Radio-induced gliomas: 20-year experience and critical review of the pathology

Radiotherapy-induced glioblastoma: distinct differences in overall survival, tumor location, pMGMT methylation and primary tumor epidemiology in Hong Kong chinese patients

INTRODUCTION

Radiotherapy-induced glioblastomas (RIGB) are a well-known late and rare complication of brain irradiation. Yet the clinical, radiological and molecular characteristics of these tumors are not well characterized.

METHODS

This was a retrospective multicentre study that analysed adult patients with newly diagnosed glioblastoma over a 10-year period. Patients with RIGB were identified according to Cahan's criteria for radiation-induced tumors. A case-control analysis was performed to compare known prognostic factors for overall survival (OS) with an independent cohort of IDH-1 wildtype de novo glioblastomas treated with standard temozolomide chemoradiotherapy. Survival analysis was performed by Cox proportional hazards regression.

RESULTS

A total of 590 adult patients were diagnosed with glioblastoma. 19 patients (3%) had RIGB. The mean age of patients upon diagnosis was 48 years ± 15. The mean latency duration from radiotherapy to RIGB was 14 years ± 8. The mean total dose was 58Gy ± 10. One-third of patients (37%, 7/19) had nasopharyngeal cancer and a fifth (21%, 4/19) had primary intracranial germinoma. Compared to a cohort of 146 de novo glioblastoma patients, RIGB patients had a shorter median OS of 4.8 months versus 19.2 months (p-value: <.001). Over a third of RIGBs involved the cerebellum (37%, 7/19) and was higher than the control group (4%, 6/146; p-value: <.001). A fifth of RIGBs (21%, 3/19) were pMGMT methylated which was significantly fewer than the control group (49%, 71/146; p-value: .01). For RIGB patients (32%, 6/19) treated with re-irradiation, the one-year survival rate was 67% and only 8% for those without such treatment (p-value: .007).

CONCLUSION

The propensity for RIGBs to develop in the cerebellum and to be pMGMT unmethylated may contribute to their poorer prognosis. When possible re-irradiation may offer a survival benefit. Nasopharyngeal cancer and germinomas accounted for the majority of original malignancies reflecting their prevalence among Southern Chinese.

Molecular Characterization of Adult Tumors Diagnosed as Cerebellar Glioblastomas Identifies Subgroups Associated With Prognosis

Adult tumors diagnosed as cerebellar glioblastoma (cGBM) are rare and their optimal classification remains to be determined. The aim of this study was to identify subgroups of cGBM based on targeted molecular analysis. cGBM diagnosed between 2003 and 2017 were identified from the French Brain Tumor Database and reviewed according to the WHO 2021 classification. The following molecular alterations were studied: IDH1/2 , H3F3A , FGFR1 , BRAF , TERT promoter mutations, EGFR amplification, MGMT promoter methylation, and alternative lengthening of telomere status. DNA methylation profile was assessed in a subset of cases. Eighty-three cGBM were included and could be classified into 6 mutually exclusive subgroups associated with median age at diagnosis (MA) and prognosis: TERT -mutant and/or EGFR -amplified tumors (n=22, 26.5%, MA=62 y, median overall survival [OS]=4 mo), H3K27M-mutant tumors (n=15, 18.1%, MA=48 y, median OS=8 mo), mitogen-activated protein kinases (MAPK) pathway-activated tumors ( FGFR1 , BRAF mutation, or occurring in neurofibromatosis type I patients, n=15, 18.1%, MA=48 y, median OS=57 mo), radiation-associated tumors (n=5, 6%, MA=47 y, median OS=5 mo), IDH-mutant tumors (n=1), and unclassified tumors (n=25, 30.1%, MA=63 y, median OS=17 mo). Most MAPK pathway-activated tumors corresponded to high-grade astrocytomas with piloid features based on DNA methylation profiling. In multivariate analysis, MAPK pathway-activating alterations, ATRX loss of expression, and alternative lengthening of telomere positivity were independently associated with a better outcome and TERT / EGFR alterations with a worse outcome. cGBM display an important intertumoral heterogeneity. Targeted molecular analysis enables to classify the majority of tumors diagnosed as cGBM into mutually exclusive and clinically relevant subgroups. The presence of MAPK pathway alterations is associated with a much better prognosis.

Clinical and Pathologic Characterization of 94 Radiation-Associated Sarcomas: Our Institutional Experience

Radiation-associated sarcomas are an uncommon complication of therapeutic radiation. However, their prevalence has increased with the more widespread use of this treatment modality. The clinical, pathologic and genetic characteristics of radiation-associated sarcomas are not fully understood. In this study we describe the features of 94 radiation-associated sarcomas reviewed at our institution between 1993 and 2018, evaluate their overall survival (OS) and progression-free survival (PFS) outcomes, and compare them with their sporadic counterparts reviewed within the same time period. Histologic subtypes of all radiation-associated sarcomas included 31 (33%) undifferentiated sarcomas, 20 (21%) osteosarcomas, 17 (18%) angiosarcomas, 10 (11%) malignant peripheral nerve sheath tumor (MPNST), 9 (10%) leiomyosarcomas, 4 (4%) myxofibrosarcomas, and 3 (3%) rhabdomyosarcomas. Six patients had a documented cancer predisposition syndrome. The most common preceding neoplasms included adenocarcinoma (47%) and squamous cell carcinoma (19%), with a mean latency of 13 years. Multivariable Cox survival analysis demonstrated that advanced stage at diagnosis based on pT category (AJCC eighth edition) and fragmented resection were associated with worse survival outcomes. In addition, there was a statistically significant difference in PFS between radiation-associated undifferentiated sarcomas and MPNST when compared to their sporadic counterparts using the Kaplan-Meier method and Log-rank analysis. Overall, our study shows that radiation-associated sarcomas comprise a wide clinico-pathologic spectrum of disease, with a tendency for aggressive clinical behavior. This study further delineates the understanding of these uncommon diseases. Future studies are necessary to better understand the genetic and epigenetic changes that drive the differences in behavior between these tumors and their sporadic counterparts, and to offer better treatment options.

Assessment of therapeutic outcome and role of reirradiation in patients with radiation-induced glioma

Background

We sought to clarify the optimal follow-up, therapeutic strategy, especially the role of reirradiation, and the diagnostic impact of isocitrate dehydrogenase (IDH) 1 and 2 mutation status in patients with radiation-induced glioma (RIG).

Methods

We retrospectively reviewed the clinical characteristics and treatment outcomes of 11 patients with high-grade glioma who satisfied Cahan’s criteria for RIG in our database during 2001–2021. IDH 1/2 mutations were analyzed by Sanger sequencing and/or pyrosequencing.

Results

The RIGs included glioblastoma with IDH 1/2 wild-type (n = 7), glioblastoma not otherwise specified (n = 2), anaplastic astrocytoma with IDH1/2 wild-type (n = 1), and anaplastic astrocytoma not otherwise specified (n = 1). The median period from primary disease and RIG diagnosis was 17 years (range: 9–30 years). All patients underwent tumor removal or biopsy, 5 patients postoperatively received reirradiation combined with chemotherapy, and 6 patients were treated with chemotherapy alone. The median progression-free and survival times were 11.3 and 28.3 months. The median progression-free survival time of patients treated with reirradiation and chemotherapy (n = 5) tended to be longer than that of patients that received chemotherapy alone (n = 6) (17.0 vs 8.1 months). However, the median survival time was similar (29.6 vs 27.4 months). Local recurrence was observed in 5 patients treated with chemotherapy alone, whereas in 2 patients among 4 patients treated with reirradiation and chemotherapy. None of the patients developed radiation necrosis. In one case, the primary tumor was diffuse astrocytoma with IDH2 mutant, and the secondary tumor was glioblastoma with IDH 1/2 wild-type. Based on the difference of IDH2 mutation status, the secondary tumor with IDH 1/2 wild-type was diagnosed as a de novo tumor that was related to the previous radiation therapy.

Conclusions

RIG can occur beyond 20 years after successfully treating the primary disease using radiotherapy; thus, cancer survivors should be informed of the long-term risk of developing RIG and the need for timely neuroimaging evaluation. Reirradiation combined with chemotherapy appears to be feasible and has favorable outcomes. Determining the IDH1/2 mutational status is useful to establish RIG diagnosis when the primary tumor is glioma.

Defining the molecular features of radiation-induced glioma: A systematic review and meta-analysis

Background

Cranial radiation therapy is essential in treating many pediatric cancers, especially brain tumors; however, its use comes with the risk of developing second malignancies. Cranial radiation-induced gliomas (RIGs) are aggressive high-grade tumors with a dismal prognosis, for which no standard therapy exists. A definitive molecular signature for RIGs has not yet been established. We sought to address this gap by performing a systematic review and meta-analysis of the molecular features of cranial RIGs.

Methods

A systematic review of the literature was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Articles and case reports that described molecular analyses of cranial radiation-induced high-grade gliomas were identified and evaluated, and data extracted for collation.

Results

Of 1727 records identified, 31 were eligible, containing 102 unique RIGs with molecular data. The most frequent genetic alterations in RIGs included PDGFRA or TP53 mutations, PDGFRA or CDK4 amplifications, and CDKN2A deletion, along with 1q gain, 1p loss and 13q loss. Of note, mutations in ACVR1, EGFR, H3F3A, HIST1H3B, HIST1H3C, IDH2, SMARCB1 or the TERT promoter were not observed. A comparative analysis revealed that RIGs are molecularly distinct from most other astrocytomas and gliomas and instead align most closely with the pedGBM_RTK1 subgroup of pediatric glioblastoma.

Conclusions

This comprehensive analysis highlights the major molecular features of RIGs, demonstrates their molecular distinction from many other astrocytomas and gliomas, and reveals potential genetic drivers and therapeutic targets for this currently fatal disease.

Radiation-induced gliomas represent H3-/IDH-wild type pediatric gliomas with recurrent PDGFRA amplification and loss of CDKN2A/B

Long-term complications such as radiation-induced second malignancies occur in a subset of patients following radiation-therapy, particularly relevant in pediatric patients due to the long follow-up period in case of survival. Radiation-induced gliomas (RIGs) have been reported in patients after treatment with cranial irradiation for various primary malignancies such as acute lymphoblastic leukemia (ALL) and medulloblastoma (MB). We perform comprehensive (epi-) genetic and expression profiling of RIGs arising after cranial irradiation for MB (n = 23) and ALL (n = 9). Our study reveals a unifying molecular signature for the majority of RIGs, with recurrent PDGFRA amplification and loss of CDKN2A/B and an absence of somatic hotspot mutations in genes encoding histone 3 variants or IDH1/2, uncovering diagnostic markers and potentially actionable targets.

Radiation induced glioma in a sexagenarian: A case report

INTRODUCTION

Radiation induced gliomas often occurs after radiation therapy for other brain tumors. Medulloblastoma often occurs in children and its associated radiation-induced glioblastoma multiforme's (GBM) after radiotherapy often has a long latency period. Our case is very unique because the medulloblastoma was detected at an advance age and the latency period of radiation-induced GBM was relatively shorter.

PATIENTS CONCERNS

A 64-year-old male was first admitted at our hospital in March 2018 with dizziness, vomiting, and blurred vision.

DIAGNOSIS

Magnetic resonance imaging of brain revealed a lesion with local mixed density and mass enhancement in left cerebellar region. Histopathology established medulloblastoma (World Health Organization) grade 4 and a classic histological subtype after surgery.

INTERVENTION

Surgical resection followed by radiation therapy were the initial therapeutic modalities.

OUTCOMES

In April 2019, the patient was readmitted with dizziness and blurred vision. Magnetic resonance imaging showed the left cerebellar hemisphere bulky enhancement lesion. Again, a multimodal therapy comprising surgical resection, radiation therapy as well as chemotherapy was adapted after histopathology established GBM.

LESION

Radiotherapy for medulloblastoma patients at advance ages is a critical predisposing factor for the development of radiation-induced GBM in a very short period of time. We suggest that, radiotherapy as adjuvant therapy for medulloblastoma patients at advance ages should be chosen with extreme caution.

Multiple, Primary Brain Tumors with Diverse Origins and Different Localizations: Case Series and Review of the Literature

Background:

Multiple, primary brain tumors with different histological types occurring in the same patient are extremely rare. Several hypotheses have been proposed, and the pathophysiology of coexisting tumors has long been debated; however, due to low incidence, standard practices for this scenario are still inconclusive.

Case Description:

The authors describe 6 cases of coexisting tumors. By conducting a literature research focused on the computed tomography (CT) era and patients without prior radiation or phakomatosis. Sixty-five such reported cases were identified. In addition, the authors summarize their experience in 6 patients including histopathological features, chronological presentations, outcomes, mortality, and management from their series as well as from previous cases from the reported literature.

Conclusion:

The coexistence of multiple, primary brain tumors is an interesting condition. Surgical management remains the major treatment; malignant histology has a poor prognostic factor.

The genetic landscape of gliomas arising after therapeutic radiation

Radiotherapy improves survival for common childhood cancers such as medulloblastoma, leukemia, and germ cell tumors. Unfortunately, long-term survivors suffer sequelae that can include secondary neoplasia. Gliomas are common secondary neoplasms after cranial or craniospinal radiation, most often manifesting as high-grade astrocytomas with poor clinical outcomes. Here, we performed genetic profiling on a cohort of 12 gliomas arising after therapeutic radiation to determine their molecular pathogenesis and assess for differences in genomic signature compared to their spontaneous counterparts. We identified a high frequency of TP53 mutations, CDK4 amplification or CDKN2A homozygous deletion, and amplifications or rearrangements involving receptor tyrosine kinase and Ras-Raf-MAP kinase pathway genes including PDGFRA, MET, BRAF, and RRAS2. Notably, all tumors lacked alterations in IDH1, IDH2, H3F3A, HIST1H3B, HIST1H3C, TERT (including promoter region), and PTEN, which genetically define the major subtypes of diffuse gliomas in children and adults. All gliomas in this cohort had very low somatic mutation burden (less than three somatic single nucleotide variants or small indels per Mb). The ten high-grade gliomas demonstrated markedly aneuploid genomes, with significantly increased quantity of intrachromosomal copy number breakpoints and focal amplifications/homozygous deletions compared to spontaneous high-grade gliomas, likely as a result of DNA double-strand breaks induced by gamma radiation. Together, these findings demonstrate a distinct molecular pathogenesis of secondary gliomas arising after radiation therapy and identify a genomic signature that may aid in differentiating these tumors from their spontaneous counterparts.

Secondary glioblastoma after treatment of intracranial germinoma - would radiation-only therapy still be safe? Case report

BACK GROUND

Intracranial germinomas are one of the most radiosensitive tumors and are curable by radiotherapy (RT) alone. RT-only therapy without chemotherapy is effective. But, as patients with germinoma can expect long-term survival, the adverse effects of RT and late sequelae in survivors are of most concern. So, recently, standard treatment protocol of combination with chemotherapy and reduced dose of RT could be widely acceptable.

CASE PRESENTATION

We report a patient with germinoma who developed RT-induced glioblastoma. He was diagnosed as biopsy-proven germinoma at the age of 12. Postoperatively, he underwent RT alone without chemotherapy and remained free of tumor without recurrence during long-term follow up. However, after almost 20 year, he developed RT-induced glioblastoma.

CONCLUSIONS

Although RT has the highest priority among treatments on intracranial germinomas, RT-only therapy with full dose for germinoma can have delayed severe complications. So, chemotherapy prior to reduced dose RT is more desirable.

Three case reports of radiation-induced glioblastoma after complete remission of acute lymphoblastic leukemia

Radiation therapy is sometimes performed to control intracranial acute lymphoblastic leukemia (ALL), but may lead to radiation-induced malignant glioma. The clinical, radiological, histological, and molecular findings are described of three cases of radiation-induced glioblastoma after the treatment for ALL. They received radiation therapy at age 6-8 years. The latency from radiation therapy to the onset of radiation-induced glioblastoma was 5-10 years. Magnetic resonance imaging demonstrated diffuse lesions with multiple small enhanced lesions in all cases. Histological examination showed that the tumors consisted of mainly small round astrocytic atypical cells in one case, and astrocytic atypical cells with elongated cytoplasm and nuclear pleomorphism with small cell component in two cases. Microvascular proliferation was present in all cases. Immunohistochemical analysis for B-Raf V600E, and mutational analysis for the isocitrate dehydrogenase (IDH) 1, IDH2, and H3F3A gene revealed the wild-type alleles in all three cases. The integrated diagnoses were IDH wild-type glioblastoma, and local irradiation and concomitant temozolomide were performed. After the initial treatment, significant shrinkage of the diffuse lesion and enhanced lesion was found in all cases. Radiation-induced glioblastoma occurring after the treatment for ALL had unique clinical, radiological, histological, and molecular characteristics in our three cases.

A 58-Year-Old Woman with Left-Sided Weakness and a History of a Pediatric Brain Tumor: A Case Report

Background

An uncommon but well-established complication of cranial irradiation is secondary neoplasm. This case presentation documents a radiation-induced malignant glioma 55 years after being diagnosed with “cerebral sarcoma,” now defined as atypical meningioma. This not only represents the longest reported latency period for a patient initially receiving over 30 Gy, but also provides a valuable historical perspective of neuro-oncology.

Clinical Presentation

A 58-year-old female presenting with progressive left-sided upper and lower extremity weakness with a past medical history significant for “cerebral sarcoma” was diagnosed with glioblastoma multiforme. This patient had previously been treated with resection and adjuvant radiation therapy via a 280-kVP orthovoltage machine and received 3,390 rad to the posterior three-quarters of the skull for “cerebral sarcoma.”

Conclusion

A comprehensive investigation of the past medical history helped uncover a mysterious pediatric diagnosis, helped drive the management 5 decades later, and serves as a reminder that seemingly safe interventions may still cause harm.

Glioblastoma Secondary to Meningioma: A Case Report and Literature Review

BACKGROUND

The pathophysiologies underlying meningioma and glioma are distinct. The coexistence of those 2 lesions in the same patient is rare, and at the same location, it is even more exceptional.

CASE DESCRIPTION

We report a case of a 79-year-old man initially presenting with a meningioma that was treated by complete excision of the lesion. The patient had 2 relapses at the same site, in which glioblastoma was confirmed histopathologically.

CONCLUSIONS

Glial transformation meningiomas remain a contentious issue, with coincidental occurrence being the most prevalent explanation. Nevertheless, impairment of the same molecular signaling pathways in both tumor types suggests a common origin. Another hypothesis is that perilesional parenchymal damage from radiotherapy or surgery may lead to glial transformation in the tissues surrounding the original meningioma lesion. Further research is needed to determine if the original tumor or surgery has an oncogenic effect on the adjacent tissue.

Glioblastoma in long-term survivors of acute lymphoblastic leukemia: Report of two cases

Acute lymphoblastic leukemia (ALL) is the most common form of cancer in children. Second neoplasms as late effects of therapy for ALL have been recognized as a significant clinical issue given the increasing number of long-term survivors of ALL, because they can be the cause of death in such cases. In contrast, glioblastoma (GBM) is the most common primary brain tumor in adults. It is a malignant brain tumor that most often occurs in elderly patients, and GBM in young adults or adolescents appears to be rare. Here, we describe our experience of two cases of GBM in young long-term survivors of ALL, and emphasize the necessity of careful follow up of patients treated for ALL for the potential occurrence of central nervous system second neoplasms, especially when the patients have previously undergone cranial radiotherapy.

De novo glioblastoma in the territory of a recent middle cerebral artery infarction and a residual meningioma: pathogenesis revisited

Background

The pathogenesis of glioblastoma is complex, and the implicated molecular mechanisms are yet to be understood. There are scattered reports describing a possible relationship between meningioma and glioblastoma and more rarely a relationship between infarction and glioblastoma.

Case presentation

We are reporting a 32-year-old male who developed left middle cerebral artery (MCA) infarction as a surgical complication for sphenoid meningioma. He developed recurrent symptoms 4 months later due to development of a glioblastoma adjacent to both the territory of the prior MCA infarct and the residual meningioma.

Conclusions

This case adds further contribution to the literature of the possible pathological association between glioblastoma and brain infarction on a background of meningioma.

Complications from radiotherapy

Radiotherapy (RT) of the brain is associated with significant stigma in the neuro-oncology community. This is primarily because of the potentially severe complications with which it may be associated. These complications, especially in subacute and latent settings, are often unpredictable, potentially progressive, and irreversible. The onset of complications may start from the first fraction of 2 Gy, continuing over several months after end of RT with persistent drowsiness and apathy. It may also extend over many years with progressive onset of neurocognitive impairments such as memory decline, and diminished focus/attention. For long-term survivors, such as young patients irradiated for a favorable low-grade glioma, quality of life can be seriously impacted by RT. It is essential, as in the pediatric field, to propose patient-specific regimens from the very outset of therapy. The use of molecular biomarkers to better predict survival, control of comorbidities along with judicious use of medications such as steroids and antiepileptics, improved targeting with the help of modern imaging and RT techniques, modulation of the dose, and fractionation aimed at limiting integral dose to the healthy brain all have the potential to minimize treatment-related complications while maintaining the therapeutic efficacy for which RT is known. Sparing "radiosensitive" areas such as hippocampi could have a modest but measurable impact with regard to cognitive preservation, an effect that can possibly be enhanced when used in conjunction with memantine and/or donepezil.

The etiology of low-grade gliomas: pathological and clinical considerations about radiation-induced low-grade gliomas

The only environmental factor undoubtedly linked to an increased risk of brain tumors (including gliomas) is therapeutic X-rays. We aim to conduct a detailed study of radiation-induced low-grade gliomas, in order to better understand the pathogenesis of such gliomas. Furthermore, we want do prove whether or not there are significant differences, according to clinical features and biological behavior, between this type of tumor and general low-grade gliomas. We analyzed the existent literature of low-grade radiation-induced glioma case reports and other epidemiological reports based on the experience of the senior author. We were able to collect 20 cases of such gliomas. Demographic data and previous X-ray details, along with latency intervals of all patients are provided. The amount of radiation able to cause mutations is not necessarily very high, as tumors occur even after low doses of radiation (as 3-5 GY). The incidence of this kind of tumors may be underestimated and may rise in the future. Care must be taken when observing patients who were irradiated more than 10 years before, especially in the recent years in which access to radiosurgical and radiation therapies has increased in the general population for treating many cerebral pathologies. Radiation-induced low-grade gliomas appear to be different from general gliomas only in terms of age in which they occur. In terms of clinical and biological behavior, there seem to be no differences, even though exceptional cases are reported.

Histologically Proven Radiation-Induced Brainstem Glioma 93 Months After External Beam Radiotherapy for Pituitary Macroadenoma: Radiation Treatment Dose and Volume Correlation

Patient is a 29-year-old with a history of recurrent growth hormone-secreting pituitary macroadenoma diagnosed 12 years prior to presentation. Eight years prior to current presentation, the patient underwent re-resection and received 50.4 Gy external beam radiotherapy (EBRT) in 28 fractions of 1.8 Gy each. Serial postradiation MRIs demonstrated regression in pituitary tumor size. Patient presented with new headaches 7.5 years after completing EBRT. Brain MRI demonstrated new FLAIR hyperintensity and contrast enhancement within the pons and medulla, corresponding to the 36 Gy isodose line of each radiation dose fraction. Differential diagnosis included radiation necrosis and radiation-induced glioma (RIG). The patient's neurologic exam worsened over the following 4 months. MRI showed progressive increase in mass effect, extent of FLAIR hyperintensity, and contrast enhancement in the brainstem. Stereotactic-assisted biopsy showed infiltrating astrocytoma with moderate atypia. A PubMed search showed this is the first case of histologically verified brainstem RIG correlated with 3-dimensional conformational radiation therapy dose and volume planning following EBRT for a pituitary adenoma. The rare occurrence of brainstem RIG after radiation therapy for pituitary tumor supports the need for long-term imaging monitoring of such patients.

Should adjuvant radiotherapy be recommended for pediatric craniopharyngiomas?

Intracranial tumors secondary to radiotherapy are rare. In this group gliomas are the rarest. Only 6 cases of glioblastoma multiforme (GBM) have been reported in patients undergoing radiotherapy (RT) for craniopharyngiomas of which only 4 have been in children less than 18 years of age. In recent years RT has become a mainstay of adjuvant therapy for recurrent or partially excised craniopharyngiomas. We report a child of 12 years who had previously undergone RT for a suprasellar craniopharyngioma and presented 10 years later with a GBM. This is the 5th pediatric case in literature demonstrating a GBM after RT for a craniopharyngioma. The implications of subjecting the pediatric population to RT for a benign lesion versus the outcome of gross total removal and management of RT induced tumors is discussed and the need to avail of safer alternatives such as stereotactic radiosurgery is stressed.

Radiation-induced neuropathy in cancer survivors

Radiation-induced peripheral neuropathy is a chronic handicap, frightening because progressive and usually irreversible, usually appearing several years after radiotherapy. Its occurrence is rare but increasing with improved long-term cancer survival. The pathophysiological mechanisms are not yet fully understood. Nerve compression by indirect extensive radiation-induced fibrosis plays a central role, in addition to direct injury to nerves through axonal damage and demyelination and injury to blood vessels by ischaemia following capillary network failure. There is great clinical heterogeneity in neurological presentation since various anatomic sites are irradiated. The well-known frequent form is radiation-induced brachial plexopathy (RIBP) following breast cancer irradiation, while tumour recurrence is easier to discount today with the help of magnetic resonance imaging and positron emission tomography. RIBP incidence is in accordance with the irradiation technique, and ranges from 66% RIBP with 60Gy in 5Gy fractions in the 1960s to less than 1% with 50Gy in 2Gy fractions today. Whereas a link with previous radiotherapy is forgotten or difficult to establish, this has recently been facilitated by a posteriori conformal radiotherapy with 3D-dosimetric reconstitution: lumbosacral radiculo-plexopathy following testicular seminoma or Hodgkin's disease misdiagnosed as amyotrophic lateral sclerosis. Promising treatments via the antioxidant pathway for radiation-induced fibrosis suggest a way to improve the everyday quality of life of these long-term cancer survivors.

Pharmacotherapeutic management of pediatric gliomas : current and upcoming strategies

Primary glial brain tumors account for the majority of primary brain tumors in children. They are classified as low-grade gliomas (LGG) or high-grade gliomas (HGG), based on specific pathologic characteristics of the tumor, resulting in disparate clinical prognoses. Surgery is a mainstay of treatment for HGG, although it is not curative, and adjuvant therapy is required. Temozolomide, an oral imidazotetrazine prodrug, while considered standard of care for adult HGG, has not shown the same degree of benefit in the treatment of pediatric HGG. There are significant biologic differences that exist between adult and pediatric HGG, and targets specifically aimed at the biology in the pediatric population are required. Novel and specific therapies currently being investigated for pediatric HGG include small molecule inhibitors of epidermal growth factor receptor, platelet-derived growth factor receptor, histone deacetylase, the RAS/AKT pathway, telomerase, integrin, insulin-like growth factor receptor, and γ-secretase. Surgery is also the mainstay for LGG. There are defined front-line, multiagent chemotherapy regimens, but there are few proven second-line chemotherapy options for refractory patients. Approaches such as the inhibition of the mammalian target of rapamycin pathway, inhibition of MEK1 and 2, as well as BRAF, are discussed. Further research is required to understand the biology of pediatric gliomas as well as the use of molecularly targeted agents, especially in patients with surgically unresectable tumors.

Second primary glioblastoma multiforme following autologous hematopoietic stem cell transplantation in a patient with acute myelogenous leukemia

Glioblastoma multiforme (GM) is one of the most aggressive primary brain tumors, and has a poor prognosis despite intensive treatment. GM is also the most malignant astrocytoma, with histopathological features that include cellular polymorphism, rapid mitotic activity, microvascular proliferation, and necrosis. The causes of GM remain obscure, but several reports have shown associations between GM and genetic alterations and radiation exposure. Furthermore, high-dose chemotherapy/radiotherapy with autologous stem cell transplantation is increasingly being used to treat patients with leukemia, and patients who undergo stem cell transplantation have a higher risk of solid tumor cancer development later in life. Based on these associations, we discuss GM development in a patient who underwent chemoradiotherapy conditioning prior to stem cell transplantation.

Radiation-induced glioblastoma multiforme in a remitted acute lymphocytic leukemia patient

Radiation therapy has been widely applied for cancer treatment. Childhood acute lymphocytic leukemia (ALL), characterized by frequent central nervous system involvement, is a well documented disease for the effect of prophylactic cranio-spinal irradiation. Irradiation, however, acts as an oncogenic factor as a delayed effect and it is rare that glioblastoma multiforme develops during the remission period of ALL. We experienced a pediatric radiation-induced GBM patient which developed during the remission period of ALL, who were primarily treated with chemotherapeutic agents and brain radiation therapy for the prevention of central nervous system (CNS) relapse. Additionally, we reviewed the related literature regarding on the effects of brain irradiation in childhood and on the prognosis of radiation induced GBM.

Therapy-associated secondary tumors in patients with non-germinomatous malignant germ cell tumors

We report three patients with non-germinomatous malignant germ cell tumor (NGMGCT) who developed therapy-associated secondary tumors. They were diagnosed as having NGMGCT by elevated serum levels of α-fetoprotein (AFP), human chorionic gonadotropin (HCG), or β-HCG. Preoperatively, all patients received a combination of etoposide and platinum-based chemotherapy and radiotherapy; neo-adjuvant therapy (NAT) was followed by complete excision of the residual tumor. Postoperatively, all underwent maintenance chemotherapy and all remained free of NGMGCT without recurrence. However, they developed therapy-associated secondary tumors, i.e. glioblastoma, meningioma, or cavernous angioma after 10.1, 9.8, and 8.2 years, respectively. The patient with glioblastoma died one year after its detection. The other two patients are currently alive; the meningioma was completely removed and the cavernous angioma is being monitored without additional treatment. To the best of our knowledge, therapy-associated secondary tumors in patients treated for NGMGCT are rare.

Radiation-induced tumors in children irradiated for brain tumor: a longitudinal study

BACKGROUND

Radiation-induced tumors (RIT) are increasingly recognized as delayed complications of brain irradiation during childhood. However, the true incidence is not established, their biology is poorly understood, and few guidelines exist regarding the long-term follow-up of irradiated children.

METHODS

We studied retrospectively patients irradiated for brain tumor under 18 years and followed in our institution since 1970. RIT were defined as new masses, different from the original tumor, occurring after delay in irradiated areas, and not related to phacomatosis.

RESULTS

Among 552 irradiated patients, 42 (7.6%) developed one or more RIT, 26 months to 29 years after irradiation (mean 12.8 years). The cumulated incidence was 2.0% at 5 years and 8.9% at 10 years. Of the patients, 73.8% were adult at the time of diagnosis of RIT, and 75% were diagnosed within 18.1 years after irradiation. We identified 60 cavernomas, 26 meningiomas, 2 malignant gliomas, 1 meningosarcoma, and 6 thyroid tumors. Compared with meningiomas, cavernomas appeared earlier, in children irradiated at an older age, and with a male predominance. Although RIT were correlated with higher irradiation doses, 80.9% of these occurred at some distance from the maximum irradiation field. Twenty-five lesions were operated in 20 patients; three patients died because of progression of the RIT.

CONCLUSION

A significant number of patients undergoing irradiation for brain tumor during childhood develop a RIT, often during adulthood. Our data suggest that radiation-induced cavernomas result from angiogenetic processes rather than true tumorigenesis. Protracted follow-up with MRI is warranted in children irradiated for brain tumor.

A glioblastoma arising from the attached region where a meningioma had been totally removed

The co-occurrence of different histological tumors in the nervous system is rare and is mainly associated with phakomatoses or radiation exposure. A 72-year-old man underwent surgery for a frontal convexity meningioma. Four years after the surgery, a new lesion was detected in the attached region where the meningioma had been removed. The second tumor exhibited a high degree of cellularity, atypical mitosis, pseudo-palisading and microvascular proliferation, and was immunohistologically positive for GFAP and was diagnosed as a glioblastoma. Wild-type isocitrate dehydrogenase 1 was found in the second specimen. A genetic analysis using comparative genomic hybridization showed a DNA copy number loss on 1p35, 9pter-21, 10, 11q23, 13q, 14q, 20q, 22q and a gain on 7 in the second specimen. Although the mechanism responsible for the consecutive occurrence of meningioma and glioblastoma has not been elucidated, five hypotheses are feasible: (i) the lesions occurred incidentally; (ii) a low-grade astrocytoma present at the time of the first operation transformed into a high-grade glioma during the next 4 years; (iii) radiation received during the endovascular treatment induced glioblastoma; (iv) a brain scar created at the time of the first operation for meningioma led to the occurrence of a glioblastoma; and (v) the previous meningioma affected the surrounding glial cells, causing neoplastic transformation.

Radiation-induced cerebellar high-grade glioma accompanied by meningioma and cavernoma 29 years after the treatment of medulloblastoma: a case report

Here, we report the case of a patient with cerebellar high-grade glioma that developed after the patient underwent treatment for medulloblastoma. A 34-year-old man visited our hospital with complaints of dizziness and truncal ataxia. Magnetic resonance image showed a cerebellar tumor with multiple cavernomas and two lesions that were suspected to be meningiomas. The cerebellar tumor was surgically removed. According to pathological examination, the tumor was a high-grade glioma that was positive for methylated O-6-methylguanine-DNA methyltransferase promoter. In the past, he had received radiotherapy at the age of 5, after which he was operated for desmoplastic medulloblastoma in his right cerebellar hemisphere. Seven years after the initial therapy, cavernoma-induced intracerebral hemorrhage of the right temporal lobe was noted. To our knowledge, this is the first case of radiation-induced double intracranial tumors accompanied by symptomatic cavernoma.

Neurotoxicity of radiation therapy

Direct or incidental exposure of the nervous system to therapeutic irradiation carries the risk of symptomatic neurologic injury. Central nervous system toxicity from radiation includes focal cerebral necrosis, neurocognitive deficits, and less commonly cerebrovascular disease, myelopathy, or the occurrence of a radiation-induced neoplasm. Brachial or lumbosacral plexopathy are the most common syndromes of radiation toxicity affecting the peripheral nervous system. This article focuses on the clinical features, diagnosis, and management options for patients with radiation neurotoxicity.

Anaplastic oligodendrogliomas after treatment of acute lymphoblastic leukemia in children: report of 2 cases

Radiation-induced brain tumors are suggested to be the late complication of acute lymphoblastic leukemia (ALL) treatment. High-grade gliomas, meningiomas, and sarcomas are the most frequent neoplasms. Secondary anaplastic oligodendrogliomas are exceedingly rare. Five cases of pure anaplastic oligodendroglioma have been reported in the literature, and only 1 case was in a child after ALL treatment. The authors present 2 cases of pediatric anaplastic oligodendroglioma after treatment of ALL. Furthermore, they performed a molecular cytogenetic study and found loss of 1p in both cases. The authors provide a review of the previous cases and discuss their findings.

Pediatric high-grade gliomas and diffuse intrinsic pontine gliomas

Pediatric high-grade gliomas represent approximately 10% of all pediatric brain tumors. Similar to adult high-grade gliomas, they behave very aggressively, and these children have a very poor prognosis despite a variety of therapies that include chemotherapy and radiotherapy. In this review, we present an overview of both pediatric high-grade gliomas and diffuse intrinsic pontine gliomas with a focus on their epidemiology, etiology, presentation, prognostic factors, biology, treatment modalities, outcomes, and future research directions.

Radiation-induced gliomas following radiotherapy for craniopharyngiomas: a case report and review of the literature

The aim of this study was to collect, describe and analyze the radiation-induced gliomas in craniopharyngioma patients reported in the literature up to date. Review of the relevant literature was performed. One personal illustrative case was added. Reports of 15 patients, including the presented illustrative case, were evaluated. The average age of the patients at the time of irradiation was 12.5 years. All patients underwent conventional fractionated radiotherapy with mean total radiation dose of 55Gy and an average latency period of 10.8 years. Glioma localization varied with the highest frequency of the temporal lobe involvement. All but one patient had high-grade gliomas on the histological exam. Although exceptionally rare, the radiation-induced gliomas in craniopharyngioma patients are potentially possible, long-term complications with devastating consequences in typically younger patients with long life-expectancy. The radiation-induced iatrogenic injury on one hand should provoke the research and elaboration of safer and at least, equally efficient alternative treatment modalities and on the other hand ought to prompt the investigation of the patients' risk factors predisposing the oncogenesis after irradiation.