Application of Drug Testing Platforms in Circulating Tumor Cells and Validation of a Patient-Derived Xenograft Mouse Model in Patient with Primary Intracranial Ependymomas with Extraneural Metastases.

Primary intracranial ependymoma is a challenging tumor to treat despite the availability of multidisciplinary therapeutic modalities, including surgical resection, radiotherapy, and adjuvant chemotherapy. After the completion of initial treatment, when resistant tumor cells recur, salvage therapy needs to be carried out with a more precise strategy. Circulating tumor cells (CTCs) have specifically been detected and validated for patients with primary or recurrent diffused glioma. The CTC drug screening platform can be used to perform a mini-invasive liquid biopsy for potential drug selection. The validation of potential drugs in a patient-derived xenograft (PDX) mouse model based on the same patient can serve as a preclinical testing platform. Here, we present the application of a drug testing model in a six-year-old girl with primary ependymoma on the posterior fossa, type A (EPN-PFA). She suffered from tumor recurrence with intracranial and spinal seeding at 2 years after her first operation and extraneural metastases in the pleura, lung, mediastinum, and distant femoral bone at 4 years after initial treatment. The CTC screening platform results showed that everolimus and entrectinib could be used to decrease CTC viability. The therapeutic efficacy of these two therapeutic agents has also been validated in a PDX mouse model from the same patient, and the results showed that these two therapeutic agents significantly decreased tumor growth. After precise drug screening and the combination of focal radiation on the femoral bone with everolimus chemotherapy, the whole-body bone scan showed significant shrinkage of the metastatic tumor on the right femoral bone. This novel approach can combine liquid biopsy, CTC drug testing platforms, and PDX model validation to achieve precision medicine in rare and challenging tumors with extraneural metastases.

The Anesthetic Strategy for Patients with Mucopolysaccharidoses: A Retrospective Cohort Study.

Anesthesia for patients with mucopolysaccharidoses (MPS) is quite challenging due to vital systemic dysfunction following progressive accumulation of lysosomal glycosaminoglycans. Previous studies focused on perioperative difficult airway management under general anesthesia but rarely depicted the concern of choosing the size of the endotracheal tube (ETT) as well as neuraxial anesthesia. This study aimed to analyze the overall anesthetic management and related complications for a thorough anesthetic strategy. Within the study period from 2002 to 2021, each record of the anesthetic and perioperative quality assurance/improvement system for patients with a diagnosis of MPS at MacKay Memorial Hospital was retrospectively reviewed. A total of 51 individuals with 151 anesthesia for 163 interventions were cohort studied, and there were 136 general anesthesia and 15 neuraxial anesthesia. We found that the most common interventions for MPS patients were otolaryngological surgeries (49.6%). Additionally, a secured airway played a marked preference for the most general anesthesia (87.1%). The incidence of difficult intubation was 12.5%. In view of ETT size, a smaller than estimated size was used in MPS type II, III, IV, and VI patients and also in patients who received intubation with multiple attempts. However, a larger than estimated size of ETT was adopted whilst choosing cuffed ones. For neuraxial anesthesia, two failed spinal anesthesia procedures were converted to general anesthesia and 73 percent of the patients received perioperative sedation. In conclusion, through the individualized anesthetic strategy and build-up of an experienced team for airway management, high-quality anesthesia can be ensured in each patient.

Compassionate Treatment of Brainstem Tumors with Boron Neutron Capture Therapy: A Case Series.

Brainstem tumors are heterogenous and cancerous glioma tumors arising from the midbrain, pons, and the medulla that are relatively common in children, accounting for 10% to 20% of all pediatric brain tumors. However, the prognosis of aggressive brainstem gliomas remains extremely poor despite aggressive treatment with chemotherapy and radiotherapy. That means there are many life-threatening patients who have exhausted all available treatment options and are beginning to face end-of-life stage. Therefore, the unique properties of highly selective heavy particle irradiation with boron neutron capture therapy (BNCT) may be well suited to prolong the lives of patients with end-stage brainstem gliomas. Herein, we report a case series of life-threatening patients with end-stage brainstem glioma who eligible for Emergency and Compassionate Use, in whom we performed a scheduled two fractions of salvage BNCT strategy with low treatment dosage each time. No patients experienced acute or late adverse events related to BNCT. There were 3 patients who relapsed after two fractionated BNCT treatment, characterized by younger age, lower T/N ratio, and receiving lower treatment dose. Therefore, two fractionated low-dose BNCT may be a promising treatment for end-stage brainstem tumors. For younger patients with low T/N ratios, more fractionated low-dose BNCT should be considered.

Bifocal lesions have a poorer treatment outcome than a single lesion in adult patients with intracranial germinoma.

Intracranial germinoma (IG) rarely occurs in adults. Its optimal treatment strategy is unclear. We evaluated the outcomes of radiotherapy in adults with intracranial germinoma. Data of 29 adult patients (age, 18-52 years; median age, 24.3 years) with IG treated with radiotherapy at Taipei Veterans General Hospital were retrospectively reviewed. They were followed up for a median time of 5.9 years (range, 1.0-12.8 years). We used the Kaplan-Meier method to estimate the progression-free survival (PFS) and overall survival (OS), and univariate and multivariate Cox proportional hazards regression models to identify the factors affecting PFS. PFS and OS were compared between adult and pediatric patients with IG. The 1-, 3-, and 5-year PFS rates were 96.6%, 85.8%, and 77.8%, respectively, in the adult patients, and the OS rate were all 100%. Seven patients (24.1%) experienced recurrence, and in six of them, salvage therapy successfully controlled the disease. Two patients (6.9%) died after 5 years of follow-up due to disease progression and central pontine myelinolysis. In the univariate and multivariate Cox analysis, bifocal lesions had a significantly lower PFS than those with single lesions (p = 0.008). Kaplan-Meier survival analysis showed that adult patients had a poorer PFS (p = 0.06) and OS (p = 0.025) than pediatric patients. Our study showed bifocal lesions were associated with lower PFS than a single lesion among adult IG patients, and adult IG patients tended to have poorer PFS and OS compared to pediatric IG patients. For adult patients with bifocal IG, we recommend treatment with craniospinal irradiation, whole ventricle irradiation (WVI) with chemotherapy, or frequent spine images follow-up for patients who received only WVI.

Notch signaling and natural killer cell infiltration in tumor tissues underlie medulloblastoma prognosis.

Medulloblastoma is the most common embryonic brain tumor in children. We investigated a cohort of 52 Asian medulloblastoma patients aged between 0 and 19 years old, who received surgical resections and post-resection treatments in the Taipei Medical University Hospital and the Taipei Veterans General Hospital. Genome-wide RNA sequencing was performed on fresh-frozen surgical tissues. These data were analyzed using the CIBERSORTx immune deconvolution software. Two external clinical and molecular datasets from United States (n = 62) and Canada (n = 763) were used to evaluate the transferability of the gene-signature scores across ethnic populations. The abundance of 13 genes, including DLL1, are significantly associated with overall survival (All Cox regression P < 0.001). A gene-signature score was derived from the deep transcriptome, capable of indicating patients' subsequent tumor recurrence (Hazard Ratio [HR] 1.645, confidence interval [CI] 1.337-2.025, P < 0.001) and mortality (HR 2.720, CI 1.798-4.112, P < 0.001). After the adjustment of baseline clinical factors, the score remains indicative of recurrence-free survival (HR 1.604, CI 1.292-1.992, P < 0.001) and overall survival (HR 2.781, CI 1.762-4.390, P < 0.001). Patients stratified by this score manifest not only distinct prognosis but also different molecular characteristics: Notch signaling ligands and receptors are comparatively overexpressed in patients with poorer prognosis, while tumor infiltrating natural killer cells are more abundant in patients with better prognosis. Additionally, immunohistochemical staining showed the DLL1 protein, a major ligand in the Notch signaling pathway, and the NCAM1 protein, a representative biomarker of natural killer cells, are present in the surgical tissues of patients of four molecular subgroups, WNT, SHH, Group 3 and Group 4. NCAM1 RNA level is also positively associated with the mutation burden in tumor (P = 0.023). The gene-signature score is validated successfully in the Canadian cohort (P = 0.009) as well as its three molecular subgroups (SHH, Group 3 and Group 4; P = 0.047, 0.018 and 0.040 respectively). In conclusion, pediatric medullablastoma patients can be stratified by gene-signature scores with distinct prognosis and molecular characteristics. Ligands and receptors of the Notch signaling pathway are overexpressed in the patient stratum with poorer prognosis. Tumor infiltrating natural killer cells are more abundant in the patient stratum with better prognosis.

Combining an Autophagy Inhibitor, MPT0L145, with Abemaciclib Is a New Therapeutic Strategy in GBM Treatment.

Glioblastoma multiforme (GBM) is the most malignant brain tumor in the world, only 25% of GBM patients were alive one year after diagnosis. Although Temozolamide combined with radiation therapy more effectively prolonged the survival rate than radiation alone, the overall survival rate is still dismal. Therefore, a new therapeutic strategy is urgently needed. CDK4/6 inhibitors are newly FDA-approved agents to treat HR-positive, HER2-negative advanced, and metastatic breast cancers, and preclinical results showed that CDK4/6 inhibitors significantly reduced cell proliferation and tumor growth. However, several studies have suggested that CDK4/6 inhibitor-induced non-genetic changes caused treatment failure, including autophagy activation. Therefore, this study aimed to combine an autophagy inhibitor, MPT0L145, with abemaciclib to improve therapeutic efficiency. The use of abemaciclib effectively inhibited cell proliferation via suppression of RB phosphorylation and induced autophagy activation in GBM cancer cells. MPT0L145 treatment alone not only blocked autophagy activation, but also induced generation of ROS and DNA damage in a concentration-dependent manner. Importantly, MPT0L145 had a comparable penetration ability to TMZ in our blood brain barrier permeability assay. Combined MPT0L145 with abemaciclib significantly reduced cell proliferation, suppressed RB phosphorylation, and increased ROS production. In conclusion, the data suggested that blocking autophagy by MPT0L145 synergistically sensitized GBM cancer cells to abemaciclib and represents a potential therapeutic strategy for treating GBM in the future.

Magnetic resonance radiomics features and prognosticators in different molecular subtypes of pediatric Medulloblastoma.

PURPOSE: Medulloblastoma (MB) is a highly malignant pediatric brain tumor. In the latest classification, medulloblastoma is divided into four distinct groups: wingless (WNT), sonic hedgehog (SHH), Group 3, and Group 4. We analyzed the magnetic resonance imaging radiomics features to find the imaging surrogates of the 4 molecular subgroups of MB. MATERIAL AND METHODS: Frozen tissue, imaging data, and clinical data of 38 patients with medulloblastoma were included from Taipei Medical University Hospital and Taipei Veterans General Hospital. Molecular clustering was performed based on the gene expression level of 22 subgroup-specific signature genes. A total 253 magnetic resonance imaging radiomic features were generated from each subject for comparison between different molecular subgroups. RESULTS: Our cohort consisted of 7 (18.4%) patients with WNT medulloblastoma, 12 (31.6%) with SHH tumor, 8 (21.1%) with Group 3 tumor, and 11 (28.9%) with Group 4 tumor. 8 radiomics gray-level co-occurrence matrix texture (GLCM) features were significantly different between 4 molecular subgroups of MB. In addition, for tumors with higher values in a gray-level run length matrix feature-Short Run Low Gray-Level Emphasis, patients have shorter survival times than patients with low values of this feature (p = 0.04). The receiver operating characteristic analysis revealed optimal performance of the preliminary prediction model based on GLCM features for predicting WNT, Group 3, and Group 4 MB (area under the curve = 0.82, 0.72, and 0.78, respectively). CONCLUSION: The preliminary result revealed that 8 contrast-enhanced T1-weighted imaging texture features were significantly different between 4 molecular subgroups of MB. Together with the prediction models, the radiomics features may provide suggestions for stratifying patients with MB into different risk groups.

Salvage Boron Neutron Capture Therapy for Malignant Brain Tumor Patients in Compliance with Emergency and Compassionate Use: Evaluation of 34 Cases in Taiwan.

Although boron neutron capture therapy (BNCT) is a promising treatment option for malignant brain tumors, the optimal BNCT parameters for patients with immediately life-threatening, end-stage brain tumors remain unclear. We performed BNCT on 34 patients with life-threatening, end-stage brain tumors and analyzed the relationship between survival outcomes and BNCT parameters. Before BNCT, MRI and 18F-BPA-PET analyses were conducted to identify the tumor location/distribution and the tumor-to-normal tissue uptake ratio (T/N ratio) of 18F-BPA. No severe adverse events were observed (grade ≥ 3). The objective response rate and disease control rate were 50.0% and 85.3%, respectively. The mean overall survival (OS), cancer-specific survival (CSS), and relapse-free survival (RFS) times were 7.25, 7.80, and 4.18 months, respectively. Remarkably, the mean OS, CSS, and RFS of patients who achieved a complete response were 17.66, 22.5, and 7.50 months, respectively. Kaplan-Meier analysis identified the optimal BNCT parameters and tumor characteristics of these patients, including a T/N ratio ≥ 4, tumor volume < 20 mL, mean tumor dose ≥ 25 Gy-E, MIB-1 ≤ 40, and a lower recursive partitioning analysis (RPA) class. In conclusion, for malignant brain tumor patients who have exhausted all available treatment options and who are in an immediately life-threatening condition, BNCT may be considered as a therapeutic approach to prolong survival.

Abemaciclib, A Selective CDK4/6 Inhibitor, Restricts the Growth of Pediatric Ependymomas.

Pediatric ependymomas are a type of malignant brain tumor that occurs in children. The overall 10-year survival rate has been reported as being 45-75%. Maximal safe surgical resection combined with adjuvant chemoradiation therapy is associated with the highest overall and progression-free survival rates. Despite aggressive treatment, one-third of ependymomas exhibit recurrence within 2 years of initial treatment. Therefore, this study aimed to find new agents to overcome chemoresistance and defer radiotherapy treatment since, in addition, radiation exposure may cause long-term side effects in the developing brains of young children. By using integrated bioinformatics and through experimental validation, we found that at least one of the genes CCND1 and CDK4 is overexpressed in ependymomas. The use of abemaciclib, a highly selective CDK4/6 inhibitor, effectively inhibited cell proliferation and reduced the expression of cell-cycle-related and DNA-repair-related gene expression via the suppression of RB phosphorylation, which was determined through RNA-seq and Western blot analyses. Furthermore, abemaciclib effectively induced cell death in vitro. The efficiency of abemaciclib was validated in vivo using subcutaneously implanted ependymoma tissues from patient-derived xenografts (PDXs) in mouse models. Treatment with abemaciclib showed encouraging results in preclinical pediatric ependymoma models and represents a potential therapeutic strategy for treating challenging tumors in children.

Upregulation of Protein Synthesis and Proteasome Degradation Confers Sensitivity to Proteasome Inhibitor Bortezomib in Myc-Atypical Teratoid/Rhabdoid Tumors.

Atypical teratoid rhabdoid tumors (ATRTs) are among the most malignant brain tumors in early childhood and remain incurable. Myc-ATRT is driven by the Myc oncogene, which directly controls the intracellular protein synthesis rate. Proteasome inhibitor bortezomib (BTZ) was approved by the Food and Drug Administration as a primary treatment for multiple myeloma. This study aimed to determine whether the upregulation of protein synthesis and proteasome degradation in Myc-ATRTs increases tumor cell sensitivity to BTZ. We performed differential gene expression and gene set enrichment analysis on matched primary and recurrent patient-derived xenograft (PDX) samples from an infant with ATRT. Concomitant upregulation of the Myc pathway, protein synthesis and proteasome degradation were identified in recurrent ATRTs. Additionally, we found the proteasome-encoding genes were highly expressed in ATRTs compared with in normal brain tissues, correlated with the malignancy of tumor cells and were essential for tumor cell survival. BTZ inhibited proliferation and induced apoptosis through the accumulation of p53 in three human Myc-ATRT cell lines (PDX-derived tumor cell line Re1-P6, BT-12 and CHLA-266). Furthermore, BTZ inhibited tumor growth and prolonged survival in Myc-ATRT orthotopic xenograft mice. Our findings suggest that BTZ may be a promising targeted therapy for Myc-ATRTs.

Molecular-Clinical Correlation in Pediatric Medulloblastoma: A Cohort Series Study of 52 Cases in Taiwan.

In 2016, a project was initiated in Taiwan to adopt molecular diagnosis of childhood medulloblastoma (MB). In this study, we aimed to identify a molecular-clinical correlation and somatic mutation for exploring risk-adapted treatment, drug targets, and potential genetic predisposition. In total, 52 frozen tumor tissues of childhood MBs were collected. RNA sequencing (RNA-Seq) and DNA methylation array data were generated. Molecular subgrouping and clinical correlation analysis were performed. An adjusted Heidelberg risk stratification scheme was defined for updated clinical risk stratification. We selected 51 genes for somatic variant calling using RNA-Seq data. Relevant clinical findings were defined. Potential drug targets and genetic predispositions were explored. Four core molecular subgroups (WNT, SHH, Group 3, and Group 4) were identified. Genetic backgrounds of metastasis at diagnosis and extent of tumor resection were observed. The adjusted Heidelberg scheme showed its applicability. Potential drug targets were detected in the pathways of DNA damage response. Among the 10 patients with SHH MBs analyzed using whole exome sequencing studies, five patients exhibited potential genetic predispositions and four patients had relevant germline mutations. The findings of this study provide valuable information for updated risk adapted treatment and personalized care of childhood MBs in our cohort series and in Taiwan.

Effect of early radiotherapy initiation and high-dose chemotherapy on the prognosis of pediatric atypical teratoid rhabdoid tumors in different age groups.

PURPOSE: The optimal treatment strategy for pediatric atypical teratoid rhabdoid tumor (ATRT) is inconclusive. This study evaluated the prognostic value of early radiotherapy (RT) and high-dose chemotherapy with autologous stem cell rescue (HDC/ASCR) in pediatric ATRT. METHODS: This pooled analysis included ATRT patients treated at our institution and from other studies who were identified by a search of the PubMed electronic database. The effect of patient demographics and treatment profiles on progression-free survival (PFS) and overall survival (OS) were analyzed using Cox regression. RESULTS: Overall, 34 patients from our institution and 436 patients from 35 published studies were included. In multivariable analysis, patients with gross total resection (GTR), early RT (time to RT interval < 2 months), and HDC/ASCR had both better PFS [hazard ratio (HR) 0.46, p[Formula: see text] 0.001; HR 0.64, p = 0.011; and HR 0.51, p = 0.005, respectively] and OS (HR 0.55, p = 0.002; HR 0.48, p = 0.004; and HR 0.42, p < 0.001, respectively). For patients aged < 3 years, both RT and HDC/ASCR were significant favorable factors for PFS (HR 0.32 and 0.46, respectively) and OS (HR 0.40 and 0.36, respectively), while early RT was not prognostic. For patients aged ≥ 3 years, early RT was significantly associated with better PFS (HR 0.51) and HDC/ASCR did not affect PFS, and neither was related to OS. CONCLUSION: Both early RT initiation and HDC/ASCR were important components in the treatment of pediatric ATRT. However, the optimal treatment strategies might differ by age.

A single-center study of treatment outcomes of pediatric basal ganglia germinoma in Taiwan.

PURPOSE: A basal ganglia (BG) germinoma is a rare tumor, and the optimal treatment remains unknown. We evaluated the clinical outcomes of treatment of BG germinoma in pediatric patients in Taiwan. METHODS: We retrospectively reviewed the medical records of 34 children with BG germinoma who were treated with radiotherapy (RT) at Taipei Veterans General Hospital between 1989 and 2016. The median follow-up time is 8.3 years (1.8-25.2 years). Survival was analyzed using the Kaplan-Meier estimate. Univariate Cox proportional-hazards models were used to identify the potential risk factors. RESULTS: Only four patients (11.8%) experienced recurrence and all successfully underwent salvage therapy. One patient (2.97%) died due to suspected radiotherapy (RT)-related sarcoma in the scalp. The 2-, 3-, and 5-year DFS rates were 91.2%, 88.2%, and 79.4%, respectively; the 2-, 3-, and 5-year OS rates were 97.1%, 94.1%, and 82.4%, respectively. Focal RT showed low DFS in the Kaplan-Meier survival curves (P = .028) compared with non-focal RT (whole ventricle, whole brain, or cranial spinal area). In the univariate Cox proportional-hazards model, there was a significant difference in DFS between focal and non-focal RT (P = .03). There is no difference in DFS and OS between BG germinoma patients and non-BG germinoma patients. CONCLUSIONS: We found an excellent DFS and OS in pediatric patients with BG germinoma treated with RT. Whole ventricle irradiation is recommended for good tumor control and low treatment-related toxicity. BG germinoma patients showed similar treatment results as germinoma patients in other common sites.

Application of Sonography in the Diagnosis and Follow-Up of Trapped Temporal Horn of Lateral Ventricle: Two Case Reports.

Trapped temporal horn of lateral ventricle (TTHLV) is a rare condition of isolated focal hydrocephalus. We report two cases with different presentations, etiologies, and surgical managements. The first case involved an extremely preterm male baby with a history of ventriculitis and intraventricular hemorrhage; he received external ventricle drainage twice due to obstructive hydrocephalus. TTHLV was detected by sonography. He received a ventriculoperitoneal shunt involving two catheters to bypass the adhesion site. There was no ventricular dilatation during 2 years of follow-up. The second case involved a term baby with an enlarged head; brain sonography revealed left focal hydrocephalus with TTHLV and mild midline shift. Neuroendoscopic cystoventriculostomy with fenestration from the left trigone to the frontal horn was performed and serial follow-up brain sonography for 3 months showed decreased ventricle size. The suitable surgical techniques for the management of TTHLV should be adjusted according to the patients' condition to obtain more favorable outcomes. Brain sonography can be a useful tool for the diagnosis and for following up the surgical outcomes in infants with TTHLV.

Role of early and aggressive post-operative radiation therapy in improving outcome for pediatric central nervous system atypical teratoid/rhabdoid tumor.

PURPOSE: The purpose of the study is to evaluate possible prognostic factors and optimal management for pediatric atypical teratoid/rhabdoid tumor (AT/RT) of the central nervous system (CNS). METHODS: Twenty-eight pediatric patients with CNS AT/RT who were treated with radiation therapy (RT) as part of multimodality treatment regimens at a single institution (1996-2015) were reviewed. Survival outcomes were analyzed in relation to possible prognostic factors. RESULTS: The 28 patients analyzed were followed up for a median 48-month period. Median progression-free survival (PFS) was 11 months, and overall survival (OS) was 57 months. Patients < 3 years old had RT delayed for a longer period after surgery (p = 0.04), and the mean RT dose to tumor bed was lower (p < 0.01) than in patients ≥ 3 years old. In multivariate analysis, a higher primary tumor bed RT dose was identified as a favorable prognostic factor for both PFS (hazard ratio [HR] = 0.85 per gray, p < 0.01) and OS (HR = 0.92 per gray, p = 0.02). In addition, an interval between surgery and RT initiation > 2 months, with disease progression observed before RT, as compared with an interval ≤ 2 months without disease progression prior to RT, was associated with worse PFS (HR = 8.50, p < 0.01) and OS (HR = 5.27, p < 0.01). CONCLUSIONS: Early and aggressive RT after surgery is critical for successful disease control in AT/RT patients. Conversely, a delay in RT until disease progression is observed that leads to unfavorable outcomes.

Prognostic factors related to intratumoral hemorrhage in pediatric intracranial germ cell tumors.

BACKGROUND: Certain types of pediatric intracranial germ cell tumors (PIGCTs) are prone to intratumoral hemorrhaging (TH) and associated with poor survival outcome. However, the impact of TH on the functional prognosis of patients with PIGCTs has not been well studied. This study aimed to evaluate the clinical and MR findings in PIGCT patients with TH to identify the factors related to patient survival and functional outcome. METHODS: This study included 17 patients diagnosed with PIGCT and TH between 2002 and 2016 and evaluated TH-associated clinical and MR findings. The modified Rankin scale (mRS) was used to evaluate functional outcome, which was poor when mRS ≧ 3. The volumes of hematomas and tumors were manually tracked within each brain magnetic resonance imaging slice. RESULTS: Among the 17 patients, 6 (35.3%) died and 9 (52.9%) had poor functional outcome. Regarding the functional outcome, the mean hematoma volume to tumor volume ratio (HTVR) was 8.5 ± 3.9% in the favorable outcome group and 42.3 ± 27.8% in the poor outcome group (p = 0.001). For the survival outcome, the mean HTVR was 15.7 ± 16.1% in the living group and 46.0 ± 31.5% in the deceased group (p = 0.016). The cutoff point of the receiver operating characteristics curve for HTVR to predict death and poor functional outcome was 19.27% and 16.8%, respectively. CONCLUSION: Our study demonstrated that patients with larger HTVR had significantly worse functional and survival outcomes than those with smaller HTVR. We suggest that early and aggressive treatment for PIGCTs in patients with large HTVR can improve their long-term prognosis.

The impact on outcomes by using thiotepa in tandem transplant for pediatric high-risk embryonal brain tumors.

BACKGROUND: Despite aggressive treatment including surgery, radiotherapy, and adjuvant chemotherapy, the outcome of pediatric high-risk embryonal brain tumors remains poor; especially in young children, in whom early radiotherapy inevitably brings significant long-term morbidities. Single or tandem autologous stem cell transplant has been reported to improve outcomes; but optimal use is not well defined. METHODS: Pediatric patients with high-risk embryonal brain tumors who underwent tandem transplant as consolidation from August 2011 to December 2017 were included. We performed a retrospective chart review and analyzed the outcomes to identify possible prognostic factors. RESULTS: Eleven pediatric patients with high-risk embryonal brain tumors were enrolled. They received double or triple autologous transplant at complete response in 5 patients and at partial response in 6 for a total of 24 transplants. There were five atypical teratoid rhabdoid tumors, four medulloblastoma, one primitive neuroectodermal tumors, and one pineoblastoma. Median age at diagnosis was 1.8 years (range, 0.6-11.2 years) and at transplant was 2.2 years (range, 1.2-11.9 years). Thiotepa-based regimens were used in 13 cycles of conditioning. All patients achieved successful engraftment. No transplant-related mortality was identified. With a median follow-up of 21.2 months (range, 6.9-51.8 months), seven patients had disease progression. Disease entity and the use of one or more cycles of thiotepa-based regimen during tandem transplant had statistically significant impact on both progression-free survival and overall survival. CONCLUSION: With successful engraftment and manageable toxicity, tandem transplant in pediatric patients with high-risk embryonal brain tumor is feasible and safe. Patients receiving tandem transplant with one or more cycles of thiotepa-based regimen might have better outcome than those without. In combination with salvage radiotherapy, a favorable 2-year overall survival could be achieved in the majority of patients.

Using subdural strip electrodes to define functional sensory nerves and the most inferior functional portion of the conus medullaris during detethering surgeries for tethered cord syndrome: a pilot study.

OBJECTIVE: The aim of this study was to investigate the feasibility of using subdural strip electrodes, placed just rostral to the surgical field, to record sensory evoked potentials (SEPs) from the lumbosacral sensory nerves and define the most inferior functional portion of the conus medullaris during detethering surgery for spinal dysraphism and/or tethered cord syndrome (TCS). METHODS: Six patients, 2 boys and 4 girls, aged 0.5 to 16 years, were enrolled in this study. One patient had lipomyelomeningocele-related, 4 had myelomeningocele-related, and 1 had diastematomyelia and lipomyelomeningocele-related TCS. In addition to the routine preparations that are needed for performing functional mapping and monitoring during surgery for spinal dysraphism and TCS, the patients had a 1 × 4 strip of electrodes placed rostral to the surgical field, where it was secured by a surgeon after opening the dura. With the patient under total intravenous anesthesia, the sensory nerves and conus medullaris were stimulated with a concentric bipolar electrode over the surgical field while SEPs were recorded with the strip electrodes to identify any possible sensory roots with remaining function and the most inferior functional portion of the conus medullaris. RESULTS: The SEP amplitudes that were recorded with the subdural strip electrodes ranged from 4 to 400 µV, and the responses to sensory nerve stimulation were frequently much larger than were those to conus stimulation. Use of the SEP recordings for sensory mapping along with the routine mapping and monitoring techniques allowed detethering to be completed such that none of the patients sustained any new functional deficit after surgery. CONCLUSIONS: Recording SEPs from the functional sensory nerves and conus medullaris through subdural strip electrodes proved to be a feasible and valuable tool during detethering surgery in young patients. This approach may help surgeons achieve maximal detethering while preserving important sensory functions, consequently retaining the patient's quality of life.

Irradiation-Induced Secondary Tumors following Pediatric Central Nervous System Tumors: Experiences of a Single Institute in Taiwan (1975-2013).

PURPOSE: Complications can occur following a prolonged latency period after radiation therapy for cancer, and this is a growing concern because secondary tumors are potentially fatal. Few studies have examined secondary tumors in patients who received radiation therapy as children. METHODS AND MATERIALS: This retrospective study examined 1697 pediatric patients with central nervous system tumors who received treatment at Taipei Veterans General Hospital from January 1, 1975, to December 31, 2013. Secondary tumors developed in 27 of 681 patients who received cranial irradiation. Overall survival was estimated using the Kaplan-Meier method, and the significance of differences was determined by the log-rank test. RESULTS: The overall cumulative incidence of secondary tumors at 25 years was 3.96%, and there were similar numbers of male patients (n = 16) and female patients (n = 11). The mean age at diagnosis was 8.8 years (range, 3-16.5 years), the median dose of cranial irradiation was 52.5 Gy (mean, 53.4 Gy), the mean latency period was 14.6 years (range, 2-33 years), and the mean age at diagnosis of a secondary tumor was 23.1 years. The secondary tumors were mainly meningiomas (n = 13), sarcomas (n = 7), and high-grade gliomas (n = 6), and the mean latency periods were 19.66, 8.00, and 10.83 years, respectively. The overall survival rate from these secondary tumors was significantly different (P < .05). Age at irradiation of <7 years and craniospinal irradiation significantly increased the risk of a secondary tumor (P < .05). Secondary tumors developed in 11 of 128 patients (8.6%) with primary medulloblastomas, which was higher than the overall cumulative incidence. CONCLUSIONS: Clinicians should consider the increased risk of secondary tumors in long-term cancer survivors who received craniospinal irradiation as children. Using a selective dose de-escalation strategy or deferring radiation therapy for young patients at highest risk of secondary cancers should be studied.