Radiosurgery in the management of pediatric brain tumors

Stereotactic Radiosurgery for Ependymoma in Pediatric and Adult Patients: A Single-Institution Experience

BACKGROUND AND OBJECTIVES

Ependymoma is commonly classified as World Health Organization grade 2 with the anaplastic variant categorized as grade 3. Incomplete resection or anaplastic features can result in unfavorable outcomes. Stereotactic radiosurgery (SRS) provides a minimally invasive approach for recurrent ependymomas. Our study investigates the efficacy and safety of SRS for grade 2 and 3 ependymomas in pediatric and adult populations.

METHODS

We conducted a retrospective analysis on 34 patients with 75 ependymomas after CyberKnife SRS between 1998 and 2023. Fourteen were pediatric (3-18 years), and 20 were adult (19-75 years) patients. The median age was 21 years, and the median tumor volume was 0.64 cc. The median single-fraction equivalent dose was 16.6 Gy, with SRS administered at 77% of the median isodose line.

RESULTS

After a median follow-up of 42.7 months (range: 3.8-438.3), 22.7% of ependymomas progressed. The 5-year local tumor control rate was 78.1%, varying between 59.6% and 90.2% for children and adults, with grade 2 at 85.9% compared with 58.5% for grade 3 tumors. The 5-year overall survival rate was 73.6%, notably higher in adults (94.7%) than in children (41%), and 100% for grade 2 but decreased to 35.9% for grade 3 patients. The 5-year progression-free survival rate was 68.5%, with 78.3% and 49.2% for adults and children, respectively, and a favorable 88.8% for grade 2, contrasting with 32.6% for grade 3 patients. Symptom improvement was observed in 85.3% of patients. Adverse radiation effects occurred in 21.4% of pediatric patients.

CONCLUSION

Our study supports SRS as a viable modality for pediatric and adult patients with grade 2 and 3 ependymomas. Despite lower local tumor control in pediatric and grade 3 cases, integrating SRS holds promise for improved outcomes. Emphasizing careful patient selection, personalized treatment planning, and long-term follow-up is crucial for optimal neurosurgical outcomes.

Radiotherapy for Primary Pediatric Central Nervous System Malignancies: Current Treatment Paradigms and Future Directions

BACKGROUND

Central nervous system tumors are the most common solid tumors in childhood. Treatment paradigms for pediatric central nervous system malignancies depend on elements including tumor histology, age of patient, and stage of disease. Radiotherapy is an important modality of treatment for many pediatric central nervous system malignancies.

SUMMARY

While radiation contributes to excellent overall survival rates for many patients, radiation also carries significant risks of long-term side effects including neurocognitive decline, hearing loss, growth impairment, neuroendocrine dysfunction, strokes, and secondary malignancies. In recent decades, clinical trials have demonstrated that with better imaging and staging along with more sophisticated radiation planning and treatment set-up verification, smaller treatment volumes can be utilized without decrement in survival. Furthermore, the development of intensity-modulated radiotherapy and proton-beam radiotherapy has greatly improved conformality of radiation.

KEY MESSAGES

Recent changes in radiation treatment paradigms have decreased risks of short- and long-term toxicity for common histologies and in different age groups. Future studies will continue to develop novel radiation regimens to improve outcomes in aggressive central nervous system tumors, integrate molecular subtypes to tailor radiation treatment, and decrease radiation-associated toxicity for long-term survivors.

The evolving role of reirradiation in the management of recurrent brain tumors

Despite aggressive management consisting of surgery, radiation therapy (RT), and systemic therapy given alone or in combination, a significant proportion of patients with brain tumors will experience tumor recurrence. For these patients, no standard of care exists and management of either primary or metastatic recurrent tumors remains challenging.Advances in imaging and RT technology have enabled more precise tumor localization and dose delivery, leading to a reduction in the volume of health brain tissue exposed to high radiation doses. Radiation techniques have evolved from three-dimensional (3-D) conformal RT to the development of sophisticated techniques, including intensity modulated radiation therapy (IMRT), volumetric arc therapy (VMAT), and stereotactic techniques, either stereotactic radiosurgery (SRS) or stereotactic radiotherapy (SRT). Several studies have suggested that a second course of RT is a feasible treatment option in patients with a recurrent tumor; however, survival benefit and treatment related toxicity of reirradiation, given alone or in combination with other focal or systemic therapies, remain a controversial issue.We provide a critical overview of the current clinical status and technical challenges of reirradiation in patients with both recurrent primary brain tumors, such as gliomas, ependymomas, medulloblastomas, and meningiomas, and brain metastases. Relevant clinical questions such as the appropriate radiation technique and patient selection, the optimal radiation dose and fractionation, tolerance of the brain to a second course of RT, and the risk of adverse radiation effects have been critically discussed.

Relapsed Medulloblastoma in Pre-Irradiated Patients: Current Practice for Diagnostics and Treatment

Relapsed medulloblastoma (rMB) accounts for a considerable, and disproportionate amount of childhood cancer deaths. Recent advances have gone someway to characterising disease biology at relapse including second malignancies that often cannot be distinguished from relapse on imaging alone. Furthermore, there are now multiple international early-phase trials exploring drug-target matches across a range of high-risk/relapsed paediatric tumours. Despite these advances, treatment at relapse in pre-irradiated patients is typically non-curative and focuses on providing life-prolonging and symptom-modifying care that is tailored to the needs and wishes of the individual and their family. Here, we describe the current understanding of prognostic factors at disease relapse such as principal molecular group, adverse molecular biology, and timing of relapse. We provide an overview of the clinical diagnostic process including signs and symptoms, staging investigations, and molecular pathology, followed by a summary of treatment modalities and considerations. Finally, we summarise future directions to progress understanding of treatment resistance and the biological mechanisms underpinning early therapy-refractory and relapsed disease. These initiatives include development of comprehensive and collaborative molecular profiling approaches at relapse, liquid biopsies such as cerebrospinal fluid (CSF) as a biomarker of minimal residual disease (MRD), modelling strategies, and the use of primary tumour material for real-time drug screening approaches.

Clinical outcomes for pediatric patients receiving radiotherapy for solid tumor central nervous system metastases

Central nervous system (CNS) metastases are rare, but devastating complications of pediatric solid tumors. Radiotherapy alone or postresection serves as an important treatment; however, data on the use of whole-brain radiotherapy (WBRT) versus focal radiotherapy, including stereotactic radiosurgery or stereotactic radiotherapy, for these indications are limited. We report a single institution experience of 26 pediatric patients treated with radiotherapy for solid tumor CNS metastases without leptomeningeal disease. Focal radiotherapy (n = 10) was well tolerated and survival outcomes did not differ between patients treated with WBRT (n = 16) versus focal radiation, suggesting that focal radiotherapy may be considered for patients with limited CNS metastases.

Current applications and safety profile of laser interstitial thermal therapy in the pediatric population: a systematic review of the literature

OBJECTIVE

Laser interstitial thermal therapy (LITT) provides a minimally invasive alternative to open brain surgery, making it a powerful neurosurgical tool especially in pediatric patients. This systematic review aimed to highlight the indications and complications of LITT in the pediatric population.

METHODS

In line with the PRISMA guidelines, the authors conducted a systematic review to summarize the current applications and safety profiles of LITT in pediatrics. PubMed and Embase were searched for studies that reported the outcomes of LITT in patients < 21 years of age. Retrospective studies, case series, and case reports were included. Two authors independently screened the articles by title and abstract followed by full text. Relevant variables were extracted from studies that met final eligibility, and results were pooled using descriptive statistics.

RESULTS

The selection process captured 303 pediatric LITT procedures across 35 studies. Males comprised approximately 60% of the aggregate sample, with a mean age of 10.5 years (range 0.5-21 years). The LITT technologies used included Visualase (89%), NeuroBlate (9%), and Multilase 2100 (2%). The most common indication was treatment of seizures (86%), followed by brain tumors (16%). The mean follow-up duration was 15.6 months (range 1.3-48 months). The overall complication rate was 15.8%, which comprised transient neurological deficits, cognitive and electrolyte disturbances, hemorrhage, edema, and hydrocephalus. No deaths were reported.

CONCLUSIONS

As of now, LITT's most common applications in pediatrics are focused on treating medically refractory epilepsy and brain tumors that can be difficult to resect. The safety of LITT can provide an attractive alternative to open brain surgery in the pediatric population.

Concise review of stereotactic irradiation for pediatric glial neoplasms: Current concepts and future directions

Brain tumors, which are among the most common solid tumors in childhood, remain a leading cause of cancer-related mortality in pediatric population. Gliomas, which may be broadly categorized as low grade glioma and high grade glioma, account for the majority of brain tumors in children. Expectant management, surgery, radiation therapy (RT), chemotherapy, targeted therapy or combinations of these modalities may be used for management of pediatric gliomas. Several patient, tumor and treatment-related characteristics including age, lesion size, grade, location, phenotypic and genotypic features, symptomatology, predicted outcomes and toxicity profile of available therapeutic options should be considered in decision making for optimal treatment. Management of pediatric gliomas poses a formidable challenge to the physicians due to concerns about treatment induced toxicity. Adverse effects of therapy may include neurological deficits, hemiparesis, dysphagia, ataxia, spasticity, endocrine sequelae, neurocognitive and communication impairment, deterioration in quality of life, adverse socioeconomic consequences, and secondary cancers. Nevertheless, improved understanding of molecular pathology and technological advancements may pave the way for progress in management of pediatric glial neoplasms. Multidisciplinary management with close collaboration of disciplines including pediatric oncology, surgery, and radiation oncology is warranted to achieve optimal therapeutic outcomes. In the context of RT, stereotactic irradiation is a viable treatment modality for several central nervous system disorders and brain tumors. Considering the importance of minimizing adverse effects of irradiation, radiosurgery has attracted great attention for clinical applications in both adults and children. Radiosurgical applications offer great potential for improving the toxicity profile of radiation delivery by focused and precise targeting of well-defined tumors under stereotactic immobilization and image guidance. Herein, we provide a concise review of stereotactic irradiation for pediatric glial neoplasms in light of the literature.

Radiosurgery, reirradiation, and brachytherapy

Radiosurgery and brachytherapy are potentially useful treatment techniques that are sparingly applied in pediatric oncology. They are often used in the setting of reirradiation for recurrent or metastatic tumors. Reirradiation in children with recurrent tumors is complicated by the tolerance of critical organs and the potential risks for overall long-term dose-dependent complications. We review the current literature available in support of reirradiation and the use of radiosurgery and brachytherapy in pediatric patients.

Image-Guided Robotic Radiosurgery for the Management of Spinal Ependymomas

Background

Ependymomas are rare neoplasms of the central nervous system (CNS), usually localized intracranially and most commonly diagnosed in children. Spinal ependymomas are more frequent in young adults. They are either primary lesions or manifest as disseminated seeding of cranial tumors. Data on the management of spinal ependymoma lesions remain scarce, especially concerning stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT). The purpose of this study is to report the treatment outcomes of two institutions using robotic radiosurgery (RRS) for the treatment of spinal ependymomas.

Materials and Methods

All patients with a histopathologically confirmed diagnosis of an ependymoma WHO grade II or III who were treated with RRS for one or more spinal lesions were included in this analysis.

Results

Twelve patients underwent RRS for the treatment of 32 spinal ependymoma lesions between 2005 and 2020. Two patients were below the age of 18 when treated, whereas nine patients (75%) suffered from a primary spinal ependymoma. The median dose was 15 Gy prescribed to a median isodose of 70%, with 27 lesions (84%) receiving a single-session treatment. The local control (LC) after a median follow-up of 56.7 months was 84%. LC rates at 1, 3, and 5 years were 92, 85, and 77%, respectively. The Kaplan-Meier estimated overall survival after 1, 3, and 5 years were 75, 75, and 64%, respectively. Five patients died, all of them suffering from an anaplastic ependymoma, with widespread CNS tumor progression being the reason for death in four patients. The majority of patients (58%) showed a stable neurological status at the last available follow-up. Overall, the treatment was well tolerated.

Conclusion

RRS appears to be a safe and efficient treatment modality for managing primary and secondary spinal ependymal tumors in patients with multiple lesions and local recurrences.

Temozolomide and oral etoposide in children with recurrent malignant brain tumors

Despite advances in the treatment of brain tumors, the prognosis of children with recurrent malignant brain tumors remains poor. Etoposide (VP-16), an inhibitor of nuclear enzyme deoxyribonucleic acid (DNA)-topoisomerase II, has shown activity in brain tumors. Its efficacy appears schedule dependent but, to date, the most effective schedule of administration has not been well defined. Temozolomide (TMZ), like VP-16, penetrates the blood–brain barrier and has activity against malignant brain tumors. This novel alkylating agent is rapidly absorbed and is highly bioavailable after oral administration. The antitumor activity of TMZ has been shown to be schedule dependent. Based on the evidence of different mechanisms of cytotoxicity, TMZ and VP-16 have been utilized in combination in patients with malignant brain tumors. This review evaluates the results derived from the combination use of TMZ and oral VP-16. The reported data suggest potential activity of oral VP-16 and TMZ alone or in combination. Further clinical trials are needed to explore and confirm their promising activity in relapsed brain neoplasms.

Outcomes of stereotactic radiosurgery for pilocytic astrocytoma: an international multiinstitutional study

OBJECTIVE

The current standard initial therapy for pilocytic astrocytoma is maximal safe resection. Radiation therapy is considered for residual, recurrent, or unresectable pilocytic astrocytomas. However, the optimal radiation strategy has not yet been established. Here, the authors describe the outcomes of stereotactic radiosurgery (SRS) for pilocytic astrocytoma in a large multiinstitutional cohort.

METHODS

An institutional review board-approved multiinstitutional database of patients treated with Gamma Knife radiosurgery (GKRS) between 1990 and 2016 was queried. Data were gathered from 9 participating International Radiosurgery Research Foundation (IRRF) centers. Patients with a histological diagnosis of pilocytic astrocytoma treated using a single session of GKRS and with at least 6 months of follow-up were included in the analysis.

RESULTS

A total of 141 patients were analyzed in the study. The median patient age was 14 years (range 2-84 years) at the time of GKRS. The median follow-up was 67.3 months. Thirty-nine percent of patients underwent SRS as the initial therapy, whereas 61% underwent SRS as salvage treatment. The median tumor volume was 3.45 cm3. The tumor location was the brainstem in 30% of cases, with a nonbrainstem location in the remainder. Five- and 10-year overall survival rates at the last follow-up were 95.7% and 92.5%, respectively. Five- and 10-year progression-free survival (PFS) rates were 74.0% and 69.7%, respectively. On univariate analysis, an age < 18 years, tumor volumes < 4.5 cm3, and no prior radiotherapy or chemotherapy were identified as positive prognostic factors for improved PFS. On multivariate analysis, only prior radiotherapy was significant for worse PFS.

CONCLUSIONS

This represents the largest study of single-session GKRS for pilocytic astrocytoma to date. Favorable long-term PFS and overall survival were observed with GKRS. Further prospective studies should be performed to evaluate appropriate radiosurgery dosing, timing, and sequencing of treatment along with their impact on toxicity and the quality of life of patients with pilocytic astrocytoma.

Radiotherapy Advances in Pediatric Neuro-Oncology

Radiation therapy (RT) represents an integral component in the treatment of many pediatric brain tumors. Multiple advances have emerged within pediatric radiation oncology that aim to optimize the therapeutic ratio—improving disease control while limiting RT-related toxicity. These include innovations in treatment planning with magnetic resonance imaging (MRI) simulation, as well as increasingly sophisticated radiation delivery techniques. Advanced RT techniques, including photon-based RT such as intensity-modulated RT (IMRT) and volumetric-modulated arc therapy (VMAT), as well as particle beam therapy and stereotactic RT, have afforded an array of options to dramatically reduce radiation exposure of uninvolved normal tissues while treating target volumes. Along with advances in image guidance of radiation treatments, novel RT approaches are being implemented in ongoing and future prospective clinical trials. As the era of molecular risk stratification unfolds, personalization of radiation dose, target, and technique holds the promise to meaningfully improve outcomes for pediatric neuro-oncology patients.

Practice Patterns of Stereotactic Radiotherapy in Pediatrics: Results From an International Pediatric Research Consortium

PURPOSE/OBJECTIVES

There is little consensus regarding the application of stereotactic radiotherapy (SRT) in pediatrics. We evaluated patterns of pediatric SRT practice through an international research consortium.

MATERIALS AND METHODS

Eight international institutions with pediatric expertise completed a 124-item survey evaluating patterns of SRT use for patients 21 years old and younger. Frequencies of SRT use and median margins applied with and without SRT were evaluated.

RESULTS

Across institutions, 75% reported utilizing SRT in pediatrics. SRT was used in 22% of brain, 18% of spine, 16% of other bone, 16% of head and neck, and <1% of abdomen/pelvis, lung, and liver cases across sites. Of the hypofractionated SRT cases, 42% were delivered with definitive intent. Median gross tumor volume to planning target volume margins for SRT versus non-SRT plans were 0.2 versus 1.4 cm for brain, 0.3 versus 1.5 cm for spine/other bone, 0.3 versus 2.0 cm for abdomen/pelvis, 0.7 versus 1.5 cm for head and neck, 0.5 versus 1.7 cm for lung, and 0.5 versus 2.0 cm for liver sites.

CONCLUSIONS

SRT is commonly utilized in pediatrics across a range of treatment sites. Margins used for SRT were substantially smaller than for non-SRT planning, highlighting the utility of this approach in reducing treatment volumes.

Does Stereotactic Radiosurgery Positively Impact the Local Control of Atypical Teratoid Rhabdoid Tumors?

BACKGROUND

Atypical teratoid rhabdoid tumors (ATRTs) are rare and aggressive tumors, usually affecting patients younger than 3 years of age, that are characterized by a poor prognosis. Nowadays multimodal management, including surgery, chemotherapy and radiation therapy (RT), is advocated depending on the patients' age and tumor stage, even if no consensus exists regarding the best treatment modality. Local RT seems to be the most effective treatment in prolonging progression-free and overall survival rates, although RT might not be used on younger children because of the risk of neurocognitive and endocrine sequelae. Stereotactic radiosurgery (SRS) is a valuable alternative therapeutic option to conventional RT because of the more conformal dose delivery. The aim of this study was to review the available literature on SRS in the management of ATRT.

METHODS

The authors carried out a systematic review of PubMed, Web of Science, and Google Scholar for clinical reports dealing with SRS for the management of ATRT.

RESULTS

Nine studies describing 12 patients treated with SRS for ATRT were included in the analysis. Patient's clinical features, radiosurgical treatment characteristics, and follow-up data of the pertinent literature were reviewed critically. SRS represents a feasible and effective therapeutic option in the management of ATRT. Local control has been reported in 66.7% of cases; however, 33.3% of patients experienced poor survival because of craniospinal tumor dissemination.

CONCLUSION

SRS should be considered in the multimodal treatment of ATRT, and future studies should focus on a better definition of the role played by SRS in their management.

Hypofractionated re-irradiation to the brainstem in children with recurrent brain tumors

To characterize radiation necrosis following hypofractionated brainstem re-irradiation in pediatric patients, we reviewed 23 cases with 28 tumors invading or abutting brainstem and treated with hypofractionated re-irradiation from 2004 to 2014. Re-irradiation delivered total doses of 16-30 Gy in two to five fractions. The most commons regimens used were 24 Gy in three fractions and 25 Gy in five fractions. At median follow-up of 12.8 months, median overall survival was 14.7 months and eight in-field recurrences were detected (median time 10.5 months). Five patients experienced symptomatic brainstem necrosis, and all having received 24 Gy in three fractions. Hypofractionated brainstem re-irradiation may be safer in five fractions.

Radiosurgery for Pediatric Brain Tumors

The utility of radiosurgery for pediatric brain tumors is not well known. For children, radiosurgery may have an important role for treating unresectable tumors, residual disease, or tumors in the recurrent setting that have received prior radiotherapy. The available evidence demonstrates utility for some children with primary brain tumors resulting in good local control. Radiosurgery can be considered for limited residual disease or focal recurrences. However, the potential toxicities are unique and not insignificant. Therefore, prospective studies need to be performed to develop guidelines for indications and treatment for children and reduce toxicity in this population.

The biology of radiosurgery and its clinical applications for brain tumors

Stereotactic radiosurgery (SRS) was developed decades ago but only began to impact brain tumor care when it was coupled with high-resolution brain imaging techniques such as computed tomography and magnetic resonance imaging. The technique has played a key role in the management of virtually all forms of brain tumor. We reviewed the radiobiological principles of SRS on tissue and how they pertain to different brain tumor disorders. We reviewed the clinical outcomes on the most common indications. This review found that outcomes are well documented for safety and efficacy and show increasing long-term outcomes for benign tumors. Brain metastases SRS is common, and its clinical utility remains in evolution. The role of SRS in brain tumor care is established. Together with surgical resection, conventional radiotherapy, and medical therapies, patients have an expanding list of options for their care. Clinicians should be familiar with radiosurgical principles and expected outcomes that may pertain to different brain tumor scenarios.

Fractionated stereotactic radiosurgery for recurrent ependymoma in children

Outcomes for children with relapsed ependymoma are poor. Re-irradiation is a potentially viable salvage option in these patients. Data were reviewed for 12 patients (median age 5.6 years) with relapsed ependymoma who received fractionated stereotactic radiosurgery (fSRS) following maximal surgical resection from 1995 to 2012. Four patients experienced a second recurrence, including 2 in-field and 2 distant failures. Median time to second recurrence (32 months) was significantly longer than time to first recurrence (24 months) (p = 0.008). Three-year local control was 89 %, and median event free survival from fSRS was 3.4 years. Radiation necrosis was observed in 6 patients, 3 who were symptomatic. In conclusion, fSRS offers durable response with a tolerable toxicity profile in children with recurrent EPN.

Role of stereotactic radiosurgery and fractionated stereotactic radiotherapy in the management of intracranial ependymoma

Ependymoma accounts for 5-10% of all childhood CNS tumors and less than 5% of intracranial tumors in adults. Ependymomas typically have a sharp tumor-brain parenchyma interface and this characteristic lends itself well to stereotactic radiation delivery. Data on the use of stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (FSRT) for ependymoma in various settings have emerged over the past 10 years. SRS has been used in recurrent disease and as a boost after external beam radiation therapy. FSRT has been used in pediatric brain tumors and can potentially limit the long-term toxicities associated with radiation therapy by reducing the amount of normal brain parenchyma treated. Long-term follow-up is needed to determine the long-term efficacy and toxicities associated with these treatment modalities.

Current treatment options for pediatric and adult patients with ependymoma

OPINION STATEMENT

Survival rates for patients with ependymoma, a glial tumor arising from the ependymal cells lining the ventricles of the brain and spinal cord canal, have changed little during the past decade. Contemporary "standard" therapy for children and adults with ependymoma consists of maximal surgical resection followed by focal irradiation except in cases of disseminated disease. Despite refinements in radiotherapy techniques and improvements in survival for patients with gross totally resected, nonanaplastic disease, many therapeutic challenges remain, especially for patients with unresectable, macroscopic, metastatic, or anaplastic disease. Moreover, radiotherapy to the developing central nervous system, especially in patients younger than age 5 years, can have potential long-term neurocognitive and neuroendocrine sequelae. Chemotherapy has not played a role in most treatment regimens for ependymoma to date, but due to the ongoing therapeutic challenges for a subset of patients, this modality is being reinvestigated in a few ongoing studies. Early recognition of patients who will not respond to primary therapy is imperative to modify treatment regimens, such as intensification with the addition of adjuvant chemotherapy, the use of novel experimental therapies, or their combination. Refinements in patient stratification schemes that are based on a combination of clinical variables and molecular profiles also require improved knowledge of tumor biology. Several molecular alterations have been identified already, some of which may be of prognostic significance. Furthermore, disruption of molecular alterations in signaling pathways involved in the development and maintenance of ependymoma by using novel molecularly targeted therapies may improve outcomes and reduce toxicity for patients with ependymoma.

Phase I study of temozolomide combined with oral etoposide in children with malignant glial tumors

The treatment of children with malignant glioma remains challenging. The aim of this multicenter phase I study is to establish the recommended dose (RD) of the combination therapy with temozolomide (TMZ) and oral etoposide (VP-16) in children with relapsed or refractory malignant glioma and brainstem glioma at diagnosis. A phase I trial was conducted to establish the maximum tolerated dose (MTD) of TMZ and oral VP-16. This orally administered combination was investigated by a classical 3 + 3 design. Cohorts of patients were enrolled at 4 different levels: (1) TMZ 120 mg/m(2) on days 1-5 and VP-16 50 mg/m(2) on days 1-8; (2) TMZ 150 mg/m(2) on days 1-5 and VP-16 50 mg/m(2) on days 1-8; (3) TMZ 150 mg/m(2) on days 1-5 and VP-16 50 mg/m(2) on days 1-10; (4) TMZ 150 mg/m(2) on days 1-5 and VP-16 50 mg/m(2) on days 1-12. Therapy was administered in 28-day courses. A total of 118 courses were administered to 18 patients with a median age of 11.2 years. At dose level 1, none displayed toxicity. Of the 6 patients at dose level 2, 1 patient had dose limiting toxicity (DLT). None of the 3 patients at dose level 3 had DLT. At dose level 4, grade III/IV thrombocytopenia and neutropenia were observed in 2 out of the 6 patients enrolled. Therefore, the MTD was established at dose level 3. The RD for phase II trial in children with malignant glial is TMZ 150 mg/m(2) for 5 days and VP-16 50 mg/m(2) for 10 days every 28 days.

Multidisciplinary management of pediatric intracranial ependymoma

Pediatric intracranial ependymoma is a rare disease representing approximately 7% of brain tumors in children aged 15 years or younger. Due to the relative rarity of these tumors, a clear standard therapy has been difficult to establish. The mainstay of treatment is surgical resection and the majority of data demonstrate improved outcome with gross total resection. The standard of care also includes postoperative radiation therapy for most patients with grade II and III tumors. Chemotherapy has been used in many capacities in this disease; however, its optimal role is yet to be defined. Current controversies such as treatment with surgery alone in completely resected tumors, use of chemotherapy for subtotally resected tumors and use of adjuvant postradiation chemotherapy are incorporated into the design of the current Children's Oncology Group clinical trial.

Gamma knife surgery of pediatric gliomas

OBJECT

While some low-grade pediatric gliomas may be cured with resection, many patients harbor tumors that cannot be completely resected safely, are difficult to access via an open surgical approach, or recur. Gamma Knife surgery may be beneficial in the treatment of these tumors.

METHODS

The authors reviewed a consecutive series of 24 pediatric patients treated at the authors' institution between 1989 and 2011. All patients harbored tumors that were either surgically inaccessible or had evidence of residual or recurrent growth after resection. Progression-free survival was evaluated and correlated with clinical variables. Additional outcomes evaluated were clinical outcome, imaging response, and overall survival.

RESULTS

Between 1989 and 2011, 13 male and 11 female patients (median age 11 years, range 4-18 years) with gliomas were treated. Tumor pathology was pilocytic astrocytoma (WHO Grade I) in 15 patients (63%), WHO Grade II in 4 (17%), and WHO Grade III in 1 (4%). The tumor pathology was not confirmed in 4 patients (17%). The mean tumor volume at the time of treatment was 2.4 cm(3). Lesions were treated with a median maximum dose of 36 Gy, median of 3 isocenters, and median marginal dose of 15 Gy. The median duration of imaging follow-up was 74 months, and the median duration of clinical follow-up was 144 months. The tumors responded with a median decrease in volume of 71%. At last follow up, a decrease in tumor size of at least 50% was demonstrated in 18 patients (75%) and complete tumor resolution was achieved in 5 (21%). Progression-free survival at last follow-up was achieved in 20 patients (83%). Progression was documented in 4 patients (17%), with 3 patients requiring repeat resection and 1 patient dying. The initial tumor volume was significantly greater in patients with disease progression (mean volume 4.25 vs 2.0 cm(3), p < 0.001). Age, tumor pathology, tumor location, previous radiation, Karnofsky Performance Scale score, symptom duration, and target dosage did not differ significantly between the 2 groups.

CONCLUSIONS

Gamma Knife surgery can provide good clinical control of residual or recurrent gliomas in pediatric patients. Worse outcomes in the present series were associated with larger tumor volumes at the time of treatment.

[Radiosurgery as adjuvant treatment of a recurrent adult medulloblastoma. Ultra-early response]

The role of radiosurgery after multimodality treatment of recurrent desmoplastic adult medulloblastoma is analyzed. The ultra-early clinical and pathological response of this tumor to adjunctive radiosurgery is stressed.

Glioblastoma in children: a single-institution experience

PURPOSE

Current treatment recommendations for pediatric glioblastoma include surgery, chemotherapy, and radiation therapy. However, even with this multispecialty approach, overall survival remains poor. To assess outcome and evaluate treatment-related prognostic factors, we retrospectively reviewed the experience at our institution.

METHODS AND MATERIALS

Twenty-four glioblastoma patients under the age of 21 were treated with radiation therapy with curative intent at Washington University, St. Louis, from 1970 to 2008. Patients underwent gross total resection, subtotal resection or biopsy alone. Fourteen (58%) of the patients received chemotherapy. All patients received radiation therapy. Radiation consisted of whole-brain radiation therapy in 7 (29%) patients with a median dose of 50.4 Gy. Seventeen (71%) patients received three-dimensional conformal radiation therapy with a median dose of 54 Gy.

RESULTS

Median follow-up was 12.5 months from diagnosis. One and 2-year overall survival rates were 57% and 32%, respectively. Median overall survival was 13.5 months. There were no differences in overall survival based on patients' age, race, gender, tumor location, radiation volume, radiation dose, or the use of chemotherapy. There was a significant improvement in overall survival for patients in whom gross total resection was achieved (p = 0.023). Three patients were alive 5 years after gross total resection, and 2 patients were alive at 10 and 24 years after diagnosis.

CONCLUSIONS

Survival for children with glioblastoma remains poor. Data from this and other studies demonstrate the importance of achieving a gross total resection. Continued investigation into new treatment options is needed in an attempt to improve outcome for these patients.

Stereotactic radiotherapy and radiosurgery in pediatric patients: analysis of indications and outcome

INTRODUCTION

We describe indications, outcomes, and risk profiles of fractionated stereotactic radiotherapy (SRT) and single fraction "radiosurgery" (SRS) in pediatric patients compared to the adult population and evaluate the causal role of SRS and SRT in inducing new neurological complications.

MATERIALS AND METHODS

Six children with AVMs and 12 children with neoplastic diseases were prospectively followed for >2 years after SRT/S. The survival, control of pathology, and specified neurological complications were analyzed. In tumor patients, the median overall survival time was 45 months (range 5-103) and the median progression free survival time was 35 months (range 5-98).

RESULTS

Control or regression of the tumor was obtained in 83% of patients with neoplastic disease. Three patients with malignant tumors died from disease progression. In AVMs the median time follow up was 52 months (range 27-100). All AVMs were obliterated. New neurological deficits occurred in 67%. SRT/S was considered the direct cause in 25%. All the neurological deficiencies related to SRT/S were focal and related to the irradiated areas. In tumor patients, midline lesions, malignant diagnosis, and additional treatment with surgery, chemotherapy, and craniospinal irradiation seemed to increase the risk of new deficits after SRT/S. In AVM patients, a high Spetzler-Martin grade seemed to carry a higher complication risk.

CONCLUSION

The risk of uncontrolled tumor disease or the risk of hemorrhage of non-obliterated AVM must be balanced against the overall risks and benefits of SRT/S. Following SRT/S, the risk of worsening pre-existing deficits is relatively high. The risk of inducing new long-term deficits is relatively low.

Stereotactic radiosurgery for pediatric recurrent intracranial ependymomas

OBJECT

To evaluate the role of stereotactic radiosurgery (SRS) in patients with recurrent or residual intracranial ependymomas after resection and fractionated radiation therapy (RT), the authors assessed overall survival, distant tumor relapse, progression-free survival (PFS), and complications.

METHODS

The authors retrospectively reviewed the records of 21 children with ependymomas who underwent SRS for 32 tumors. There were 17 boys and 4 girls with a median age of 6.9 years (range 2.9-17.2 years) in the patient population. All patients underwent resection of an ependymoma followed by cranial or neuraxis (if spinal metastases was confirmed) RT. Eleven patients had adjuvant chemotherapy. Twelve patients had low-grade ependymomas (17 tumors), and 9 patients had anaplastic ependymomas (15 tumors). The median radiosurgical target volume was 2.2 cm(3) (range 0.1-21.4 cm(3)), and the median dose to the tumor margin was 15 Gy (range 9-22 Gy).

RESULTS

Follow-up imaging demonstrated therapeutic control in 23 (72%) of 32 tumors at a mean follow-up period of 27.6 months (range 6.1-72.8 months). Progression-free survival after the initial SRS was 78.4%, 55.5%, and 41.6% at 1, 2, and 3 years, respectively. Factors associated with a longer PFS included patients without spinal metastases (p = 0.033) and tumor volumes < 2.2 cm(3) (median tumor volume 2.2 cm(3), p = 0.029). An interval ≥ 18 months between RT and SRS was also associated with longer survival (p = 0.035). The distant tumor relapse rate despite RT and SRS was 33.6%, 41.0%, and 80.3% at 1, 2, and 3 years, respectively. Factors associated with a higher rate of distant tumor relapse included patients who had spinal metastases before RT (p = 0.037), a fourth ventricle tumor location (p = 0.002), and an RT to SRS interval < 18 months (p = 0.015). The median survival after SRS was 27.6 months (95% CI 19.33-35.87 months). Overall survival after SRS was 85.2%, 53.2%, and 23.0% at 1, 2, and 3 years, respectively. Adverse radiation effects developed in 2 patients (9.5%).

CONCLUSIONS

Stereotactic radiosurgery offers an additional option beyond repeat surgery or RT in pediatric patients with residual or recurrent ependymomas after initial management. Patients with smaller-volume tumors and a later recurrence responded best to radiosurgery.

Salvage chemotherapy for metastatic and recurrent ependymoma of childhood

INTRODUCTION

Chemotherapy has limited role in the up-front management of ependymoma. At the time of recurrence, the role of chemotherapy is also ill defined and the choice of chemotherapeutic agents is often arbitrary, based on anecdotal data and personal experience.

METHODS

The purpose of this review is to describe and critically analyze the published literature on chemotherapy in patients with recurrent and metastatic ependymoma.

DISCUSSION

The disappointing response rate with single agents (12.9%) and combinations (17.4%) emphasizes the need to re-evaluate the current chemotherapeutic approach of intracranial ependymoma, and biological studies are needed to identify targets that may be considered for clinical trials.

Survival following treatment for intracranial ependymoma: a review

The actual definition of survival rates following treatment for intracranial ependymomas is substantially influenced by the strict interaction among different factors. Age, location, and grading, for example, act together, negatively influencing the prognosis of younger children also invariably influenced by the more demanding role of surgery and the still limited use, up to recently, of radiotherapy under 3 years of age. In the same direction, the worse prognosis in most series of infratentorial ependymomas if compared with their supratentorial counterpart should be cautiously considered, midline posterior fossa tumors having completely different implications from those originating or predominantly extending to the cerebellopontine angle, where the extent of surgery has more invariably to compare with patients' quality of life. New radiotherapic regimens and their applications in infancy are promisingly demonstrating an improvement of present prognostic criteria, with the limit of still insufficient information on their long-term secondary effects. Similarly, molecular biology research studies, though still in their preclinical stage, are prompting to change the concept of a substantially chemoresistant tumor helping to stratify these lesions with the final aim of targeted pharmacological therapies. In the present review paper, we investigated singularly the role that the more commonly considered prognostic factors have had in the literature on survival of children affected by intracranial ependymomas, trying to elucidate their cumulative effect on the actual knowledge of this issue.

The role of stereotactic radiotherapy in the management of ependymomas

INTRODUCTION

Intracranial ependymomas in children have high rates of recurrence. Salvage therapy typically includes repeat resection, possibly chemotherapy, and re-irradiation. Stereotactic radiosurgery has been used for re-irradiation. It offers the theoretical advantages of delivering a high dose of radiation to a small target, providing a maximum dose to the tumor while avoiding surrounding critical brain structures and previously irradiated tissue.

DISCUSSION

Few reports in the literature describe this technique, with mixed, but not often successful, outcomes.

The history of ependymoma management

INTRODUCTION

The ependymomas are relatively not a common tumor. However, most clinicians agree that the radical removal of the tumor is the most important prognostic factor.

MORBIDITY OF TREATMENT

Tumor removal was not sufficient before the era of magnetic resonance imaging (MRI) and resulted in a considerable operative morbidity and mortality. As the microneurosurgical techniques and microsurgical anatomy become popular and the MRI provide more detailed anatomical information preoperatively, radical removal of this complex and complicated tumor can be more feasible. In childhood ependymoma, the treatment-related morbidity and mortality can be the special issues, which can modify the policy of management safe tumor removal and minimal adjuvant treatment, which are extremely important.

RADIATION THERAPY

Radiation treatment has been the option for disseminated disease and residual tumor. With the advancement of detailed MR anatomical information, safer and more delicate radiation becomes possible with newer radiation modalities, three-dimensional conformal radiotherapy, intensity modulating radiotherapy, and tomotherapy.

PROGNOSTIC FACTORS

Although many clinicians believe that the ependymomas are inheritably chemoresistant, the new targets for the treatment are under investigation or clinically tried. Also, the genetic alterations of ependymoma are developing and might be a promising target.

CONCLUSION

The surgical techniques and assistant modalities for tumor removal are still advancing. So, the outcome of ependymoma is still improving. Unfortunately, newer treatment modalities, such as new chemotherapeutic agent and gene modification agent, are still not promising. The history of ependymoma management is still in progress.

Three-dimensional conformal radiation therapy for ependymoma

INTRODUCTION

The application of conformal radiation therapy in the treatment of pediatric ependymoma is a success story resulting from advances in radiation therapy planning and delivery. These advances occurred at a time when clinical trial results confirmed that radiotherapy avoidance strategies were unsuccessful.

DISCUSSION

Investigators have been keen to confirm the promise of newer radiation therapy methods even for the youngest children. When preliminary results suggested that high-dose focal irradiation could be safely administered through systematic targeting and that cognitive function could be preserved, investigators moved to include conformal therapy in the frontline management of children regardless of age. The results with postoperative conformal radiation therapy were further enhanced when neurosurgeons increased the rate of gross-total resection and recognized that second surgery could be safely accomplished after incomplete initial resection. With more than a decade of experience, the role of conformal radiation therapy in the treatment of childhood ependymoma has been firmly established as investigators consider new trials to increase disease control and improve functional outcomes.

Pediatric brain tumors: current treatment strategies and future therapeutic approaches

Pediatric CNS tumors are the most common solid tumors of childhood and the second most common cancer after hematological malignancies accounting for approximate 20 to 25% of all primary pediatric tumors. With over 3,000 new cases per year in the United States, childhood CNS tumors are the leading cause of death related to cancer in this population. The prognosis for these patients has improved over the last few decades, but current therapies continue to carry a high risk of significant side effects, especially for the very young. Currently a combination of surgery, radiation, and chemotherapy is often used in children greater than 3 years of age. This article will outline current and future therapeutic strategies for the most common pediatric CNS tumors, including primitive neuroectodermal tumors such as medulloblastoma, as well as astrocytomas and ependymomas.

OUTCOME PREDICTORS FOR INTRACRANIAL EPENDYMOMA RADIOSURGERY

OBJECTIVE

To develop outcome predictors after stereotactic radiosurgery (SRS) in patients with intracranial ependymomas who had received previous fractionated radiation therapy, we compared tumor control, survival, and complications with tumor grade, volume, age of patients, and imaging characteristics.

METHODS

We retrospectively reviewed records of 39 consecutive ependymoma patients who underwent SRS for 56 tumors. The median patient age was 22.8 years (range, 2.9–71.1 years). All patients had previous surgical resection of their ependymomas followed by radiotherapy, and 14 patients underwent previous chemotherapy. Twenty-five patients had low-grade ependymomas (34 tumors), and 14 patients had anaplastic ependymomas (22 tumors). The median radiosurgery target volume was 3.6 cm3 (range, 0.1–36.8 cm3), and the median margin dose was 15.0 Gy (range, 10–22 Gy).

RESULTS

At a median of 23.5 months after SRS (range, 6.1–155.2 months), 25 patients died as a result of metastases (12 patients) or disease progression (13 patients). The overall survival rates after SRS were 60.1, 36.1, and 32.1% at 1, 3, and 5 years, respectively. The progression-free survival rates after SRS at 1, 3, and 5 years were 81.6, 45.8, and 45.8%, respectively, for all grades of ependymomas. Lower histological tumor grade was not significantly associated with better progression-free survival (P = 0.725). Factors associated with an improved progression-free survival included smaller tumor volume and homogeneous tumor contrast enhancement in low-grade ependymomas.

CONCLUSION

SRS provides another management option for patients with residual or recurrent ependymomas that have failed surgery and radiation therapy. Predictors of response include smaller volume and homogeneous contrast enhancement.

Clinical Application of PET in Pediatric Brain Tumors

While rare in adults, central nervous system tumor is the most common solid tumor in childhood and is the leading cause of cancer death in children. Childhood brain tumors are different from those in adults in epidemiology, histologic features, and responses to treatment. Gliomas make up over one-half of all childhood brain tumors. Clinical application of PET imaging in brain tumors has demonstrated that it is helpful in tumor grading, establishing prognosis, defining targets for biopsy, and planning resection. This article emphasizes PET applications in childhood brain tumors, focusing on mainly gliomas with regard to tumor-grading and prognosis, distinguishing tumor recurrence from radiation necrosis, and PET guided diagnosis and treatment.

Boost Gamma Knife surgery during multimodality management of adult medulloblastoma

OBJECT

The aim of this paper was to determine prognostic factors for adult medulloblastoma treated with boost Gamma Knife surgery (GKS) following resection and craniospinal irradiation.

METHODS

The authors performed a retrospective analysis of 12 adult patients with histologically proven medulloblastoma or supratentorial primitive neuroectodermal tumor who between February 1991 and December 2004 underwent >or=1 sessions of GKS for posttreatment residual or recurrent tumors (6 tumors in each group). Before GKS, all patients had undergone a maximal feasible resection followed by craniospinal irradiation. Nine patients also received systemic chemotherapy. Stereotactic radiosurgery was applied to residual and recurrent posterior fossa tumor as well as to foci of intracranial medulloblastoma metastases. The median time interval from initial diagnosis and resection to the first GKS treatment was 24 months (range 2-37 months). The mean GKS-treated tumor volume was 9.4 cm3 (range 0.5-39 cm3).

RESULTS

Following adjunctive radiosurgery, 5 patients had no evidence of tumor on magnetic resonance (MR) imaging, 3 patients had stable tumor burden on MR imaging, and 4 patients had evidence of tumor progression locally with or without intracranial metastases. All patients with tumor progression died. Eight patients survive with a mean cumulative follow-up of 72.4 months (range 21-152 months). No acute radiation toxicity or delayed radiation necrosis was observed among any of the 12 patients. The majority of patients who achieved tumor eradication (80%) and tumor stabilization (67%) after GKS had residual tumor as the reason for their referral for GKS. The best outcomes were attained in patients with residual disease who were younger, had smaller tumor volumes, had no evidence of metastatic disease, and had received higher cumulative GKS doses.

CONCLUSIONS

Single or multiple GKS sessions were a well-tolerated, feasible, and effective adjunctive treatment for posterior fossa residual or recurrent medulloblastoma as well as intracranial metastatic medulloblastoma in adult patients.

Hypofractionated stereotactic radiotherapy in the management of recurrent or residual medulloblastoma/PNET

PURPOSE

To evaluate the efficacy and toxicity of hypofractionated stereotactic radiotherapy in the management of locally recurrent or residual central nervous system (CNS) primitive neuroectodermal tumors (PNETs).

PATIENTS AND METHODS

Between 1991 and 2005, 12 patients with locally recurrent medulloblastoma and two patients with residual supratentorial PNET were treated with hypofractionated stereotactic conformal radiotherapy (SCRT). Nine patients were treated for first recurrence, two patients after the 2nd, and one patient after 3rd recurrence. Median age at diagnosis was 20 years (range: 4-35 years) and median age at SCRT 25 years (range: 7-41 years). Nine of 12 patients underwent resection at recurrence and 13 patients received at least one cycle of chemotherapy prior to SCRT. All received focal SCRT (30-40 Gy/6-8 #) using non-coplanar arcs (n = 6) or fixed conformal non-coplanar fields (n = 8).

RESULTS

Median overall survival was 29 months (95% CI: 6-51 months) and median progression-free survival was 12 months (95% CI: 5-19 months). Local progression-free survival at 1 and 3 years was 80% (95% CI: 55-100%) and 48% (95% CI: 11-85%). Causes of death were recurrent CNS disease (n = 7), herpes encephalitis (n = 1), and metastatic PNET outside the CNS (n = 1).

CONCLUSION

Hypofractionated SCRT provides effective local control with acceptable toxicity for patients with recurrent localized PNET. However, overall long-term disease control is rare and limited by the occurrence of CSF mediated relapses, which thus could benefit from intensive systemic chemotherapy as part of the primary relapse strategy even in local recurrences. Larger multi-national studies will be necessary to assess the value of such combined treatment approaches.

Role of stereotactic radiosurgery and fractionated stereotactic radiotherapy in pediatric brain tumors

Brain tumors are the most common solid tumor in childhood. Surgery and/or fractionated radiotherapy are conventional treatment modalities. Stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (FSRT) are advanced radiation therapy techniques that have been frequently used in adults with brain tumors but they are less frequently used in pediatric patients. SRS and FSRT can potentially add to the armamentarium against brain tumors in children. This article will review the role of SRS and FSRT in the management of pediatric brain tumors.

Treatments for astrocytic tumors in children: current and emerging strategies

Strategies for the treatment of childhood cancer have changed considerably during the last 50 years and have led to dramatic improvements in long-term survival. Despite these accomplishments, CNS tumors remain the leading cause of death in pediatric oncology. Astrocytic tumors form the most common histologic group among childhood brain tumors. They are a heterogeneous group that from a practical therapeutic point of view can be subdivided into low-grade astrocytomas (LGA), optic pathway gliomas (OPG), high-grade astrocytomas (HGA), and brainstem gliomas (BSG). This article focuses on the practical application of treatments that lead to long-term survival, improved quality of life, and reduced long-term complications. Improvement in therapy has led to better outcomes for patients with LGA and OPG. Careful follow-up without any treatment is indicated for a small percentage of patients diagnosed with LGA with an indolent course including children with neurofibromatosis type 1 (NF1). Surgery is the main recommended treatment for children with resectable LGA. Radiation therapy is generally recommended for children with progressive LGA, or after failure of chemotherapy, accomplishing tumor control at 10 years in over 60% of patients. Cytotoxic chemotherapy is usually reserved for children who have had treatment failure with surgery and radiation therapy. It is also offered for children who are too young to be treated with radiation or to defer or avoid radiotherapy. Carboplatin and vincristine achieve 5% complete and 28% partial responses but the use of vincristine is criticized due to poor penetration of the CNS. A regimen of tioguanine, procarbazine, mitolactol, lomustine, and vincristine is frequently administered as an alternative to carboplatin and vincristine in LGA. The introduction of temozolomide has allowed better responses, including a 24% complete response rate compared with 0-5% complete response rates with the previous regimens. OPG are usually histologically LGA, and are treated with similar chemotherapy regimens. OPG is the most common type of brain tumor associated with NF1. Tumor growth in some of these patients is slow with no treatment recommended for an extended period of time. The prognosis for children with the remaining types of astrocytomas remains poor. Surgical resection is typically the first step in the treatment of HGA followed in older children by radiation therapy. The data regarding chemotherapy are mixed. Combination chemotherapy before or after radiation, including cisplatin, carmustine, cyclophosphamide, and vincristine or carboplatin, ifosfamide, cyclophosphamide, and etoposide has provided disappointing results. Clinical trials with temozolomide and agents directed against single targets have not shown substantially better results, but it is hoped that currently conducted studies will provide better outcomes. Diffuse intrinsic BSG are among the most difficult-to-treat brain tumors. Surgical treatment is not recommended for diffuse intrinsic BSG and standard radiation therapy is typically given in children aged >3 years. None of the numerous chemotherapy regimens, including temozolomide, has provided a significant response rate or an improvement in survival. It is expected that newer agents affecting multiple targets such as AEE-788 and antineoplastons, and combinations of single-targeted agents with chemotherapy will provide better results. Careful evaluation of histology, location of the tumor, patient age, and consideration of treatment-related morbidity play an important part in selecting between clinical observation, surgery, radiation, chemotherapy, or investigational agents. The goals of treatment for astrocytic tumors should extend well beyond objective responses and increased survival. Improvement of quality of life is an equally important objective of treatment. Radiation therapy and chemotherapy result in serious late toxicities.

Hypothalamic hamartoma associated with anterior paraclinoid aneurysm of the internal carotid artery

A 15-year-old boy presented with a history of medically refractory gelastic seizures and cognitive impairments. Neuroimaging demonstrated a sessile type hypothalamic hamartoma, which was treated by gamma knife surgery. However, the gelastic seizures only partially decreased and the frequency of seizures remained unchanged. One year later, angiography before surgery detected anterior paraclinoid aneurysm of the left internal carotid artery. Blood pressure and endocrinological examinations showed no abnormality. Direct surgery was performed to treat the aneurysm and hamartoma. No sclerotic changes were noted in the arterial wall. The aneurysm was treated with clipping, and the hamartoma was partially removed. Postoperative course was uneventful and the gelastic seizures disappeared. No evidence for a causal relationship between the hamartoma and aneurysm was found.

Temozolomide and oral VP-16 for children and young adults with recurrent or treatment-induced malignant gliomas

BACKGROUND

Children and young adults with recurrent or treatment-induced malignant gliomas have limited responses to temozolomide or oral VP-16 when either is administered as a single agent. We postulated that a combination of these two drugs for patients with recurrent or treatment-induced malignant gliomas might result in better and more prolonged responses. A retrospective analysis was performed on patients treated with the combination of temozolomide and VP-16.

PROCEDURE

Eleven patients with recurrent or treatment-induced malignant gliomas were treated with varying combinations of temozolomide (150-210 mg/m2/d for 5 days) and oral VP-16 (50 mg/m2/d for 4-12 days). Responses were assessed by MRI scan, and data on clinical course and toxicity were retrospectively obtained from the medical record.

RESULTS

The median age of the 11 patients was 17 years (range 5-23 years). Diagnoses included recurrent brain stem glioma (2), recurrent anaplastic astrocytoma (2), and glioblastoma (7) (3 treatment-induced, 2 malignant transformations of lower grade tumors, 1 recurrence, and 1 second tumor arising 10 months after diagnosis of medulloblastoma). All 11 patients had received radiotherapy (including 4 who received craniospinal radiation), and 7 had prior chemotherapy. Nine patients were treated at first recurrence, two at second recurrence. One patient had a complete response (CR), six had partial responses (PR), and four had progressive disease (PD). The median progression-free survival for the seven responding patients was 6 months (range 4-15+ months). There was one grade 4 neutropenia, but no other grade 3 or 4 toxicities.

CONCLUSIONS

These data suggest there is activity of temozolomide in combination with oral VP-16 for children and young adults with recurrent malignant gliomas.

Advances in treatment of pediatric brain tumors

The long-term survival of children with brain tumor has improved considerably in the last three decades, owing to advances in neuroimaging, neurosurgical, and radiation therapy modalities, coupled with the application of conventional chemotherapy. MRI, MR spectroscopy and diffusion-weighted MRI have contributed to more accurate diagnosis, prognostication and better treatment planning. Neurosurgical treatment has been advanced by the use of functional MRI, and intraoperative image-guided stereotactic techniques and electrophysiologic monitoring. The use of 3-D conformal and intensity-modulated radiation therapy, stereotactic radiosurgery, and radiosensitizing agents has made radiation therapy safer and more effective. Conventional chemotherapy, administered either alone or combined with radiation therapy has improved survival and quality of life of children with brain tumors. These improved outcomes have also occurred, due, in part, to their treatment on collaborative national and international studies. Recent promising diagnostic and therapeutic strategies have resulted from advances in understanding molecular brain tumor biology. Important new approaches include the refinement of drug-delivery strategies, the evaluation of biologic markers to stratify patients for optimal treatment and to exploit these molecular differences using "targeted" therapeutic strategies. These approaches include blocking tumor cell drug resistance mechanisms, immunotherapy, inhibition of molecular signal transduction pathways important in tumorigenesis, anti-angiogenic therapy, and gene therapy. The thrust of such approaches for children with brain tumors is especially directed at reducing the toxicity of therapy and improving quality-of-life, as well as increasing disease-free survival.