syndrome) [8]. Early diagnosis of these cancer predisposition syndromes is therefore critical, in both unaffected and affected patients. Genetic counselors are uniquely trained master's level healthcare providers with a focus on the identification of hereditary disorders, including hereditary cancer, or cancer predisposition syndromes. Genetic counseling, defined as "the process of helping people understand and adapt to the medical, psychological and familial implications of genetic contributions to disease" plays a vital role in the adaptation to a genetic diagnosis and the overall management of these diseases. Cancer predisposition syndromes that increase risks for NS tumor development in childhood include classic neurocutaneous disorders like neurofibromatosis type 1 and type 2 (NF1, NF2) and tuberous sclerosis complex (TSC) type 1 and 2 (TSC1, TSC2). Li Fraumeni Syndrome, Constitutional Mismatch Repair Deficiency, Gorlin syndrome (Nevoid Basal Cell Carcinoma), Rhabdoid Tumor Predisposition syndrome, and Von Hippel-Lindau disease. Ataxia Telangiectasia will also be discussed given the profound neurological manifestations of this syndrome. In addition, there are other cancer predisposition syndromes like Cowden/PTEN Hamartoma Tumor Syndrome, DICER1 syndrome, among many others which also increase the risk of NS neoplasia and are briefly described. Herein, we discuss the NS tumor spectrum seen in the abovementioned cancer predisposition syndromes as with their respective germline genetic abnormalities and recommended surveillance guidelines when applicable. We conclude with a discussion of the importance and rationale for genetic counseling in these patients and their families.

Congenital subpendymal giant cell astrocytoma in children with tuberous sclerosis complex: growth patterns and neurological outcome

BACKGROUND

Literature regarding congenital subependymal giant cell astrocytomas (SEGA) is limited, and suggests they are at risk of rapid growth and complications. We sought to characterise the growth patterns of congenital SEGA. The second part of the study was an exploratory analysis of congenital SEGA as a possible biomarker for poor neurological outcome.

METHODS

This single-centre case series describes ten patients with TSC who had SEGA diagnosed before 12 months. SEGA diameter and volumetric growth were analysed using serial MRIs. Neurological outcomes were compared to a genotype-matched group.

RESULTS

All children with congenital SEGA had a TSC2 mutation. Patients were followed for 1-8.7 years, during which median SEGA growth rate was 1.1 mm/yr in diameter or 150 mm³/yr volumetrically. SEGA with volume > 500 mm³ had a significantly higher growth rate compared with smaller SEGA (462 mm³/yr vs. 42 mm³/yr, p = 0.0095). Children with congenital SEGA had a high prevalence of severe epilepsy, developmental disability and autism spectrum disorder.

CONCLUSION

Congenital SEGA can follow a relatively benign course with a lower growth rate compared with published literature. Frequent neuroimaging surveillance is recommended for congenital SEGA with volumes exceeding 500 mm³.

IMPACT

Congenital SEGA occur in 9.2% of paediatric patients with tuberous sclerosis complex. There are few published cases of congenital SEGA to date. This case series of ten patients adds our experience seen in a tertiary referral hospital over 10 years. Congenital SEGA can follow a relatively benign course with a lower growth rate compared with published literature. Congenital SEGA with volume exceeding 500 mm³ had a significantly higher growth rate compared with smaller SEGA and should have more frequent neuroimaging surveillance.

Experience using mTOR inhibitors for subependymal giant cell astrocytoma in tuberous sclerosis complex at a single facility

BACKGROUND

Subependymal giant cell astrocytoma (SEGA) is occasionally seen in tuberous sclerosis complex (TSC). Two main options are currently available for treating SEGA: surgical resection or pharmacotherapy using mammalian target of rapamycin inhibitors (mTORi). We hypothesized that opportunities for surgical resection of SEGA would have reduced with the advent of mTORi.

METHODS

We retrospectively reviewed the charts of patients treated between August 1979 and July 2020, divided into a pre-mTORi era group (Pre-group) of patients treated before November 2012, and a post-mTORi era group (Post-group) comprising patients treated from November 2012, when mTORi became available in Japan for SEGA. We compared groups in terms of treatment with surgery or mTORi. We also reviewed SEGA size, rate of acute hydrocephalus, recurrence of SEGA, malignant transformation and adverse effects of mTORi.

RESULTS

In total, 120 patients with TSC visited our facility, including 24 patients with SEGA. Surgical resection was significantly more frequent in the Pre-group (6 of 7 patients, 86 %) than in the Post-group (2 of 17 patients, 12 %; p = 0.001). Acute hydrocephalus was seen in 1 patient (4 %), and no patients showed malignant transformation of SEGA. The group treated using mTORi showed significantly smaller SEGA compared with the group treated under a wait-and-see policy (p = 0.012). Adverse effects of pharmacotherapy were identified in seven (64 %; 6 oral ulcers, 1 irregular menstruation) of the 11 patients receiving mTORi.

CONCLUSIONS

The Post-group underwent surgery significantly less often than the Pre-group. Since the treatment option to use mTORi in the treatment of SEGA in TSC became available, opportunities for surgical resection have decreased in our facility.

Focal Status and Sub-Ependymal Tumor as Features of the First Presentation in a Child With Tuberous Sclerosis

Tuberous sclerosis (TS) is an autosomal dominant inherited disorder that affects multiple organ systems. Usually, children with TS present either with neurocutaneous stigmata or seizures during the early years of life. The mortality and morbidity are related to refractory epilepsy, giant cell astrocytoma and related complications, and multiple angiomyolipomas. The authors have reported an eleven-year-old child in whom focal status and sub-ependymal tumor were the features of the first presentation of tuberous sclerosis. The report further highlights the importance of early identification of cutaneous features by primary care providers and parents to enable early comprehensive multi-disciplinary management.

Stereotactic laser ablation for subependymal giant cell astrocytomas: personal experience and review of the literature

PURPOSE

Subependymal giant cell astrocytomas (SEGAs) are rare tumors typically found in tuberous sclerosis patients. They typically grow in the region of the foramen of Monro and can occlude it, leading to hydrocephalus. Currently, gross total resection is the standard of care, with low rates of recurrence but high rates of complication, especially with larger lesions. Laser interstitial thermal therapy (LITT) is a newly emerging treatment modality for a variety of pathologies. Here, we present a case series of SEGAs managed via LITT and endoscopic, stereotactic septostomy.

METHODS

A retrospective chart review was performed to identify three cases in which SEGAs were treated via LITT and septostomy. Stereotactic ablation was performed via magnetic resonance (MR) thermometry with laser output set to 69% for 2.5 min, with post-ablation scans for visualization of treatment area.

RESULTS

Average age at surgery was 8.2 years. Pre-operative tumor volumes were 0.43, 1.51, and 3.88 cm³. Post-operative tumor volumes were 0.25, 0.21, and 0.68 cm³. Mean tumor volume reduction was 70%. No complications occurred.

CONCLUSION

LITT with septostomy should be considered a viable primary or adjunct treatment modality for SEGAs.

The natural history of subependymal giant cell astrocytomas in tuberous sclerosis complex: a review

Tuberous sclerosis complex (TSC) is an auto-somal-dominant inherited condition with an incidence of approximately 1:6000 births, characterised by deregulated mTOR activity with multi-site hamartomas. Subependymal giant cell astrocytomas (SEGA) are one such hamartoma, affecting up to 24% of patients with TSC. Their intraventricular location may lead to life-threatening obstructive hydrocephalus. Current management is hampered by a lack of understanding regarding the natural history, behaviour and growth patterns of SEGA. We review the current literature to summarise what is known about SEGA in the following areas: (1) diagnostic criteria, (2) prevalence, (3) origin, (4) imaging characteristics, (5) growth rate, (6) genotype-phenotype correlation, (7) congenital SEGA and (8) SEGA as a marker of severity of other TSC manifestations.

Trapped ventricle after laser ablation of a subependymal giant cell astrocytoma complicated by intraventricular gadolinium extravasation: case report

Magnetic resonance imaging-guided stereotactic laser ablation of intracranial targets, including brain tumors, has expanded dramatically over the past decade, but there have been few reports of complications, especially those occurring in a delayed fashion. Laser ablation of subependymal giant cell astrocytomas (SEGAs) is an attractive alternative to maintenance immunotherapy in some children with tuberous sclerosis complex (TSC); however, the effect of treatment on disease progression and the nature and frequency of potential complications remains largely unknown. The authors report the case of a 5-year-old boy with TSC who underwent stereotactic laser ablation of a SEGA at the right foramen of Monro on 2 separate occasions. After the second ablation, immediate posttreatment MRI revealed gadolinium extravasation from the tumor into the lateral ventricle. Nine months later, the patient presented with papilledema and delayed obstructive hydrocephalus secondary to intraventricular adhesions causing a trapped right lateral ventricle. This was successfully treated with endoscopic septostomy. The authors discuss the potential cause and clinical management of a delayed complication not previously reported after a relatively novel surgical therapy.

Subependymal Giant Cell Astrocytoma Presenting with Tumoral Bleeding: A Case Report

We report a rare case of subependymal giant cell astrocytoma (SEGA) associated with tumoral bleeding in a pediatric patient without tuberous sclerosis complex (TSC). A 10-year-old girl presented with a 2-week history of an increasingly aggravating headache. Brain magnetic resonance imaging revealed an approximately 3.6-cm, well-defined, heterogeneously enhancing mass with multistage hemorrhages on the right-sided foramen of Monro. The tumor was completely resected using a transcallosal approach. Intraoperatively, the mass presented as a gray-colored firm tumor associated with acute and subacute hemorrhages. The origin of the mass was identified as the ventricular septum adjacent to the foramen of Monro. A pathological analysis revealed pleomorphic multinucleated eosinophilic tumor cells with abundant cytoplasm. These cells showed positive staining for the glial fibrillary acidic protein and S100 protein. A diagnosis of SEGA was established. The patient recovered without any neurological symptoms. There was no evidence of TSC. The radiological follow-up showed no recurrence for 2 years. This was a case of SEGA with intratumoral hemorrhage, for which a favorable outcome was achieved, without any neurological deficit after tumoral resection.

Laser interstitial thermal therapy for subependymal giant cell astrocytoma: technical case report

Subependymal giant cell astrocytoma (SEGA) is a rare tumor occurring almost exclusively in patients with tuberous sclerosis complex. Although open resection remains the standard therapy, complication rates remain high. To minimize morbidity, less invasive approaches, such as endoscope-assisted resection, radiosurgery, and chemotherapy with mTOR pathway inhibitors, are also used to treat these lesions. Laser interstitial thermal therapy (LITT) is a relatively new modality that is increasingly used to treat a variety of intracranial lesions. In this report, the authors describe two pediatric cases of SEGA that were treated with LITT. In both patients the lesion responded well to this treatment modality, with tumor shrinkage observed on follow-up MRI. These cases highlight the potential of LITT to serve as a viable minimally invasive therapeutic approach to the management of SEGAs in the pediatric population.

Stereotactic laser ablation for hypothalamic and deep intraventricular lesions

OBJECTIVE Laser ablation is a novel, minimally invasive procedure that utilizes MRI-guided thermal energy to treat epileptogenic and other brain lesions. In addition to treatment of mesial temporal lobe epilepsy, laser ablation is increasingly being used to target deep or inoperable lesions, including hypothalamic hamartoma (HH), subependymal giant cell astrocytoma (SEGA), and exophytic intrinsic hypothalamic/third ventricular tumors. The authors reviewed their early institutional experience with these patients to characterize clinical outcomes in patients undergoing this procedure. METHODS A retrospective cohort (n = 12) of patients undergoing laser ablation at a single institution was identified, and clinical and radiographic records were reviewed. RESULTS Laser ablation was successfully performed in all patients. No permanent neurological or endocrine complications occurred; 2 (17%) patients developed acute obstructive hydrocephalus or shunt malfunction following treatment. Laser ablation of HH resulted in seizure freedom (Engel Class I) in 67%, with the remaining patients having a clinically significant reduction in seizure frequency of greater than 90% compared with preoperative baseline (Engel Class IIB). Treatment of SEGAs resulted in durable clinical and radiographic tumor control in 2 of 3 cases, with one patient receiving adjuvant everolimus and the other receiving no additional therapy. Palliative ablation of hypothalamic/third ventricular tumors resulted in partial tumor control in 1 of 3 patients. CONCLUSIONS Early experience suggests that laser ablation is a generally safe, durable, and effective treatment for patients harboring HHs. It also appears effective for local control of SEGAs, especially in combination therapy with everolimus. Its use as a palliative treatment for intrinsic hypothalamic/deep intraventricular tumors was less successful and associated with a higher risk of serious complications. Additional experience and long-term follow-up will be beneficial in further characterizing the effectiveness and risk profile of laser ablation in treating these lesions in comparison with conventional resective surgery or stereotactic radiosurgery.

Rare glial tumors

This chapter describes the epidemiology, pathology, molecular characteristics, clinical and neuroimaging features, treatment, outcome, and prognostic factors of the rare glial tumors. This category includes subependymal giant cell astrocytoma, pleomorphic xanthoastrocytoma, astroblastoma, chordoid glioma of the third ventricle, angiocentric glioma, ganglioglioma, desmoplastic infantile astrocytoma and ganglioma, dysembryoplastic neuroepithelial tumor, papillary glioneuronal tumor, and rosette-forming glioneuronal tumor of the fourth ventricle. Many of these tumors, in particular glioneuronal tumors, prevail in children and young adults, are characterized by pharmacoresistant seizures, and have an indolent course, and long survival following surgical resection. Radiotherapy and chemotherapy are reserved for recurrent and/or aggressive forms. New molecular alterations are increasingly recognized.

Direct medical costs for patients with tuberous sclerosis complex and surgical resection of subependymal giant cell astrocytoma: a US national cohort study

OBJECTIVE

To estimate direct medical costs for patients with tuberous sclerosis complex (TSC) and surgical resection of subependymal giant-cell astrocytoma (SEGA).

METHODS

This retrospective cohort study selected patients who had SEGA surgery and TSC claims between 2000-2011 from three large US nationwide claims databases. Selected patients were age 35 or less and had continuous health insurance in the year before and the year after their first SEGA surgery claim. The study examined the patients' demographic and clinical characteristics and estimated inpatient, outpatient, medication, and total medical costs paid by insurance companies for the pre-surgery year, post-surgery year, and other study periods, respectively. Repeated measures analysis and bootstrapping technique were used to assess the impact of the surgery on the direct medical costs.

RESULTS

Select patients (n = 47) had a mean baseline age of 11.6 years and 66% were male. Many had seizures (91.0%), hydrocephalus (59.6%), vision disorders (38.3%), stroke and hemiparesis (36.2%), and shunt (34.0%) in the pre-surgery year. The mean direct medical costs were $8543 (inpatient: $3770; outpatient: $3473; medication: $1300) for the pre-surgery year, and $85,397 (inpatient: $71,562; outpatient: $11,497; medication: $2338) for the post-surgery year. With the exclusion of the costs during the surgery month, the inpatient, outpatient, medication, and total costs in the post-surgery year were 1.6-4.3 times as much as the costs in the pre-surgery year (inpatient: 4.3:1; outpatient: 2.5:1; medication: 1.6:1; total: 3.1:1, p < 0.05). Repeated measures analysis with bootstrapping confirmed a link between the surgery and increases in direct medical costs (p < 0.05).

CONCLUSIONS

SEGA surgery had a substantial impact on direct medical costs. TSC patients with the surgery experienced significant post-surgery increases in their inpatient, outpatient, and medication costs. Additional research should be conducted to examine the surgery's cost-impact in a longer duration, or to compare the cost-effectiveness of the surgery vs other treatments.

Subependymal giant cell astrocytomas in patients with tuberous sclerosis complex: considerations for surgical or pharmacotherapeutic intervention

Tuberous sclerosis complex is a genetic disorder caused by mutations in either the TSC1 or TSC2 gene that can result in the growth of hamartomas in multiple organ systems. Subependymal giant cell astrocytomas are slow-growing brain tumors associated primarily with tuberous sclerosis complex. They are usually located in the ventricles, often near the foramen of Monro, where they can cause an obstruction if they grow too large, leading to increased intracranial pressure. Surgery to remove a tumor has been the mainstay of treatment but can be associated with postoperative morbidity and mortality. Not all tumors and/or patients are suitable for surgery. The recent development of mammalian target of rapamycin inhibitors that target the pathway affected by TSC1/TSC2 mutations offers a novel pharmacotherapeutic option for these patients. We review the timing and use of surgery versus pharmacotherapy for the treatment of subependymal giant cell astrocytoma in patients with tuberous sclerosis complex.

Subependymal giant cell astrocytoma: current concepts, management, and future directions

BACKGROUND

Subependymal giant cell astrocytoma (SEGA) is the most common central nervous system tumor in patients with tuberous sclerosis complex (TSC). SEGAs are generally benign, non-infiltrative lesions, but they can lead to intracranial hypertension, obstructive hydrocephalus, focal neurologic deficits, and even sudden death.

DISCUSSION

Surgical resection has been the standard treatment for SEGAs, and it is generally curative with complete resection. However, not all SEGAs are amenable to safe and complete resection. Gamma Knife stereotactic radiosurgery provides another treatment option as a primary or adjuvant treatment for SEGAs, but it has highly variable response effects with sporadic cases demonstrating its efficacy. Recently, biologically targeted pharmacotherapy with mammalian target of rapamycin (mTOR) inhibitors such as sirolimus and everolimus has provided a safe and efficacious treatment option for patients with SEGAs. However, SEGAs can recur few months after drug discontinuation, indicating that mTOR inhibitors may need to be continued to avoid recurrence. Further studies are needed to evaluate the advantages and adverse effects of long-term treatment with mTOR inhibitors. This review presents an overview of the current knowledge and particularly highlights the surgical and medical options of SEGAs in patients with TSC.

A management strategy for intraventricular subependymal giant cell astrocytomas in tuberous sclerosis complex

OBJECT

Subependymal giant cell astrocytomas (SEGAs) are benign tumors, most commonly associated with tuberous sclerosis complex (TSC). The vast majority of these tumors arise from the lateral ependymal surface adjacent to the foramen of Monro, therefore potentially encroaching on one or both foramina, and resulting in obstructive hydrocephalus that necessitates surgical decompression. The indications for surgery, intraoperative considerations, and evolution of the authors' management paradigm are presented.

METHODS

Patients with TSC who underwent craniotomy for SEGA resection at New York University Langone Medical Center between January 1997 and March 2011 were identified. Preoperative imaging, clinical characteristics, management decisions, operative procedures, and outcomes were reviewed.

RESULTS

Eighteen patients with TSC underwent 22 primary tumor resections for SEGAs. The indication for surgery was meaningful radiographic tumor progression in 16 of 21 cases. The average age at the time of operation was 10.3 years. Average follow-up duration was 52 months (range 12-124 months). The operative approach was intrahemispheric-transcallosal in 16 cases, transcortical-transventricular in 5, and neuroendoscopic in 1. Nine tumors were on the right, 9 on the left, and 3 were bilateral. Gross-total resection was documented in 16 of 22 cases in our series, with radical subtotal resection achieved in 4 cases, and subtotal resection (STR) in 2 cases. Two patients had undergone ventriculoperitoneal shunt placement preoperatively and 7 patients required shunt placement after surgery for moderate to severe ventriculomegaly. Two patients experienced tumor progression requiring reoperation; both of these patients had initially undergone STR.

CONCLUSIONS

The authors present their management strategy for TSC patients with SEGAs. Select patients underwent microsurgical resection of SEGAs with acceptable morbidity. Gross-total resection or radical STR was achieved in 90.9% of our series (20 of 22 primary tumor resections), with no recurrences in this group. Approximately half of our patient series required CSF diversionary procedures. There were no instances of permanent neurological morbidity associated with surgery.

Management of subependymal giant cell astrocytoma (SEGA) associated with tuberous sclerosis complex (TSC): Clinical recommendations

Subependymal giant cell astrocytoma (SEGA) is a type of brain tumour that develops in 10-15% of individuals with tuberous sclerosis complex (TSC). SEGAs can be unilateral or bilateral, developing from benign subependymal nodules (hamartomas) located near the foramen of Monro. These are usually slow-growing, glialneuronal tumours that develop within the first 2 decades of life. Traditionally, the management of SEGA involved monitoring using periodic neuroimaging, and surgical resection of tumours that exhibited growth and/or caused clinical signs of intracranial hypertension. Recent clinical research has demonstrated that mammalian target of rapamycin (mTOR) inhibitors can induce partial regression of SEGA associated with TSC and so might provide an acceptable alternative to neurosurgery for these tumours. This report summarizes the clinical recommendations for the management of SEGA made by a panel of European experts in March 2012. Current treatment options and outstanding questions are outlined.

Advances in the management of subependymal giant cell astrocytoma

BACKGROUND

Subependymal giant cell astrocytoma (SEGA) is the most common central nervous system tumor in patients with tuberous sclerosis complex (TSC). Although these lesions are generally benign and non-infiltrative, they commonly arise in the region of the foramen of Monro, where they can cause obstructive hydrocephalus and sudden death.

METHODS

Surgical resection has been, and presently remains, the standard treatment for SEGAs demonstrating serial growth on neuroimaging in the setting of symptomatic hydrocephalus or progressive ventriculomegaly.

DISCUSSION

Surgery can be curative; however, not all SEGAs are amenable to safe and complete resection. Gamma Knife stereotactic radiosurgery provides another treatment option but has highly variable response rates with limited data demonstrating its efficacy. Newer medical therapy targeting mammalian target of rapamycin (mTOR), the key protein kinase that is constitutively activated in TSC, has demonstrated promising results in recent clinical trials. In both case reports and clinical trials, treatment with mTOR inhibitors results in a significant reduction in SEGA volume and improvement or resolution of ventriculomegaly. This has led to the approval of everolimus for the treatment of SEGA in tuberous sclerosis patients who are not candidates for surgery. This review summarizes the surgical and medical management of SEGA in patients with TSC.

Surgical resection of subependymal giant cell astrocytomas (SEGAs) and changes in SEGA-related conditions: a US national claims database study

OBJECTIVES

To compare the prevalence rates of clinical conditions related to subependymal giant cell astrocytomas (SEGAs) before and after SEGA surgery among patients with tuberous sclerosis complex (TSC).

METHODS

Based on three US national claims databases, we analyzed and compared the prevalence rates of 21 SEGA-related conditions (including seizures, hydrocephalus, headaches and stroke or hemiparesis) in the six months preceding surgery with the rates in the second through sixth post-surgery months and in the seventh through twelfth post-surgery months among TSC patients who underwent SEGA surgery during 2000-2009. Repeated measures analysis with a bootstrapping method was used to assess the surgery impact.

RESULTS

Patients (N = 47) had a mean age of 11.5 years at their first SEGA surgery, and 66% were male. Compared with the six months preceding surgery, the post-surgery prevalence rates increased by 23-26% for seizures, 21-26% for hydrocephalus, 17-19% for headache and 6-9% for stroke or hemiparesis (all p < 0.05). Repeated measures analysis confirmed the impact of surgery on the prevalence rate of these five conditions (all p < 0.05).

CONCLUSIONS

SEGA surgery has its important role in SEGA treatment. However, after SEGA surgery this group of TSC patients had increased prevalence rates of seizures, hydrocephalus, vision disorders, headaches, stroke or hemiparesis, and autism. Future research to examine the causes of these symptoms is imperative.

LIMITATIONS

The study results have limitations in data source representativeness, coding accuracy, and study design.

Outcomes of resecting subependymal giant cell astrocytoma (SEGA) among patients with SEGA-related tuberous sclerosis complex: a national claims database analysis

OBJECTIVE

To examine the outcomes following resection of subependymal giant cell astrocytoma (SEGA) among patients with SEGA-associated tuberous sclerosis complex (TSC).

METHODS

Using three large US national healthcare claims databases, we retrospectively examined the outcomes of SEGA surgery among TSC patients who underwent SEGA surgery between 2000 and 2009. The examined outcomes were: prevalence rates of post-surgery SEGA, repeated SEGA surgery, and postoperative complications (surgical procedure complications, nervous system complications, postoperative infections, complications of subdural empyemas, and complications of epidural abscesses). Descriptive data analysis and two-sided one sample t-test for mean or proportion were used to assess the characteristics of patients and the outcomes of SEGA surgery.

RESULTS

The selected patients (N = 47) had a mean age of 11.6 years at their first SEGA surgery and 66% were male. During the third through twelfth months following surgery, 34% had post-surgery SEGA (diagnosis) and 12% underwent repeated SEGA surgeries. During the first post-surgery year, 48.9% of patients developed postoperative complications (34.0% had complications relating to the surgical procedure, 12.8% had nervous system complications, 6.4% developed postoperative infections, 17.0% had complications of subdural empyemas, and 2.1% had complications of epidural abscesses).

CONCLUSIONS

SEGA surgery was associated with statistically significant risks of developing post-surgery SEGA, requiring repeated SEGA surgery and developing postoperative complications. Future efforts in reducing these outcomes, either through improving surgical procedures or through alternative treatments, are urgently needed.

LIMITATIONS

This study has its limitation in data source representativeness and measurement accuracy.

Subependymal Giant Cell Astrocytoma (SEGA) Treatment Update

OPINION STATEMENT

Rates of regrowth after resection of subependymal giant cell astrocytoma (SEGA) are low, making surgical resection a successful and permanent therapeutic strategy. In addition to surgical resection of SEGAs, other treatment options now include medications and Gamma Knife™ therapy. Advising patients on medical versus surgical management of SEGAs is currently not easy. SEGAs have been reported to regrow if mTOR inhibitor therapy is stopped, raising the possibility that long-term medication may be required to prevent tumor growth and hydrocephalus. The question of regrowth following medication withdrawal will need to be addressed in more patients to help establish the optimal duration of therapy. The risks of surgery include acute morbidity and the permanent need for ventriculoperitoneal shunting, which must be balanced against the adverse effects of mTOR inhibitors, including immunosuppression (infections, mouth sores), hypercholesterolemia, and the need for chronic drug monitoring. Some additional benefits of mTOR inhibition in patients with tuberous sclerosis complex, however, may include shrinkage of angiofibromas and angiomyolipomas as well as a possible decrease in seizure burden. Recent reports of successful nonsurgical treatment of SEGAs are promising, and it is hoped that further specifics on dosing, duration, and long-term outcome will help patients and physicians to make informed therapeutic choices.Present treatment recommendations for SEGAs include routine surveillance neuroimaging and close clinical follow-up, paying particular attention to signs and symptoms of acute hydrocephalus. If symptoms arise, or if serial neuroimaging demonstrates tumor growth, neurosurgical intervention is recommended. When gross total resection is impossible, rapamycin and everolimus should be considered, but may not offer a durable response.