A report on radiation-induced gliomas

Machine learning identification of cuproptosis and necroptosis-associated molecular subtypes to aid in prognosis assessment and immunotherapy response prediction in low-grade glioma

Both cuproptosis and necroptosis are typical cell death processes that serve essential regulatory roles in the onset and progression of malignancies, including low-grade glioma (LGG). Nonetheless, there remains a paucity of research on cuproptosis and necroptosis-related gene (CNRG) prognostic signature in patients with LGG. We acquired patient data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) and captured CNRGs from the well-recognized literature. Firstly, we comprehensively summarized the pan-cancer landscape of CNRGs from the perspective of expression traits, prognostic values, mutation profiles, and pathway regulation. Then, we devised a technique for predicting the clinical efficacy of immunotherapy for LGG patients. Non-negative matrix factorization (NMF) defined by CNRGs with prognostic values was performed to generate molecular subtypes (i.e., C1 and C2). C1 subtype is characterized by poor prognosis in terms of disease-specific survival (DSS), progression-free survival (PFS), and overall survival (OS), more patients with G3 and tumour recurrence, high abundance of immunocyte infiltration, high expression of immune checkpoints, and poor response to immunotherapy. LASSO-SVM-random Forest analysis was performed to aid in developing a novel and robust CNRG-based prognostic signature. LGG patients in the TCGA and GEO databases were categorized into the training and test cohorts, respectively. A five-gene signature, including SQSTM1, ZBP1, PLK1, CFLAR, and FADD, for predicting OS of LGG patients was constructed and its predictive reliability was confirmed in both training and test cohorts. In both the training and the test datasets (cohorts), higher risk scores were linked to a lower OS rate. The time-dependent ROC curve proved that the risk score had outstanding prediction efficiency for LGG patients in the training and test cohorts. Univariate and multivariate Cox regression analyses showed the CNRG-based prognostic signature independently functioned as a risk factor for OS in LGG patients. Furthermore, we developed a highly reliable nomogram to facilitate the clinical practice of the CNRG-based prognostic signature (AUC > 0.9). Collectively, our results gave a promising understanding of cuproptosis and necroptosis in LGG, as well as a tailored prediction tool for prognosis and immunotherapeutic responses in patients.

Radiation-induced Supratentorial Osteosarcoma Following Curative Treatment of Infratentorial Ependymoma in a Child

The development of secondary neoplasms following therapeutic cranial irradiation is rare and quite often lethal. Meningiomas, sarcomas, and high-grade gliomas are the most common tumors that manifest as a result of radiation therapy. We report the case of an 11-year-old child who presented with symptoms of supratentorial space-occupying lesion 7 years after curative surgery and cranial irradiation for a posterior fossa ependymoma. Magnetic resonance imaging of the brain revealed a right-sided temporoparietal dural-based contrast-enhancing lesion with evidence of overlying bone and skin involvement. The histological report of ependymoma from the previous surgery led us to suspect that we were dealing with a recurrence until the histopathology of the second surgery revealed highly malignant osteosarcoma. The child recovered fully and underwent chemotherapy, but ultimately succumbed to the disease. We report this case to highlight the importance of recognizing these neoplasms and to review its management.

Lower Grade Gliomas

PURPOSE OF REVIEW

Low-grade gliomas (LGG) are a group of primary brain tumors that arise from supporting glial cells. They are characterized by a mutation in the isocitrate dehydrogenase (IDH) enzyme and include astrocytomas and oligodendrogliomas. They usually affect young adults, and their main treatment consists of surgical resection, followed by radiation and chemotherapy in selected patients. This article reviews recent research on the clinical and molecular aspects of the disease and innovative therapeutic modalities in the process.

RECENT FINDINGS

Newly identified clinical and molecular features are currently used in the classification of LGG and applied in treatment-planning decisions. Advanced studies on the cellular level have an advanced understanding of the metabolic effects induced by IDH mutations, offering opportunities for specific targeted therapies that may improve patient outcomes. Such findings may lead to a paradigm shift in the treatment of these tumors. Although LGG are sensitive to radiation and chemotherapy, these therapies are not curative, and patient survival remains limited, raising the need for more creative and effective interventions.

Incidence of brain and spinal cord cancer and county-level radon levels in New Jersey, Wisconsin, Minnesota, Pennsylvania, and Iowa, USA

Ionizing radiation at diagnostic and therapeutic doses is a known contributor to the development of brain and spinal cord (CNS) cancer. However, little is known about risk from exposure to radon, a natural radiation source which the general population is exposed to residentially and environmentally. This study investigated correlations between mean county radon levels and CNS cancer incidence in five highly populated and radon-enriched US states (Minnesota, mean radon level 4.6 pCi/L; Wisconsin, 5.7 pCi/L; Pennsylvania, 8.6 pCi/L; Iowa, 6.1 pCi/L; and New Jersey, 4.4 pCi/L). Mean radon levels per county were accessed through AirChek, which provides publicly available radon data measured in residences and workplaces. CNS cancer incidence data were accessed through the states' health department websites and span differing amounts of time due to the publicly accessible nature of the data, though all time spans were over 10 years. Negative binomial regressions were run to assess correlations between mean radon and CNS cancer incidence per county. Quantile maps were constructed and Moran's I was calculated to assess spatial autocorrelation in residuals; no spatial autocorrelation was evident. Iowa was the only state with a significant positive association between radon and CNS incidence; no associations were detected in other states, and a negative association was observed in the 5 states combined. This study does not provide evidence that radon is a risk factor for CNS cancer; however, the possibility of an association cannot be ruled out due to limitations of the study, principally its ecologic nature and lack of individual-level exposure data.

Radiation-Induced Schwannomas of the Neuraxis. Report of Three Cases

We report 3 cases of possible radiation-induced schwannomas observed in our Department. Their salient clinical and pathogenetic features are analyzed and the role of radiation therapy in the oncogenesis of these lesions is discussed. Several cases of radiation-induced tumors, including some of the nervous system, have been reported, but schwannomas have only occasionally been reported in connection with ionizing radiation. The possible adjuvant role of antineoplastic drugs is also discussed, and the literature on this topic is reviewed.

Post-Radiation Gliomas

Aims and background

Radiotherapy is important in the treatment of neoplasm of the central nervous system, but various side effects, particularly neoplastic, have been described. Recently, post-radiation gliomas have been reported.

Methods

The authors review 88 cases of cerebral glioma following radiotherapy in patients operated for neoplasms of the nervous system, including 6 personal cases of post-radiation gliomas treated in the Neurosurgical Division of the Department of Neurological Sciences, “La Sapienza” University, Rome. The criteria used to define this unusual pathologic association are discussed.

Results

There was a male predominance. Post-radiation gliomas were particularly malignant, the average dose was 33 Gy, and average free latency was 9.6 years. The first disease was most frequently acute lymphatic leukemia.

Conclusions

Post-radiation gliomas have particular features but do not present a histologic or clinical behavior different from analogous spontaneous gliomas. The fact that 88 cases have been reported in recent years suggests that a thorough biological, clinical studies be carried out on this association.

Radiation-Induced Primary Brain Lymphoma: A Case Report

A patient who developed primary brain lymphoma 6 years following whole brain irradiation due to a low-grade glioma is described. The patient had no evidence of congenital or acquired immunodeficiency state and achieved a good and prompt response to aggressive chemotherapy, including high-dose methotrexate. The previous radiation therapy is implicated in the etiology of the lymphoma because of the geometric coincidence, the relatively long latency period and the different histology. A brief review of current literature is reported.

High-Dose Radiation-Induced Meningiomas. Report of Five Cases and Critical Review of the Literature

Radiotherapy is an important modality for the treatment of tumors and arteriovenous malformations affecting the central nervous system, even though several significant side effects have been described (radionecrosis, tumors, etc.). Meningiomas induced by high-dose radiation therapy are uncommon. In this study we describe five cases treated at our institute and review all previously published reports of meningioma occurring after high-dose radiotherapy. These tumors develop mainly in patients irradiated in childhood; their incidence peaks in the second decade of life, there is a predominance in females and a high frequency of malignant forms. Although rare, meningiomas may represent a late complication of radiation treatment. The behavior of the radiation-induced variety of meningioma seems to differ from that of its “spontaneous” counterpart. The use of radiotherapy should be carefully evaluated for relatively benign or congenital lesions which generally affect young patients with a long life expectancy.

A case of multiple radiation-induced gliomas 24 years after radiation therapy against pituitary adenoma

We treated a case in which multiple astrocytomas of varying grades developed in the irradiation field 24 years after radiation therapy. Differentiation from radiation necrosis based on presurgical diagnostic imaging was difficult; therefore, we feel it is essential to aggressively pursue histological diagnoses to select the optimal treatment method.

A Case of Radiation-Induced Osteosarcoma after the Treatment of Pineoblastoma

Radiation therapy has an important role in postoperative treatment of neoplasms originated from central nervous system, but may induce secondary malignancies like as sarcomas, gliomas, and meningiomas. The prognosis of radiation-induced osteosarcomas is known as poor, because they has aggressive nature invasive locally and intractable to multiple treatment strategies like as surgical resection, chemotherapy, and so on. We report a case of radiation-induced osteosarcoma developed from skull after 7 years of craniospinal radiotherapy for pineoblastoma.

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.

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.

Radiation-induced malignant gliomas: is there a role for reirradiation?

PURPOSE

To review the literature regarding the role of radiotherapy (RT) in the treatment of patients with radiation-induced malignant gliomas (RIMGs).

METHODS AND MATERIALS

A PubMed search of English-language articles dealing with RIMG was performed, yielding 52 articles with 92 patients available for review.

RESULTS

Initial tumor types treated with RT included brain tumor in 37 patients (40%), acute lymphoblastic leukemia in 33 (36%), benign disease in 11 (12%), and other in 11 (12%). Median time from RT to development of an RIMG was 8.75 years (range, 2.5-61 years). The RIMG occurred within 10 years after RT in 81% of patients with acute lymphoblastic leukemia/lymphoma, 59% of patients with brain/other, and 18% of patients with benign conditions (p = 0.002). Type of RIMG was glioblastoma in 69 (75%) and anaplastic astrocytoma in 23 (25%). One-, 2-, and 5-year overall survival rates were 29.3%, 7.3%, and 0% for patients with glioblastoma and 59.7%, 30.3%, and 20.2% for patients with anaplastic astrocytoma. For the 85 patients with data regarding treatment for RIMG, 35 underwent reirradiation to a median dose of 50 Gy (range, 30-76 Gy). For patients undergoing reirradiation, 1-, 2- and 5-year overall survival rates were 58.9%, 20.5%, and 6.8%. For those not undergoing reirradiation, they were 15.1%, 3%, and 0% (p = 0.0009).

CONCLUSIONS

The RIMG appeared earlier in patients treated for leukemia and lymphoma and latest for those treated for a benign condition. Patients who underwent reirradiation for RIMG have longer survival times compared with those not receiving RT.

RADIATION-INDUCED TUMOR AFTER STEREOTACTIC RADIOSURGERY FOR AN ARTERIOVENOUS MALFORMATION

OBJECTIVE

To present a rare case of a radiation-induced malignancy after stereotactic radiosurgery.

CLINICAL PRESENTATION

A 34-year-old woman presented with headaches. Imaging studies demonstrated a 4.5-cm arteriovenous malformation located in the pineal region. She was treated with a two-isocenter plan to a total dose of 1500 cGy prescribed to the 70% isodose line. She was lost to follow-up and presented with a change in mental status, nausea, headaches, and a generalized seizure 9 years later. Magnetic resonance imaging scans demonstrated a large, heterogeneously enhancing mass partially in the treatment volume.

INTERVENTION

Surgical debulking demonstrated an infiltrating glial neoplasm consistent with a glioblastoma multiforme. There was no staining for epidermal growth factor receptor, whereas greater than 75% of nuclei stained positively with p53.

CONCLUSION

The risk of radiation-induced tumors is currently unknown but needs to be determined to assess the risk-benefit profile for each patient.

Microsatellite analysis of recurrent vestibular schwannoma (acoustic neuroma) following stereotactic radiosurgery

HYPOTHESIS

Genetic and immunohistochemical studies may provide insight into the mechanisms of vestibular schwannoma (VS) recurrence following radiation therapy.

BACKGROUND

Stereotactic radiation therapy is an increasingly common alternative to microsurgical resection for the primary management of sporadic VS. The molecular mechanisms associated with recurrent vestibular schwannoma (VS) following radiation therapy are not known.

METHODS

Primary or irradiated VS tumors were fresh-frozen at the time of surgical resection and microdissected to undergo DNA extraction. Lymphocytic control DNA was isolated from blood obtained by venipuncture. Paired normal and tumor DNA specimens were analyzed for allelic loss by PCR amplification of polymorphic dinucleotide repeat sequences. Immunohistochemical studies were performed on paraffin-embedded, irradiated surgical specimens.

RESULTS

Using 16 polymorphic microsatellite markers, 20 of 26 non-irradiated VS demonstrated loss of heterozygosity (LOH) in at least one locus of chromosome 22q. In contrast, none of the four irradiated recurrent VS demonstrated LOH on chromosome 22q (p = 0.008). No allelic loss was seen in either the primary or irradiated VS utilizing markers mapping to chromosome 10. Deletions on chromosome 10 are seen in both benign and higher-grade meningiomas and intracranial malignancies associated with radiotherapy. Immunohistochemical studies were performed to detect the protein product of the NF2 gene, merlin, in the four irradiated VS. NF2 staining was not observed.

CONCLUSION

This study represents the first microsatellite and immunohistochemical analysis of recurrent VS following radiation therapy. Our preliminary observations suggest an alternative mechanism of NF2 inactivation that may correlate with radioresistance in VS.

Diffuse high-grade gliomas as second malignant neoplasms after radio-chemotherapy for pediatric malignancies

OBJECTS

Diffuse high-grade gliomas are known to develop in children after cranial irradiation for other malignancies. Here, clinicopathological characteristics are outlined.

METHODS

Nine children received cranial irradiation and chemotherapy for medulloblastoma (n=2) or acute lymphoblastic leukemia (n=7). They developed a high-grade glioma 7-14 years thereafter. Clinical charts, radiologic findings, and pathologic specimens were reviewed. Archival material was stained immunohistochemically.

CONCLUSION

Gliomas evolving as second malignant neoplasms show peculiarities and differ in some aspects from their "spontaneous" counterparts. Most are supratentorial, contrast-enhancing, space-occupying lesions. They are composed mainly of small undifferentiated cells, which are mainly negative for glial fibrillary acidic protein and positive for microtubule associated proteins 2 (MAP2). Epidermal growth factor receptor labeling could not be detected in any of them. Ki67-labeling was usually high, whereas p53- and h-ras p21-staining was variable. The median survival was only 12 months despite intensive treatment.

Glioblastoma multiforme following cranial irradiation and chemotherapy for acute lymphocytic leukaemia. Report of 3 cases

The most common secondary neoplasms which occur following cranial radiation therapy are sarcoma and meningioma. The occurrence of glioblastoma multiforme following radiation and chemotherapy in acute lymphocytic leukaemia (ALL) is rare. We report 3 cases of glioblastoma multiforme in children developing 11-72 months following completion of chemotherapy/radiotherapy for ALL. The exact cause for the development of glioblastoma multiforme following therapy for ALL is not clear. A genetic predisposition may be essential for the occurrence of such a highly malignant primary brain tumour in leukaemia patients, irrespective of radiation and/or chemotherapy. The pathogenesis and surgical management are discussed, and the literature on the subject is reviewed.

Radiation-Induced Osteosarcoma 16 Years After Surgery and Radiation for Glioma-Case Report-

A 35-year-old man developed osteosarcoma of the left parietal and occipital bones 16 years after radiotherapy for glioma in the right occipital lobe. Radiotherapy of the primary neoplasm used 50 Gy administered to a localized field through two lateral ports. The secondary neoplasm arose contralateral to the primary lesion but within the irradiated field. The tumor had a multilocular cyst with considerable intracranial extension, and symptoms of elevated intracranial pressure were prominent early in the course. After a short-lived initial remission following surgical intervention and chemotherapy, the patient deteriorated because of tumor recurrence and died 18 months after the diagnosis. Radiation-induced osteosarcoma is a well-known but rare complication of radiotherapy for brain neoplasms with a poor prognosis.

Response to chemotherapy of a radiation-induced glioblastoma multiforme

BACKGROUND

Radiation-induced glioblastoma multiforme (GBM) is particularly resistant to treatment and therapeutic options are limited. We report a patient with a radiation-induced GBM who had a complete response to carmustine and survived for 44 months.

PATIENTS AND METHODS

Case report of a 38-year-old man with a radiation-induced GBM that responded to carmustine.

RESULTS

Our patient developed a left occipital GBM 35 years after a left cerebellar astrocytoma was treated with surgery and radiation therapy (4500 rad). The GBM was treated with subtotal resection followed by four cycles of carmustine; a complete response was achieved. He relapsed 34 months after diagnosis and with further surgery survived 44 months from his diagnosis of GBM.

CONCLUSION

GBMs may be a late complication of radiation treatment for pediatric brain tumors. If further radiotherapy is not a therapeutic option, chemotherapy may result in prolonged survival.

Glioblastoma in irradiated elderly patients: two case reports

We report our experience with two elderly patients with histologically proven diagnosis of glioblastoma multiforme who were treated 25 and 18 years earlier for tinea capitis and scalp cutaneous hemangioma respectively in the same areas where the glioblastoma multiforme had grown. These pathologies were benign, and nowadays can be treated with alternative approaches rather than radiotherapy. Radiotherapeutic treatment should be carefully considered before using it in young patients with benign pathologies who have a long life expectancy and subsequently a higher risk of developing radio-induced malignant lesions. Radio-induced gliomas are typical of patients younger than the ones with "spontaneous" glioblastomas; however, the subjects of our study were elderly (78 and 72 years).

Current management of glioblastoma multiforme

Glioblastoma multiforme is the most common primary brain tumor in adults. Despite major research efforts and progress in neuroimaging, neurosurgery, and radiation and medical oncology, the overall survival of patients with this disease has changed little over the past 30 years. Surgery and radiation therapy remain critical components in the care of patients with glioblastoma multiforme. Treatment with chemotherapy has been hampered by the apparent resistance of these tumor cells to available agents and challenges in delivering agents to the tumor cells. The blood-brain barrier can restrict entry of some agents and the effect of antiepileptic drugs inducing hepatic P450 can significantly affect the pharmacology of a wide range of antineoplastic agents. As a result, new agents and novel approaches are required. Translational research efforts should: (1) pursue a broad research agenda until productive avenues are identified; (2) quantify the delivery of novel agents to the malignant brain tumor cells; (3) determine the maximum tolerated dose (MTD) and preliminary efficacy data on novel agents before initiating combination therapies; (4) optimize trial designs; and (5) improve psychosocial and supportive care for patients with this devastating illness.

Radiation-induced gliomas: report of 10 cases and review of the literature

BACKGROUND

Radiotherapy and more recently radiosurgery represent important therapeutic methods for the treatment of tumors and arterovenous malformations affecting the central nervous system, even though several significant side-effects have been described (radionecrosis, tumors, etc.). Gliomas induced by radiation therapy are decidedly unusual, and the first descriptions of this association only appeared in the 1960s.

METHODS

The pertinent literature was reviewed to yield 116 cases in which a glioma developed after radiotherapy for cranial pathologies (included 10 personal cases treated in our Institution). One of our patients had undergone radiosurgery for a cavernous angioma.

RESULTS

Patients who developed a radiation-induced glioma were younger, as a group, than those affected with so-called "spontaneous" gliomas. The tumor originated in the previously irradiated area, after average doses of 32 Gy and an average latency period of 9.6 years in accordance with the findings reported by the authors and in our experience as well. Radiotherapy had most frequently been performed for acute lymphoblastic leukemia. Our Case 10 is the fourth case of intracranial tumor arising after radiosurgery to be described in the literature.

CONCLUSIONS

Though rare, gliomas may represent a late complication of radiation treatment. The behavior of the radiation-induced variety of glioma does not seem to differ significantly from that of its "spontaneous" counterpart. Late complications of the radiosurgery are probably underestimated because of the relatively recent introduction of this technique. On the contrary, these should be scrupulously evaluated when deciding whether to employ this method for therapeutic purposes for relatively benign or congenital lesions (which generally affect young patients with a long life expectancy).

Clinical and histopathologic features of recurrent vestibular schwannoma (acoustic neuroma) after stereotactic radiosurgery

OBJECTIVE

Stereotactic radiosurgery for vestibular schwannoma entails uncertain long-term risk of tumor recurrence and delayed cranial neuropathies. In addition, the underlying histopathologic changes to the tumor bed are not fully characterized. We seek to understand the clinical and histologic features of recurrent vestibular schwannoma after stereotactic radiation therapy.

STUDY DESIGN

Retrospective review.

SETTING

Tertiary referral center.

PATIENTS

Four patients who underwent microsurgical resection of vestibular schwannoma after primary stereotactic radiation therapy.

INTERVENTION

Patients were treated primarily with gamma knife radiosurgery or fractionated stereotactic radiotherapy followed by salvage microsurgery. Retrosigmoid craniotomy was used in all cases.

MAIN OUTCOME MEASURES

Histopathologic review. Preoperative and postoperative facial nerve function was assessed with the House-Brackmann scale.

RESULTS

We observed highly inconsistent radiation changes in the cerebellopontine angle and internal auditory canal. Fibrosis outside and within the tumor bed varied markedly, complicating microsurgical dissection. Light microscopy confirmed the presence of viable tumor in all cases. Histopathologic features were typical of vestibular schwannoma, and there was no significant scarring that could be attributed to radiation effect.

CONCLUSIONS

The variable fibrosis in the cerebellopontine angle and lack of radiation changes seen histopathologically in irradiated vestibular schwannoma suggest that a uniform treatment effect was not achieved in these cases. Although all four patients with preoperative cranial neuropathies were found intraoperatively to have fibrosis in the cerebellopontine angle, excellent preservation of facial nerve anatomy and function was possible with salvage microsurgical resection. Additional analyses are needed to clarify the histopathologic and molecular characteristics associated with vestibular schwannoma growth after stereotactic radiation.

Supratentorial grade II astrocytoma: biological features and clinical course

Because of its unpredictable clinical course, treatment strategies for low-grade (grade II) astrocytoma vary from "wait and see" to gross tumour resection followed by immediate radiotherapy. Clinical studies on grade II astrocytoma show that 5-year-survival ranges from 27% to 85% of patients with very few consistent prognostic variables besides the patient's age and the presence of neurological deficit. There is no universally recognised choice of therapy for patients with astrocytoma grade II, partly because of the shortcomings of histological classification systems. Routine microscopy tends to underestimate malignancy grading of astrocytomas and in most cases cannot distinguish between indolent and progressive subtypes. Recent studies suggest that proliferation and genetic markers can be used to identify subgroups of astrocytoma grade II with a rapid progressive clinical course. Therefore these markers should be included in ongoing and future clinical studies of patients with astrocytoma grade II.

Trauma-induced tumorigenesis of cells implanted into the rat spinal cord

OBJECT

Findings in several clinical cases have suggested a correlation between tumor formation and previous injury to the central nervous system (CNS); however, the relationship between trauma and tumorigenesis has not been investigated well experimentally. In this study the authors provide evidence correlating tumorigenesis with trauma in the rat spinal cord.

METHODS

A glial cell line, C6R-G/H, which expresses green fluorescent protein (GFP) and hygromycin phosphotransferase (HPT), was implanted into normal and injured rat spinal cords. In all rats in which the cells were implanted into an injured site, locomotor function deteriorated and histological analysis demonstrated glioblastoma multiforme by 6 weeks; tumorigenesis was correlated with a loss of both GFP expression and resistance to hygromycin treatment. In contrast, no evidence of tumor formation was found at 6 weeks in rats in which the cells were implanted into healthy tissue. When C6R-G/H cells were treated with contused spinal cord extract in culture before implantation, they lost GFP expression and hygromycin resistance, and later formed tumors after implantation into normal spinal cord.

CONCLUSIONS

The findings of this study indicate that trauma can induce tumorigenesis. Implantation of C6R-G/H cells into traumatized spinal cords resulted in their transformation, which was signaled by loss of GFP expression and hygromycin resistance accompanied by tumor formation. Exposure to extracts derived from injured spinal cord produced similar transformation and gene expression changes, as well as tumor formation after such cells were implanted into normal cords. Care, therefore, should be taken when cells are implanted into an injured CNS because of potential mutagenesis due to trauma-induced factors.

Intensity modulated radiotherapy (IMRT) for recurrent, residual, or untreated skull-base meningiomas: preliminary clinical experience

OBJECTIVE

To investigate the feasibility of using intensity modulated radiotherapy (IMRT) for complex-shaped benign meningiomas of the skull base and report clinical experience.

METHODS

Twenty patients with benign skull-base meningiomas WHO degrees I (histopathologically proven in 16/20) were treated with IMRT between June 1998 and August 1999. Each tumor was complex in shape and adherent to, or encompassed, organs at risk (cranial nerves, optic apparatus, and brainstem). All patients, immobilized in a customized head mask integrated into a stereotactic system, were planned on an inverse treatment planning system using 5 or 7 coplanar, equidistant beams and 5 intensity steps. Each treatment plan was verified extensively before treatment. Follow-up with MRI and clinical examination was performed at 6 and 18 weeks and every 6 months thereafter.

RESULTS

Target volumes ranged from 27 to 278 cc (median: 108 cc). Mean dose in 32 fractions ranged between 55.8 and 58.2 Gy. At median follow-up of 36 months (range: 31-43 months), pre-existing neurologic symptoms improved in 12/20 (60%), remained stable in 7/20 (35%), and worsened in 1 (5%) patient. Radiographic follow-up revealed significant tumor shrinkage 6 weeks post-IMRT in 2 patients and partial remission in 3 more patients at 9-17 months; other tumor volumes remained stable. There was no radiation-induced peritumoral edema, increase in tumor size, or new onset of neurologic deficits. Transient acute treatment side effects included nausea and vomiting and single occurrences of conjunctivitis/increased tearing and serous tympanitis.

CONCLUSION

IMRT in the treatment of central nervous system meningiomas is feasible and safe, offering highly conformal irradiation for complex-shaped skull-base tumors while sparing adjacent critical structures. If the tumor remissions seen here are found in the ongoing treatments, IMRT may be considered the treatment of choice for inoperable or subtotally resected meningiomas and for otherwise difficult-to-treat, complex-shaped tumors of the central nervous system adjacent to critical structures, with the potential of dose escalation for malignant tumors.

Gamma knife radiosurgery and its possible relationship to malignancy: a review

✓ The question has been raised recently whether gamma knife radiosurgery (GKS) can induce secondary neoplasia. Because there is little or no detailed knowledge about this potential complication, background information culled from the radiotherapy literature is reviewed as a guide to the clinical situations in which radiotherapy may induce secondary neoplastic change. Available case reports are then reviewed and discussed against the background of the current knowledge. On the basis of the review, the following suggestions are proposed on how to limiting the extent of this complication, document its frequency, and inform patients. It should be remembered that: the benefits of GKS are great; its alternatives also have risks; there often are no alternatives to GKS; follow-up documentation should be pursued more actively so that, if possible, no patient falls through the net; practitioners should be proactive in defining the problem, and genetic analysis of tumor biopsy specimens obtained in patients who will undergo or have undergone GKS should become routine; the extent of secondary neoplasia is not known; and patient information should be guided by what is known rather than by what is feared.

Radiation-induced meningioma: a descriptive study of 253 cases

OBJECT

Ionizing radiation is the only established risk factor recognized today in the causation of meningioma. The aim of the present report is to describe the demographic and clinical characteristics of a large series of 253 patients with radiation-induced meningiomas (RIMs). These parameters were compared with those of 41 patients with meningiomas in whom there was no previous history of irradiation (non-RIM group) and with other series of patients presented in the literature.

METHODS

The cases of RIM were recruited from a cohort of approximately 11,000 individuals who had been treated with ionizing radiation during childhood for tinea capitis and from a group of individuals who, as adults, applied for compensation because of that treatment. The non-RIM group was identified through the Israeli Cancer Registry. Exposure to radiation was carefully validated among all cases of RIM and absence of previous irradiation was verified for all patients in the non-RIM group. Significantly, a lower patient age at diagnosis, higher prevalence of calvarial tumors, higher proportion of multiple meningiomas, and a nonsignificant higher recurrence rate were observed among patients with RIM compared with the non-RIM group. The mean latency period from date of radiation exposure to development of a meningioma among the RIM group was approximately 36 years.

CONCLUSIONS

The findings of this study agree with those of other studies indicating the demographic, clinical, and even genetic variability between RIM and non-RIM cases. The existence of two different subtypes of meningiomas may have profound implications for screening, early diagnosis, and therapy of meningiomas.

Radiation-induced glioma presenting as diffuse leptomeningeal gliomatosis: a case report

BACKGROUND

Leptomeningeal gliomatosis is a rare and fatal disease.

METHODS

Case report.

RESULTS

We report the case of a man who was presented with severe intractable headaches, lymphocytic CSF pleocytosis, and spinal leptomeningeal enhancement on contrast MRI. Meningeal biopsy demonstrated diffuse infiltration by malignant glial cells, and symptom alleviation was achieved by CSF diversion. He later developed an enhancing thalamic tumor arising within the treatment field of a remotely irradiated pituitary adenoma. Subsequent management included chemotherapy and further radiotherapy with transient response, before death from leptomeningeal and parenchymal tumor progression 16 months after diagnosis.

CONCLUSION

We report a unique case embodying two rare conditions: radiation induced glioma and leptomeningeal gliomatosis. Our patient's course is novel in that symptomatic relief was achieved with CSF diversion and a combination of chemotherapy and focal radiation allowed prolonged survival.

Radiation-induced meningiomas involving the orbit

PURPOSE

To review the clinical features and outcomes of patients with radiation-induced meningiomas involving the orbit.

DESIGN

Retrospective case series.

PARTICIPANTS

Eight patients with radiation-induced meningiomas affecting the orbit.

METHODS

Clinical and pathologic data of the patients were reviewed.

MAIN OUTCOME MEASURES

Age at diagnosis, mean interval between radiation therapy and meningioma diagnosis, tumor recurrence, histologic atypia, and mean follow-up time after initial diagnosis.

RESULTS

The mean age at diagnosis was 42 years (range, 21 years to 70 years). The mean interval between radiation therapy and meningioma diagnosis was 26 years (range, 3 years to 54 years). All patients underwent gross total resection or subtotal resection of the meningioma. Five tumors (62.5%) recurred, based on clinical findings and CT imaging. The mean interval between resection of the meningioma and recurrence was 3 years (range, 9 months to 9 years). Three patients (37.5%) had atypical meningiomas. One patient (12.5%) had multiple tumors. The mean follow-up interval was 7 years after initial diagnosis of the meningioma (range, 15 months to 19 years).

CONCLUSIONS

This series of radiation-induced meningiomas, the first in the ophthalmic literature, illustrates the aggressive nature of this tumor.

[Radiation-induced intracerebral sarcoma]

We report a case of radiation-induced sarcoma in a 50 year-old male patient who was treated with total resection and radiation for right temporal lobe PNET. He received a dose of 60-Gy. A sequential magnetic resonance image 32 months after the completion of radiation therapy and 34 months after surgery showed a mass in the right temporal cerebral convexity. The postoperative diagnosis was sarcoma. Two years later the patient was operated because of a new lesion with similar characteristics. The follow up from the PNET diagnosis is 5 years and 10 months and the survival from sarcoma diagnosis is now 3 years and there is no evidence of recurrence. The development of sarcoma subsequent to cranial irradiation is an infrequent event but it should be considered in the differential diagnosis of a lesion that progresses several years after radiation therapy or when a new lesion appear.

Glioblastoma induction after radiosurgery for meningioma

A 70-year-old woman developed a glioblastoma in the irradiated field 7 years after stereotactic radiosurgery for meningioma. Glioma induction has been previously reported after external beam radiation for leukaemia, pituitary adenoma, tinea capitus, and meningioma. This radiosurgery-induced malignancy may portend further reports of tumour induction. The theoretical risk of tumour induction by low doses of radiation to normal neural tissue after radiosurgery is now confirmed. Reports of additional cases of radiosurgery-induced tumours might temper the use of this increasingly used technique for benign surgically accessible lesions.

[Radiation-induced glioblastoma and myxoma after treatment for undifferentiated carcinoma of the naspharynx]

Radio-induced tumor have been known for a long time to occur after treatment of cancer during childhood. This entity is exceptional following radiotherapy of the cavum. Skull and facial osteosarcoma were described after treatment of UCNT. We report two observations of radio-induced tumors arising, respectively three and seven years after treatment of UCNT. The first one is a temporoparietal glioblastoma and the second is a rhino- and pharyngeal myxoma. The two patients are alive after treatment of the second tumor. The delay of appearance of these tumors, their situation in the field's irradiated and dose received suggests their radio-induced nature. However, the cytogenetic study is necessary to confirm the implication of radiotherapy in the genesis of these cancers.

Second cancers in patients with brain tumours--impact of treatment

The records of the Finnish Cancer Registry from 1953 to 1994 were used to assess the risk of subsequent primary cancer among 14,493 brain tumour patients. They had been treated with surgery only (n = 9804), radiotherapy (n = 4099), chemotherapy and radiotherapy (n = 493) or chemotherapy alone (n = 97). By the end of 1994, 403 subsequent primary cancers were registered in these patients, whilst the expected number based on national incidence was 332. The standardised incidence ratio (SIR) was 1.2 (95% confidence interval (CI) 1.1-1.3). A significant excess risk of tumours in the central nervous system (CNS) including meningeomas (SIR 2.6, 95% CI 1.7-3.8), non-Hodgkin's lymphoma (SIR 2.6, 95% CI 1.6-4.1) and skin melanoma (SIR 1.9, 95% CI 1.0-3.1) was observed. CNS tumours were observed in excess among patients treated with surgery alone (SIR 2.0, 95% CI 1.2-3.2) and with radiotherapy (SIR 5.1, 95% CI 2.5-9.4). In conclusion, brain tumours are associated with an increased risk of both CNS second tumours and non-CNS second cancers, especially non-Hodgkin's lymphoma and melanoma. A moderately increased risk of second tumours in the CNS was observed among brain tumour patients treated with surgery only and a larger excess among those treated with radiotherapy.

Accumulation of p53 and Ki-67 expression do not predict survival in patients with fibrillary astrocytomas or the response of these tumors to radiotherapy

OBJECTIVE

Although radiotherapy is often used in the treatment of patients with low-grade astrocytomas, its value is still uncertain. Radiotherapy carries a risk of morbidity for patients and has time and cost implications for health services. We have assessed the value of two histological variables, p53 accumulation and Ki-67 expression, in predicting the response of astrocytomas to radiotherapy. The former antigen was assessed because many astrocytic tumors show mutations in the p53 gene, the function of which is crucial for mediating cell death after radiotherapy, and the latter was assessed because it is expressed only in proliferating tumor cells, which may show greater radiosensitivity than nonproliferating cells.

METHODS

Immunohistochemistry was used to detect the accumulation of p53 and expression of Ki-67 in a retrospective series of 96 patients with supratentorial fibrillary astrocytomas, 58 of whom had received postoperative radiotherapy. The immunohistochemical data were correlated with survival after radiotherapy.

RESULTS

There was no significant difference in survival between the patients who did and those who did not receive radiotherapy. The p53 and Ki-67 labeling indices did not correlate with survival in either the irradiated or the nonirradiated cohort, nor with overall survival in the series as a whole.

CONCLUSION

Immunohistochemical assessment of p53 accumulation and Ki-67 expression does not help in predicting the survival of patients with supratentorial fibrillary astrocytomas or in predicting whether particular patients are likely to benefit from radiotherapy.

Multiple radiation-induced intracranial lesions after treatment for pituitary adenoma. Case report

This 53-year-old man presented with a syncopal episode 31 years after undergoing craniotomy and external-beam radiation for a pituitary macroadenoma. A gadolinium-enhanced magnetic resonance (MR) image of the brain demonstrated a 2.5-cm enhancing mass in the right caudate region that had not been seen on previous studies. A stereotactically guided biopsy procedure was performed to obtain specimens from the mass, which were consistent with ependymoma. The MR image also revealed two additional lesions that appeared to be within the radiation fields: a right temporal meningioma and a left frontal cavernous malformation. A review of the literature found three previous reports in which ependymomas presented after radiation therapy.

Cerebral primitive neuro-ectodermal tumour following treatment of a unilateral retinoblastoma

Cerebral primitive neuro-ectodermal tumour (PNET) occurring as a second primary malignancy in childhood is exceedingly rare. We present a 7-year-old boy who developed a proven supratentorial PNET five years after enucleation and radio-/chemotherapy for a sporadic, unilateral retinoblastoma with optic nerve invasion. The association with this malignant eye disease as well as the effect of irradiation and multi-agent chemotherapy on second tumour induction are evaluated.

Glioblastoma multiforme after radiotherapy for metastatic brain tumor of testicular cancer

A patient with left testicular cancer and metastases to retroperitoneal lymph nodes, lung, and brain was treated by chemotherapy, radiotherapy and surgery, and obtained the state of no evidence of disease, but 10 years after radiotherapy, a glioblastoma multiforme tumor appeared in the brain. This is the first report of a glioma appearing after radiotherapy in a testicular cancer patient.

Late sequelae of treated pleomorphic xanthoastrocytoma: malignant brain stem astrocytoma occurring 15 years after radiation therapy

The pleomorphic xanthoastrocytoma (PXA) is a unique astrocytic neoplasm with an unexpectedly favorable prognosis despite striking pleomorphism of the cellular constituents. Although a majority of patients experience extended survival, these tumors may recur and some cases progress to high-grade astrocytoma. Recurrence inevitably involves the anatomic vicinity of the primary tumor. In this report, we describe a malignant brain stem astrocytoma that occurred 15 years after surgery and radiation treatment of a 16-year-old patient who had a temporal lobe PXA. To our knowledge, this is the first reported case of a malignant astrocytoma arising outside the primary anatomic site of a previously treated PXA and likely represents a radiation-induced secondary neoplasm.