Management of optic-hypothalamic gliomas in children: still a challenging problem

Impact of Childhood Cancer on Growth

Along with improvements in cancer treatment over time, the number of childhood cancer survivors has been growing. Survivors are at risk for serious medical complications, and growth impairment is among the most common. There are multiple factors that may cause impaired growth among survivors. In this article, we review the impact of cancer on growth in children and adolescents. We first provide an overview of growth disturbance among childhood cancer patients and survivors due to nonhormonal causes, including a recent understanding of the effect of targeted cancer therapies (eg, tyrosine kinase inhibitors and immune checkpoint inhibitors) on growth. Then we describe the hormonal causes of growth impairment among survivors, focusing on growth hormone deficiency, including the prevalence, risk factors, and treatment. Lastly, we briefly summarize overgrowth and tall stature in childhood cancer. It is critical to assess the linear growth of children and adolescents, especially in cancer survivors who are at risk for growth disturbance, since growth is an important measure of their health.

Optic Pathway Gliomas: The Trends of Basic Research to Reduce the Impact of the Disease on Visual Function

Pediatric optic pathway gliomas (OPG) are low-grade brain tumors characterized by slow progression and invalidating visual loss. Common therapeutic strategies include surgery, radiotherapy, chemotherapy, and combinations of these modalities, but despite the different treatment strategies, no actual treatment exists to prevent or revert visual impairment. Nowadays, several reports of the literature show promising results regarding NGF eye drop instillation and improvement of visual outcome. Such results seem to be related with the NGF-linked prevention in caspase activation, which reduces retinal ganglion cell loss.Reducing retinal ganglion cell loss results clinically in visual field improvement as well as visual electric potential and optical coherence tomography gain. Nonetheless, visual acuity fails to show significant changes.Visual impairment represents nowadays one of the major issues in dealing with OPGs. Secondary to the interesting results offered by NGF eye drop administration, further studies are warranted to better comprehend potential treatment strategies.

Rethinking the Management of Optic Pathway Gliomas: A Single Center Experience

Background

Optic pathway gliomas (OPGs) are rare neoplasms in children with an unpredictable clinical course. Approximately 15% of OPGs occur in patients affected by neurofibromatosis type 1 (NF1): the clinical course of these cases is more indolently than sporadic ones, and NF1 patients less frequently require treatment including surgery. Instead, over 90% of sporadic OPGs require one or more therapeutic approaches. The management of OPG is controversial. They are also characterized by a high risk of morbidity including hypothalamic damage, endocrine deficits, visual deficit and/or neurological impairment.

Materials and Methods

In this paper, we evaluated visual and endocrinological outcomes of a population of OPG followed at our center from 2013 to 2021, with a particular emphasis on the role of surgery.

Results

Twenty-six patients were included in this study (mean age of 40.7 months). Tumor location on imaging was described by the Dodge classification. Five cases had NF 1. Thirteen cases received biopsy and 13 were partially resected. Histopathology revealed 19 cases of pilocytic astrocytomas, 2 pilomyxoid astrocytoma and 5 ganglioglioma. All the patients required a post-surgical adjuvant treatment according to current indications for low-grade gliomas. Molecular studies (BRAF status and mTOR/pmTOR pathway) have been performed in 24/26 patients, following for the use of target therapy in 11 of these patients. In our study we found that patients underwent biopsy have a better visual and endocrinological outcomes rather than patients with a tumor debulking. The five-year overall survival rate is 98% with a mean follow-up of 60 months.

Conclusions

Many children with OPGs survive with a residual tumor. They suffer from chronic diseases such as endocrine dysfunction, visual disturbance, motor deficits and poor quality of life. All patients need comprehensive diagnostic work-up including neuroimaging, clinical evaluations and neuropathology approach; at the same time, they need therapeutic decisions and concepts for the choice of timing and type of neurosurgical intervention, chemotherapy and target therapy as well as surveillance and rehabilitation to maximize survival and overall functional outcomes. Our study showed that minimal invasive surgery with the purpose of molecular characterization of the tumor is desirable to reduce morbidity correlate to surgery.

Monomodality versus Combined Therapy in Optic Pathway Gliomas—20-Year Experience from a Singapore Children’s Hospital

Introduction

The treatment of pediatric optic pathway gliomas (OPG) is challenging. At present, most centers provide individualized treatment to maximize progression free survival (PFS) and minimize morbidity. We aim to report our experience in the management of pediatric OPG, and investigate factors associated with an increased duration of remission after treatment.

Methods

This is a single-institution study approved by the hospital ethics board. A retrospective review of consecutive OPGs managed from 2000 to 2020 was performed. Patients were divided into those managed with monomodality treatment (MT) and those who received combined therapy (CT). MT included various forms of surgery, chemotherapy and radiotherapy given alone, while CT involves a combination of surgery and adjuvant chemotherapy and/or radiotherapy.

Results

Twenty-two patients were selected for this study. They had 40 treatment cycles; and a total follow up duration of 194.8 patient-years. Most of them were male (63.6%) and presented with visual deficits (72.7%). The mean age at initial presentation was 65 months and majority (86.4%) had their tumors arising directly from the optic chiasm, with 77.3% with hypothalamic extension. One patient had Neurofibromatosis type I (4.5%). The most common histological diagnosis was pilocytic astrocytoma (90.9%), followed by pilomyxoid astrocytoma (9.1%). The 5- and 10- year PFS were 46.2% and 36.4% respectively, while the 5- and 10-year OS were both 100%. When accounting for treatment type, there were 24 treatment cycles with MT (60.0%) and 16 CT (40.0%). After adjustment, treatments with MT were shown to have a shorter mean duration of remission (MT: 45 ± 49, CT: 84 ± 79 months; p = 0.007). Cox regression curve plotted after adjusting for patient’s age at treatment demonstrated a significantly longer PFS in the CT group (p = 0.037).

Conclusions

Our results suggest a significant survival benefit of CT over MT for affected patients due to the prolonged the duration of disease remission, for both primary and subsequent treatments. Nonetheless, we acknowledge that our study reflects the outcomes of treatment strategies that have evolved over time. We emphasize the need for collective efforts from a dedicated multidisciplinary team and international collaborations for better disease understanding.

The role of imaging features and resection status in the survival outcome of sporadic optic pathway glioma children receiving different adjuvant treatments

Optic pathway glioma (OPG) is a rare brain tumor affecting children, with no standard treatment strategy. This study described the sporadic OPG survival outcomes after surgical treatment and analyzed the role of imaging features and resection status in children receiving different adjuvant treatments. This retrospective study included 165 OPG patients whose clinical information were obtained from the hospital record system. Tumor volume and residual tumor volume were calculated by delineating the lesion area. Kaplan-Meier method and Cox proportional hazards model were conducted to analyze the independent prognosis factor. A total of 165 patients were included in this study. Respectively, the 5-year overall survival (OS) and progression-free survival (PFS) were 87.58% and 77.87%. Residual tumor size and first adjuvant treatment (AT) after surgery were both associated with PFS. In patients with small-size residual tumors, there was no significant difference in PFS between the AT treatment groups. Moreover, age, exophytic cystic components, leptomeningeal metastases, and AT were associated with OS. In patients with exophytic cystic components and those with leptomeningeal metastases, there was no significant difference in OS. Our results revealed that OPG patients could avoid or defer AT by maximized resection. Age ≤ 2 years was a disadvantageous factor for OS. Patients with exophytic cystic components were more likely to benefit from primary surgery, and CT or RT was not beneficial for these patients. Patients with leptomeningeal metastases had a poor prognosis regardless of the treatment they received. Future prospective clinical studies are needed to develop more effective treatment regimens.

Treatment with endoscopic transnasal resection of hypothalamic pilocytic astrocytomas: a single-center experience

Backgrounds

Pilocytic astrocytomas (PAs) are World Health Organization (WHO) grade I tumors, which are relatively common, and are benign lesions in children. PAs could originate from the cerebellum, optic pathways, and third ventricular/hypothalamic region. Traditional various transcranial routes are used for hypothalamic PAs (HPAs). However, there are few studies on hypothalamic PAs treated through the endoscopic endonasal approach (EEA). This study reports the preliminary experience of the investigators and results with HPAs via expanded EEAs.

Methods

All patients with HPAs, undergone EEA in our hospital from 2017 to 2019, were retrospectively reviewed. The demographic data, clinical symptoms, complications, skull base reconstruction, prognosis, and endocrinological data were all recorded and analyzed in detail.

Results

Finally, five female patients were enrolled. The average age of patients was 28.6 ± 14.0. All patients had complaints about their menstrual disorder. One patient had severe bilateral visual impairment. Furthermore, only one patient suffered from severe headache due to acute hydrocephalus, although there were four patients with headache or dizziness. Four cases achieved gross-total resection, and one patient achieved subtotal resection. Furthermore, there was visual improvement in one patient (case 5), and postoperative worsening of vision in one patient (case 4). However, only one patient had postoperative intracranial infection. None of the patients experienced a postoperative CSF leak, and in situ bone flap (ISBF) techniques were used for two cases for skull base repair. In particular, ISBF combined with free middle turbinate mucosal flap was used for case 5. After three years of follow-up, three patients are still alive, two patients had no neurological or visual symptoms, or tumor recurrence, and one patient had severe hypothalamic dysfunction. Unfortunately, one patient died of severe postoperative hypothalamus reaction, which presented with coma, high fever, diabetes insipidus, hypernatremia and intracranial infection. The other patient died of recurrent severe pancreatitis at one year after the operation.

Conclusion

Although the data is still very limited and preliminary, EEA provides a direct approach to HPAs with acceptable prognosis in terms of tumor resection, endocrinological and visual outcomes. ISBF technique is safe and reliable for skull base reconstruction.

Dual activating FGFR1 mutations in pediatric pilomyxoid astrocytoma

BACKGROUND

Pilomyxoid astrocytomas are an aggressive subtype of astrocytoma, not graded by WHO, frequently located in hypothalamic/chiasmatic region, affecting diencephalic structures, and characterized by shorter survival and high recurrence rates. Pilomyxoid astrocytoma management remains controversial, with pathologic tissue diagnosis and relief of mass effect being the main goals of surgery while avoiding treatment-related morbidity, including vision loss, panhypopituitarism, and hypothalamic dysfunction. Chemotherapy (typically vincristine and carboplatin) in all pediatric patients and radiation therapy in pediatric patients over 5 years of age are used for treatment.

METHODS

We report clinical presentation, surgical management, and whole exome sequencing results in a pediatric patient with the subtotally resected pilomyxoid astrocytoma.

RESULTS

We identified two somatic activating missense mutations affecting FGFR1, including FGFR1 p.K656E and FGFR1 p.V561M. While the former is a known hotspot mutation that is both activating and transforming, the latter has been described as a gatekeeper mutation imparting resistance to FGFR inhibitors. Interestingly, both mutations were present with similar variant allele frequency within the tumor.

CONCLUSION

Similar variant allele frequencies of FGFR1 p.K656E and FGFR1 p.V561M mutations in our patient's tumor suggest that these mutations may have occurred at similar time points. Use of FGFR inhibitors in addition to STAT3 or PI3K/mTOR inhibition may prove a useful strategy in targeting our patient's pilomyxoid astrocytoma.

Optic pathway tumor in children: Toward a new classification for neurosurgical use

OBJECT

Optic pathway tumors (OPT) represent a challenge for pediatric neurosurgeons. Role of surgery is debated due to the high risk of iatrogenic damage, and in lasts decades it lost its importance in favor of chemotherapy. However, in some cases surgery is necessary to make biomolecular and histological diagnosis, to manage intracranial hypertension (IH) and to cooperate with medical therapies in controlling tumor relapse. With the aim to standardize selection of surgical OPT cases, we propose a simple, practical and reproducible classification.

METHODS

We retrospectively analyzed data of 38 patients with OPT treated at our institution (1990-2018). After careful analysis of MRI images, we describe a new classification system. Group 1: lesion limited to one or both optic nerve(s). Group 2: chiasmatic lesions extending minimally to hypothalamus. Group 3: hypothalamo-chiasmatic exophitic lesions invading the third ventricle; they can be further divided on the base of concomitant hydrocephalus. Group 4: hypothalamo-chiasmatic lesions extending widely in lateral direction, toward the temporal or the frontal lobes. Patients' data and adopted treatment are reported and analyzed, also depending on this classification.

RESULTS

Twenty children were operated on for treatment of OPT during the study period. Permanent clinical impairment was noted in 5 (25%) of operated patients, while visual improvement was noted in 1 patient. OS rate was 100% at 5 years, with a median follow up of 9 years (ranging from 2 to 23). Prevalence of intracranial hypertension and proportion of first-line surgical treatment decision were significantly higher in groups 3-4 compared to groups 1-2 (P<0.001 for both tests).

CONCLUSION

Surgery can offer a valuable therapeutic complement for OPT without major risk of iatrogenic damage. Surgery is indispensable in cases presenting with IH, as in groups 3 and 4 lesions. Eligibility of patients to surgery can be based on this new classification system.

The Visual Acuity Outcome and Relevant Factors Affecting Visual Improvement in Pediatric Sporadic Chiasmatic-Hypothalamic Glioma Patients Who Received Surgery

Background: The role and effectiveness of primary surgical treatment for sporadic chiasmatic–hypothalamic glioma (CHG) are not clear. The present study was to describe sporadic CHG visual acuity (VA) outcomes after surgery and to analyze the relevant factors affecting VA improvement.

Methods: Forty-five pediatric sporadic CHG patients who met the inclusion criteria were included in a retrospective study. All patients received primary intratumor partial resection. Disease characteristics, treatment strategies, complications, and VA outcome were analyzed. Univariate and multivariate analyses were performed to identify relevant factors of VA improvement. Receiver operating characteristic (ROC) analysis was performed to evaluate the predictive accuracy of measurement indexes.

Results: There were 77 eyes of 45 children suffering from various levels of VA impairment before surgical treatment, and only 13 eyes had normal vision. Patients with resection extents >70, 50–70, and <50% accounted for 26.67, 24.44, and 48.89%, respectively. The percentages of VA maintained and deteriorated in normal vision eyes were 61.54 and 38.46%. The percentages of VA improved, maintained, and deteriorated in visually impaired eyes after surgery were 29.87, 45.45, and 24.68%, respectively. There was a positive correlation between the IVA level and VA improvement. There was no significant difference in VA improvement between the different resection extents. Blindness occurred in ~4.4%. Approximately 11.1% of the children had complications that affected quality of life, which correlated with resection extent. IVA and tumor size were correlated with VA improvement. The AUC for IVA + tumor size predicting VA improvement was 0.831. The cutoff points for IVA level and tumor volume were 4.5 and 43.50 cm³, respectively.

Conclusions: IVA and tumor size were correlated with VA improvement after primary intratumor partial resection. Children with IVA ≥ level 5 were more likely to achieve visual improvement after decompression surgery, but decompression had limited effectiveness on vision improvement in patients with tumor volumes ≥ 43.50 cm³. Performing resections < 50% was safe and did not reduce the effect of decompression to improve VA.

Brain tumors in Neurofibromatosis type 1

As a cancer predisposition syndrome, individuals with neurofibromatosis type 1 (NF1) are at increased risk for the development of both benign and malignant tumors. One of the most common locations for these cancers is the central nervous system, where low-grade gliomas predominate in children. During early childhood, gliomas affecting the optic pathway are most frequently encountered, whereas gliomas of the brainstem and other locations are observed in slightly older children. In contrast, the majority of gliomas arising in adults with NF1 are malignant cancers, typically glioblastoma, involving the cerebral hemispheres. Our understanding of the pathogenesis of NF1-associated gliomas has been significantly advanced through the use of genetically engineered mice, yielding new targets for therapeutic drug design and evaluation. In addition, Nf1 murine glioma models have served as instructive platforms for defining the cell of origin of these tumors, elucidating the critical role of the tumor microenvironment in determining tumor growth and vision loss, and determining how cancer risk factors (sex, germline NF1 mutation) impact on glioma formation and progression. Moreover, these preclinical models have permitted early phase analysis of promising drugs that reduce tumor growth and attenuate vision loss, as an initial step prior to translation to human clinical trials.

Early and late adverse renal effects after potentially nephrotoxic treatment for childhood cancer

BACKGROUND

Improvements in diagnostics and treatment for paediatric malignancies resulted in a major increase in survival. However, childhood cancer survivors (CCS) are at risk of developing adverse effects caused by multimodal treatment for their malignancy. Nephrotoxicity is a known side effect of several treatments, including cisplatin, carboplatin, ifosfamide, radiotherapy and nephrectomy, and can cause glomerular filtration rate (GFR) impairment, proteinuria, tubulopathy, and hypertension. Evidence about the long-term effects of these treatments on renal function remains inconclusive. It is important to know the risk of, and risk factors for, early and late adverse renal effects, so that ultimately treatment and screening protocols can be adjusted. This review is an update of a previously published Cochrane Review.

OBJECTIVES

To evaluate existing evidence on the effects of potentially nephrotoxic treatment modalities on the prevalence of renal dysfunction in survivors treated for childhood cancer with a median or mean survival of at least one year after cessation of treatment, where possible in comparison with the general population or CCS treated without potentially nephrotoxic treatment. In addition, to evaluate evidence on associated risk factors, such as follow-up duration, age at time of diagnosis and treatment combinations, as well as the effect of doses.

SEARCH METHODS

On 31 March 2017 we searched the following electronic databases: CENTRAL, MEDLINE and Embase. In addition, we screened reference lists of relevant studies and we searched the congress proceedings of the International Society of Pediatric Oncology (SIOP) and The American Society of Pediatric Hematology/Oncology (ASPHO) from 2010 to 2016/2017.

SELECTION CRITERIA

Except for case reports, case series and studies including fewer than 20 participants, we included studies with all study designs that reported on renal function (one year or longer after cessation of treatment), in CCS treated before the age of 21 years with cisplatin, carboplatin, ifosfamide, radiation involving the kidney region, a nephrectomy, or a combination of two or more of these treatments. When not all treatment modalities were described or the study group of interest was unclear, a study was not eligible for the evaluation of prevalence. We still included it for the assessment of risk factors if it had performed a multivariable analysis.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, 'Risk of bias' assessment and data extraction using standardised data collection forms. We performed analyses according to the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

Apart from the remaining 37 studies included from the original review, the search resulted in the inclusion of 24 new studies. In total, we included 61 studies; 46 for prevalence, six for both prevalence and risk factors, and nine not meeting the inclusion criteria, but assessing risk factors. The 52 studies evaluating the prevalence of renal dysfunction included 13,327 participants of interest, of whom at least 4499 underwent renal function testing. The prevalence of adverse renal effects ranged from 0% to 84%. This variation may be due to diversity of included malignancies, received treatments, reported outcome measures, follow-up duration and the methodological quality of available evidence.Seven out of 52 studies, including 244 participants, reported the prevalence of chronic kidney disease, which ranged from 2.4% to 32%.Of these 52 studies, 36 studied a decreased (estimated) GFR, including at least 432 CCS, and found it was present in 0% to 73.7% of participants. One eligible study reported an increased risk of glomerular dysfunction after concomitant treatment with aminoglycosides and vancomycin in CCS receiving total body irradiation (TBI). Four non-eligible studies assessing a total cohort of CCS, found nephrectomy and (high-dose (HD)) ifosfamide as risk factors for decreased GFR. The majority also reported cisplatin as a risk factor. In addition, two non-eligible studies showed an association of a longer follow-up period with glomerular dysfunction.Twenty-two out of 52 studies, including 851 participants, studied proteinuria, which was present in 3.5% to 84% of participants. Risk factors, analysed by three non-eligible studies, included HD cisplatin, (HD) ifosfamide, TBI, and a combination of nephrectomy and abdominal radiotherapy. However, studies were contradictory and incomparable.Eleven out of 52 studies assessed hypophosphataemia or tubular phosphate reabsorption (TPR), or both. Prevalence ranged between 0% and 36.8% for hypophosphataemia in 287 participants, and from 0% to 62.5% for impaired TPR in 246 participants. One non-eligible study investigated risk factors for hypophosphataemia, but could not find any association.Four out of 52 studies, including 128 CCS, assessed the prevalence of hypomagnesaemia, which ranged between 13.2% and 28.6%. Both non-eligible studies investigating risk factors identified cisplatin as a risk factor. Carboplatin, nephrectomy and follow-up time were other reported risk factors.The prevalence of hypertension ranged from 0% to 50% in 2464 participants (30/52 studies). Risk factors reported by one eligible study were older age at screening and abdominal radiotherapy. A non-eligible study also found long follow-up time as risk factor. Three non-eligible studies showed that a higher body mass index increased the risk of hypertension. Treatment-related risk factors were abdominal radiotherapy and TBI, but studies were inconsistent.Because of the profound heterogeneity of the studies, it was not possible to perform meta-analyses. Risk of bias was present in all studies.

AUTHORS' CONCLUSIONS

The prevalence of adverse renal effects after treatment with cisplatin, carboplatin, ifosfamide, radiation therapy involving the kidney region, nephrectomy, or any combination of these, ranged from 0% to 84% depending on the study population, received treatment combination, reported outcome measure, follow-up duration and methodological quality. With currently available evidence, it was not possible to draw solid conclusions regarding the prevalence of, and treatment-related risk factors for, specific adverse renal effects. Future studies should focus on adequate study designs and reporting, including large prospective cohort studies with adequate control groups when possible. In addition, these studies should deploy multivariable risk factor analyses to correct for possible confounding. Next to research concerning known nephrotoxic therapies, exploring nephrotoxicity after new therapeutic agents is advised for future studies. Until more evidence becomes available, CCS should preferably be enrolled into long-term follow-up programmes to monitor their renal function and blood pressure.

Endoscopic transnasal resection of optic pathway pilocytic astrocytoma

PURPOSE

Optic pathway gliomas (OPGs) are low-grade neoplasms that primarily affect children. The management of OPGs remains controversial. Reports on the use of the endoscopic endonasal approach (EEA) in OPGs are extremely limited, and no such reports exist on its utility for pediatric OPGs. Here, we report our results and experience with OPGs treated with the EEA.

METHODS

We retrospectively reviewed the medical records of OPG patients who were treated surgically via the EEA at our institutions from 2015 to 2017. Data on the demographics, clinical presentation, surgical complications, clinical outcomes, radiological imaging, and visual outcomes were recorded for each patient.

RESULTS

Four cases were identified, with visual disturbances being the predominant complaint. The mean patient age was 15.5 years. Three cases showed normal preoperative hormonal profiles, but one patient had hypothyroidism. All tumors identified in this study were World Health Organization grade I pilocytic astrocytomas. Surgical complications included hypopituitarism in two patients, meningitis in two patients, cerebrospinal fluid leak in one patient, and transient diabetes insipidus in one patient. No patient experienced worsening neurological or visual symptoms postoperatively.

CONCLUSIONS

Although our data are preliminary, the EEA provides a direct corridor to OPG with acceptable results in terms of tumor resection and visual outcomes. Hypothalamic-pituitary axis dysfunction remains a limitation of any treatment modality for OPGs and should be considered whenever possible. Definitive conclusions are pending as the learning curve of this approach is steep. Further work is needed to understand patient selection for such an approach.

Pediatric Glioma at the Optic Pathway and Thalamus

Gliomas are the most common pediatric tumors of the central nervous system. In this review, we discuss the clinical features, treatment paradigms, and evolving concepts related to two types of pediatric gliomas affecting two main locations: the optic pathway and thalamus. In particular, we discuss recently revised pathologic classification, which adopting molecular parameter. We believe that our review contribute to the readers' better understanding of pediatric glioma because pediatric glioma differs in many ways from adult glioma according to the newest advances in molecular characterization of this tumor. A better understanding of current and evolving issues in pediatric glioma is needed to ensure effective management decision.

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.

Circadian Alterations in a Murine Model of Hypothalamic Glioma

The mammalian circadian system is controlled by a central oscillator located in the suprachiasmatic nuclei (SCN) of the hypothalamus, in which glia appears to play a prominent role. Gliomas originate from glial cells and are the primary brain tumors with the highest incidence and mortality. Optic pathway/hypothalamic gliomas account for 4–7% of all pediatric intracranial tumors. Given the anatomical location, which compromises both the circadian pacemaker and its photic input pathway, we decided to study whether the presence of gliomas in the hypothalamic region could alter circadian behavioral outputs. Athymic nude mice implanted with LN229 human glioma cells showed an increase in the endogenous period of the circadian clock, which was also less robust in terms of sustaining the free running period throughout 2 weeks of screening. We also found that implanted mice showed a slower resynchronization rate after an abrupt 6 h advance of the light-dark (LD) cycle, advanced phase angle, and a decreased direct effect of light in general activity (masking), indicating that hypothalamic tumors could also affect photic sensitivity of the circadian clock. Our work suggests that hypothalamic gliomas have a clear impact both on the endogenous pacemaking of the circadian system, as well as on the photic synchronization of the clock. These findings strongly suggest that the observation of altered circadian parameters in patients might be of relevance for glioma diagnosis.

Endocrine Long-Term Follow-Up of Children with Neurofibromatosis Type 1 and Optic Pathway Glioma

BACKGROUND/AIMS

Children with optic pathway glioma (OPG) face sequelae related to tumour location and treatment modalities. We aimed to assess the prevalence of hypothalamic-pituitary dysfunctions in children with neurofibromatosis type 1 (NF1) and OPG who did not receive radiotherapy or surgical resection. The causative role of tumour location on endocrinopathy development is investigated.

METHODS

A retrospective follow-up study of 40 children with NF1 and OPG evaluated between August 1996 and May 2015 was undertaken. Patients who underwent radiotherapy or surgical resection were excluded and 36 patients were studied. Tumour location was classified according to the Dodge criteria: stage I, optic nerve alone; stage II, optic chiasm with or without optic nerve involvement; and stage III, involvement of the hypothalamus or other adjacent structures.

RESULTS

Endocrinopathies were diagnosed in 20/36 (55.6%) children during a mean follow-up of 9.1 (0.2-13.6) years: 0/4 OPGs were Dodge stage I, 12/21 (57.1%) stage II, and 8/11 (72.7%) stage III. The first endocrinopathy was found at a mean age of 7.4 (5.0-13.2) years, 2.4 (0-6.7) years after tumour diagnosis. We found growth hormone deficiency (GHD; 36.1%), central precocious puberty (33.3%), obesity with insulin resistance/impaired glucose tolerance (11.1%), early puberty (5.5%), GH excess (5.5%), ACTH deficiency (5.5%), hypogonadotropic hypogonadism (2.7%), and thyrotropin deficiency (2.7%). GHD was transient in all of those who were retested.

CONCLUSION

This population is at high risk of endocrinopathies due to tumour location. Lifelong endocrine follow-up is recommended.
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Spontaneous intratumoural and intraventricular haemorrhage associated with a pilomyxoid astrocytoma in the hypothalamic/chiasmatic region

Pilomyxoid astrocytoma (PMA) is a rare, low-grade glioma that is recognised as a variant of pilocytic astrocytoma. There have been few reports on this pathologic entity presenting with spontaneous haemorrhage. In this study, we report a rare case of PMA in the hypothalamic/chiasmatic region presenting with intratumoural and intraventricular haemorrhage. An external ventricular drain was urgently inserted. A ventriculo-peritoneal shunt (VP) was undergone 4weeks thereafter. The patient received fractionated Gamma Knife radiosurgery in another hospital 3weeks after the VP shunt. Three months later, subtotal resection of the tumour was performed in our hospital via a pterional approach. The pathological diagnosis was PMA. Postoperatively, no adjuvant therapy was given, and the neurologic deficits were improved. However, the presentation of endocrine deficits remained. Notably, PMAs in the hypothalamic/chiasmatic region presenting with massive intratumoural and intraventricular haemorrhage may result in a severe condition and long-term impairment of endocrine function. Long-term follow-up is required to monitor the recurrence of the tumour and endocrinopathy.

The role of early intra-operative MRI in partial resection of optic pathway/hypothalamic gliomas in children

INTRODUCTION

Optic pathway/hypothalamic gliomas (OPHGs) are generally benign but situated in an exquisitely sensitive brain region. They follow an unpredictable course and are usually impossible to resect completely. We present a case series of 10 patients who underwent surgery for OPHGs with the aid of intra-operative MRI (ioMRI). The impact of ioMRI on OPHG resection is presented, and a role for ioMRI in partial resection is discussed.

METHODS

Ten patients with OPHGs managed surgically utilising ioMRI at Alder Hey Children's Hospital between 2010 and 2013 were retrospectively identified. Demographic and relevant clinical data were obtained. MRI was used to estimate tumour volume pre-operatively and post-resection. If ioMRI demonstrated that further resection was possible, second-look surgery, at the discretion of the operating surgeon, was performed, followed by post-operative imaging to establish the final status of resection. Tumour volume was estimated for each MR image using the MRIcron software package.

RESULTS

Control of tumour progression was achieved in all patients. Seven patients had, on table, second-look surgery with significant further tumour resection following ioMRI without any surgically related mortality or morbidity. The median additional quantity of tumour removed following second-look surgery, as a percentage of the initial total volume, was 27.79% (range 11.2-59.2%). The final tumour volume remaining with second-look surgery was 23.96 vs. 33.21% without (p = 0.1).

CONCLUSIONS

OPHGs are technically difficult to resect due to their eloquent location, making them suitable for debulking resection only. IoMRI allows surgical goals to be reassessed intra-operatively following primary resection. Second-look surgery can be performed if possible and necessary and allows significant quantities of extra tumour to be resected safely. Although the clinical significance of additional tumour resection is not yet clear, we suggest that ioMRI is a safe and useful additional tool, to be combined with advanced neuronavigation techniques for partial tumour resection.

Pediatric anterior visual pathway gliomas: trends in fluid and electrolyte dynamics and their management nuances

PURPOSE

Trends in pre- and postoperative fluid, electrolyte and osmolarity changes, and incidence of diabetes insipidus (DI) were assessed in pediatric patients with anterior visual pathway gliomas (AVPGs).

METHODS

Thirty-three patients with AVPGs (age < 16 years) were divided into two groups: (1) no hypothalamic involvement [NHI; n = 17 (51.5 %) including optic (5, 15.2 %); chiasmal (5, 15.2 %); and optico-chiasmal (7, 21.2 %)] and (2) hypothalamic involvement [HI; n = 16 (48.5 %) including chiasmal-hypothalamic (12, 36.4 %) and optico-chiasmal-hypothalamic (4, 12.1 %)]. Frontotemporal transylvian decompression/biopsy was undertaken in 32 patients, while one patient (with severe diencephalic syndrome) was treated conservatively. Their endocrinal and fluid/electrolyte balance, serum osmolarity, and DI status were noted. Chi-square test compared clinical/endocrinological parameters, and unpaired T test evaluated mean daily water/electrolyte changes (p value < 0.05: significant).

RESULTS

Significant visual deterioration (perception of light (PL) positive (left: n = 4; right: n = 4) and PL negative (left: n = 5; right: n = 5) was encountered due to optic atrophy. Larger lesions (>3 cm), hydrocephalus [(NHI: n = 7, 41.18 %; HI: n = 12, 75 %), endocrinopathies (p = 0.047), Na(+)/K(+) derangements, and preoperative DI (n = 8, p = 0.004)] were present in the group HI. Increased postoperative urine output (almost double in those with hypothalamic involvement) and hypernatremia/hyperkalemia were seen in group HI until the sixth postoperative day (p < 0.05). Two patients with progressive hypernatremia without increased urine output showed dehydration on central venous pressure monitoring and improved with vasopressin administration. Five patients [NHI: n = 4 (23.5 %); HI: n = 1 (6.3 %)] had neurofibromatosis types I and 3 (NHI: n = 1, 5.9 %; HI: n = 2, 12.5 %) had a diencephalic syndrome.

CONCLUSIONS

Hypothalamic infiltration significantly increases the incidence of DI and fluid and electrolyte disturbances. Strict vigilance over postoperative fluid balance is mandatory during the first postoperative week. Rapidly rising serial serum sodium values without increased urine output mandates immediate central venous pressure measurement to detect DI associated with dehydration.

Optic pathway gliomas

Optic pathway gliomas (OPGs) are among the most challenging neoplasms in modern pediatric neuro-oncology. Recent technological advances in imaging, surgery, and chemotherapy may lead to better understanding of the pathophysiology and better clinical results. This chapter reviews these advances and the current treatment paradigms.

Familial syndromes associated with intracranial tumours: a review

BACKGROUND

Most cancers of the central nervous system (CNS) occur sporadically in the absence of any known underlying familial disorder or multi-systemic syndrome. Several syndromes are associated with CNS malignancies, however, and their recognition has significant implications for patient management and prognosis. Patients with syndrome-associated CNS malignancies often have multiple tumours (either confined to one region or distributed throughout the body), with similar or different histology.

OBJECTIVE

This review examines syndromes that are strongly associated with CNS cancers: the phakomatosis syndromes, familial syndromes such as Li-Fraumeni and familial polyposis syndromes and dyschondroplasia.

The role of surgery in optic pathway/hypothalamic gliomas in children

OBJECT

Optic pathway/hypothalamic gliomas (OPHGs) are generally benign tumors situated in an exquisitely sensitive brain region. The location and natural history of OPHGs has led to much debate about optimal treatment. This paper revisits the role of and optimal timing of debulking surgery in OPHG.

METHODS

This paper presents a series of cases managed by the neuro-oncology team at Alder Hey Children's Hospital and a single surgeon. Data were collected retrospectively for periods prior to 2009 and prospectively thereafter. Tailored treatment strategies were used, including observation and combinations of surgery, chemotherapy, and radiotherapy. Tumor control rates and outcomes are reviewed.

RESULTS

Forty-two patients were treated between 1998 and 2011. Their median age at diagnosis was 5 years 7 months. Nineteen patients were positive for neurofibromatosis Type 1 (NF1) and 23 patients were negative for NF1. The median duration of follow-up was 77 months (range 21.8-142.3 months). Presenting symptoms included visual impairment (in 50% of cases), headache (in 24%), and hypothalamic/pituitary dysfunction (in 29%). Twenty-two debulking procedures were performed in 21 patients. Four biopsies (3 open, 1 endoscopic) were also performed. The histological diagnosis was pilocytic astrocytoma in 21 patients and pilomyxoid astrocytoma in 2 patients. Ten patients (Group 1) had primary surgical debulking alone and were then observed. Four patients (Group 2) had surgical debulking, plus planned chemotherapy within 3 months. Seven patients (Group 3) required surgical debulking for progressive disease following a variety of treatments. Patient age had the greatest impact on subsequent tumor progression. In total, 13 patients received chemotherapy, 4 on initial presentation, 4 in combination with surgery, and 5 for further tumor progression. Five patients were treated with radiotherapy, 3 prior to referral to Alder Hey. Eleven patients required shunt insertion for hydrocephalus. Vision was stabilized for 74% of patients. The number of patients with hypothalamic/pituitary dysfunction increased from 12 at presentation to 16 by the end of treatment. The overall survival rate was 93%. Three patients died-1 from tumor progression, 1 from infective complications from tumor biopsy, and 1 from a spontaneous posterior fossa hemorrhage. NF1 was associated with improved outcome-fewer patients required active intervention and rates of visual impairment and/or or hypothalamic/pituitary dysfunction were lower.

CONCLUSIONS

Good long-term survival and functional outcomes can be achieved in children with OPHG. Tumor control was achieved through an individualized approach using surgery, chemotherapy, or radiotherapy in varied combinations. The authors aim to limit radiotherapy to cases involving older children in whom other therapies have failed, due to the well-described and often devastating late effects associated with midline cranial irradiation. Surgery has a clear role for diagnosis, tumor control, and relief of mass effect. In particular, primary surgical debulking of tumor (without adjuvant therapy) is safe and effective. Recent advances in intraoperative MRI may add value and need further assessment.

Early and late renal adverse effects after potentially nephrotoxic treatment for childhood cancer

BACKGROUND

Great improvements in diagnostics and treatment for malignant disease in childhood have led to a major increase in survival. However, childhood cancer survivors (CCS) are at great risk for developing adverse effects caused by multimodal treatment for their malignancy. Nephrotoxicity is one of these known (acute) side effects of several treatments, including cisplatin, carboplatin, ifosfamide, radiotherapy and nephrectomy, and can cause glomerular filtration rate impairment, proteinuria, tubulopathy and hypertension. However, evidence about the long-term effects of these treatments on renal function remains inconclusive. To reduce the number of (long-term) nephrotoxic events in CCS, it is important to know the risk of, and risk factors for, early and late renal adverse effects, so that ultimately treatment and screening protocols can be adjusted.

OBJECTIVES

To evaluate existing evidence on the effects of potentially nephrotoxic treatment modalities on the prevalence of and associated risk factors for renal dysfunction in survivors treated for childhood cancer with a median or mean survival of at least one year after cessation of treatment, where possible in comparison with healthy controls or CCS treated without potentially nephrotoxic treatment.

SEARCH METHODS

We searched the following electronic databases: the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 4, 2011), MEDLINE/PubMed (from 1945 to December 2011) and EMBASE/Ovid (from 1980 to December 2011).

SELECTION CRITERIA

With the exception of case reports, case series and studies including fewer than 20 participants, we included studies with all study designs that reported on renal function (one year or longer after cessation of treatment) in children and adults who were treated for a paediatric malignancy (aged 18 years or younger at diagnosis) with cisplatin, carboplatin, ifosfamide, radiation including the kidney region and/or a nephrectomy.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, risk of bias assessment and data extraction using standardised data collection forms. Analyses were performed according to the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

The search strategy identified 5504 studies, of which 5138 were excluded on the basis of title and/or abstract. The full-text screening of the remaining 366 articles resulted in the inclusion of 57 studies investigating the prevalence of and sometimes also risk factors for early and late renal adverse effects of treatment for childhood cancer. The 57 studies included at least 13,338 participants of interest for this study, of whom at least 6516 underwent renal function testing. The prevalence of renal adverse effects ranged from 0% to 84%. This variation may be due to diversity in included malignancies, prescribed treatments, reported outcome measurements and the methodological quality of available evidence.Chronic kidney disease/renal insufficiency (as defined by the authors of the original studies) was reported in 10 of 57 studies. The prevalence of chronic kidney disease ranged between 0.5% and 70.4% in the 10 studies and between 0.5% and 18.8% in the six studies that specifically investigated Wilms' tumour survivors treated with a unilateral nephrectomy.A decreased (estimated) glomerular filtration rate was present in 0% to 50% of all assessed survivors (32/57 studies). Total body irradiation; concomitant treatment with aminoglycosides, vancomycin, amphotericin B or cyclosporin A; older age at treatment and longer interval from therapy to follow-up were significant risk factors reported in multivariate analyses. Proteinuria was present in 0% to 84% of all survivors (17/57 studies). No study performed multivariate analysis to assess risk factors for proteinuria.Hypophosphataemia was assessed in seven studies. Reported prevalences ranged between 0% and 47.6%, but four of seven studies found a prevalence of 0%. No studies assessed risk factors for hypophosphataemia using multivariate analysis. The prevalence of impairment of tubular phosphate reabsorption was mostly higher (range 0% to 62.5%; 11/57 studies). Higher cumulative ifosfamide dose, concomitant cisplatin treatment, nephrectomy and longer follow-up duration were significant risk factors for impaired tubular phosphate reabsorption in multivariate analyses.Treatment with cisplatin and carboplatin was associated with a significantly lower serum magnesium level in multivariate analysis, and the prevalence of hypomagnesaemia ranged between 0% and 37.5% in the eight studies investigating serum magnesium.Hypertension was investigated in 24 of the 57 studies. Reported prevalences ranged from 0% to 18.2%. A higher body mass index was the only significant risk factor noted in more than one multivariate analysis. Other reported factors that significantly increased the risk of hypertension were use of total body irradiation, abdominal irradiation, acute kidney injury, unrelated or autologous stem cell donor type, growth hormone therapy and older age at screening. Previous infection with hepatitis C significantly decreased the risk of hypertension.Because of the profound heterogeneity of the studies, it was not possible to perform any meta-analysis.

AUTHORS' CONCLUSIONS

The prevalence of renal adverse events after treatment with cisplatin, carboplatin, ifosfamide, radiation therapy involving the kidney region and/or nephrectomy ranged from 0% to 84%. With currently available evidence, it was not possible to draw any conclusions with regard to prevalence of and risk factors for renal adverse effects. Future studies should focus on adequate study design and reporting and should deploy multivariate risk factor analysis to correct for possible confounding. Until more evidence becomes available, CCS should be enrolled into long-term follow-up programmes to monitor their renal function and blood pressure.

The transventricular preforniceal approach for exophytic chiasmatic/hypothalamic astrocytomas extending into the anterior third ventricle

BACKGROUND

Surgical treatment of large exophytic chiasmatic/hypothalamic astrocytomas extending into the anterior third ventricle remains a challenging task for neurosurgeons. In particular, when the tumor extends from the chiasmatic region upward to the foramen of Monro, damage to the fornix and other neurovascular structures is a major concern.

OBJECTIVE

To describe the technique used in the transventricular preforniceal surgical approach to remove the superior and superoposterior part of the tumor in the third ventricle for treatment of exophytic chiasmatic/hypothalamic astrocytoma.

METHODS

The transventricular preforniceal approach was used in two cases of exophytic chiasmatic/hypothalamic astrocytoma. The approach is summarized in 4 procedures: 1) exposure of the anterior horn of the lateral ventricle by the transcallosal approach, 2) identification of the foramen of Monro and the fornix, 3) incision of the septum pellucidum or the wall of the lateral ventricle, in front of the columns of the fornix, and 4) removal of the tumor through the space between the anterior commissure and the columns of the fornix.

RESULTS

Because the tumor compressed the foramen of Monro posteriorly and stretched the space between the anterior commissure and the columns of the fornix, the posterosuperior part of the tumor in the third ventricle was successfully removed through the surgical corridor in front of the columns of the fornix. In both cases, tumors were successfully removed using this approach without damaging the fornix and the anterior commissure. Residual tumor was removed using an anterior interhemispheric translamina terminalis approach in a two-stage surgery.

CONCLUSIONS

The transventricular preforniceal approach can be applied for removing the superior part of exophytic chiasmatic/hypothalamic astrocytomas, because the space between the anterior commissure and the fornix is stretched by the tumor, providing an appropriate surgical corridor.

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.

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.

Phase II TPDCV protocol for pediatric low-grade hypothalamic/chiasmatic gliomas: 15-year update

To report long-term results for children with low-grade hypothalamic/chiasmatic gliomas treated on a phase II chemotherapy protocol. Between 1984 and 1992, 33 children with hypothalamic/chiasmatic LGGs received TPDCV chemotherapy on a phase II prospective trial. Median age was 3.0 years (range 0.3-16.2). Twelve patients (36%) underwent STRs, 14 (42%) biopsy only, and seven (21%) no surgery. Twenty patients (61%) had pathologic JPAs, nine (27%) grade II gliomas, and four (12%) no surgical sampling. Median f/u for surviving patients was 15.2 years (range 5.3-20.7); 20 of the 23 surviving patients had 14 or more years of follow-up. Fifteen-year PFS and OS were 23.4 and 71.2%, respectively. Twenty-five patients progressed, of whom 13 are NED, two are AWD, and 10 have died. All children who died were diagnosed and first treated at age three or younger. Age at diagnosis was significantly associated with relapse and survival (P = 0.004 for PFS and P = 0.037 for OS). No PFS or OS benefit was seen with STR versus biopsy/no sampling (P = 0.58 for PFS, P = 0.59 for OS). For patients with JPAs and WHO grade II tumors, the 15-year PFS was 18.8 and 22.2% (P = 0.95) and 15-year OS was 73.7 and 55.6% (P = 0.17), respectively. Upfront TPDCV for children with hypothalamic/chiasmatic LGGs resulted in 15-year OS of 71.2% and 15-year PFS of 23.4%. No survival benefit is demonstrated for greater extent of resection. Age is a significant prognostic factor for progression and survival.

Proton beam radiation therapy in the treatment of pediatric central nervous system malignancies: a review of the literature

One of 5 pediatric cancers occurs within the central nervous system. Although outcomes have improved, the greatest challenge with these patients remains the balance between cure and long-term morbidity. Patients who have undergone radiation therapy remain at high risk for developing a multitude of severe long-term sequelae. As radiation therapy remains a mainstay of treatment much attention has gone into improving its quality and precision. Multiple options exist for these patients, including conventional photon radiotherapy, conformal radiation, and now, proton beam radiotherapy. Proton beams are able to provide utmost precision for targeting the site of the tumor while decreasing radiation doses to surrounding tissues. Studies are showing that the benefits of proton therapy surpass both conventional radiation as well as conformal radiation therapy, and as a result medical centers around the United States are working to open more facilities and improve patient access. As research becomes more readily available and new centers open, pediatric patients will have the option to be treated with this technology in order to preserve cognitive function and decrease long-term effects.

Primary optic nerve tumours

PURPOSE OF REVIEW

Advances have been made in the treatment of primary optic nerve tumours. With a focus on the last few years' publications, recommendations for clinical management are being developed.

RECENT FINDINGS

In low-grade optic nerve glioma, two divergent developments are observed: an increasing reluctance in treating such tumours because of reports about treatment toxicity (secondary tumours, moyamoya syndrome) and a steady and marked improvement both in radiotherapy and chemotherapy. Many reports on beneficial effects of radiotherapy on optic nerve meningioma have been published. Radiotherapy does not only preserve but in many cases even improves or restores visual function and has, therefore, become the therapy of choice in this tumour.

SUMMARY

Establishing a treatment plan in cases of optic nerve glioma is difficult and must be made on an individual basis. Although both chemotherapy and radiotherapy can stabilize and sometimes improve vision in progressive tumours, chemotherapy is the preferred modality in children younger than 9 years and in patients with neurofibromatosis 1. In functionally progressive optic nerve meningioma with useful visual function, multifractioned stereotactic conformal radiotherapy is the treatment of choice.

[Phacomatosis and genetically determined tumors: the transition from childhood to adulthood]

Phacomatoses, or neurocutaneous disorders, are a group of congenital and hereditary diseases characterized by developmental lesions of the neuroectoderm, leading to pathologies affecting the skin and the central nervous system. There is a wide range of pathologies affecting individuals at different moments of life. The genetics is variable: while neurofibromatosis 1 and 2, tuberous sclerosis and von Hippel-Lindau disease are all inherited as autosomal dominant traits, Sturge-Weber syndrome is sporadic. Other neurocutaneous disorders can be inherited as autosomal recessive traits (i.e., ataxia-telangiectasia), X-linked (i.e., incontinentia pigmenti) or explained by mosaicism (i.e., hypomelanosis of Ito, McCune-Albright syndrome). In this review, we discuss the major types of neurocutaneous disorders most frequently encountered by the neurosurgeon and followed beyond childhood. They include neurofibromatosis types 1 and 2, tuberous sclerosis, Sturge-Weber syndrome and von Hippel-Lindau disease. In each case, a review of the literature, including diagnosis, genetics and treatment will be presented. The lifespan of the disease with the implications for neurosurgeons will be emphasized. A review of cases, including both pediatric and adult patients, seen in neurosurgical practices in the Lille, France and Lausanne, Switzerland hospitals between 1961 and 2007 is presented to illustrate the pathologies seen in different age-groups. Because the genes mutated in most phacomatoses are involved in development and are activated following a timed schedule, the phenotype of these diseases evolves with age. The implication of the neurosurgeon varies depending on the patient's age and pathology. While neurosurgeons tend to see pediatric patients affected with neurofibromatosis type 1, tuberous sclerosis and Sturge-Weber syndrome, there will be a majority of adult patients with von Hippel-Lindau disease or neurofibromatosis type 2.