PP2A activation overcomes leptomeningeal dissemination in Group 3 medulloblastoma.

Leptomeningeal dissemination (LMD) is the primary cause of treatment failure in children with Group 3 medulloblastoma (MB). Building on our previous work on protein phosphatase 2A (PP2A) activation in MB, here we present pre-clinical and molecular data on the effects of two novel classes of PP2A activators on disease processes of LMD in Group 3 MB. The PP2A activators employed in this study are ATUX-6156 and ATUX-6954 (diarylmethylcycloamine sulfonylureas), and ATUX-1215 and ATUX-5800 (diarylmethyl-4-aminotetrahydropyran-sulfonamides). Treatment with these compounds led to suppression of the endogenous PP2A inhibitor, cancerous inhibitor of PP2A (CIP2A), enhanced phosphatase activity (10-60%), and reduced MB viability, migration, and invasion, prerequisites for MB cells to access the cerebrospinal fluid, affecting the initiation stage of LMD. PP2A activator treatment of MB cells led to apoptosis mediated via caspase 9/PARP signaling due to decreased phosphorylation of Bad, impeding the dispersal stage of LMD. Cell proliferation and LMD-driving cellular traits and molecules pertinent to the third stage, colonization, were also affected. Treatment with ATUX-1215 or ATUX-5800 prevented LMD in an intraventricular murine model of MB, possibly mediated by disruption of the CCL2-CCR2 axis by altered NF-kB phosphorylation via disrupted AKT signaling. The present investigation offers proof-of-principle data for PP2A-based reactivation therapy for Group 3 MB and provides the first indications that PP2A reactivation may challenge the current paradigm in targeting the 3-stage process of MB LMD. Further investigations of PP2A activators are warranted as these compounds may prove beneficial as therapeutics for MB.

Postoperative disappearance of leptomeningeal enhancement around the brainstem in glioblastoma.

PURPOSE: Leptomeningeal enhancement (LME) suggests leptomeningeal dissemination (LMD) of tumor cells, which is a complication of end-stage glioblastoma, and is associated with a poor prognosis. However, magnetic resonance imaging (MRI) occasionally indicates the disappearance of peri-brainstem LME after surgical resection of glioblastoma. Since preoperative LMD may affect treatment indications, we aimed to analyze the clinical significance of preoperative LME of the brainstem in glioblastoma. METHODS: We retrospectively collected clinical and radiological data from consecutive patients with glioblastoma and preoperative LME of the brainstem, who were treated at our hospital between 2017 and 2020. RESULTS: Among 112 patients with glioblastoma, nine (8%) showed preoperative LME of the brainstem. In comparison with tumors without LME, tumor size was significantly associated with the preoperative LME of the brainstem (p = 0.016). In addition, there was a trend toward significance for a relationship between deep tumor location and preoperative LME of the brainstem (p = 0.058). Notably, among six patients who underwent surgical resection for glioblastoma with LME of the brainstem, four showed significant radiological disappearance of the LME on postoperative MRI. This suggests that the LME did not result from LMD in these cases. Moreover, these four patients lived longer than would be expected from the presence of LMD. However, this LME disappearance was not observed after biopsy or chemoradiotherapy. CONCLUSIONS: These findings suggest that preoperative LME does not necessarily indicate the presence of untreatable LMD; moreover, LME may disappear after surgical tumor resection. Thus, transient preoperative LME could be attributed to other mechanisms, including impaired venous flow due to intratumoral arteriovenous shunts, which can be resolved by reducing the tumor burden.

Understanding diffuse leptomeningeal glioneuronal tumors.

INTODUCTION: Diffuse leptomeningeal glioneuronal tumors (DLGNTs) pose a rare and challenging entity within pediatric central nervous system neoplasms. Despite their rarity, DLGNTs exhibit complex clinical presentations and unique molecular characteristics, necessitating a deeper understanding of their diagnostic and therapeutic nuances. METHODS: This review synthesizes contemporary literature on DLGNT, encompassing epidemiology, clinical manifestations, pathological features, treatment strategies, prognostic markers, and future research directions. To compile the existing body of knowledge on DLGNT, a comprehensive search of relevant databases was conducted. RESULTS: DLGNT primarily affects pediatric populations but can manifest across all age groups. Its diagnosis is confounded by nonspecific clinical presentations and overlapping radiological features with other CNS neoplasms. Magnetic resonance imaging (MRI) serves as a cornerstone for DLGNT diagnosis, revealing characteristic leptomeningeal enhancement and intraparenchymal involvement. Histologically, DLGNT presents with low to moderate cellularity and exhibits molecular alterations in the MAPK/ERK signalling pathway. Optimal management of DLGNT necessitates a multidisciplinary approach encompassing surgical resection, chemotherapy, radiotherapy, and emerging targeted therapies directed against specific genetic alterations. Prognostication remains challenging, with factors such as age at diagnosis, histological subtypes, and genetic alterations influencing disease progression and treatment response. Long-term survival data are limited, underscoring the need for collaborative research efforts. CONCLUSION: Advancements in molecular profiling, targeted therapies, and international collaborations hold promise for improving DLGNT outcomes. Harnessing the collective expertise of clinicians, researchers, and patient advocates, can advance the field of DLGNT research and optimize patient care paradigms.

Pediatric spinal cord diffuse midline glioma with H3 K27M-alteration with leptomeningeal dissemination: a rare case with intracranial hypertension onset and no spinal cord-related symptom.

PURPOSE: Spinal cord diffuse midline glioma (DMG) with H3 K27-alteration is a group of spinal cord high-grade glioma with poor outcome. We present a case with rare onset symptom pattern of pediatric spinal DMG, contributing to the understanding of the clinical presentations and natural history of pediatric spinal cord DMG. METHODS AND RESULTS: A 7-year-old boy was admitted due to symptoms of intracranial hypertension without obvious spinal cord-related symptoms. Head radiological examinations, blood and cerebral spinal fluid tests did not support intracranial lesion, infection, or autoimmune diseases. Spinal magnetic resonance imaging revealed intraspinal occupying lesion with leptomeningeal dissemination. Pathology of the lesion verified DMG with H3 K27M-alteration. CONCLUSION: Pediatric DMG with leptomeningeal dissemination could present with initial symptoms of intracranial hypertension without obvious spinal cord-related symptoms. Spinal cord examinations in cases of intracranial hypertension with negative head radiological examination results could be valuable in finding the etiology.

Ventricular entry during surgical resection is associated with intracranial leptomeningeal dissemination in glioblastoma patients.

PURPOSE: Glioblastoma (GBM) is associated with a poorer prognosis when leptomeningeal dissemination (LMD) occurs. Recently, the role of both ventricular entry (VE) during surgery and subventricular zone localization of tumors in promoting LMD in GBM patients has been debated. This article investigates the role of VE in causing LMD in GBM patients. METHODS: We conducted a retrospective analysis of GBMs operated on at our Institution between March 2018 and December 2020. We collected pre- and post-surgical images, anamnestic information, and surgical reports. RESULTS: Two hundred cases were collected. The GBM localization was periventricular in 69.5% of cases, and there was a VE during the surgical procedure in 51% of cases. The risk of post-surgical LMD in the case of VE was 16%. The rate of LMD was higher in the case of VE than not-VE (27.4% vs. 4%, p < 0.0001). The rate of LMD in periventricular GBM was 19% (p = 0.1131). CONCLUSION: According to our data, VE is an independent factor associated with a higher rate of post-surgical LMD, and the periventricular localization is not independently correlated to this negative outcome. Neurosurgeons should avoid VE when possible. The correct surgical strategy should be founded on balancing the need for maximal EOR and the risks associated with VE.

Leptomeningeal Dissemination of Low-Grade Neuroepithelial Tumor with FGFR1_TACC1 Fusion with Clinical and Radiographic Response to Pazopanib and Topotecan.

INTRODUCTION: Low-grade neuroepithelial tumors are a heterogeneous group of central nervous system tumors that are generally indolent in nature but in rare instances can progress to include leptomeningeal dissemination. CASE PRESENTATION: We present a case of a patient with a low-grade neuroepithelial tumor of indeterminate type with symptomatic leptomeningeal dissemination despite 3 chemotherapy regimens and radiotherapy. Somatic targetable mutation testing showed an FGFR1_TACC1 fusion. Therapy with pazopanib/topotecan was initiated, and disease stabilization was achieved. He received pazopanib/topotecan for a total of 2 years and is now >2 years from completion of treatment and continues to do well with no evidence of disease. DISCUSSION: This case highlights the utility of targetable mutation testing in therapeutic decision-making and the novel use of systemic pazopanib/topotecan therapy for refractory low-grade neuroepithelial tumor within the context of this clinical situation and specific mutation profile.

Leptomeningeal dissemination of anaplastic medullary cone astrocytoma: an unexpected findings in a patient with leptomeningeal enhancement and clinical history of multiple myeloma.

We report a challenging autopsy case with an insidious clinical presentation with diffuse lepto- and pachymeningeal enhancement in a context of a complex clinical history. Clinical features, neuroradiological and anamnestic data were consistent with central nervous system (CNS) dissemination of a previously known lambda restricted multiple myeloma. Autoptic findings allowed to discard this hypothesis. Unexpectedly, CNS sampling revealed an atypical glial cell proliferation within the sacral meningeal layers. No primary intraparenchymal CNS glial lesion was found. Findings supported the final diagnosis of anaplastic astrocytoma IDH1-wild type of the medullary cone with diffuse leptomeningeal and cerebrospinal fluid (CSF) dissemination. This occurrence represents an extremely rare condition itself, further complicated by the clinical history of the patient that led to formulate the most probable diagnosis of localization of the primary known disease. This autopsy case underlines that patients previously diagnosed with a primary tumor are not only at risk of recurrences or progression of the original disease, but they must be always accurately checked for eventual onset of a second tumor, including rare conditions such as gliomatosis.

A primary third ventricle mixed germ cell tumor with leptomeningeal dissemination of immature teratoma component.

A 17-year-old male patient presented to the clinic with a headache, nausea, and vomiting. Magnetic resonance imaging demonstrated a fat-containing and -enhancing heterogeneous tumor in the third ventricle, and fat droplets within the ventricles and the subarachnoid space. Obstructive hydrocephalus was also present. Emergency subtotal removal of the mass was performed via interhemispheric transcallosal approach. The histopathological diagnosis was a mixed germ cell tumor that was composed of embryonal carcinoma, yolk-sac tumor, germinoma, and immature teratoma containing a large amount of mature elements. The patient was referred for postoperative chemoradiotherapy. A mixed germ cell tumor is a rare type of nongerminomatous germ cell tumor that is made up of at least two different types of germ cell tumors. These may include germinoma, choriocarcinoma, embryonal carcinoma, yolk sac tumor, mature teratoma, immature teratoma, or teratoma with malignant degeneration. As far as we know, this is the first reported case of a primary third ventricle mixed germ cell tumor with leptomeningeal dissemination of the immature teratoma component that contains grossly visible mature elements at admission.

Baseline multicentric tumors, distant recurrences and leptomeningeal dissemination predict poor survival in patients with recurrent glioblastomas receiving bevacizumab.

PURPOSE: There are no widely accepted MRI markers that predict treatment outcomes of bevacizumab among patients with recurrent glioblastoma (GB). We aimed to determine if conventional MRI features of recurrent GB predict survival of patients receiving bevacizumab. METHODS: Patients with recurrent GB were retrospectively included if they received bevacizumab monotherapy between 2008 and 2017 after failure of standard treatment. Their MRI studies obtained at baseline and tumor recurrence, prior to bevacizumab treatment, were evaluated for multiple MRI features including measurable tumor, baseline multicentric tumors, distant recurrence, non-contrast-enhancing tumor, deep white matter invasion, multiple parenchymal tumors, bilateral cerebral involvement, ependymal extension and leptomeningeal dissemination. Predictive values of MRI features and patient characteristics on patient survival were statistically analyzed. RESULTS: A total of 103 patients were included. Baseline multicentric tumors (OR = 4.07; P = 0.042) and distant recurrence (OR = 28.5; P < 0.001) were two significant predictors of 3-month progression-free survival (PFS) rate. Distant recurrence (HR = 3.94; P < 0.001) was the only independent predictor of PFS. Baseline multicentric tumors (HR = 1.97; P = 0.028), distant recurrence (HR = 4.73; P < 0.001) and leptomeningeal dissemination (HR = 2.28; P = 0.044) were three independent predictors of overall survival. CONCLUSIONS: Baseline multicentric tumors, distant recurrence and leptomeningeal dissemination predicted poor survival among patients receiving bevacizumab for recurrent GB. Conventional MRI may help selecting patients with recurrent GB for bevacizumab treatment.

Characteristics of cerebellar glioblastomas in adults.

Adult cerebellar glioblastomas (cGBM) are rare and their characteristics remain to be fully described. We analyzed the characteristics of 17 adult patients with cGBM and compared them to a series of 103 patients presenting a supra-tentorial glioblastoma (stGBM). The mean age at GBMc diagnosis was 53.4 years (range 28-77). A history of neurofibromatosis type I was noted in 3 patients. cGBM were hemispheric in 10 patients (58.8%), only vermian in 4 patients (23.5%), and both vermian and hemispheric in 3 patients (17.7%). A H3 K27M mutation was identified in 3/14 patients, a TERT promoter mutation in 3/14 patients and a methylated MGMT promoter in 3/14 patients. None of the patients (0/14) harbored an EGFR amplification, an IDH or a BRAF mutation. Association with neurofibromatosis type I and H3K27M mutations were mutually exclusive. Compared with stGBM, cGBM occurred in younger patients (53.4 vs. 63.2, p = 0.02), were more frequently associated with neurofibromatosis type I (18 vs. 1%, p = 0.009) and with a H3 K27M mutation (21 vs. 3%, p = 0.02). They also tended to have a more frequent multifocal presentation at diagnosis (21 vs. 4.3%, p = 0.06), more frequently resulted in leptomeningeal or intra-axial metastasis (44.5 vs. 5%, p = 0.002) and were associated with a shorter median overall survival (5.9 vs. 14.2 months, p = 0.004). The present study suggests that adult cGBM differ from their supra-tentorial counterpart and constitute a heterogeneous group of IDH wild-type gliomas with at least two subgroups, one associated with H3K27M mutations and the other with neurofibromatosis type I.

Evaluation of new lesions and symptoms after gamma knife radiosurgery for brain metastases: a retrospective cohort study.

BACKGROUND: Symptomatic new lesions that appear after gamma knife radiosurgery (GKRS) for brain metastases have not been thoroughly described. METHODS: Among 238 patients who underwent a single session of GKRS without whole-brain radiotherapy or surgery for brain metastases between 2009 and 2014, a total of 165 (69.3%) patients underwent follow-up magnetic resonance imaging (MRI). Their electrical health records were reviewed retrospectively. The median age was 68 years, and 62.4% patients were men. The median number of brain metastases was 2. The most frequent primary organ site was the lung (71.5%). Then, we evaluated predictors for the symptoms of new lesions. RESULTS: New lesions and leptomeningeal dissemination were observed in 101 (61.2%) and 23 (14.2%) patients, respectively. The median number of new lesions was 2; moreover, 20 of 101 patients (19.8%) with new lesions had tumours with the largest diameters of > 1 cm. Among 101 patients with new lesions, 13 were symptomatic (12.9%). Patients with larger new lesions (> 1 cm of the largest diameter) experienced symptoms more frequently (odds ratio 7.6, P < 0.01). Symptoms resolved after salvage GKRS in seven of 11 patients who abided by the recommended follow-up MRI schedule. No significant risk factors were found for symptoms of new lesions. CONCLUSIONS: The incidence of symptomatic new lesions that appeared after GKRS was low, and more than half of the patients showed improvements in their symptoms after salvage GKRS. However, careful MRI-based assessments and salvage GKRS are critical for the quality of life.

A Case of Leptomeningeal Dissemination of Pilocytic Astrocytoma in a Child.

We present the case of a 2-year-old boy with progressive left-sided weakness and a cranial magnetic resonance imaging (MRI) scan showing a lesion with a cystic component in the right thalamus and basal ganglia. The lesion was subtotally resected and diagnosed as a pilocytic astrocytoma by histopathology. Tumor seeding along the surgical tract was seen on MRI 16 days and 10 weeks after surgery. The patient received vincristine and carboplatin, and MRI performed 4 months after chemotherapy revealed no additional or residual lesions. This case illustrated that a World Health Organization grade I astrocytoma could disseminate along the surgical tract.

Leptomeningeal dissemination and vertebral bone involvement in a child with pilocytic astrocytoma.

In low-grade glioma, metastasis is rarely seen. Few cases of leptomeningeal dissemination have been reported in children. Vertebral bone metastasis has not been reported so far. Herein is described the case of a pediatric patient with the diagnosis of pilocytic astrocytoma, and leptomeningeal dissemination detected at the time of diagnosis, who then received radiotherapy and chemotherapy upon development of vertebral bone metastasis during treatment.

The Impact of Lateral Ventricular Opening in the Resection of Newly Diagnosed High-Grade Gliomas: A Single Center Experience.

Given the importance of maximizing resection for prognosis in patients with HGG and the potential risks associated with ventricle opening, this study aimed to assess the actual increase in post-surgical complications related to lateral ventricle opening and its influence on OS and PFS. A retrospective study was conducted on newly diagnosed HGG, dividing the patients into two groups according to whether the lateral ventricle was opened (69 patients) or not opened (311 patients). PFS, OS, subependymal dissemination, distant parenchymal recurrences, the development of hydrocephalus and CSF leak were considered outcome measures. A cohort of 380 patients (154 females (40.5%) and 226 males (59.5%)) was involved in the study (median age 61 years). The PFS averaged 10.9 months (±13.3 SD), and OS averaged 16.6 months (± 16.3 SD). Among complications, subependymal dissemination was registered in 15 cases (3.9%), multifocal and multicentric progression in 56 cases (14.7%), leptomeningeal dissemination in 12 (3.2%) and hydrocephalus in 8 (2.1%). These occurrences could not be clearly justified by ventricular opening. The act of opening the lateral ventricles itself does not carry an elevated risk of dissemination, hydrocephalus or cerebrospinal fluid (CSF) leak. Therefore, if necessary, it should be pursued to achieve radical removal of the disease.

Leptomeningeal Dissemination Complicated With Acute Tetraplegia From a Supratentorial Multicentric Isocitrate Dehydrogenase (IDH)-Wildtype Glioblastoma: A Case Report.

Glioblastoma (GBM) is a major concern for neurosurgeons and oncologists, being a malignant tumor with a high recurrence rate and reduced survival. Leptomeningeal dissemination (LMD) of GBM is rare and difficult to diagnose due to the low rate of cellular detection in the cerebrospinal fluid and clinical and imaging similarities with fungal and tuberculous meningitis. We report the case of a 25-year-old female patient suffering from multicentric GBM who developed hydrocephalus and extensive LMD three months after surgery for a left frontal parafalcine cerebral GBM isocitrate dehydrogenase (IDH)-wildtype.

Leptomeningeal dissemination in pediatric brain tumors.

Leptomeningeal disease (LMD) in pediatric brain tumors (PBTs) is a poorly understood and categorized phenomenon. LMD incidence rates, as well as diagnosis, treatment, and screening practices, vary greatly depending on the primary tumor pathology. While LMD is encountered most frequently in medulloblastoma, reports of LMD have been described across a wide variety of PBT pathologies. LMD may be diagnosed simultaneously with the primary tumor, at time of recurrence, or as primary LMD without a primary intraparenchymal lesion. Dissemination and seeding of the cerebrospinal fluid (CSF) involves a modified invasion-metastasis cascade and is often the result of direct deposition of tumor cells into the CSF. Cells develop select environmental advantages to survive the harsh, nutrient poor and turbulent environment of the CSF and leptomeninges. Improved understanding of the molecular mechanisms that underlie LMD, along with improved diagnostic and treatment approaches, will help the prognosis of children affected by primary brain tumors.

Pineocytoma with malignant transformation to pineal parenchymal tumor with intermediate differentiation and leptomeningeal dissemination after subtotal tumor resection and adjuvant radiotherapy.

Pineocytoma is a rare tumor. It is rare for pineocytoma to present as leptomeningeal metastasis. We present a rare case of pineocytoma with malignant transformation and leptomeningeal metastasis after subtotal tumor resection and adjuvant radiotherapy. This case was a 58-year-old male with an unsteady gait for 2 months. Enhanced brain magnetic resonance imaging revealed a heterogeneous mass involving the pineal region. The initial pathological diagnosis of pineocytoma was confirmed after subtotal tumor resection. Two years after adjuvant radiotherapy to the primary site, the magnetic resonance imaging showed C2 and T2 metastatic lesions, with the final pathological diagnosis being pineal parenchymal tumor (PPT) with intermediate differentiation after the removal of T2 intramedullary tumor. After that adjuvant radiotherapy at the cervical and thoracic spinal cord was completed. There was no recurrence of the tumor 1 year after the radiotherapy. We report a rare case of pineocytoma with malignant transformation to PPT with intermediate differentiation and leptomeningeal dissemination.

UBE2C promotes leptomeningeal dissemination and is a therapeutic target in brain metastatic disease.

Background: Despite current improvements in systemic cancer treatment, brain metastases (BM) remain incurable, and there is an unmet clinical need for effective targeted therapies. Methods: Here, we sought common molecular events in brain metastatic disease. RNA sequencing of thirty human BM identified the upregulation of UBE2C, a gene that ensures the correct transition from metaphase to anaphase, across different primary tumor origins. Results: Tissue microarray analysis of an independent BM patient cohort revealed that high expression of UBE2C was associated with decreased survival. UBE2C-driven orthotopic mouse models developed extensive leptomeningeal dissemination, likely due to increased migration and invasion. Early cancer treatment with dactolisib (dual PI3K/mTOR inhibitor) prevented the development of UBE2C-induced leptomeningeal metastases. Conclusions: Our findings reveal UBE2C as a key player in the development of metastatic brain disease and highlight PI3K/mTOR inhibition as a promising anticancer therapy to prevent late-stage metastatic brain cancer.

Inhibition of metastatic brain cancer in Sonic Hedgehog medulloblastoma using caged nitric oxide albumin nanoparticles.

Medulloblastoma is a tumor of the cerebellum that metastasizes to the leptomeninges of the central nervous system (CNS), including to forebrain and to spinal cord. The inhibitory effect of polynitroxylated albumin (PNA), a caged nitroxide nanoparticle, on leptomeningeal dissemination and metastatic tumor growth was studied in a Sonic Hedgehog transgenic mouse model. PNA treated mice showed an increased lifespan with a mean survival of 95 days (n = 6, P<0.05) compared with 71 days in controls. In primary tumors, proliferation was significantly reduced and differentiation was significantly increased (P<0.001) as shown by Ki-67+ and NeuN+ immunohistochemistry, while cells in spinal cord tumors appeared unaffected. Yet, histochemical analysis of metastatic tumor in spinal cord showed that the mean total number of cells in spinal cord was significantly reduced in mice treated with PNA compared to albumin vehicle (P<0.05). Examination of various levels of the spinal cord showed that PNA treated mice had significantly reduced metastatic cell density in the thoracic, lumbar and sacral spinal cord levels (P<0.05), while cell density in the cervical region was not significantly changed. The mechanism by which PNA may exert these effects on CNS tumors is discussed.

CyberKnife Radiosurgery for Spinal Leptomeningeal Metastases Secondary to Esthesioneuroblastoma: A Clinical Case Report.

Esthesioneuroblastoma (ENB), also known as olfactory neuroblastoma, is a rare malignant tumor of neuroectodermal origin that arises from the olfactory epithelium. We present a case of ENB metastasizing through the leptomeningeal route to the spinal dura, which was treated with CyberKnife (CK) stereotactic radiosurgery (SRS), and aim to assess the safety and effectiveness of SRS in such cases. To the best of our knowledge, this is the first case report in the literature that discusses ENB spinal leptomeningeal metastases treated with CK radiosurgery. We retrospectively review the clinical and radiological outcomes in a 70-year-old female with ENB metastasis to the spine. Progression-free survival (PFS), overall survival (OS), and local tumor control (LTC) are investigated. In our patient, ENB had been diagnosed at the age of 58 years and spinal metastases had been first noted at the age of 65 years. A total of six spinal lesions received CK SRS. Lesions were present at the level of C1, C2, C3, C6-C7, T5, and T10-11. The median target volume was 0.72 cc (range: 0.32-2.54). A median marginal dose of 24 Gy was delivered to the tumors with a median of three fractions to a median isodose line of 80% (range: 78-81). LTC at the 24-month follow-up was 100%. PFS and OS were 27 months and 40 months, respectively. No adverse radiation effects were reported. Even though the treated spinal lesions remained stable, the number of new metastatic lesions had increased with progressive osseous and dural metastatic lesions within the cervical, thoracic, and lumbar spine at the last follow-up. SRS provides relatively good LTC for patients with ENB metastasizing to the spine, with no radiation-induced adverse events.