Nongerminomatous Germ Cell Tumors Research Articles

EPID-36. CLINICAL FEATURES OF 614 PRIMARY INTRACRANIAL GERM CELL TUMORS: AN 15-YEAR EXPERIENCE OF A SINGLE CENTER IN CHINA

Abstract Incidence of primary intracranial germ cell tumors (ICGCT) in Asian countries is higher than Western countries. This study aims to describe the characteristics of ICGCT patients in China. Data on all patients with ICGCT who were seen at the Department of Neuro-oncology, Sanbo Brain Hospital, Capital Medical University from 2007 to 2022 were collected retrospectively. Patient demographics, disease characteristics and treatment outcomes were analyzed. A total of 614 patients were identified, with 309 germinomas and 305 non-germinomatous germ cell tumors (NGGCT). The median age at diagnosis was 12.8 years. The male-female ratio is 2.4 to 1. The primary disease sites were mainly pineal gland and suprasellar region. Adults (age≥23) were more likely to develop germinomas (65.3%). 78% patients received radiotherapy after initial diagnosis. In M0 patients, whole brain radiotherapy was the most common approach, while in M+ was craniospinal radiotherapy. Whole ventricle radiotherapy was uncommon (4%). The most common chemotherapy regimen for germinoma was a combination of bleomycin, cisplatin and etoposide/tenipside; while for the NGGCT was ifosfamide combined with carboplatin/cisplatin and etoposide. For germinoma, the median recurrence-free survival (RFS) and overall survival (OS) were 150.3 months and 222 months; the 10 year RFS and OS were 58.2% and 85.1%, respectively. For NGGCT, the median RFS and OS were 80.4 months and 166.7 months; the 10 year RFS and OS were 46.9% and 60.5%. At relapse, four (0.65%) developed secondary malignancies. Seven (1.14%) developed extracranial dissemination. Chemotherapy and radiotherapy could improve the RFS and OS. Higher radiation dose was associated with better prognosis. The prognosis of focal radiotherapy alone was poor. M0 germinoma treated with focal radiotherapy alone were more likely relapse. This study suggested that treatment outcomes of our ICGCT patients are comparable with those in Western centers. Adjuvant chemotherapy and whole brain/craniospinal radiotherapy are pivotal treatment.

PATH-24. NOVEL MOLECULAR SUBTYPES IDENTIFIED IN INTRACRANIAL GERM CELL TUMORS SHOWED UNIQUE WHOLE-GENOME METHYLATION PROFILE

Abstract BACKGROUND By integrating whole-genome sequencing (WGS) and RNA-seq data, we found that intracranial germ cell tumors (IGCTs) can be divided into three distinct molecular subtypes: immune-hot, MYC/E2F, and SHH, each characterized by a unique profile of genomic abnormalities. To further define these subtypes, we subsequently performed whole-genome bisulfate sequencing (WGBS) on IGCT tumors METHODS Within our prior discovery cohort (n=110), DNA from 84 samples was available for profiling methylation levels using Whole Genome Bisulfite Sequencing (WGBS). Fastq data was aligned to the human reference genome (hg19), with duplicates removed, and DNA methylation was extracted using bismark pipeline (ver0.24.0). After quality control, weight methylation level was calculated for each CpG island as the sum of methylated reads divided by coverage. To identify IGCTs molecular groups, we applied hierarchical consensus k-means clustering to the most variant methylated CpG island (n=1000) across 84 IGCTs tumor tissues. The methylation level of RNA-seq subtypes was visualized to further clarify the molecular subtypes of IGCTs RESULTS Unsupervised clustering revealed that IGCTs can be divided into three groups based on the CpG island methylation levels: hypomethylation group (n=32), moderate methylation group (n=27), and hyper methylation group (n=25). The hypomethylation and moderate methylation group are predominantly observed in germinoma (>90%). In contrast, hypermethylation group comprises the majority of non-germinomatous germ cell tumors. Furthermore, these subgroups derived from methylation analysis are highly consistent with the molecular subtypes previously defined through gene transcription profile analysis. We observed that the majority of MYC/E2F subtype (24/33) belonged to the hypomethylation group, whereas the majority of immune-hot subtype (14/23) fell into the moderate methylation group. The SHH subtype was the most common within the hypermethylation group (18/26) CONCLUSIONS The three molecular IGCT subtypes showed unique methylation profile. These results indicate different mechanisms of tumorigenesis among the subtypes and pave the way for the clinical application of methylation-based subtyping.

Phase II Trial of Pathology-based Tripartite Treatment Stratification for Patients with CNS Germ Cell Tumors: A Long-term Follow-up Study.

A previous Phase II clinical trial, conducted from 1995 to 2003, evaluated CNS germ cell tumors (GCTs) using a three-group treatment stratification based on histopathology. The primary objective of the study was to assess the long-term efficacy of standardized treatment regimens, while the secondary objective focused on identifying associated long-term complications. Total 228 patients were classified into three groups for treatment: germinoma (n=161), intermediate prognosis (n=38), and poor prognosis (n=28), excluding one mature teratoma case. Treatment involved stratified chemotherapy regimens and varied radiation doses/coverage. Clinical data was retrospectively analyzed at a median follow-up of 18.5 years. The treatment outcomes for germinoma, with or without syncytiotrophoblastic giant cell, were similar. The 10- and 20-year event-free survival rates for the germinoma, intermediate, and poor prognosis groups were 82/76/49% and 73/66/49%, respectively. Overall survival (OS) rates were 97/87/61% at 10 years and 92/70/53% at 20 years. Germinomas in the basal ganglia, treated without whole-brain radiation therapy (WBRT), frequently relapsed but were effectively managed with subsequent WBRT. Deaths in germinoma cases had varied causes, whereas deaths in the poor prognosis group were predominantly disease-related. Nineteen treatment-related complications were identified in 16 patients, with cumulative event rates of 1.9% at 10 years and 11.3% at 20 years. OS rates at 1 and 2 years post-relapse for tumors initially classified as germinoma, intermediate, and poor prognosis were 94/88/18% and 91/50/9%, respectively. Initial treatment intensity is crucial for managing non-germinomatous GCTs, while long-term follow-up for relapse and complications is imperative in germinomas. Irradiation extending beyond the immediate tumor site is essential for basal ganglia germinomas. Addressing relapse in non-germinomatous GCT remains a significant challenge.

A deep learning model for differentiating paediatric intracranial germ cell tumour subtypes and predicting survival with MRI: a multicentre prospective study

BackgroundThe pretherapeutic differentiation of subtypes of primary intracranial germ cell tumours (iGCTs), including germinomas (GEs) and nongerminomatous germ cell tumours (NGGCTs), is essential for clinical practice because of distinct treatment strategies and prognostic profiles of these diseases. This study aimed to develop a deep learning model, iGNet, to assist in the differentiation and prognostication of iGCT subtypes by employing pretherapeutic MR T2-weighted imaging.MethodsThe iGNet model, which is based on the nnUNet architecture, was developed using a retrospective dataset of 280 pathologically confirmed iGCT patients. The training dataset included 83 GEs and 117 NGGCTs, while the retrospective internal test dataset included 31 GEs and 49 NGGCTs. The model’s diagnostic performance was then assessed with the area under the receiver operating characteristic curve (AUC) in a prospective internal dataset (n = 22) and two external datasets (n = 22 and 20). Next, we compared the diagnostic performance of six neuroradiologists with or without the assistance of iGNet. Finally, the predictive ability of the output of iGNet for progression-free and overall survival was assessed and compared to that of the pathological diagnosis.ResultsiGNet achieved high diagnostic performance, with AUCs between 0.869 and 0.950 across the four test datasets. With the assistance of iGNet, the six neuroradiologists’ diagnostic AUCs (averages of the four test datasets) increased by 9.22% to 17.90%. There was no significant difference between the output of iGNet and the results of pathological diagnosis in predicting progression-free and overall survival (P = .889).ConclusionsBy leveraging pretherapeutic MR imaging data, iGNet accurately differentiates iGCT subtypes, facilitating prognostic evaluation and increasing the potential for tailored treatment.Graphical

Third ventricle teratoma with malignant transformation

Intracranial germ cell tumors(GCTs) are rare and heterogeneous group of primary brain tumors, mainly affecting pediatric population and young adults. The current understanding of the etiology of intracranial GCTs and their optimal management strategies remain controversial. Treatment plans differ depending on the subtype GCT and may vary among physicians and institutions. Central nervous system non-germinomatous germ cell tumor (NGGCT) usually requires surgical resection with histological verification, chemotherapy, and radiation. The extent of surgical resection is an important prognostic factor alongside the etiology and genetics of NGGCT. This article presents a rare clinical case of a rapidly growing teratoma located in the posterior part of third ventricle of a 17-year-old male presenting with symptoms of intracranial hypertension. Surgical total resection was preceded by endoscopic third ventriculostomy. Immunohistochemistry revealed the presence of embryonal carcinoma and immature teratoma cells turning the tumor into mixed type NGGCT with unfavorable prognosis. Despite the complete resection of the tumor and the timely initiation of adjuvant therapy, a rapid progression of the disease with subsequent unfavorable outcome was observed 3.6 months after the surgical treatment.

Monitoring pediatric CNS non-germinomatous germ cell tumors via cerebrospinal fluid circulating tumor DNA.

Accurate molecular and clinical stratification of patients with central nervous system (CNS) non-germinomatous germ cell tumors (NGGCTs) remains challenging, impeding the development of personalized therapeutic approaches. Herein, we investigated the translational significance of cerebrospinal fluid (CSF) circulating tumor DNA (ctDNA) in pediatric NGGCTs to identify characteristic features of CNS NGGCTs and to identify a subset of patients for whom the presence of residual disease is a risk factor and an indicator of shorter progression-free survival (PFS) and overall survival (OS). Medical records of patients with CNS NGGCTs between January 1, 2018 and December 31, 2022 were reviewed retrospectively. The cohort consisted of 11 male and six female patients. Tumor markers were elevated in four of the five people who underwent surgery. The remaining 12 patients were diagnosed with malignant NGGCTs according to elevated tumor markers. Among them, ctDNA before chemotherapy as well as ctDNA clearance were consistently associated with PFS and OS (p<.05). By setting a ctDNA positivity threshold of 6%, patients with high ctDNA (above the threshold) levels, which had limitation due to the selection based on optimal statistic from the survival analysis, had significantly inferior 5-year PFS and OS compared to those with low levels (below the threshold). ctDNA or ctDNA clearance combined with the presence of residual disease predicted significantly worse OS and PFS (p<.05). CSF ctDNA might allow the study of genomic evolution and the characterization of tumors in pediatric NGGCTs. CSF ctDNA analysis may facilitate the clinical management of pediatric NGGCT patients, and aid in designing personalized therapeutic strategies.

AB039. Malignant transformation of intracranial germinoma to non-germinomatous germ cell tumors-incidence, treatment strategy and outcome: a case report and literature review.

Intracranial germ cell tumors are rare neoplasms seen mainly in children and adolescents. Compared to non-germinomatous germ cell tumors (NGGCTs), germinomas typically respond well to chemo-radiotherapy and portend a better prognosis. We report here a patient with intracranial germinoma which showed complete remission following chemo-radiotherapy but re-presented with malignant transformation to NGGCT thirteen years later. We then performed a literature review to understand the treatment strategy and outcome of this rare phenomenon. Review of the patient's case note, followed by a literature review of the topic. A 13-year-old male presented with 6 weeks of polyuria and polydipsia. Imaging showed bifocal (suprasellar and pineal) lesions. Histology from an open biopsy diagnosed a germinoma. He underwent extended whole ventricular irradiation with local boost and chemotherapy, which led to complete resolution on imaging. Thirteen years later, he re-presented with headaches and diabetes insipidus. Imaging showed a new right frontal lesion with elevated serum beta-human chorionic gonadotropin (β-hCG) and alpha-fetoprotein (AFP). The tumor was excised with histology confirming a mixed tumor comprising germinoma, yolk sac, and choriocarcinoma. A literature review returned eight case reports of malignant transformation of intracranial germinoma to NGGCTs, covering eight patients (seven males, and one female; aged 5-23 years old). Four had the primary tumor located in the pineal region, three in the suprasellar region, and one at both sites. Recurrence with malignant transformation occurred at a median of 24.5 months after initial diagnosis (range, 5 months to 14 years). Five patients had recurrences intra-abdominally, all of whom had a ventriculoperitoneal shunt (VPS) inserted during the treatment of the initial tumor. Of the remaining three intracranial recurrences, two were at the same site while one at a distant site. The most common histology was yolk sac tumor (five patients), followed by two each of immature teratoma, choriocarcinoma, and embryonal carcinoma (some were mixed germ cell tumors). Of those with intra-abdominal recurrence, four died within 2 months of diagnosis. Those with intracranial recurrences survived longer, with a median survival of 15 months, and one longer than 27 months. Malignant transformation to NGGCTs is rare. Relapse can occur intracranially, or in cases where VPS was present, intraabdominally. Outcomes following transformation were poor despite aggressive treatment, with those intra-abdominal recurrences faring much worse.

Increased Human Chorionic Gonadotropin Level in a Nonsexually Active Young Female

BackgroundQuantitative and qualitative human chorionic gonadotropin (hCG) tests are obtained in the emergency department (ED) to determine if a female of child-bearing age is pregnant. A positive hCG result is commonly assumed to indicate an intrauterine or other form of pregnancy. However, elevated hCG levels can also result from various other conditions, such as ovarian tumors, pituitary tumors, and thyroid disorders. Intracranial germ cell tumors, rare central nervous system tumors capable of secreting hCG, primarily affect adolescent and young adult females. Case ReportA 16-year-old female student without significant past medical history presented to our ED with a complaint of intermittent bilateral frontal headache for two days. Last menstrual period started two days prior to presentation. The headache was associated with phonophobia, photophobia, nausea, and vomiting. Serum quantitative hCG was elevated. She denied history of sexual activity or sexual assault. Transabdominal ultrasound was negative for intrauterine pregnancy. Obstetrics and gynecology as well as pediatric oncology were consulted. Subsequent investigations, including brain imaging, revealed a 3.5 cm mass in the right caudate nucleus and corpus callosum. The patient was diagnosed with an intracranial nongerminomatous germ cell tumor, necessitating hospitalization and prompt initiation of chemotherapy. Why Should an Emergency Physician Be Aware of This?An elevated quantitative hCG is not always indicative of pregnancy, especially in a young patient without sexual history. In the case of a nonrevealing transabdominal ultrasound, obstetrics and gynecology should be consulted for discussion of further testing and imaging. Emergency physicians should include malignancy high on their differential since prompt initiation of chemotherapy, evaluation by surgical services, and family planning will be required.

GCT-26. INTRACRANIAL NON-GERMINOMATOUS GERM CELL TUMOR WITH MALIGNANT TRANSFORMATION TO EMBRYONAL RHABDOMYSARCOMA

Abstract BACKGROUND Non-germinomatous germ cell tumors (NGGCT) constitute 35%- 45% of intracranial germ cell tumors. Growing teratoma syndrome has been observed in patients with NGGCTs after starting chemotherapy. While growing teratomas are typically benign, this process can rarely involve malignant transformation and result in poor prognosis. We present the case of a patient with pineal NGGCT and growing teratoma syndrome with malignant transformation to embryonal rhabdomyosarcoma. CASE REPORT A 13-year-old male presented with headaches and vision changes. An MRI brain demonstrated a 26 x 25 x 19 mm (AP X TR X CC) mixed solid and cystic pineal mass with no evidence of metastatic disease. Due to elevated alpha fetoprotein levels in the serum and cerebrospinal fluid, he was diagnosed with intracranial NGGCT. Treatment was initiated with alternating cycles of Carboplatin/Etoposide and Ifosfamide/Etoposide. After 2 cycles of chemotherapy, a complete biochemical response was noted but MRI showed increased tumor size (presumed growing teratoma syndrome). The patient underwent complete tumor resection. Histology showed embryonal rhabdomyosarcoma as a somatic malignancy arising in a mature teratoma. Further molecular characterization revealed somatic NF1 and KRAS pathogenic mutations that are consistent with the primary diagnosis. Methylation profiling, however, did not exhibit a match with any known malignancies. Continued complete response was noted following two additional chemotherapy cycles. The patient is planned for six total chemotherapy cycles followed by high-dose craniospinal radiation with boost to the primary tumor. CONCLUSIONS Malignant transformation is a rare phenomenon in NGGCT. There is no standard of care for these patients. Further studies are needed to define ideal therapy for this patient population.

GCT-07. CONTRIBUTORS TO DELAYED TREATMENT OF NON-GERMINOMATOUS GERM CELL TUMORS IN CHINA: A TERTIARY-CENTER REVIEW

Abstract BACKGROUND Non-Germinomatous Germ Cell Tumors (NGGCT) are rare malignancies with potential for treatment delays. This study aims to identify risk factors and systemic challenges contributing to delayed management of NGGCT in China. METHODS We reviewed the clinical features and referral pattern of 56 consecutively diagnosed NGGCT patients at Shanghai Children’s Medical Center (SCMC) from 9/2018-2/2023. Patients were diagnosed by pathology (n=42), or by elevated markers alone (n=14, AFP&amp;gt;10ng/ml, and/or β-HCG&amp;gt;50mIU/ml). Patients were treated per COG ACNS0122. Delay of treatment was defined as chemotherapy initiated more than 6 months after symptom onset. RESULTS Forty-three males and 13 females were included. Median age at diagnosis was 9.17year (4month-16year). Primary tumor locations included the pineal region (n=31), sellar region (n=19), basal ganglia (n=5), and posterior fossa (n=1). Presenting symptoms included features of increased intracranial pressure (ICP, n=29), endocrine symptoms (n=21), blurred vision or squint (n=7), and hemiplegia (n=4). Delayed treatment occurred in 16 cases (29%), and was more likely in patients with non-pineal region primary (Chi-square p=0.003), and absence of symptoms pertaining to increased ICP (Chi-square p&amp;lt;0.001). Reasons for delay included lack of parental recognition on symptoms (n=7), misdiagnosis (n=3), and inappropriate/incomplete workup (n=6). As a national referral center, patients commuted a median of 483 km (range: 12-2943km) to SCMC (median 2 hospitals (1,5) before SCMC), including 10 patients with obvious hydrocephalus travelling before any CSF diversion procedure. Three-year Event-Free Survival (EFS) was 76.9% and Overall Survival was 86.0%. There was a trend to inferior outcome in patients with delay in treatment (3y EFS 69.6%) compared with those without (3year EFS 80.6%, p=0.112). CONCLUSIONS Delay in treatment is common for children with NGGCT managed at a tertiary referral center in China. Improving public awareness, training for primary-care clinicians, and establishing a national referral network are potential strategies to enhancing the outcome.

GCT-08. THE PURSUIT OF OPTIMUM TREATMENT FOR NONGERMINOMATOUS GERM CELL TUMOURS (NGGCT) OF THE CNS – A PROGRESS REPORT FROM THE EUROPEAN GROUP (SIOP CNS GCT II)

Abstract BACKGROUND Controversy surrounds the optimum treatment for localised nongerminomatous germ-cell-tumours (NGGCT). The European group has employed more dose-intense chemotherapy followed by 54 Gy focal radiotherapy (fRT), whilst others additionally apply whole-ventricular or craniospinal radiotherapy (CSI). Historically, these approaches have led to comparable outcomes. PATIENTS/METHODS SIOP-CNS-GCT-II aimed to improve event free survival (EFS) for NGGCT by standardising the surgical approach for residual disease and by chemotherapy dose escalation in patients identified as high-risk (age &amp;lt;6 years and/or serum/CSF AFP &amp;gt;1000 ng/ml). Standard treatment with four courses of cisplatin, etoposide and ifosfamide (PEI) followed by 54 Gy fRT with 30 Gy CSI for metastatic disease, was retained from the SIOP-CNS-GCT-96 trial for patients not defined as high-risk. Radiotherapy technique (protons or photons) was not dictated in the trial, but the number of cases receiving proton beam therapy has increased over time. Between 02/2012 and 07/2018, 112 patients with NGGCT from eight European countries were treated according to the SIOP-CNS-GCT-II protocol; 89 were standard-risk, and 14 of these were metastatic. This compared with 149 NGGCT patients treated overall in SIOP-CNS-GCT-96, of which 33 were metastatic. RESULTS In SIOP-CNS-GCT-96, 3-year EFS for localised NGGCT receiving PEI chemotherapy and 54 Gy fRT was 0.72, and for metastatic cases, receiving PEI and 30 Gy CSI with boost, 0.68. In SIOP-CNS-GCT-II, 3-year EFS for metastatic cases receiving similar treatment was excellent at 0.94 (p=0.087 compared with SIOP-CNS-GCT-96) but for localised cases, only 0.63 (p=0.032). CONCLUSION To understand the impact of radiotherapy volumes on EFS and guide future trials, a detailed dosimetric study on the patterns of relapses is in progress. In the meantime, based on our current understanding, most participating countries are recommending addition of whole ventricular radiotherapy to fRT for localised NGGCT.

GCT-09. VENTRICULAR RELAPSES OF INTRACRANIAL GERM CELL TUMORS FOLLOWING FOCAL RADIOTHERAPY

Abstract BACKGROUND Non-germinomatous germ cell tumors (NGGCTs) require treatment involving combinations of chemotherapy, surgery, and radiotherapy. The radiotherapy field is typically focal in Europe and craniospinal in North America. Unlike germinomas, there are conflicting results for the effectiveness of ventricular field irradiation, and there is not enough data documenting the histology and tumor markers for tumors that relapse along the ventricles in patients who receive focal irradiation. METHODS We performed a literature review for English-language literature from 1998 to 2024 to to analyze the incidence, histopathology and tumor marker levels for NGGCT patients who initially received chemotherapy followed by focal radiotherapy and ended up having of ventricular relapses. RESULTS We identified 47 cases with relapsed NGGCT. However, only 8 cases were along the ventricles. Six of these were ventricular only, including two presumed germinomas based on tumor markers, three biopsy-proven germinomas, and only one case with bHCG levels exceeding ≥1000 IU/l. Two had combined relapses involving both the ventricular and spinal regions; one had pathology-proven germinoma but with elevated alpha-fetoprotein, and the other exhibited bHCG levels between 50 and 200 IU/l. CONCLUSION Ventricular relapses in NGGCT patients who receive focal radiotherapy should be investigated further. Whole ventricular radiotherapy may be required to prevent the relapse of germinoma elements. However, further information is essential before making any changes in the radiotherapy doses and fields.

GCT-21. MULTINATIONAL ANALYSIS OF PEDIATRIC RELAPSED/REFRACTORY CENTRAL NERVOUS SYSTEM NON-GERMINOMATOUS GERM CELL TUMORS

Abstract BACKGROUND Patients with relapsed/refractory central nervous system (CNS) non-germinomatous germ cell tumors (NGGCTs) have poor prognosis. We explored prognostic factors to guide the management of these patients. METHODS We performed a multinational retrospective study of relapsed/refractory CNS NGGCTs. Data were summarized using standard descriptive statistics. Overall survival (OS) was evaluated using Kaplan-Meier and Fisher’s exact test to estimate odds ratios (OR) and 95% confidence intervals (CI). RESULTS We identified 31 patients from eight centers. The median age at initial diagnosis was 11 years (interquartile range (IQR): 9-15.3). Twenty patients (64.5%) suffered a relapse, and 11 patients (35.5%) had refractory disease. The median follow-up time since relapse/progression was 17.5 months (range:1-295). The median time to relapse/progression was 12.1 months (IQR: 5.5-27.5). Ten patients (32.3%) received high-dose chemotherapy (HDCx) with stem cell rescue. Sixteen patients (51.6%) received re-irradiation at relapse/progression. Nine patients (29%) achieved complete remission (CR). Ten patients (32.3%) were alive at the time of the last follow-up. Among the ten survivors, the median serum and cerebrospinal fluid (CSF) alpha-fetoprotein levels were 2.3 ng/dl (range: 0-17) and 2.1 ng/dl (range: 0-55), respectively, the median serum and CSF beta-human chorionic gonadotropin were 23 IU/L (0-168) and 139 IU/L(0-601), none underwent gross total resection, eight received HDCx, and seven received radiotherapy (craniospinal irradiation (n=6), abdominal radiotherapy (n=1)). HDCx (OR=19.8, 95%CI: 2.7-145.7; p=0.01) and achieving CR at the end of relapse treatment (OR=160, 95%CI: 8.9-2880.5; p=&amp;lt;0.001) were associated with a survival benefit. Re-irradiation (OR=3.3 95%CI: 0.53-20.9; p=0.24) was not associated with a survival benefit. CONCLUSIONS A subset of patients with relapsed NGGCTs are salvageable at relapse. HDCx and achieving CR at the end of relapse therapy were associated with a survival benefit. More studies are required to identify these patients who would benefit from salvage therapy.

RADT-08. BASAL GANGLIA TOXICITY FOLLOWING PROTON THERAPY OF THE PINEAL REGION WITH BILATERAL ACTION-INDUCED MYOCLONUS

Abstract INTRODUCTION We sought to evaluate the toxicity profile for children receiving 54Gy to the pineal region with a significant dose delivered to posterior thalamus and basal ganglia. METHODS We performed a retrospective review of patients treated at a single institution with intensity modulated proton therapy (IMPT) receiving 54Gy to the pineal region. Multiple beam angles were utilized for planning. Patient characteristics and dosimetric data were correlated with late-toxicity and imaging. RESULTS From 2021-2023, six children were treated, and at a median follow-up of 13 months [9-26], all patients remain disease-free. Three patients had non-germinomatous germ cell tumors, 1 low-grade glioma, 1 atypical teratoid rhabdoid tumor (ATRT), and 1 embryonal tumor with multilayered rosettes. Age range was 2.4 to 16.8 years. All patients received chemotherapy prior to IMPT. Neuropsychological evaluation indicated range of intellectual functioning (mean = 98.3 [83-118]). One patient, a 4-year-old female with ATRT, developed T2 changes within the globus pallidus and thalamus on 3 month follow-up. At 5 months, she developed bilateral action-induced myoclonus with corresponding enhancing lesions in the globus pallidus bilaterally. Neuropsychological evaluation at 5 months post-treatment indicated memory impairments. She was treated with dexamethasone without improvement. Between 912 months post-treatment, tremors improved with physical therapy and imaging showed near complete resolution of enhancement within globus pallidus. CONCLUSION One of six children developed grade 3 toxicity manifesting as bilateral action-induced myoclonus with imaging changes in the globus pallidus bilaterally following IMPT and exhibited related neuropsychological deficits. While brainstem toxicity from IMPT is well documented, globus pallidus toxicity is not well characterized. Given the contiguous neuronal tracts with the brainstem, it is logical to apply similar treatment planning techniques, i.e. minimizing hotspots within the globus pallidus and thalamic “core” structures, and being cognizant of LET/RBE effects for treatment involving the pineal region in young children.

GCT-10. OUTCOME OF CHILDREN AND ADOLESCENTS DIAGNOSED WITH GERMINOMA WITH HCGΒ VALUES BETWEEN 100-200 MUI/ML TREATED ACCORDING TO THE BRAZILIAN CNS GCT PROTOCOL

Abstract BACKGROUND Primary central nervous system (CNS) germ cell tumors (GCT) are rare tumors, classified according to histological components and tumor markers (TM) as Germinomas and Non-Germinomatous Germ Cell Tumors (NGGCT). The aim of this study is to assess the outcome of patients with Germinoma and HCGβ levels between 100-200mIU/ml treated according to the Brazilian CNS GCT Consortium Protocol. METHODS From 2013 to 2021, forty-three patients presented with histological and/or TM (serum and CSF) consistent with the diagnosis of germinoma, five of them with HCGβ levels between 100-200mIU/ml. The treatment plan performed was four cycles of carboplatin/etoposide followed by whole ventricular field irradiation (WVFI) of 18Gy with a boost to primary site(s) up to 30Gy and 24Gy craniospinal irradiation (CSI) for disseminated disease. RESULTS Average age 13.7 years (6.3-20.3 years), four males and one female. Diagnosis was made by TM (n=2), and biopsy +TM (n=3). The primary tumor location was pineal (n=2), suprasellar (n=1), and bifocal (n=2) with 1 case presenting ventricular spread at diagnosis. Three patients achieved complete response (CR) after two cycles of chemotherapy and one after four cycles. One patient showed partial radiological response (PR) with negative TM after four cycles and was submitted to a second-look surgery, with pathological report of residual scar tissue. Radiotherapy was performed as described in all patients with four patients receiving WVFI (18Gy+30Gy) and one CSI (24Gy+30Gy). In a mean follow-up of 64 months, overall and event-free survival was 100%. CONCLUSION Despite the small sample, the present study shows effectivity with excellent results and a possibility of increasing the cutoff and therefore reducing treatment for patients with HCGβ at levels up to 200mlU/ml currently treated in some protocols as NGGCT cases.

QOL-32. COGNITIVE AND PSYCHOLOGICAL LATE EFFECTS IN CHILDREN AND ADOLESCENTS WITH PINEAL REGION TUMORS: A 35-YEAR-LONG EXPERIENCE IN A TERTIARY REFERRAL HOSPITAL

Abstract BACKGROUND Pineal region tumors (PRT) account for 2.8% of all central nervous system tumors in children and adolescents up to 19 years of age. Modern therapies allow more than 2/3 of patients to overcome their disease, but late effects impair quality of life of survivors. This study aimed to define the prevalence of cognitive and psychological late effects in PRT-survivors. METHODS Demographic information, medical variables, cognitive and psychological age-appropriated assessments of childhood and adolescence PRT-survivors, followed-up at Gaslini Children’s Hospital between 1988 and 2023, were retrospectively collected. Neurocognitive assessment was performed using the Wechsler scale. Psychological assessment was obtained using the Child Behavior Checklist, Beck Depression Inventory, State-Trait Anxiety Inventory, Trauma Symptom Checklist for children and Impact of Event Scale–Revised. RESULTS Sixty patients were included (53 males, 88%); median age at diagnosis was 12.8 years (Interquartile range, IQR, 9.0–15.7 years). Main entities were: germinoma (17, 28%), non-germinomatous germ cell tumor (16, 27%), bifocal germinoma (13, 22%), pineoblastoma (6, 10%), teratoma (3, 5%). 20/60 patients (33%) had neuroaxis spread, 48/60 (80%) presented hydrocephalus, 41/60 (68%) underwent surgery, 16/60 (27%) needed ventricular-peritoneal shunt, 51/60 (86%) received chemotherapy and 56/60 (93%) required radiotherapy. Median follow-up was 8.9 years (IQR 4.1–15.2). Six patients died, 5/6 died for progressive disease. Intelligence quotient (IQ) score was available for 43/60 patients with a median value of 91 (IQR 85-107). Complete cognitive and neuropsychological assessment was available for 25/60 patients showing presence of: anxiety symptoms (16/25, 64%), depression symptoms (20/25, 80%) and post-traumatic symptoms (7/25, 28%). CONCLUSIONS In our cohort, PRT-survivors showed IQ scores within expected average and a high frequency of anxiety and depression symptoms. Deeper insights into the mechanisms underlying cognitive and psychological late effects are needed, focusing on the role of demographics, treatments and disease-specific variables as well as on tumor location.

GCT-11. CENTRAL NERVOUS SYSTEM GERM TUMORS (CNS GCTS): RESULTS FROM A SINGLE INSTITUTION IN BRAZIL - SÃO PAULO UNIVERSITY

Abstract INTRODUCTION Central Nervous System Germ Tumors (CNS GCTs) are broadly classified as germinomatous (commonly called germinoma) and non-germinomatous germ cell tumors (NGGCTs) based on clinicopathological and laboratory characteristics, including tumor markers. OBJECTIVES Compare data from patients admitted from 2000 to 2023, with the usual presentation in the literature, identifying possible specific variables. METHODOLOGY Retrospective study involving 27 patients admitted to the institution without previous treatment. RESULTS In western countries, GCTs account for 3% to 4% of primary brain tumors in children, with a peak incidence between 10 and 19 years of age. In Japan and other Asian countries, one series reported that the incidence of GCTs in the CNS consists of approximately 15% of all pediatric CNS tumors. The genetic or environmental reasons for these differences remain unknown. In general, males have a higher incidence of GCT than females. Male patients have a preponderance of primary tumors of the pineal region. The data collected by our institution are compatible with those in the literature. CONCLUSION Our discussion and data analysis on GCTs are comparable to those presented in the literature, with the majority of cases treated being: adolescents between 10 and 15 years old, predominantly male and with a satisfactory response to therapy.

GCT-01. CENTRAL NERVOUS SYSTEM GERM CELL TUMORS – GENERATING A CONSENSUS IN THEIR DIAGNOSIS AND MANAGEMENT

Abstract BACKGROUND Despite the excellent outcomes of central nervous system (CNS) germ cell tumors (GCTs), there still exists significant differences in how GCTs are diagnosed and managed in different parts of the world. Additionally, the long-term toxicities and morbidities of the current therapies, and their substantial negative impact on the social wellbeing of our patients should clearly indicate that the current achievements are not enough. Further, important molecular data have emerged over the past decade that we have not witnessed their translation into any of the ongoing clinical trials. METHODS A comprehensive review of all major CNS GCT clinical trials will be discussed, in addition to a detailed review of the several issues of debate. Moreover, the latest developments in molecular landscape of GCTs will be provided in order to identify the hurdles that affect their incorporation in GCT clinical trials. RESULTS Tumor marker cut-offs that differentiate between germinoma and non-germinomatous germ cell tumors are clearly different between the various groups around the world. Additionally, differences exist in the chemotherapy backbones, radiation therapy field and dose, and the appropriate regimens to treat some of the rarer GCTs. Furthermore, there is no clear guideline on how to treat patients who do not achieve complete response after chemotherapy. CONCLUSIONS Discussing the clear differences that exist in the diagnosis and management of CNS GCTs is a critical first step in generating a clear consensus between the North American, European, Asian, and Latin American groups, which will certainly guide future clinical trials, improve the outcomes as well as the long-term treatment effects for this group of patients.

PALC-03. MEDICAL AID IN DYING: EXPERIENCE IN THE CENTER FOR CANCER AND BLOOD DISORDERS AT CHILDREN’S HOSPITAL COLORADO

Abstract BACKGROUND Medical Aid in Dying (MAiD) is now legal in 10 US states and Washington, DC, allowing terminally ill patients to self-administer medications to peacefully end their life. There is little published on pediatric hospitals’ approach to young adult patients requesting MAiD. METHODS We review the two patients who have participated in MAiD at the Center for Cancer and Blood Disorders at Children’s Hospital Colorado (CHCO). We also explore publicly available Colorado MAiD statistics. RESULTS Between 2017 and 2022, there have been 1,090 prescriptions written for MAiD medication in Colorado, 5 of which were for patients aged 18-34 (0.5%). Two of these patients were treated at CHCO. Patient A was a 26 year old male with a CNS non-germinomatous germ cell tumor whose treatment was complicated by mucormycosis and severe engraftment syndrome. He relapsed 23 months after completing therapy. He had neurologic decline including ataxia and blindness, at which time he requested MAiD. Patient B was a 24 year old male with multiply recurrent IDH-mutant medullary high grade glioma. With metastatic progression, he had many tumor-related symptoms including dysphagia, dysarthria, and weakness impacting his activities of daily living, so he requested MAiD. Both patients had multidisciplinary care conferences with neuro-oncology, social work, ethics, psychology, and palliative care. After completing psychological evaluation and all steps required by law, they were prescribed DDAMP2 (digoxin 50 mg, diazepam 1 gram, morphine 15 grams, and propranolol 2 grams). Both patients took the medications and died peacefully. Barriers encountered included infrequency of MAiD requests leading to unclear policies and processes. CONCLUSIONS Young adults represent a small but important subset of those seeking MAiD prescriptions. Despite challenges, patients were able to receive MAiD without delay in a compassionate manner. Our experience may be applicable to other pediatric hospitals facing these requests.

Imaging in malignant germ cell tumors involving the hypothalamo-neurohypophyseal axis: the evaluation of the posterior pituitary bright spot is essential

PurposeMalignant intracranial germ cell tumors (GCTs) are rare diseases in Western countries. They arise in midline structures and diagnosis is often delayed. We evaluated imaging characteristics and early tumor signs of suprasellar and bifocal GCT on MRI.MethodsPatients with the diagnosis of a germinoma or non-germinomatous GCT (NGGCT) who received non-contrast sagittal T1WI on MRI pre-therapy were included. Loss of the posterior pituitary bright spot (PPBS), the expansion and size of the tumor, and the expansion and infiltration of surrounding structures were evaluated. Group comparison for histologies and localizations was performed.ResultsA total of 102 GCT patients (median age at diagnosis 12.3 years, range 4.4–33.8; 57 males; 67 in suprasellar localization) were enrolled in the study. In the suprasellar cohort, NGGCTs (n = 20) were noticeably larger than germinomas (n = 47; p < .001). Each tumor showed involvement of the posterior lobe or pituitary stalk. A PPBS loss (total n = 98) was observed for each localization and entity in more than 90% and was related to diabetes insipidus. Osseous infiltration was observed exclusively in suprasellar GCT (significantly more frequent in NGGCT; p = .004). Time between the first MRI and therapy start was significantly longer in the suprasellar cohort (p = .005), with an even greater delay in germinoma compared to NGGCT (p = .002). The longest interval to treatment had circumscribed suprasellar germinomas (median 312 days).ConclusionA loss of the PPBS is a hint of tumor origin revealing small tumors in the neurohypophysis. Using this sign in children with diabetes insipidus avoids a delay in diagnosis.