Results of three-dimensional stereotactically-guided radiotherapy in recurrent medulloblastoma

Brain and Brain Stem Necrosis After Reirradiation for Recurrent Childhood Primary Central Nervous System Tumors: A PENTEC Comprehensive Review

PURPOSE

Reirradiation is increasingly used in children and adolescents/young adults (AYA) with recurrent primary central nervous system tumors. The Pediatric Normal Tissue Effects in the Clinic (PENTEC) reirradiation task force aimed to quantify risks of brain and brain stem necrosis after reirradiation.

METHODS AND MATERIALS

A systematic literature search using the PubMed and Cochrane databases for peer-reviewed articles from 1975 to 2021 identified 92 studies on reirradiation for recurrent tumors in children/AYA. Seventeen studies representing 449 patients who reported brain and brain stem necrosis after reirradiation contained sufficient data for analysis. While all 17 studies described techniques and doses used for reirradiation, they lacked essential details on clinically significant dose-volume metrics necessary for dose-response modeling on late effects. We, therefore, estimated incidences of necrosis with an exact 95% CI and qualitatively described data. Results from multiple studies were pooled by taking the weighted average of the reported crude rates from individual studies.

RESULTS

Treated cancers included ependymoma (n = 279 patients; 7 studies), medulloblastoma (n = 98 patients; 6 studies), any CNS tumors (n = 62 patients; 3 studies), and supratentorial high-grade gliomas (n = 10 patients; 1 study). The median interval between initial and reirradiation was 2.3 years (range, 1.2-4.75 years). The median cumulative prescription dose in equivalent dose in 2-Gy fractions (EQD22; assuming α/β value = 2 Gy) was 103.8 Gy (range, 55.8-141.3 Gy). Among 449 reirradiated children/AYA, 22 (4.9%; 95% CI, 3.1%-7.3%) developed brain necrosis and 14 (3.1%; 95% CI, 1.7%-5.2%) developed brain stem necrosis with a weighted median follow-up of 1.6 years (range, 0.5-7.4 years). The median cumulative prescription EQD22 was 111.4 Gy (range, 55.8-141.3 Gy) for development of any necrosis, 107.7 Gy (range, 55.8-141.3 Gy) for brain necrosis, and 112.1 Gy (range, 100.2-117 Gy) for brain stem necrosis. The median latent period between reirradiation and the development of necrosis was 5.7 months (range, 4.3-24 months). Though there were more events among children/AYA undergoing hypofractionated versus conventionally fractionated reirradiation, the differences were not statistically significant (P = .46).

CONCLUSIONS

Existing reports suggest that in children/AYA with recurrent brain tumors, reirradiation with a total EQD22 of about 112 Gy is associated with an approximate 5% to 7% incidence of brain/brain stem necrosis after a median follow-up of 1.6 years (with the initial course of radiation therapy being given with conventional prescription doses of ≤2 Gy per fraction and the second course with variable fractionations). We recommend a uniform approach for reporting dosimetric endpoints to derive robust predictive models of late toxicities following reirradiation.

Radiotherapy for Recurrent Medulloblastoma in Children and Adolescents: Survival after Re-Irradiation and First-Time Irradiation

BACKGROUND

Radiotherapy (RT) involving craniospinal irradiation (CSI) is important in the initial treatment of medulloblastoma. At recurrence, the re-irradiation options are limited and associated with severe side-effects.

METHODS

For pre-irradiated patients, patients with re-irradiation (RT2) were matched by sex, histology, time to recurrence, disease status and treatment at recurrence to patients without RT2.

RESULTS

A total of 42 pre-irradiated patients with RT2 were matched to 42 pre-irradiated controls without RT2. RT2 improved the median PFS [21.0 (CI: 15.7-28.7) vs. 12.0 (CI: 8.1-21.0) months] and OS [31.5 (CI: 27.6-64.8) vs. 20.0 (CI: 14.0-36.7) months]. Concerning long-term survival after ten years, RT2 only lead to small improvements in OS [8% (CI: 1.4-45.3) vs. 0%]. RT2 improved survival most without (re)-resection [PFS: 17.5 (CI: 9.7-41.5) vs. 8.0 (CI: 6.6-12.2)/OS: 31.5 (CI: 27.6-NA) vs. 13.3 (CI: 8.1-20.1) months]. In the RT-naïve patients, CSI at recurrence improved their median PFS [25.0 (CI: 16.8-60.6) vs. 6.6 (CI: 1.5-NA) months] and OS [40.2 (CI: 18.7-NA) vs. 12.4 (CI: 4.4-NA) months].

CONCLUSIONS

RT2 could improve the median survival in a matched cohort but offered little benefit regarding long-term survival. In RT-naïve patients, CSI greatly improved their median and long-term survival.

Stereotactic radiosurgery for recurrent pediatric brain tumors: clinical outcomes and toxicity

OBJECTIVE

Recurrence of brain tumors in children after the initial course of treatment remains a problem. This study evaluated the efficacy and safety of reirradiation using stereotactic radiosurgery (SRS) in patients with recurrent pediatric primary brain tumors.

METHODS

This IRB-approved retrospective review included pediatric patients with recurrent primary brain tumors treated at Stanford University from 2000 to 2019 using frameless SRS. Time to local failure (LF) and distant intracranial failure (DIF) were measured from the date of SRS and analyzed using competing risk analysis. Overall survival (OS) and progression-free survival (PFS) were analyzed with the Kaplan-Meier method.

RESULTS

In total, 37 patients aged 2–24 years (median age 11 years at recurrence) were treated for 48 intracranial tumors. Ependymoma (38%) and medulloblastoma (22%) were the most common tumor types. The median (range) single fraction equivalent dose of SRS was 16.4 (12–24) Gy. The median (range) follow-up time was 22.9 (1.5–190) months. The median OS of all patients was 36.8 months. Eight of 40 (20%) lesions with follow-up imaging locally recurred. The 2-year cumulative incidence of LF after reirradiation with SRS was 12.8% (95% CI 4.6%–25.4%). The 2-year cumulative incidence of DIF was 25.3% (95% CI 12.9%–39.8%). The median PFS was 18 months (95% CI 8.9–44). Five (10.4%) patients developed toxicities potentially attributed to SRS, including cognitive effects and necrosis.

CONCLUSIONS

Reirradiation using SRS for recurrent pediatric brain tumors appears safe with good local control. Innovations that improve overall disease control should continue because survival outcomes after relapse remain poor.

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.

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.

A rapid review of evidence and recommendations from the SIOPE radiation oncology working group to help mitigate for reduced paediatric radiotherapy capacity during the COVID-19 pandemic or other crises

OBJECTIVE

To derive evidence-based recommendations for the optimal utilisation of resources during unexpected shortage of radiotherapy capacity.

METHODS AND MATERIALS

We have undertaken a rapid review of published literature on the role of radiotherapy in the multimodality treatment of paediatric cancers governing the European practise of paediatric radiotherapy. The derived data has been discussed with expert paediatric radiation oncologists to derive a hierarchy of recommendations.

RESULTS

The general recommendations to mitigate the potential detriment of an unexpected shortage of radiotherapy facilities include: (1) maintain current standards of care as long as possible (2) refer to another specialist paediatric radiotherapy department with similar level of expertise (3) prioritise use of existing radiotherapy resources to treat patients with tumours where radiotherapy has the most effect on clinical outcome (4) use chemotherapy to defer the start of radiotherapy where timing of radiotherapy is not expected to be detrimental (5) active surveillance for low-grade tumours if appropriate and (6) consider iso-effective hypofractionated radiotherapy regimens only for selected patients with predicted poor prognosis. The effectiveness of radiotherapy and recommendations for prioritisation of its use for common and challenging paediatric tumours are discussed.

CONCLUSION

This review provides evidence-based treatment recommendations during unexpected shortage of paediatric radiotherapy facilities. It has wider applications for the optimal utilisation of facilities, to improve clinical outcome in low- and middle-income countries, where limited resources continue to be a challenge.

EANO-EURACAN clinical practice guideline for diagnosis, treatment, and follow-up of post-pubertal and adult patients with medulloblastoma

The European Association of Neuro-Oncology (EANO) and EUropean RAre CANcer (EURACAN) guideline provides recommendations for the diagnosis, treatment, and follow-up of post-pubertal and adult patients with medulloblastoma. The guideline is based on the 2016 WHO classification of tumours of the CNS and on scientific developments published since 1980. It aims to provide direction for diagnostic and management decisions, and for limiting unnecessary treatments and cost. In view of the scarcity of data in adults with medulloblastoma, we base our recommendations on adult data when possible, but also include recommendations derived from paediatric data if justified. Our recommendations are a resource for professionals involved in the management of post-pubertal and adult patients with medulloblastoma, for patients and caregivers, and for health-care providers in Europe. The implementation of this guideline requires multidisciplinary structures of care, and defined processes of diagnosis and treatment.

Salvage Re-irradiation Options in Adult Medulloblastoma: A Case Report and Review of the Literature

BACKGROUND/AIM

Medulloblastoma is a rare tumor of adult age, while it occurs more frequently in children. Given the rarity, there is a lack of evidence for the treatment of recurrent disease. Few data are available about salvage re-irradiation collecting very heterogeneous series.

CASE REPORT

A 51-year-old male presented with headache, nausea, double vision, and gait disorders. A contrast-enhanced brain-MRI showed the presence of multifocal medulloblastoma. After surgery, adjuvant craniospinal radiotherapy was performed, chemotherapy was stopped due to toxicity. After 27 months, a new MRI and a Methionine-PET revealed a late pontocerebellar relapse; multidisciplinary board decided for a SBRT treatment. The second course of RT was well tolerated and 14 months later, the patient is alive in good general conditions, with no evidence of disease.

CONCLUSION

Our experience supports the use of salvage stereotactic radiotherapy as a safe and effective treatment option.

Outcomes of salvage re-irradiation in recurrent medulloblastoma correlate with age at initial diagnosis, primary risk-stratification, and molecular subgrouping

PURPOSE

To report outcomes of salvage re-irradiation (re-RT) in recurrent/progressive medulloblastoma (MB).

METHODS

Medical records of patients treated with curative-intent re-RT as multi-modality management for recurrent/progressive MB between 2008 and 2018 were analyzed retrospectively.

RESULTS

A total of 28 patients (median age 18 years at index diagnosis) were included. Molecular subgrouping was done using real-time reverse transcriptase polymerase chain reaction (RT-PCR) based on the differential expression of select set of 12 protein coding genes and 9 microRNAs. Fifteen of 17 (88%) patients with sonic hedgehog (SHH)-MB developed isolated local recurrence within the index tumor-bed, while 5 of 7 (72%) patients with Group 4 MB developed localized relapse outside the posterior fossa. Diffuse neuraxial dissemination was seen in 2 patients with SHH-MB, and one each of Group 4 and wingless (WNT)-MB. Molecular subgrouping was not known in 3 patients. The dose and volume of re-RT was based on site and patterns of relapse, comprising unifocal in 18 (64%), multi-focal in 3 (11%), and repeat craniospinal irradiation (re-CSI) in 7 (25%) patients. Median interval from primary irradiation to re-RT was 49.5 months (range 24-98 months) with median cumulative biologically effective dose of 117 Gy (range 78-132 Gy). All patients received platinum-based salvage chemotherapy either before or after re-RT. One patient developed symptomatic radiation necrosis following re-CSI. At a median follow-up of 24 months (range 6-84 months), 2-year post-re-RT progression-free survival (PFS) and overall survival (OS) was 46% and 51% respectively. Younger age (< 18 years) at index diagnosis, primary risk stratification (standard-risk) and molecular subgrouping (Group 4) were associated with significantly better post-re-RT outcomes.

CONCLUSION

Salvage re-RT provides good local control and encouraging survival outcomes with acceptable toxicity in selected patients with recurrent/progressive MB.

Radiosurgery or hypofractionated stereotactic radiotherapy after craniospinal irradiation in children and adults with medulloblastoma and ependymoma

PURPOSE

To assess the results and tolerance of radiosurgery/hypofractionated stereotactic radiotherapy performed after craniospinal irradiation for recurrent tumor.

METHODS

Fourteen patients aged 3-46 years, diagnosed with medulloblastoma (10), anaplastic ependymoma (3), and primitive neuroectodermal tumor (1). All patients had craniospinal irradiation (CSI) with the total dose of 30.6-36 Gy and boost to 53.9-60 Gy either during primary or during second-line treatment. Twelve patients were irradiated with a single dose of 6-15 Gy (median 14.5 Gy). One received three fractions of 5 Gy and one six fractions of 5 Gy. In statistical analysis, the Kaplan-Meier method and log-rank test were used. The overall survival was calculated from the date of the end of stereotactic radiosurgery to the date of death or last contact.

RESULTS

Recurrences were diagnosed after the median time of 16 months after the end of primary treatment. Eleven patients died during the follow-up. The follow-up for the 3 patients still alive was 6.7, 40.5, and 41.4 months, respectively. One- and 2-year overall survival (OS) was 70% and 39%. Patients who had ECOG performance status of 0 at the time of diagnosis of the disease trended to have better 2-year OS compared to those evaluated as ECOG 1 (p = 0.057). Treatment results were evaluable in 12 patients. Local control (stabilization or regression of the lesion) was achieved in 9 (75%). Overall disease progression was 67%. No patient developed radiation-induced necrosis. The treatment was well tolerated and no serious adverse effects were observed. Eleven patients were given steroids as a prevention of brain edema and four of them needed continuation of this treatment afterwards. In 7 patients, symptoms of brain edema were observed during the first weeks after reirradiation.

CONCLUSIONS

Stereotactic radiosurgery or hypofractionated stereotactic radiotherapy is an effective treatment method of the local recurrence after CSI and can be performed safely in heavily pre-treated patients.

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.

Analysis of risk and predictors of brain radiation necrosis after radiosurgery

In this study, we examined the factors contributing to brain radiation necrosis and its predictors of patients treated with Cyberknife radiosurgery. A total of 94 patients with primary or metastatic brain tumours having been treated with Cyberknife radiotherapy from Sep. 2006 to Oct. 2011 were collected and retrospectively analyzed. Skull based tracking was used to deliver radiation to 104 target sites. and the prescribed radiation doses ranged from 1200 to 4500 cGy in 1 to 8 fractions with a 60% to 87% isodose line. Radiation necrosis was confirmed by imaging or pathological examination. Associations between cerebral radiation necrosis and factors including diabetes, cardio-cerebrovascular disease, target volume, isodose line, prescribed dosage, number of fractions, combination with whole brain radiation and biologically equivalent dose (BED) were determined by logistic regression. ROC curves were created to measure the predictive accuracy of influence factors and identify the threshold for brain radiation necrosis. Our results showed that radiation necrosis occurred in 12 targets (11.54%). Brain radiation necrosis was associated by BED, combination with whole brain radiotherapy, and fractions (areas under the ROC curves = 0.892±0.0335, 0.650±0.0717, and 0.712±0.0637 respectively). Among these factors, only BED had the capability to predict brain radiation necrosis, and the threshold dose was 7410 cGy. In conclusion, BED is the most effective predictor of brain radiation necrosis, with a dose of 7410 cGy being identified as the threshold.

Medulloblastoma

Medulloblastoma accounts for nearly 10% of all childhood brain tumors. These tumors occur exclusively in the posterior fossa and have the potential for leptomeningeal spread. Treatment includes a combination of surgery, radiation therapy (in patients >3 years old). Patients >3 years old are stratified based on the volume of postoperative residual tumor and the presence or absence of metastases into "standard risk" and "high risk" categories with long-term survival rates of approximately 85% and 70%, respectively. Outcomes are inferior in infants and children younger than 3 years with exception of those patients with the medulloblastoma with extensive nodularity histologic subtype. Treatment for medulloblastoma is associated with significant morbidity, especially in the youngest patients. Recent molecular subclassification of medulloblastoma has potential prognostic and therapeutic implications. Future incorporation of molecular subgroups into treatment protocols will hopefully improve both survival outcomes and posttreatment quality of life.

Reirradiation of Pediatric Tumors Using Hypofractionated Stereotactic Radiotherapy

BACKGROUND

This study aimed to evaluate the efficacy and safety of hypofractionated stereotactic radiotherapy for reirradiation of recurrent pediatric tumors.

METHODS AND MATERIALS

The study included 23 pediatric patients who were reirradiated using hypofractionated stereotactic radiotherapy in the radiation oncology department between January 2008 and November 2013. In total, 33 tumors were treated-27 (82%) cranial and 6 (18%) extracranial. Hypofractionated stereotactic radiotherapy was administered due to recurrent disease in 31 (94%) tumors and residual disease in 2 (6%) tumors. The median total dose was 25 Gy (range: 15-40 Gy), and the median follow-up was 20 months (range: 2-68 months).

RESULTS

The 1-year and 2-year local control rates in the entire study population were 42% and 31%, respectively. The median local control time was 11 months (range: 0-54 months) following hypofractionated stereotactic radiotherapy. The patients with tumor response after hypofractionated stereotactic radiotherapy had significantly longer local control than the patients with post-hypofractionated stereotactic radiotherapy tumor progression (21 vs 3 months, P < .001). Tumor volume <1.58 cm³ was correlated (not significantly) with better local control (23 vs 7 months, P = .064).

CONCLUSION

Reirradiation of pediatric tumors using hypofractionated stereotactic radiotherapy is a safe and effective therapeutic approach. This treatment modality should be considered as a treatment option in selected pediatric patients.

Medulloblastoma in an Adult With Late Extraneural Metastases to the Mediastinum

Background. Medulloblastoma, although the most common brain tumor of childhood, is exceedingly rare in adults. These tumors have a propensity for local recurrence and to metastasize along the leptomeninges; however, extraneural metastases are very rare and typically occur in the bone or bone marrow. We have not come across any case in literature of medulloblastoma with mediastinal metastases in an adult. Case Presentation. We report a case of medulloblastoma in a 38-year-old lady who was treated with surgery followed by craniospinal radiation. Ten years later she presented with hoarseness from true vocal cord paralysis. She was diagnosed to have infiltrating metastases of her medulloblastoma to the mediastinum, which was confirmed by biopsy. There was no local recurrence. This was treated with chemotherapy followed by stem cell rescue, and she remained progression free for 2 years. Conclusion. Medulloblastomas are rare in adults and can present with late extraneural metastases following treatment. Although most common reported sites are bone and bone marrow, late metastases to other unexpected areas like the mediastinum are possible too and warrant awareness. This can be treated with chemotherapy followed by high-dose chemotherapy and stem cell rescue in a young patient with good performance status.

Management of recurrent medulloblastoma in adult patients: a systematic review and recommendations

Medulloblastoma accounts for almost one-third of pediatric central nervous system (CNS) cancers, but is very rare in the adult population. As a result, adult patients with medulloblastoma are often treated according to therapies developed for children with similarly staged disease at diagnosis, based on the assumption that adult and pediatric tumors have similar properties. The purpose of this review was to summarize the evidence and to make recommendations for the management of recurrent disease in adult patients with medulloblastoma. We conducted a systematic literature search to find publications addressing treatment of recurrent medulloblastoma in adults. Current treatment strategies for adult patients with relapsed medulloblastoma are based on the results of retrospective case series and published consensus recommendations, and include maximal safe re-resection where possible, combined with chemotherapy and/or re-irradiation. We describe the results of 13 publications involving 66 adult patients treated with high-dose chemotherapy (HDCT) plus stem cell transplantation for recurrent medulloblastoma. HDCT with stem cell transplantation may be a treatment option for a small proportion of adult patients who are unlikely to benefit from conventional chemotherapy and who are fit and have their disease recurrence contained within the CNS. Potential cases in which stem cell transplantation is being considered should be discussed at a multidisciplinary tumor board which includes involvement by hematologic oncologists and transplant specialists.

Response to bevacizumab, irinotecan, and temozolomide in children with relapsed medulloblastoma: a multi-institutional experience

PURPOSE

Chemotherapy for relapsed medulloblastoma has been inadequate, and most patients succumb to disease.

METHODS

We retrospectively reviewed nine cases of relapsed medulloblastoma treated with bevacizumab, irinotecan, ± temozolomide. Patients received one to three prior therapeutic regimens. Five patients received 10 mg/kg bevacizumab and 125-150 mg/m(2) irinotecan IV every 2 weeks, with temozolomide, starting at a median dose of 150 mg/m(2) orally for 5 days monthly. Two patients received bevacizumab and irinotecan, but not temozolomide, due to provider preference. Two of nine patients received 15 mg/kg bevacizumab IV, 90 mg/m(2) irinotecan orally for five consecutive days, 100 mg/m(2)/day temozolomide IV for 5 days, and 1.5 mg/m(2) vincristine IV, each administered every 21 days.

RESULTS

Median time to progression was 11 months. Median overall survival was 13 months. Objective tumor response at 3 months was 67 %, including six patients with partial response (PR) and three patients with stable disease (SD). At 6 months, objective response was 55 %, with two patients with PR and three with complete response. Additionally, one patient had SD and three had PD. Two patients remain alive and progression free at 15 and 55 months; another is alive with disease at 20 months. Toxicities included two patients with grade III neutropenia, two with grade III thrombocytopenia, one with grade III elevation of liver function tests, and one patient with grade III diarrhea.

CONCLUSIONS

The combination of bevacizumab and irinotecan, with or without temozolomide, produces objective responses with minimal toxicity in children with recurrent medulloblastoma. Prospective clinical trials are needed to evaluate the efficacy of this strategy.

[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.

Reirradiation and concomitant metronomic temozolomide: an efficient combination for local control in medulloblastoma disease?

Medulloblastoma (MB) is the most common malignant pediatric brain tumor and a rare adulthood tumor. Twenty percent to 30% of patients relapses and displays a poor prognosis. The management of recurrent disease represents a medical challenge as salvage therapy with high-dose chemotherapy is disappointing. We report a pilot study of reirradiation and concomitant metronomic temozolomide of MB focal recurrence. Five patients from 10 to 27 years old at time of first diagnosis were treated initially with upfront radiation therapy at full dose. They relapsed focally and progressed under chemotherapy with a time recurrence ranged from 2 to 15 years after initial diagnosis. Patients were then treated with 3-dimensional conformal reirradiation focused on the relapsed disease with a median dose of 28 Gy (1.8 Gy per fraction) and concomitant temozolomide (75 mg/m/d) alone or as part of a multidrug metronomic regimen. Five complete responses were obtained at the end of metronomic radiochemotherapy. The median follow-up was 28 months. At last follow-up, 3 patients progressed outside radiation field under maintenance chemotherapy, and 1 is free of disease. Only 1 patient relapsed in the reirradiation field. No neurological toxicity was observed. These results indicate a possible radiosensitizing effect of concomitant metronomic temozolomide with radiation therapy. This association could play a role in the management of high-risk MB patient with oligometastasis disease to increase local control.

Reirradiation of relapsed brain tumors in children

AIM

The aim of this study was to evaluate toxicity and response to fractionated reirradiation (FR) of relapsed primary brain tumors in children.

BACKGROUND

The treatment options for recurrent brain tumors in children previously irradiated are limited. Reirradiation is performed with fear due to the cumulative late CNS toxicity and the lack of a significant chance of cure.

MATERIALS AND METHODS

Between 2008 and 2009, eight children with a median age of 14.5 years with a diagnosis of a recurrent brain tumor underwent reirradiation. Initially, all patients were treated with surgery, chemotherapy and radiotherapy. The median time to the first recurrence after the initial treatment was 19.5 months. Intervals between radiotherapy courses were in the range of 5-51 mos. All retreatments were carried out with 3D image-based conformal methods. The total prescription dose was 40 Gy in a fraction of 5 × 2 Gy/week. The total cumulative dose ranged from 65 to 95 Gy (median: 75 Gy). The median cumulative biologically effective dose was 144 Gy (range: 126-181 Gy).

RESULTS

The median overall survival and progression free survival measured from the beginning of reirradiation was 17.5 and 6.5 months, respectively. During the first evaluation, four patients showed a complete or partial response, two did not respond radiologically. Two children were progressive at the time of reirradiation. Among children with progression that occurred during the first year after reirradiation, only two progressed in the treatment area. The repeated irradiation was well tolerated by all patients. No late complications have been observed.

CONCLUSION

In the absence of other treatment possibilities, the fractionated reirradiation with highly conformal three-dimensional planning could be a therapeutic choice in case of recurrent brain tumors in children. The control of craniospinal dissemination remains to be the main problem.

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.

A retrospective study of surgery and reirradiation for recurrent ependymoma

PURPOSE

To report disease control for patients with recurrent ependymoma (EP) treated with surgery and a second course of radiation therapy (RT(2)).

PATIENTS AND METHODS

Thirty-eight pediatric patients (median age, 2.7 years) with initially localized EP at the time of definitive RT underwent a second course of RT after local (n = 21), metastatic (n = 13), or combined (n = 4) failure. Reirradiation included radiosurgery (n = 6), focal fractionated reirradiation (n = 13), or craniospinal irradiation (CSI; n = 19).

RESULTS

Initial time to failure was 16 months, and median age at second treatment was 4.8 years. Radiosurgery resulted in significant brainstem toxicity and one death (median dose, 18 Gy). Progression-free survival ratio was greater than unity for 4 of 6 patients; there was one long-term survivor. Three of 13 patients treated using focal fractionated reirradiation (median combined dose, 111.6 Gy) experienced metastasis. The CSI was administered to 12 patients with metastatic failure, 3 patients with local failure, and 4 patients with combined failure. The 4-year event-free survival rate was 53% +/- 20% for 12 patients with metastatic failure treated with CSI. Failure after CSI was observed in 1 of 3 patients with a history of local failure and 3 of 4 patients with a history of combined failure.

CONCLUSION

Patients with locally recurrent EP experience durable local tumor control, but remain at risk of metastasis. Patients with metastatic EP failure may receive salvage therapy that includes a component of CSI. Durability of disease control and long-term effects from this approach require further follow-up.

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.

Phase I study of intraoperative radiotherapy with photon radiosurgery system in children with recurrent brain tumors: preliminary report of first dose level (10 Gy)

PURPOSE

To describe the preliminary results after intraoperative radiotherapy (IORT) with the photon radiosurgery system in children with recurrent brain tumors treated at the first dose level (10 Gy) of a Phase I protocol.

METHODS AND MATERIALS

A Phase I IORT dose escalation protocol was initiated at Children's Memorial Hospital to determine the maximal tolerated IORT dose in children with recurrent brain tumors.

RESULTS

Fourteen children have received IORT thus far. Eight had been previously irradiated. Thirteen children had ependymoma. The median follow-up was 16 months. Three patients (21%) developed radiation necrosis on follow-up MRI scans 6 to 12 months after IORT. They had not been previously irradiated and had received 10 Gy to a depth of 5 mm. One required surgery and the other two had resolution of their lesions without treatment. All 3 patients were asymptomatic at the last follow-up. No other late toxicity was observed at the last follow-up visit. Eight patients (57%) had tumor control within the surgical bed after IORT.

CONCLUSION

Our findings have demonstrated the safety and feasibility of IORT to a dose of 10 Gy to 2 mm in children with previously irradiated brain tumors. IORT to a dose of 10 Gy at 5 mm was associated with a greater complication rate.

Stereotactic radiation therapy with chemotherapy in the management of recurrent medulloblastomas

Medulloblastomas are highly lethal tumors when they recur. Very few patients survive with conventional treatment. This report documents the preliminary study results of a treatment for recurrent medulloblastomas consisting of stereotactic radiation therapy (SRT) with chemotherapy. Four patients had local recurrence without apparent metastases and 8 patients had metastases with or without local recurrence. Twelve patients with 18 lesions underwent SRT as a single session (n=8) or in a hypofractionated manner (n=10) using a gamma knife or modified linear accelerator. All patients then received systemic chemotherapy. Five patients were treated with one to two sequential courses of high-dose chemotherapy with peripheral blood stem cell transplantation. The reduction in tumor size after SRT was often remarkable. Fourteen of 18 lesions treated disappeared 1-6 months after SRT. Two of 4 patients who had local recurrences without apparent metastasis at the time of SRT are alive without evidence of disease 70 and 72 months after SRT, respectively. In contrast, all 8 patients with metastasis had new lesions either in the spinal canal or on the surface of the brain outside the target area of SRT. Median progression-free survival and overall survival from the time of SRT were 9 and 19 months, respectively. The Kaplan-Meier estimates of PFS and overall survival at 3 years were 17 and 25%, respectively. One patient had brainstem edema after SRT causing bulbar palsy and quadriparesis. One patient died of toxicity of chemotherapy. Our experience suggests that local recurrence can be controlled by SRT with chemotherapy but survival of patients with metastases can not be improved effectively by SRT in conjunction with aggressive chemotherapy.

Review of the prognostic factors in medulloblastoma of children and adults

Medulloblastoma (MB) is rare in adults, accounting for 1% of all primary tumours of the central nervous system (CNS). Based on the assumption that the disease pattern in adults is similar to that in children, adults with medulloblastoma are treated using paediatric protocols. Thanks to progress made in recent years, long-term survival is now possible, with overall ranging from 50 to 60% at 5 years and 40 to 50% at 10 years. However, effective therapy may have devastating long-term side effects, including neuro-psychic and neuro-endocrine sequelae and cognitive dysfunction, especially in young adults. Great interest has been expressed in new biological and molecular prognostic factors, which, combined with clinical variables, may allow a more satisfactory stratification of patients.