Management of Optic Pathway Glioma: A Systematic Review and Meta-Analysis

Background: OPG accounts for 3−5% of childhood central nervous system (CNS) tumors and about 2% of pediatric glial lesions. Methods: Article selection was performed by searching PubMed, Web of Science, and Cochrane databases. Results: The pooled mortality rate was 0.12 (95%CI 0.09−0.14). Due to the unrepresentative data, improved and not changed outcomes were classified as favorable outcomes and worsened as unfavorable. Meta-analyses were performed to determine the rate of clinical and radiological favorable outcomes. In terms of visual assessment, the pooled rate of a favorable outcome in chemotherapy, radiotherapy, and surgery was 0.74, 0.81, and 0.65, respectively, and the overall pooled rate of the favorable outcome was 0.75 (95%CI 0.70−0.80). In terms of radiological assessment, the rate of a favorable outcome following chemotherapy, radiotherapy, and surgery was 0.71, 0.74, and 0.67, respectively, and the overall pooled rate of the favorable outcome is 0.71 (95%CI 0.65−0.77). The subgroup analysis revealed no significant difference in the rate of clinical and radiological favorable outcomes between the different treatment modalities (p > 0.05). Conclusion: Our analyses showed that each therapeutic modality represents viable treatment options to achieve remission for these patients.

Bevacizumab for optic pathway glioma with worsening visual field in absence of imaging progression: 2 case reports and literature review

Children with optic pathway gliomas (OPGs) frequently suffer from problems of visual function resulting from tumors. Previous reports showed that bevacizumab improved visual function in patients with OPG via tumor response to treatment. In these two case reports, we show that bevacizumab improved visual field without tumor response as seen in imaging. Both, a 10-year-old girl and a 6-year-old boy, had previous history of treatment with platinum-based chemotherapy. They had visual deterioration without tumor progression on MR imaging. Bevacizumab effectively and immediately improved visual field in both patients without imaging response of OPG. We emphasize that bevacizumab should be considered for patients with OPGs having visual deterioration without tumor progression.

MicroRNA profile of pediatric pilocytic astrocytomas identifies two tumor-specific signatures when compared to non-neoplastic white matter

PURPOSES

Pilocytic astrocytoma (PA) is a low-grade neoplasm frequently found in childhood. PA is characterized by slow growth and a relatively good prognosis. Genetic mechanisms such as activation of MAPK, BRAF gene deregulation and neurofibromatosis type 1 (NF1) syndrome have been associated with PA development. Epigenetic signature and miRNA expression profile are providing new insights about different types of tumor, including PAs.

METHODS

In the present study we evaluated global miRNA expression in 16 microdissected pediatric PA specimens, three NF1-associated PAs and 11 cerebral white matter (WM) samples by the microarray method. An additional cohort of 20 PAs was used to validate by qRT-PCR the expression of six miRNAs differentially expressed in the microarray data.

RESULTS

Unsupervised hierarchical clustering analysis distinguished one cluster with nine PAs, including all NF1 cases and a second group consisting of the WM samples and seven PAs. Among 88 differentially expressed miRNAs between PAs and WM samples, the most underexpressed ones regulate classical pathways of tumorigenesis, while the most overexpressed miRNAs are related to pathways such as focal adhesion, P53 signaling pathway and gliomagenesis. The PAs/NF1 presented a subset of underexpressed miRNAs, which was also associated with known deregulated pathways in cancer such as cell cycle and hippo pathway.

CONCLUSIONS

In summary, our data demonstrate that PA harbors at least two distinct miRNA signatures, including a subgroup of patients with NF1/PA lesions.

Pediatric Optic Pathway/Hypothalamic Glioma

Optic pathway/hypothalamic gliomas (OP/HGs) are rare astrocytic tumors that appear more commonly among young children and often are unresectable. They comprise approximately 2% of all central nervous system tumors and account for 3–5% of pediatric intracranial tumors. Initial manifestations are often visual disturbances, endocrinopathies and hypothalamic dysfunction such as the diencephalic syndrome, and sometimes hydrocephalus due to cerebrospinal fluid (CSF) outflow obstruction. In many cases, the tumors are diagnosed late in the clinical course because they silently enlarge. These tumors consist mostly of histologically benign, World Health Organization (WHO) grade I tumors represented by pilocytic astrocytomas (PA), the rest being pilomyxoid astrocytomas (PXA) – WHO grade II tumors. In young pediatric patients, however, can be seen PXA that show aggressive clinical course such as CSF dissemination. Our small series of 14 non-Neurofibromatosis type 1 (NF-1) OP/HGs PA patients underwent extended resection without any adjuvant treatments. The median age at initial treatment was 11.5 ± 6.90 years (range, 1–25 years) and median follow up 85.5 ± 25.0 months. Surgical resection for OP/HGs results in acceptable middle-term survival, tumor control and functional outcome equivalent to chemotherapy. There is, however, no longer doubt that chemotherapy with or without biopsy and as-needed debulking surgery remains the golden standard in management of OP/H. Clinical conditions and treatment plans for OP/HGs vary depending on their structure of origin.

Pediatric low-grade gliomas: how modern biology reshapes the clinical field

Low-grade gliomas represent the most frequent brain tumors arising during childhood. They are characterized by a broad and heterogeneous group of tumors that are currently classified by the WHO according to their morphological appearance. Here we review the clinical features of these tumors, current therapeutic strategies and the recent discovery of genomic alterations characteristic to these tumors. We further explore how these recent biological findings stand to transform the treatment for these tumors and impact the diagnostic criteria for pediatric low-grade gliomas.

Sustained response to weekly vinblastine in 2 children with pilomyxoid astrocytoma associated with diencephalic syndrome

Diencephalic syndrome (DS) related to hypothalamic/chiasmatic region tumor has mainly been reported with low-grade glioma. We described 2 young children with DS related to pilomyxoid astrocytoma. Despite the recognized more agressive clinical behavior of this histologic subtype, we report successful resolution of DS and sustained tumor response with prolonged use of single-agent vinblastine.

Stereotactic brachytherapy with iodine-125 seeds for the treatment of inoperable low-grade gliomas in children: long-term outcome

PURPOSE

Resection is generally considered the gold standard for treatment of low-grade (WHO grades I and II) gliomas (LGGs) in childhood. However, approximately 30% to 50% of these tumors are inoperable because of their localization in highly eloquent brain areas. A few reports have suggested stereotactic brachytherapy (SBT) with implantation of iodine-125 ((125)I) seeds as a safe and effective local treatment alternative. This single-center study provides a summary of the long-term outcome after SBT in one of the largest reported patient series.

PATIENTS AND METHODS

All pediatric patients treated with SBT ((125)I seeds; cumulative therapeutic dose 50-65 Gy within 9 months) by our group for LGG with follow-up of more than 6 months were included. Clinical and radiologic outcome, time to progression, and overall survival were evaluated. Prognostic factors (age, sex, Karnofsky performance score, tumor volume, and histology) for survival and disease progression were investigated.

RESULTS

In all, 147 of 160 pediatric patients treated with SBT (from 1982 through 2009) were analyzed in detail. Procedure-related mortality was zero, and the 30-day morbidity was transient and low (5.4%). Survival rates at 5 and 10 years were 93%, and 82%, respectively, with no significant difference between WHO grades I and II tumors (median follow-up, 67.1 ± 57.7 months). Twenty-one (14.8%) of 147 patients presented with tumor relapse. The remaining 126 patients revealed complete response in 24.6%, partial response in 31.0%, and stable disease in 29.6%. Neurologic status improved (57.8%) or remained stable (23.0%). None of the evaluated factors had significant impact on the study's end points except tumor volume more than 15 mL, which caused significantly higher rates of tumor recurrence (P < .05).

CONCLUSION

We demonstrate that SBT represents a safe, minimally invasive, and highly effective local treatment option for pediatric patients with inoperable LGG WHO grades I and II.

Visual outcome following chemotherapy for progressive optic pathway gliomas

BACKGROUND

Optic pathway gliomas (OPG) are relatively indolent tumors that may occur sporadically or in association with neurofibromatosis 1. Treatment is initiated only when a clear clinical or radiological deterioration is documented. Chemotherapy is the standard first line of treatment. Due to the indolent nature of this tumor, the most important challenge in OPG treatment is vision preservation.

METHODS

In this study we determined the visual outcome of 19 patients with progressive OPGs who received chemotherapy and correlated it with imaging.

RESULTS

Mean neuro-ophthalmological follow-up is 4 years and 3 months. Indications for treatment were radiological tumor progression (6 patients), visual decline (6 patients), or both (7 patients). Fifteen patients (78%) had to change to 2nd line chemotherapy (7 due to allergies and 8 due to treatment failure). During the course of chemotherapy, 11 patients (57.8%) displayed radiological tumor progression, 4 (21.5%) demonstrated stable tumor, and 4 (21.5%) displayed tumor regression. During the follow-up period, 14 (73.6%) had an overall visual deterioration, 4 (21%) had stable vision, and 1 patient (5.2%) improved. Visual acuity was examined in 38 eyes. Seventeen eyes (47.2%) deteriorated, fourteen (38.8%) were stable, and five (13.8%) improved. Ten eyes (27.7%) deteriorated to legal blindness. There was no correlation between radiological tumor growth and visual deterioration.

CONCLUSIONS

The majority of our patients, who received chemotherapy for progressive OPG, experienced a decline in their visual function. New, more effective treatments are needed in order to preserve vision in this group.