Brainstem gliomas--retrospective analysis of 86 patients

Brain Stem Glioma Recurrence: Exploring the Therapeutic Frontiers

Gliomas of the brainstem represent a small percentage of central nervous system gliomas in adults. Due to the proximity of the tumor to critical structures, radical surgery is highly challenging and limited to selected cases. In addition, postoperative treatments, which become exclusive to non-operable patients, do not guarantee satisfactory disease control, making the progression of the disease inevitable. Currently, there is a lack of therapeutic options to control tumor growth after the diagnosis of recurrence. The rarity of these tumors, their distinct behavioral characteristics, and the limited availability of tumor tissue necessary for the development of prognostic and predictive biomarkers contribute to the absence of a standardized approach for treating recurrent brainstem gliomas. A salvage radiotherapy (RT) retreatment could represent a promising approach for recurrent brainstem gliomas. However, to date, it has been mainly evaluated in pediatric cases, with few experiences available to assess the most appropriate RT dose, safety, and clinical responses in adult patients. This comprehensive review aims to identify instances of adult patients with recurrent brainstem gliomas subjected to a secondary course of RT, with a specific focus on the analysis of treatment-related toxicity and outcomes. Through this investigation, we endeavor to contribute valuable insights into the viability and efficacy of salvage RT retreatment in managing recurrent brainstem gliomas in the adult population.

Decoding Diffuse Midline Gliomas: A Comprehensive Review of Pathogenesis, Diagnosis and Treatment

Diffuse midline gliomas (DMGs) are a group of aggressive CNS tumors, primarily affecting children and young adults, which have historically been associated with dismal outcomes. As the name implies, they arise in midline structures in the CNS, primarily in the thalamus, brainstem, and spinal cord. In more recent years, significant advances have been made in our understanding of DMGs, including molecular features, with the identification of potential therapeutic targets. We aim to provide an overview of the most recent updates in the field of DMGs, including classification, molecular subtypes, diagnostic techniques, and emerging therapeutic strategies including a review of the ongoing clinical trials, thus providing the treating multidisciplinary team with a comprehensive understanding of the current landscape and potential therapeutic strategies for this devastating group of tumors.

11C-methionine PET imaging characteristics in children with diffuse intrinsic pontine gliomas and relationship to survival and H3 K27M mutation status

PURPOSE

This study aimed to describe ¹¹C-methionine (¹¹C-MET) PET imaging characteristics in patients with paediatric diffuse intrinsic pontine glioma (DIPG) and correlate them with survival and H3 K27M mutation status.

METHODS

We retrospectively analysed 98 children newly diagnosed with DIPG who underwent ¹¹C-MET PET. PET imaging characteristics evaluated included uptake intensity, uniformity, metabolic tumour volume (MTV), and total lesion methionine uptake (TLMU). The maximum, mean, and peak of the tumour-to-background ratio (TBR), calculated as the corresponding standardised uptake values (SUV) divided by the mean reference value, were also recorded. The associations between the PET imaging characteristics and clinical outcomes in terms of progression-free survival (PFS) and overall survival (OS) and H3 K27M mutation status were assessed, respectively.

RESULTS

In univariate analysis, imaging characteristics significantly associated with shorter PFS and OS included a higher uniformity grade, higher TBRs, larger MTV, and higher TLMU. In multivariate analysis, larger MTV at diagnosis, shorter symptom duration, and no treatment were significantly correlated with shorter PFS and OS. The PET imaging features were not correlated with H3 K27M mutation status.

CONCLUSION

Although several imaging features were significantly associated with PFS and OS, only MTV, indicating the size of the active tumour, was identified as a strong independent prognostic factor.

Exploration of the prognostic value of the resection of adult brainstem high-grade glioma based on competing risk model, propensity score matching, and conditional survival rate

BACKGROUND

Adult brainstem high-grade glioma (HGG) is a refractory disease, and the treatment strategy of resection is still controversial.

OBJECTIVE

To investigate the prognostic value of brainstem HGG resection in adults.

METHODS

We collected 126,386 samples from the Surveillance, Epidemiology, and End Results (SEER) database between 1998 and 2016, and screened 973 patients diagnosed with adult brainstem HGG, who were in turn, grouped into 899 cases of non-resections and 74 cases of resections. Competing risk models were used to screen independent prognostic factors. Propensity score matching (PSM) was performed to reduce the influence of confounding factors. Conditional survival (CS) rate was considered to evaluate the changes in overall survival (OS) and disease-specific survival (DSS) of patients with HGG over time.

RESULTS

Based on the competing risk model and PSM, univariate analysis showed that age ≥ 45 years and male gender were poor prognostic factors for adult brainstem HGG. No previous history of glioma was a beneficial factor. Multivariate analysis revealed only the absence of a history of glioma to be a favorable prognostic factor. Considering the CS rate of the resection group, after the patient had survived for 3 years, the OS and DSS remained unchanged at 100% during the fourth and fifth years, whereas in the non-resection group, the OS and DSS of the patients were 82% and 74%, respectively.

CONCLUSION

Adult brainstem HGG resection has a poor prognosis in the early stage; however, patients have a potentially significant survival benefit after 3 years of survival.

Pediatric Diffuse Midline Gliomas: An Unfinished Puzzle

Diffuse midline glioma (DMG) is a heterogeneous group of aggressive pediatric brain tumors with a fatal prognosis. The biological hallmark in the major part of the cases is H3K27 alteration. Prognosis remains poor, with median survival ranging from 9 to 12 months from diagnosis. Clinical and radiological prognostic factors only partially change the progression-free survival but they do not improve the overall survival. Despite efforts, there is currently no curative therapy for DMG. Radiotherapy remains the standard treatment with only transitory benefits. No chemotherapeutic regimens were found to significantly improve the prognosis. In the new era of a deeper integration between histological and molecular findings, potential new approaches are currently under investigation. The entire international scientific community is trying to target DMG on different aspects. The therapeutic strategies involve targeting epigenetic alterations, such as methylation and acetylation status, as well as identifying new molecular pathways that regulate oncogenic proliferation; immunotherapy approaches too are an interesting point of research in the oncology field, and the possibility of driving the immune system against tumor cells has currently been evaluated in several clinical trials, with promising preliminary results. Moreover, thanks to nanotechnology amelioration, the development of innovative delivery approaches to overcross a hostile tumor microenvironment and an almost intact blood-brain barrier could potentially change tumor responses to different treatments. In this review, we provide a comprehensive overview of available and potential new treatments that are worldwide under investigation, with the intent that patient- and tumor-specific treatment could change the biological inauspicious history of this disease.

Prognostic factors in adult brainstem glioma: a tertiary care center analysis and review of the literature

Introduction

Adult brainstem gliomas (BSGs) are rare central nervous system tumours characterized by a highly heterogeneous clinical course. Median survival times range from 11 to 84 months. Beyond surgery, no treatment standard has been established. We investigated clinical and radiological data to assess prognostic features providing support for treatment decisions.

Methods

34 BSG patients treated between 2000 and 2019 and aged ≥ 18 years at the time of diagnosis were retrospectively identified from the databases of the two largest Austrian Neuro-Oncology centres. Clinical data including baseline characteristics, clinical disease course, applied therapies, the outcome as well as neuroradiological and neuropathological findings were gathered and analysed. The tumour apparent diffusion coefficient (ADC), volumetry of contrast-enhancing and non-contrast-enhancing lesions were determined on magnetic resonance imaging scans performed at diagnosis.

Results

The median age at diagnosis was 38.5 years (range 18–71 years). Tumour progression occurred in 26/34 (76.5%) patients after a median follow up time of 19 months (range 0.9–236.2). Median overall survival (OS) and progression-free survival (PFS) was 24.1 months (range 0.9–236.2; 95% CI 18.1–30.1) and 14.5 months (range 0.7–178.5; 95% CI 5.1–23.9), respectively. Low-performance status, high body mass index (BMI) at diagnosis and WHO grading were associated with shorter PFS and OS at univariate analysis (p < 0.05, log rank test, respectively). ADC values below the median were significantly associated with shorter OS (14.9 vs 44.2 months, p = 0.018).

Conclusion

ECOG, BMI, WHO grade and ADC values were associated with the survival prognosis of BSG patients and should be included in the prognostic assessment.

Circular RNA circCCDC66 promotes glioma proliferation by acting as a ceRNA for miR-320a to regulate FOXM1 expression

BACKGROUND

In this study, we determine the potential roles and uncover the regulatory mechanisms of circCCDC66 in regulating cell growth and cell metastasis of glioma.

METHODS

qRT-PCR was used to detect the expressions of circCCDC66 in gliomas and tissues. The biological function of circCCDC66 in glioma cell lines was elucidated by functional experiments. Cell counting kit-8 and transwell were used to detect the effect of circCCDC66 on the proliferation, migration and invasion of glioma cells. Bioinformatics analysis was applied to reveal the targets of circCCDC66.

RESULTS

The results showed circCCDC66 was overexpressed in glioma and acted as an oncogene. CircCCDC66 knockdown suppressed the proliferation, migration, and invasion of glioma cells. We constructed a circCCDC66 regulating miRNA network and revealed miR-320a was a potential target of circCCDC66, which was down-regulated in high-grade gliomas compared to low-grade gliomas. Bioinformatics analysis showed circCCDC66-miR-320a/b axis was involved in regulating multiple cancer-related pathways. Furthermore, we identified FOXM1 as a key target of circCCDC66, which was involved in regulating DNA damage response pathways. In mechanism study, circCCDC66 could sponge miR-320a, thereby increasing the expression of FOXM1.

CONCLUSIONS

CircCCDC66 could facilitate glioma cells proliferation, invasion and migration by down-regulating miR-320a and up-regulating FOXM1.

Design considerations of an IL13Rα2 antibody-drug conjugate for diffuse intrinsic pontine glioma

Diffuse intrinsic pontine glioma (DIPG), a rare pediatric brain tumor, afflicts approximately 350 new patients each year in the United States. DIPG is noted for its lethality, as fewer than 1% of patients survive to five years. Multiple clinical trials involving chemotherapy, radiotherapy, and/or targeted therapy have all failed to improve clinical outcomes. Recently, high-throughput sequencing of a cohort of DIPG samples identified potential therapeutic targets, including interleukin 13 receptor subunit alpha 2 (IL13Rα2) which was expressed in multiple tumor samples and comparably absent in normal brain tissue, identifying IL13Rα2 as a potential therapeutic target in DIPG. In this work, we investigated the role of IL13Rα2 signaling in progression and invasion of DIPG and viability of IL13Rα2 as a therapeutic target through the use of immunoconjugate agents. We discovered that IL13Rα2 stimulation via canonical ligands demonstrates minimal impact on both the cellular proliferation and cellular invasion of DIPG cells, suggesting IL13Rα2 signaling is non-essential for DIPG progression in vitro. However, exposure to an anti-IL13Rα2 antibody-drug conjugate demonstrated potent pharmacological response in DIPG cell models both in vitro and ex ovo in a manner strongly associated with IL13Rα2 expression, supporting the potential use of targeting IL13Rα2 as a DIPG therapy. However, the tested ADC was effective in most but not all cell models, thus selection of the optimal payload will be essential for clinical translation of an anti-IL13Rα2 ADC for DIPG.

Modality of Radiotherapy and Overall Survival in Pediatric Diffuse Brainstem Gliomas: Implications for Resource-Constrained Settings

BACKGROUND

Childhood diffuse brainstem glioma (dBSG) is a rare tumor with a poor prognosis. Any tumor-directed surgical intervention is difficult. Magnetic resonance imaging forms the mainstay of diagnosis and radiation therapy has remained the backbone of therapy. In this study, we compare the outcomes of conformal radiotherapy with conventional therapy in the context of resource-constrained settings.

METHODS

In this retrospective analysis, conducted between 2010 and 2019, all pediatric patients with a diagnosis of dBSG were analyzed. The survival data were calculated in months from the date of diagnosis. Survival differences between variables were compared using the Log-rank test and the risk of death was calculated using Cox regression analysis.

RESULTS

A total of 20 patients (11 males, 55%) with a diagnosis of dBSG were included. Median age at diagnosis was 6.5 years. No surgical resection or biopsy was done in any patient. Fifteen (75%) patients received radiotherapy and only 4 (20%) patients received additional chemotherapy. Five (25%) patients did not receive any form of anti-cancer therapy. Median overall survival (OS) was 8 months (95% CI 5.2-10.8). Females were at a higher risk of death than males. Children treated with radiotherapy had a longer OS than untreated children; however, the modality of radiotherapy employed or the addition of chemotherapy did not affect the OS.

CONCLUSION

Radiotherapy, irrespective of the modality, increases the survival of children with dBSG in resource-poor settings. Additionally, socioeconomic concerns need to be addressed in the management of these tumors, especially in the case of female children. Lay summaryChildhood diffuse brainstem glioma (dBSG) is a rare tumor with a poor prognosis. Any tumor-directed surgical intervention is difficult. Magnetic resonance imaging forms the mainstay of diagnosis and radiation therapy has remained the backbone of therapy. In this 10-year retrospective study, we compare the outcomes of conformal radiotherapy with conventional therapy in the context of resource-constrained settings. A total of 20 patients with a diagnosis of dBSG were included with a median age at diagnosis of 6.5 years (5.25-8.75). No surgical resection or biopsy was done in any patient. Fifteen (75%) patients received radiotherapy and only 4 (20%) patients received additional chemotherapy. Five (25%) patients did not receive any form of anti-cancer therapy. Median overall survival (OS) was 8 months (95% CI 5.2-10.8). Females were at a 3.4-fold (95% CI 1.0-12.1) higher risk of death than males. Children treated with radiotherapy had a longer OS than untreated children; however, the modality of radiotherapy employed or the addition of chemotherapy did not affect the OS. Radiotherapy, irrespective of the modality, increases the survival of children with dBSG in resource-poor settings. Additionally, socioeconomic concerns need to be addressed in the management of these tumors, especially in the case of female children.

The Surgical Resection of Brainstem Glioma: Outcomes and Prognostic Factors

BACKGROUND

The management of brainstem glioma remains controversial, with increasing evidence supporting surgical resection as the primary treatment for a select subgroup of tumors. However, there remains no consensus on the specific benefits and risks, the selection of surgical candidates, and prognostic factors that may further refine surgical indications.

METHODS

A retrospective single-surgeon chart review was performed for all patients who underwent surgical treatment for radiographically suspected brainstem glioma between 2000 and 2017. Preoperative and postoperative radiographic evaluations on magnetic resonance imaging were conducted. Survival outcomes were collected, and machine-learning techniques were used for multivariate analysis.

RESULTS

Seventy-seven patients with surgical treatment of brainstem glioma were identified, with a median age of 9 years (range, 0-58 years). The cohort included 64% low-grade (I and II) and 36% high-grade (III and IV) tumors. For all patients, the 1-year and 5-year overall survival were 76.4% and 62.3%, respectively. Transient neurologic deficit was present in 34% of cases, and permanent deficit in a further 29%.

CONCLUSIONS

The radical surgical resection of brainstem gliomas can be performed with acceptable risk in well-selected cases and likely confers survival advantage for what is otherwise a rapidly and universally fatal disease. Various radiographic features are useful during patient selection and may guide treatment selection.

Time to diagnosis and clinical characteristics in pediatric brain tumor patients

PURPOSE

We aimed to identify factors that affect the time to diagnosis in pediatric brain tumors and investigate the effect of time to diagnosis on clinical outcome.

METHODS

A retrospective study of children with brain tumors aged less than 18 years diagnosed at the University of Tsukuba Hospital over a period of 7 years was conducted.

RESULTS

Eighty-five consecutive patients, with a mean age of 9.1 years, were included in the study. The median interval from symptom onset to diagnosis was 45 days (range 0-1673); median interval from symptom onset to first presentation was 31.0 days; and median interval from first presentation to diagnosis was 13.5 days. Germinoma had the longest interval from symptom onset to first presentation, and from first presentation to diagnosis. Patients presenting with endocrine disorder had a significantly longer interval from symptom onset to first presentation (p = 0.019); those with visual disturbance (p = 0.016) or endocrine disorder (p = 0.030) had significantly longer intervals from first presentation to diagnosis.

CONCLUSION

Pediatric brain tumor patients with germinoma and presenting symptoms of endocrine disorder or visual disturbance have a longer time to diagnosis. Although improved prognosis is not clearly related to a shorter time to diagnosis, we believe that early diagnosis can lead to improved treatment and better quality of life. A detailed medical history and neuroimaging studies at the earliest time possible are important for early diagnosis.

The Epidemiological Characteristics and Prognostic Factors of Low-Grade Brainstem Glioma: A Real-World Study of Pediatric and Adult Patients

Purpose: Our current understanding of low-grade brainstem glioma (LGBSG) is still limited. This study aimed to conduct a large-scale population-based real-world study to understand the epidemiological characteristics of LGBSG and determine the predictive factors of cancer-specific survival (CSS) and overall survival (OS) of LGBSG patients.

Patients and Methods: We used Surveillance Epidemiology and End Results database to conduct this study of patients with histologically confirmed LGBSG. Patient demographics, tumor characteristics, and treatment options were compared between pediatric and adult patients. Univariate and multivariate analyses were employed to determine prognostic factors of CSS and OS. Kaplan–Meier curve and decision tree were used to confirm the prognostic factors. All variables were further identified by L1-penalized (Lasso) regression and then a nomogram was established to predict the 5- and 8-year CSS and OS rate. The precision of the nomogram was evaluated by calibration plots, Harrell's concordance index, and time-dependent receiver operating characteristic curve. The clinical use of nomogram was estimated by decision curve analysis.

Results: A cohort of 305 patients with LGBSG, including 165 pediatric and 140 adult patients, was analyzed. Adult and pediatric patients showed different patterns concerning tumor size, tumor extension, adjuvant therapy, and survival rate. Univariate analysis revealed that pediatric group, gross total resection (GTR), World Health Organization grade II, radiotherapy, extension to ventricular system, and diffuse astrocytic and oligodendroglial tumor (DAOT) were significantly associated with CSS. Multivariate analysis showed that pediatric group, metastasis, ventricular system involvement, and DAOT were independently associated with CSS. The prognostic factors were further confirmed by Kaplan–Meier curve and decision tree. Kaplan–Meier curve also showed that adjuvant therapy added no benefits in patients with GTR and non-GTR. In addition, the nomogram was developed and the C-index of internal validation for CSS was 0.87 (95% CI, 0.78–0.96).

Conclusion: This study shows that pediatric and adult patients have different tumor characteristics, treatment options, and survival rate. Pediatric group, DAOT, ventricular system involvement, and metastasis were identified as independent prognostic factors for CSS by multivariate analysis. Adjuvant therapy showed no benefits on CSS in patients with GTR and non-GTR. The nomogram was discriminative and clinically useful.

Incidence and risk factors of communication, swallowing, and orofacial myofunctional disorders in children and adolescents with cancer and benign neoplasms

PURPOSE

To describe the incidence and risk factors of communication, swallowing, and orofacial myofunctional disorders in a cohort of children and adolescents with cancer and benign neoplasms.

METHODS

A prospective cohort study conducted with children aged ⩾ 2 years and adolescents of both genders admitted at the Pediatric Oncology Department of the Instituto Nacional de Câncer (INCA) between March 2014 and April 2015. Study participants were submitted to a Speech-Language Pathology (SLP) assessment at three different times: (T1) at hospital admission; (T2) six months after admission; (T3) one year after admission.

RESULTS

One hundred and sixty individuals were evaluated. At the time of hospital admission, 68 individuals (42.5%) presented with some type of SLP disorder. After one year of follow-up, 22.8% of the patients had developed new impairments. The occurrence of new speech-language disorders had a statistically significant association with the tumor site. In the risk analysis for the development of speech-language disorders with respect to the primary tumor site, compared to other sites, the central nervous system (CNS) tumor group was 8.29 times more likely to present some new alterations, while the head and neck (HN) tumor group had a 10.36-fold higher risk.

CONCLUSION

An incidence of 22.8% for communication, swallowing, and orofacial myofunctional disorders was observed. The development of these disorders was greater in individuals with tumors in the CNS and in the HN region.

The role of radiation and chemotherapy in adult patients with high-grade brainstem gliomas: results from the National Cancer Database

INTRODUCTION

Surgical resection of high-grade brainstem gliomas is challenging and treatment mostly involves radiation and chemotherapy. In this study, we utilized registry data to determine prognostic features and impact of chemotherapy and radiation on overall survival.

METHODS

The National Cancer Database was queried from 2006 to 2015 for adult cases with histologically confirmed high-grade brainstem glioma. Covariates including patient demographics, comorbidities, tumor characteristics and treatment parameters were captured. Multivariable Cox proportional hazards regression was performed to identify predictors of survival.

RESULTS

A total of 422 patients were analyzed. Most patients (66.6%) underwent postoperative radiation with chemotherapy, 9.2% underwent radiation alone, while the remaining had no postoperative treatment (24.2%). Overall median survival was 9.8 months (95% CI 8.8-12). Survival was longer (p < 0.001) in the radiation + chemotherapy group (median: 14.2 months, 95% CI 11.7-17.1) compared to radiation alone (median: 5.7 months, 95% CI 3.7-12) and no postoperative treatment (median: 1.8 months, 95% CI 1.4-4) groups. In multivariable analysis, increasing age was associated with worse survival (HR: 1.87, 95% CI 1.47-2.37, p < 0.001), whereas radiation + chemotherapy was associated with lower mortality compared to radiation alone (HR: 0.67, 95% CI 0.46-0.98, p = 0.038). In subgroup analysis, postoperative chemotherapy with radiation was associated with significant survival benefit compared to radiation alone for grade IV (HR: 0.46, 95% CI 0.28-0.76, p = 0.003), but not for grade III tumors (HR: 0.87, 95% CI 0.48-1.58, p = 0.65).

CONCLUSION

Analysis from a national registry illustrated the effectiveness of radiation with chemotherapy for adult patients with high-grade brainstem gliomas, particularly grade IV. Further research should identify specific patient profiles and molecular subgroups that are more likely to benefit from multimodality therapy.

Pediatric Brainstem Gliomas: A Retrospective Study of 180 Patients from the SEER Database

BACKGROUND/AIMS

Large population-based studies are needed to assess the epidemiology and survival risk factors associated with pediatric brainstem gliomas. This retrospective study explores factors that may influence survival in this population.

METHODS

Utilizing the SEER database, the authors retrospectively assessed survival in histologically confirmed brainstem gliomas in patients aged 17 and younger. Survival was described with Kaplan-Meyer curves and multivariate regression analysis.

RESULTS

This analysis of 180 cases showed that age (hazard ratio [HR] 1.04, 95% CI 0.96-1.14, p = 0.34), non-white race (HR 1.00, 95% CI 0.35-2.85 p > 0.99), distant or invasive extension of the tumor (HR 0.4, 95% CI 0.08-2.53, p = 0.37), and radiation therapy (HR 1.27, 95% CI 0.52-3.11, p = 0.61) were not associated with decreased survival. High-grade tumor status (HR 8.64, 95% CI 3.49-21.41, p < 0.001) was associated with decreased survival. Partial resection (HR 0.11, 95% CI 0.04-0.30, p < 0.001) and gross-total resection (HR 0.03, 95% CI 0.01-0.14, p < 0.001) were associated with improved survival.

CONCLUSIONS

High-grade brainstem gliomas have a worse prognosis. Early diagnosis and surgery appear to be associated with improved survival, while the role of radiation is unclear.

Population-based Study Determining Predictors of Cancer-Specific Mortality and Survival in Pediatric High-grade Brainstem Glioma

BACKGROUND

Pediatric high-grade brainstem gliomas are aggressive tumors with dismal prognoses. Large-scale studies are needed to further characterize these tumors and determine factors influencing cancer-specific mortality and survival at varying time points.

METHODS

We used the SEER (Surveillance Epidemiology and End Results) database to conduct a population-based study of pediatric patients with histologically confirmed anaplastic astrocytoma or glioblastoma tumors located within the brainstem. Multivariate analyses incorporating patient demographics, tumor characteristics, and treatments were used to determine predictors of cancer-specific mortality and survival at 6 months, 9 months, 1 year, and 2 years.

RESULTS

We included 154 patients from the SEER database: 72 patients with anaplastic astrocytoma (47%) and 82 (53%) with glioblastoma. Median survival for the entire cohort was 10.0 months. Glioblastoma histology, developmental stage, and large tumor size were significantly associated with cancer-specific mortality. Six-month, 9-month, 1-year, and 2-year survival was 75%, 57%, 42%, and 20%, respectively. Glioblastoma histology was associated with worsened survival at 6 months (odds ratio [OR], 0.19; P = 0.0081), 9 months (OR, 0.18; P < 0.001), 1 year (OR, 0.19; P < 0.001), and 2 years (OR, 0.14; P = 0.0055). Radiation therapy was associated with improved survival at 6 (OR, 8.53; P = 0.0012) and 9 months (OR, 3.58; P = 0.035) but not at 1 or 2 years. Radiation therapy was associated with improved survival in glioblastoma (9.0 vs. 3.0 months; P < 0.001).

CONCLUSIONS

This population-based study showed that glioblastoma histology is associated with a poor prognosis in pediatric patients with high-grade brainstem gliomas. Regardless of histology, radiation therapy improved survival at 6 and 9 months but not long-term.

Brainstem glioma: Prediction of histopathologic grade based on conventional MR imaging

Objective The objective of this article is to investigate the association between specific MR imaging findings and histopathologic grading (low-grade vs. high-grade) of brainstem gliomas (BSGs). Methods Sixty-two males and 34 females (mean (standard deviation, SD) age of 24.61 (17.20) years, range = 3 to 70 years) with histologically diagnosed BSG underwent conventional 1.5 T MR imaging, which included T1-weighted (T1W), T2W, and post-contrast T1W sequences. There were 39 children (mean age of 9.38 years) and 57 adults (mean age of 35 years). A binary logistic regression analysis was used to explore associations between MRI features and histopathological grade of the BSG. Results Binary logistic regression revealed that necrosis (adjusted odds ratio (OR) = 16.07; 95% confidence interval (CI) = 3.20 to 80.52; p = 0.001) and inhomogeneous contrast enhancement (adjusted OR = 8.04; 95% CI = 1.73 to 37.41; p = 0.008) as significant predictors of high-grade BSG. The equation (Nagelkerke R²= 0.575) is Logit ( p high-grade BSG) = (2.77 × necrosis) + (2.08 × heterogeneous contrast enhancement) - 3.13. Sensitivity and specificity values were respectively 66.7% and 96.0% for necrosis and 85.7% and 65.9% for inhomogeneous contrast-enhancing lesions. In the pediatric age group, only inhomogeneous contrast enhancement (adjusted OR = 40; 95% CI = 3.95 to 445.73; p = 0.002) was a significant predictor for high-grade BSG. Conclusion Conventional MR imaging features such as necrosis and inhomogeneous contrast enhancement in adults and heterogeneous contrast enhancement in children suggest high-grade BSG.

External validation of the diffuse intrinsic pontine glioma survival prediction model: a collaborative report from the International DIPG Registry and the SIOPE DIPG Registry

We aimed to perform external validation of the recently developed survival prediction model for diffuse intrinsic pontine glioma (DIPG), and discuss its utility. The DIPG survival prediction model was developed in a cohort of patients from the Netherlands, United Kingdom and Germany, registered in the SIOPE DIPG Registry, and includes age <3 years, longer symptom duration and receipt of chemotherapy as favorable predictors, and presence of ring-enhancement on MRI as unfavorable predictor. Model performance was evaluated by analyzing the discrimination and calibration abilities. External validation was performed using an unselected cohort from the International DIPG Registry, including patients from United States, Canada, Australia and New Zealand. Basic comparison with the results of the original study was performed using descriptive statistics, and univariate- and multivariable regression analyses in the validation cohort. External validation was assessed following a variety of analyses described previously. Baseline patient characteristics and results from the regression analyses were largely comparable. Kaplan-Meier curves of the validation cohort reproduced separated groups of standard (n = 39), intermediate (n = 125), and high-risk (n = 78) patients. This discriminative ability was confirmed by similar values for the hazard ratios across these risk groups. The calibration curve in the validation cohort showed a symmetric underestimation of the predicted survival probabilities. In this external validation study, we demonstrate that the DIPG survival prediction model has acceptable cross-cohort calibration and is able to discriminate patients with short, average, and increased survival. We discuss how this clinico-radiological model may serve a useful role in current clinical practice.

[Brain stem glioma: a rare cause of central vertigo in adults]

Unlike children, brainstem gliomas in adults are rare and represent a heterogeneous group of tumors: often low grade tumors having a better prognosis. These tumors are a rare cause of central vertigo in adults. The treatment of diffuse gliomas is based on radiation therapy. We here report the case of a 35-year old female patient with low grade brainstem glioma revealed by balance disorders, in order to highlight the different clinical, paraclinical and radiological aspects of this disease as well as the therapeutic tools and the progressive methods.

Brainstem Glioma in Adults

Brainstem gliomas are not nearly as common in adults as they are in children. They are likely the final common consequence not of a single disease process but of several. They can be difficult to diagnose, and are challenging to treat. Clinical studies of this diagnosis are few and generally small. Because of these factors, our understanding of the biology of adult brainstem glioma is incomplete. However, the knowledge base is growing and progress is being made. In this article, we review the current state of knowledge for brainstem glioma in adults and identify key areas for which additional information is required.

Adult Diffuse Astrocytoma in the Medulla Oblongata: Molecular Biological Analyses Including H3F3A Mutation of Histone H3.3

Unlike in children, brain stem gliomas in adult are rare and still poorly understood. In addition, most adult brain stem gliomas result predominantly in the pons and are less often found in the medulla oblongata. Here, we report a case of an adult glioma in the medulla oblongata and its molecular biological features. A 46-year-old male presented with gait disturbance, paresthesia, and dysphagia. Magnetic resonance imaging (MRI) showed a diffuse hyper-intensive lesion in the medulla oblongata on a T₂-weighted image without gadolinium contrast enhancement. We performed an open biopsy and the lesion was pathologically diagnosed as a diffuse astrocytoma. Molecular biological analyses revealed the absence of histone H3.3 mutation (H3F3A K27M), and presence of methylation of O-6-methylguanine-DNA methyltransferase (MGMT) promoter and a mutation in isocitrate dehydrogenase 1 (IDH-1). The patient received local radiotherapy and temozolomide chemotherapy. The patient’s symptoms were ameliorated, and MRI showed no tumor growth at 6 months after the initial treatment. Biopsy for brain stem lesions is generally thought to have risk of complications, but if performed minimally, it is useful to diagnose and determine treatment strategy. Obtaining patient characteristics and molecular biological features will provide insight towards therapeutic treatment for adult brain stem gliomas.

Analysis of survival in pediatric high-grade brainstem gliomas: A population-based study

Background:

The purpose of this study was to use the National Cancer Institutes’ Surveillance, Epidemiology, and End Results (SEER) database to perform a large-scale analysis of brainstem anaplastic astrocytoma (AA) and glioblastoma multiforme (GBM). Use of the SEER database gave us a larger sample size of this rare tumor type, allowing for the analysis of the relationship between prognostic factors and survival.

Materials and Methods:

We selected pediatric patients (<18 years old) from the SEER database with histologically confirmed diagnoses of primary high-grade gliomas (World Health Organization Grade III/IV) of the brainstem. In univariate and multivariate analysis, we analyzed the relationship between demographic (age, gender, race, diagnosis date), histologic (AA, GBM), and treatment (surgery, radiation) factors on survival.

Results:

In our cohort of 124 patients, those with AA had a median survival of 13 months and those with GBM 9 months. Higher-grade tumors were associated with statistically significantly increased mortality (hazard ratio [HR]: 1.74, confidence intervals [CIs]: 1.17-2.60). Surgical intervention was associated with a significantly lower mortality, either alone (HR: 0.14, CI: 0.04-0.5) or in combination with radiation (HR: 0.35, CI: 0.15-0.82). Radiation therapy alone was significantly associated with decreased mortality within the first 9 months after diagnosis but not with overall mortality. No demographic characteristics were significantly associated with mortality.

Conclusions:

Outcome remains poor in the pediatric high-grade brainstem glioma population. Survival is correlated with lower-grade tumor histology, radiation therapy only in the first 9 months after diagnosis, and surgical resection.

Clinicopathological features and treatment outcomes of brain stem gliomas in Saudi population

AIM: To analyze experiences to identify treatment outcomes and prognostic factors in a Saudi population.

METHODS: Medical records of patients with brainstem gliomas treated from July 2001 to December 2012 were reviewed to identify treatment outcomes of surgery, radiation therapy and chemotherapy and associated prognostic factors in a Saudi population.

RESULTS: We analyzed 49 brain stem glioma (BSG) patients from July 2001 to December 2012; 31 of them were males (63.3%) with a median age of 12.6 years (range: 8-64 mo). Twenty-two patients (44.9%) had diffuse intrinsic pontine gliomas (DIPG) and 15 (30.6%) presented with focal/tectal BSG. Histopathology was available in 30 patients (61.2%). Median survival time for the whole cohort was 1.5 years. One and two year OS rates were 51.1% and 41.9% respectively. Two year OS rates for focal/tectal, dorsally exophytic, cervicomedullary and DIPG tumors were 60%, 33.3%, 33.3% and 13.6% respectively (P < 0.0001). Significant prognostic factors related to OS were age at diagnosis (worse for > 18 years) P = 0.01, KPS < 70 P = 0.02, duration of symptoms (< 60 d) P = 0.002, histology (better for favorable) P = 0.002, surgery (maximal resection) P = 0.002, and concurrent chemotherapy with radiation therapy in DIPG (better if given) P = 0.01.

CONCLUSION: BSG, especially the DIPG subgroup, had a dismal prognosis, needing more aggressive neurosurgical, radiation and chemotherapy techniques, while focal and tectal tumors were found to have a better prognosis.

Survival prediction model of children with diffuse intrinsic pontine glioma based on clinical and radiological criteria

BACKGROUND

Although diffuse intrinsic pontine glioma (DIPG) carries the worst prognosis of all pediatric brain tumors, studies on prognostic factors in DIPG are sparse. To control for confounding variables in DIPG studies, which generally include relatively small patient numbers, a survival prediction tool is needed.

METHODS

A multicenter retrospective cohort study was performed in the Netherlands, the UK, and Germany with central review of clinical data and MRI scans of children with DIPG. Cox proportional hazards with backward regression was used to select prognostic variables (P < .05) to predict the accumulated 12-month risk of death. These predictors were transformed into a practical risk score. The model's performance was validated by bootstrapping techniques.

RESULTS

A total of 316 patients were included. The median overall survival was 10 months. Multivariate Cox analysis yielded 5 prognostic variables of which the coefficients were included in the risk score. Age ≤3 years, longer symptom duration at diagnosis, and use of oral and intravenous chemotherapy were favorable predictors, while ring enhancement on MRI at diagnosis was an unfavorable predictor. With increasing risk score categories, overall survival decreased significantly. The model can distinguish between patients with very short, average, and increased overall survival (medians of 7.0, 9.7, and 13.7 mo, respectively). The area under the receiver operating characteristic curve was 0.68.

CONCLUSIONS

We developed a DIPG survival prediction tool that can be used to predict the outcome of patients and for stratification in trials. Validation of the model is needed in a prospective cohort.

Clinical management and outcome of histologically verified adult brainstem gliomas in Switzerland: a retrospective analysis of 21 patients

Because of low incidence, mixed study populations and paucity of clinical and histological data, the management of adult brainstem gliomas (BSGs) remains non-standardized. We here describe characteristics, treatment and outcome of patients with exclusively histologically confirmed adult BSGs. A retrospective chart review of adults (age >18 years) was conducted. BSG was defined as a glial tumor located in the midbrain, pons or medulla. Characteristics, management and outcome were analyzed. Twenty one patients (17 males; median age 41 years) were diagnosed between 2004 and 2012 by biopsy (n = 15), partial (n = 4) or complete resection (n = 2). Diagnoses were glioblastoma (WHO grade IV, n = 6), anaplastic astrocytoma (WHO grade III, n = 7), diffuse astrocytoma (WHO grade II, n = 6) and pilocytic astrocytoma (WHO grade I, n = 2). Diffuse gliomas were mainly located in the pons and frequently showed MRI contrast enhancement. Endophytic growth was common (16 vs. 5). Postoperative therapy in low-grade (WHO grade I/II) and high-grade gliomas (WHO grade III/IV) consisted of radiotherapy alone (three in each group), radiochemotherapy (2 vs. 6), chemotherapy alone (0 vs. 2) or no postoperative therapy (3 vs. 1). Median PFS (24.1 vs. 5.8 months; log-rank, p = 0.009) and mOS (30.5 vs. 11.5 months; log-rank, p = 0.028) was significantly better in WHO grade II than in WHO grade III/IV tumors. Second-line therapy considerably varied. Histologically verification of adult BSGs is feasible and has an impact on postoperative treatment. Low-grade gliomas can simple be followed or treated with radiotherapy alone. Radiochemotherapy with temozolomide can safely be prescribed for high-grade gliomas without additional CNS toxicities.

"Occult" post-contrast signal enhancement in pediatric diffuse intrinsic pontine glioma is the MRI marker of angiogenesis?

INTRODUCTION

In diffuse intrinsic pontine gliomas (DIPG), subtracting pre-contrast from post-contrast T1-weighted images (T1WI) occasionally reveals subtle, "occult" enhancement. We hypothesized that this represents intravascular enhancement related to angiogenesis and hence that these tumors should have greater blood volume fractions than do non-enhancing tumors.

METHODS

We retrospectively screened MR images of 66 patients initially diagnosed with DIPG and analyzed pretreatment conventional and dynamic susceptibility contrast (DSC) perfusion MRI studies of 61 patients. To determine the incidence of occult enhancement, cerebral blood volume (CBV) values were compared in areas of occult enhancement (OcE), no enhancement (NE), and normal-appearing deep cerebellar white matter (DCWM).

RESULTS

Tumors of 10 patients (16.4 %) had occult enhancement; those of 6 patients (9.8 %) had no enhancement at all. The average CBV in areas of occult enhancement was significantly higher than that in non-enhancing areas of the same tumor (P = .03), within DCWM in the same patient (P = .03), and when compared to anatomically paired/similar regions of interest (ROI) in patients with non-enhancing tumors (P = .005).

CONCLUSION

Areas of OcE correspond to areas of higher CBV in DIPG, which may be an MRI marker for angiogenesis, but larger scale studies may be needed to determine its potential relevance to grading by imaging, treatment stratification, biopsy guidance, and evaluation of response to targeted therapy.

Brainstem gliomas: surgical indications and technical considerations in a series of 58 cases

OBJECTIVES. To analyze the indications of surgical treatment, surgical management strategies and post-surgical outcome in patients with brainstem glioma (BSG). METHODS. In this retrospective study conducted from 1998 to 2012, 58 patients of surgically treated intrinsic BSG, meeting the inclusion criterion were enrolled. There were 40 males and 18 females, with age range varying from 3 to 55 years. The most common presentation was gait disturbances, either due to cerebellar involvement or motor weakness, followed by motor weakness, ocular involvement and headache. The posteriorly located tumors were operated by midline suboccipital approach (42 patients) and supracerebellar-infratentorial approach (4 patients). Posterolaterally located tumors were operated by retromastoid (10 patients) and all the ventrolateral tumors by subtemporal approach (4 patients). RESULTS. Above 90% patients improved in their neurological status, while 5% deteriorated. Pilocytic astrocytoma was the most common histopathology (41.4%), followed by Grade II astrocytoma (34.5%) and Grade III astrocytoma (24.1%). Overall, 19% patients had postoperative complications and three patients (5%) died in the perioperative period. CONCLUSIONS. Surgery is advocated for patients with well delineated, posteriorly, posterolaterally and ventrolaterally located tumors having slow progression and relative preservation of motor power. BSG can have excellent surgical results with surgeon's experience and modern surgical facilities.

Management and outcome of focal low-grade brainstem tumors in pediatric patients: the St. Jude experience

OBJECT

Whereas diffuse intrinsic pontine gliomas generally have a short symptom duration and more cranial nerve involvement, focal brainstem gliomas are commonly low grade, with fewer cranial neuropathies. Although these phenotypic distinctions are not absolute predictors of outcome, they do demonstrate correlation in most cases. Because there is a limited literature on focal brainstem gliomas in pediatric patients, the objective of this paper was to report the management and outcome of these tumors.

METHODS

The authors reviewed the records of all children diagnosed with radiographically confirmed low-grade focal brainstem gliomas from 1986 to 2010. Each patient underwent biopsy or resection for tissue diagnosis. Event-free survival (EFS) and overall survival were evaluated. Univariate analysis was conducted to identify demographic and treatment variables that may affect EFS.

RESULTS

Fifty-two patients (20 girls, 32 boys) with follow-up data were identified. Median follow-up was 10.0 years, and the median age at diagnosis was 6.5 years (range 1-17 years). The tumor locations were midbrain (n = 22, 42%), pons (n = 15, 29%), and medulla (n = 15, 29%). Surgical extirpation was the primary treatment in 25 patients (48%). The 5- and 10-year EFS and overall survival were 59%/98% and 52%/90%, respectively. An event or treatment failure occurred in 24 patients (46%), including 5 deaths. Median time to treatment failure was 3.4 years. Disease progression in the other 19 patients transpired within 25.1 months of diagnosis. Thirteen of these patients received radiation, including 11 within 2 months of primary treatment failure. Although children with intrinsic tumors had slightly better EFS at 5 years compared with those with exophytic tumors (p = 0.054), this difference was not significant at 10 years (p = 0.147). No other variables were predictive of EFS.

CONCLUSIONS

Surgery suffices in many children with low-grade focal brainstem gliomas. Radiation treatment is often reserved for disease progression but offers comparable disease control following biopsy. In the authors' experience, combining an assessment of clinical course, imaging, and tumor biopsy yields a reasonable model for managing children with focal brainstem tumors.

Favorable outcome with conservative treatment for children with low grade brainstem tumors

BACKGROUND

Pediatric brainstem tumors (BST) comprise a heterogeneous group of entities. Data regarding treatment options and outcome of BST, specifically brainstem low grade tumors (BSLGT) are limited. In order to better define risk groups and evaluate treatment options for pediatric BST, we performed a comprehensive analysis of all BST patients treated in our hospital during the MRI era.

PROCEDURES

We retrospectively analyzed clinical, imaging, and pathology data at presentation, treatment, and outcome of all BST patients followed at the Hospital for Sick Children in Toronto over the last 25 years.

RESULTS

Of 1,801 children with brain tumors, 223 (12%) had a brainstem primary location. Tumors without pontine involvement were BSLGT in 98.3%, whereas 75% of tumors involving the pons were high grade (P = 0.0001). Patients with BSLGT had 5-year progression-free survival (PFS) and overall survival (OS) of 57 ± 3% and 89 ± 5%, respectively. Upfront observation of tumor residual conferred no survival disadvantage with 5-year PFS and OS of 57 ± 5% and 93 ± 3%, respectively. In the group of patients requiring further treatment, 5-year PFS and OS were comparable between chemotherapy and radiotherapy with 53 ± 12% and 93 ± 4% and 66 ± 11% and 83 ± 6%, respectively (P = 0.26 and 0.3, respectively).

CONCLUSION

BST without pontine involvement are almost invariably BSLGT. Children with BSLGT have an excellent outcome even with careful initial observation. No clear benefit was observed for radiotherapy over chemotherapy when adjuvant treatment was needed. A conservative approach may be warranted for children with non-pontine brainstem lesions.

Neoplasms associated with germline and somatic NF1 gene mutations

INTRODUCTION

Neurofibromatosis 1 is a tumor predisposition genetic syndrome with autosomal dominant inheritance and virtually 100% penetrance by the age of 5 years. NF1 results from a loss-of-function mutation in the NF1 gene, resulting in decreased levels of neurofibromin in the cell. Neurofibromin is a negative regulator of various intracellular signaling pathways involved in the cellular proliferation. Although the loss of heterozygosity in the NF1 gene may predispose NF1 patients to certain malignancies, additional genetic alterations are a prerequisite for their development. The precise nature of these additional genetic alterations is not well defined, and genetic testing of all malignancies in NF1 patients becomes an essential component of future research in this subset of patients. In addition to germline NF1 mutations, alteration of the somatic NF1 gene is associated with sporadic malignancies such as adenocarcinoma of the colon, myelodysplastic syndrome, and anaplastic astrocytoma.

MATERIALS AND METHODS

A comprehensive English and non-English language search for all articles pertinent to malignancies associated with NF1 was conducted using PubMed, a search engine provided by the U.S. National Library of Medicine and the National Institutes of Health. Key words searched included the following: "malignancies associated with NF1", "tumors associated with NF1", and "NF1 and malignancies". A comprehensive analysis in terms age and mode of presentation, investigation and therapeutic modalities, and outcome of the published data was performed and compared with similar information on the sporadic cases.

RESULTS

Malignancies in NF1 patients typically occur at an earlier age and, with an exception of optic pathway gliomas, certain types of malignancies carry a poor prognosis compared with their sporadic counterparts. Malignancies are the leading cause of death in NF1 patients, resulting in a 10- to 15-year decreased life expectancy compared with the general population.

CONCLUSIONS

The lack of well-defined screening tests for early detection and the nonspecific clinical presentation contributes to a poorer outcome in malignancies associated with NF1. Small study group size, mixed patient population, and a lack of uniformity in reporting research results make comparison of treatment outcome for this group difficult. An International Consensus Meeting to address and recommend best practices for screening, diagnosis, management, and follow-up of malignancies associated with NF1 is needed.

Proton magnetic resonance spectroscopy predicts survival in children with diffuse intrinsic pontine glioma

Patients with diffuse intrinsic pontine glioma (DIPG) face a grim prognosis with limited treatment options. Many patients will enroll on investigational trials though the role of chemotherapy or immunotherapy is unclear. Radiographic changes on conventional MRI are used to evaluate tumor response and progression, but are not predictive of outcome in these patients. More sensitive measures of tumor biology are needed to improve patient management. We evaluated changes in magnetic resonance spectroscopy (MRS) biomarkers in patients with DIPG. Thirty-eight patients were enrolled prospectively on an IRB-approved protocol, which included standard MRI, single voxel spectroscopy (SVS) and multi-slice multi-voxel spectroscopy (MRSI). Scans were performed at multiple time points during each patient's clinical course, with a total of 142 scans. The prognostic values of Choline:N-acetylaspartate (Cho:NAA), Cho:Creatine (Cho:Cr) and the presence of lactate and lipids (+Lac/Lip) were evaluated. Cho:NAA and variance in Cho:NAA values among different voxels within a tumor were each predictive of shorter survival. This prospective study shows that MRS can be used to identify high-risk patients and monitor changes in tumor metabolism, which may reflect changes in tumor behavior.

Hydrocephalus with brain tumors in children

BACKGROUND

Tumor-associated hydrocephalus is common in primary pediatric brain tumors. The managements involve radical tumor resection, temporary external ventricular drainage, and different definite shunting procedures. The purpose of this study is to sum up our experience of definite shunting procedures for tumoral hydrocephalus in children and correlate with reported literatures.

METHODS

This is a retrospective review of a series of 1,250 cases of primary pediatric brain tumors in patients <18 years of age collected in Taipei Veterans General Hospital from 1971 to 2008. Cases with questionable records about hydrocephalus were excluded.

RESULTS

A total of 56.7% of cases presented hydrocephalus, including hydrocephalus that occurred at tumor diagnosis (51.5%), and hydrocephalus developed after tumor diagnosis (5.1%). At tumor diagnosis, the hydrocephalus was mainly obstructive type (98%) and rarely communicating type (1.9%). Definite shunting procedures in this series comprised of ventriculoperitoneal (VP) shunt in 54.4%, endoscopic third ventriculostomy (ETV) in 10.9%, subduroperitoneal (SP) shunt in 4.8%, septostomy in 0.7%, lumboperitoneal shunt in 0.6%, and ventriculoatrial shunt in 0.1% of patients with hydrocephalus. There was a tendency of decreasing requirement and changing timing for VP shunt implantation. There was a gradual increase in usage of ETV for hydrocephalus in specific types and locations of tumors.

CONCLUSION

In the past two decades, we tended to use the VP shunt more cautiously for obstructive tumoral hydrocephalus. We try to perform initial radical resection of tumors as indicated and the more frequent use of ETV in selective cases that help to decrease the requirement of VP shunt implantation.

Tectal plate glioblastoma multiforme

BACKGROUND

Tectal plate tumors have traditionally been considered low-grade, indolent lesions. We report a patient who presented with a tectal region glioblastoma multiforme (GBM), a rare pathology in this anatomic location.

CASE DESCRIPTION

This is a case report of a 45-year-old female that presented with worsening confusion, memory loss, and loss of bladder control for 3 days. There was no family history of brain malignancy. The patient presented with Parinaud's phenomenon. Pronator drift was not present. The patient had dysarthric speech. An elevated white blood cell count was also noted. Non-contrast CT scan of the head showed the presence of a tectal region mass and hydrocephalus. A follow-up MRI with and without contrast confirmed the presence of a 4.2 × 3.3 × 4.6 cm(3) mass. Magnetic Resonance Spectroscopy (MRS) demonstrated an elevated choline/N-acetylaspartate ratio and an increase in lactate suggesting an aggressive neoplasm. A ventriculoperitoneal shunt was initially placed to relieve the hydrocephalus. The patient subsequently underwent a suboccipital craniotomy for debulking of tumor and for tissue diagnosis. Pathology of the lesion was consistent with GBM. The patient declined postoperative treatment with chemotherapy and radiation.

CONCLUSION

Although tectal region masses are predominantly low-grade lesions, high-grade lesions can present in this anatomical location. Furthermore, MRS can help to differentiate benign lesions from more aggressive lesions in the tectal plate. Biopsy of tectal plate lesions should be considered in select cases to establish diagnosis and prognosis in order to optimize treatment.

Magnetic resonance spectroscopic detection of lactate is predictive of a poor prognosis in patients with diffuse intrinsic pontine glioma

Diffuse brainstem glioma has a poor prognosis, and there are few long-term survivors. We looked for clinical, conventional magnetic resonance (MR), and MR spectroscopic (MRS) findings predictive of the prognosis of patients with brainstem glioma. Our institutional review board approved this retrospective study of 23 patients with diffuse intrinsic pontine or diffuse medullary brainstem glioma treated during the period 2000-2009. To evaluate prognostic values, we performed a Kaplan-Meier survival analysis (log-rank test) that incorporated the patients' age and sex, symptom duration, the presence or absence of cranial nerve palsy, long tract sign, ataxia, and cysts, the chemotherapeutic regimen, Gd enhancement, longitudinal and cerebellar extension, basilar artery encasement, and MRS parameters. Of the 23 diffuse brainstem gliomas, 19 were located at the pons (ratio of male to female patients, 1.1:1). The mean age of the 23 patients was 15.9 years (range, 4-50 years); 16 were aged <20 years. The duration of overall survival was 19.7 months; in patients with diffuse intrinsic pontine glioma, it was 16.6 months, and in patients aged <20 years, it was 11.8 months. Clinical and conventional MR findings at presentation were not predictive of the prognosis in children with diffuse intrinsic pontine glioma. In addition, a patient age <20 years and the detection of lactate by MRS were poor prognostic factors. The MRS detection of lactate is a prognostic factor in patients with diffuse intrinsic pontine glioma. Additional studies of larger patient populations using other imaging modalities are needed.

MRI as a central component of clinical trials analysis in brainstem glioma: a report from the Pediatric Brain Tumor Consortium (PBTC)

We report MRI findings from 2 pediatric clinical trials of diffuse intrinsic brainstem glioma (BSG) incorporating concurrent radiation therapy (RT) with molecularly targeted agents (gefitinib and tipifarnib). We determined associations of MRI variables with progression-free survival and overall survival and investigated effects of treatment on these variables. MRI (including diffusion and perfusion) was done before treatment, every 8 weeks (first year), every 12 weeks (thereafter), and at the end of treatment or disease progression. Reduced tumor volume (P < .0001) and tumor diffusion values (P <.0001) were apparent on the first post-RT/drug studies. Decreases in tumor volume correlated with pre-RT volume (P < .0001) and pre-RT diffusion values (P < .0001); larger decreases were noted for tumors with higher volumes and diffusion values. Patients with larger pre-RT tumors had longer progression-free survival (P < .0001). Patients with ≥ 25% decrease in tumor volume and diffusion values after RT had longer progression-free survival (P = .028) and overall survival (P = .0009). Enhancement at baseline and over time was significantly associated with shorter survival. Tumor diffusion values with baseline enhancement were significantly lower than those without (P = .0002). RT of BSG is associated with decreased tumor volume and intralesional diffusion values; patients with ≥ 25% decrease in values post-RT had relatively longer survival intervals, apparently providing an early imaging-based surrogate for relative outcomes. Patients with larger tumors and greater decreases in tumor volume and diffusion values had longer survival intervals. Tumor enhancement was associated with shorter survival, lower tumor diffusion values (increased cellularity), and a smaller drop in diffusion values after RT (P = .006). These associations justify continued investigation in other large clinical trials of brainstem glioma patients.

The ecology of brain tumors: lessons learned from neurofibromatosis-1

Traditionally, cancer studies have primarily focused on mutations that activate growth or survival pathways in susceptible pre-neoplastic/neoplastic cells. However, recent research has revealed a critical role for non-neoplastic cells within the tumor microenvironment in the process of cancer formation and progression. In addition, the existence of regional and developmental variations in susceptible cell types and supportive microenvironments support a model of tumorigenesis in which the dynamic symbiotic relationship between neoplastic and non-neoplastic cell types dictate where and when cancers form and grow. In this review, we highlight advances in neurofibromatosis type 1 (NF1) genetically engineered mouse brain tumor (glioma) modeling to reveal how cellular and molecular heterogeneity in both the pre-neoplastic/neoplastic and non-neoplastic cellular compartments contribute to gliomagenesis and glioma growth.

Differential diagnosis of T2 hyperintense brainstem lesions: Part 2. Diffuse lesions

Diffuse brainstem lesions are poorly defined, often large abnormalities and include tumors (gliomas and lymphomas) vasculitis (Behçet's disease), traumatic brainstem injury, degenerative disorders (Wallerian degeneration), infections, processes secondary to systemic conditions (central pontine myelinolysis, hypertensive or hepatic encephalopathy), and ischemic pathology (leukoaraiosis). Magnetic resonance imaging is the most appropriate imaging modality to use in evaluating lesions of this type, but often findings are nonspecific. Therefore, radiologists need to bear in mind such additional information as patient age and clinical features in making a differential diagnosis.