Irinotecan and temozolomide in combination with dasatinib and rapamycin versus irinotecan and temozolomide for patients with relapsed or refractory neuroblastoma (RIST-rNB-2011): a multicentre, open-label, randomised, controlled, phase 2 trial.

BACKGROUND: Neuroblastoma is the most common extracranial solid tumour in children. Relapsed or refractory neuroblastoma is associated with a poor outcome. We assessed the combination of irinotecan-temozolomide and dasatinib-rapamycin (RIST) in patients with relapsed or refractory neuroblastoma. METHODS: The multicentre, open-label, randomised, controlled, phase 2, RIST-rNB-2011 trial recruited from 40 paediatric oncology centres in Germany and Austria. Patients aged 1-25 years with high-risk relapsed (defined as recurrence of all stage IV and MYCN amplification stages, after response to treatment) or refractory (progressive disease during primary treatment) neuroblastoma, with Lansky and Karnofsky performance status at least 50%, were assigned (1:1) to RIST (RIST group) or irinotecan-temozolomide (control group) by block randomisation, stratified by MYCN status. We compared RIST (oral rapamycin [loading 3 mg/m2 on day 1, maintenance 1 mg/m2 on days 2-4] and oral dasatinib [2 mg/kg per day] for 4 days with 3 days off, followed by intravenous irinotecan [50 mg/m2 per day] and oral temozolomide [150 mg/m2 per day] for 5 days with 2 days off; one course each of rapamycin-dasatinib and irinotecan-temozolomide for four cycles over 8 weeks, then two courses of rapamycin-dasatinib followed by one course of irinotecan-temozolomide for 12 weeks) with irinotecan-temozolomide alone (with identical dosing as experimental group). The primary endpoint of progression-free survival was analysed in all eligible patients who received at least one course of therapy. The safety population consisted of all patients who received at least one course of therapy and had at least one post-baseline safety assessment. This trial is registered at ClinicalTrials.gov, NCT01467986, and is closed to accrual. FINDINGS: Between Aug 26, 2013, and Sept 21, 2020, 129 patients were randomly assigned to the RIST group (n=63) or control group (n=66). Median age was 5·4 years (IQR 3·7-8·1). 124 patients (78 [63%] male and 46 [37%] female) were included in the efficacy analysis. At a median follow-up of 72 months (IQR 31-88), the median progression-free survival was 11 months (95% CI 7-17) in the RIST group and 5 months (2-8) in the control group (hazard ratio 0·62, one-sided 90% CI 0·81; p=0·019). Median progression-free survival in patients with amplified MYCN (n=48) was 6 months (95% CI 4-24) in the RIST group versus 2 months (2-5) in the control group (HR 0·45 [95% CI 0·24-0·84], p=0·012); median progression-free survival in patients without amplified MYCN (n=76) was 14 months (95% CI 9-7) in the RIST group versus 8 months (4-15) in the control group (HR 0·84 [95% CI 0·51-1·38], p=0·49). The most common grade 3 or worse adverse events were neutropenia (54 [81%] of 67 patients given RIST vs 49 [82%] of 60 patients given control), thrombocytopenia (45 [67%] vs 41 [68%]), and anaemia (39 [58%] vs 38 [63%]). Nine serious treatment-related adverse events were reported (five patients given control and four patients given RIST). There were no treatment-related deaths in the control group and one in the RIST group (multiorgan failure). INTERPRETATION: RIST-rNB-2011 demonstrated that targeting of MYCN-amplified relapsed or refractory neuroblastoma with a pathway-directed metronomic combination of a multkinase inhibitor and an mTOR inhibitor can improve progression-free survival and overall survival. This exclusive efficacy in MYCN-amplified, relapsed neuroblastoma warrants further investigation in the first-line setting. FUNDING: Deutsche Krebshilfe.

Approaches for bridging therapy prior to chimeric antigen receptor T cells for relapsed/refractory acute lymphoblastic B-lineage leukaemia in children and young adults.

The ongoing development of immunotherapies, including chimeric antigen receptor (CAR) T cells, has revolutionized cancer treatment. In paediatric relapsed/refractory B-lineage acute leukaemia antiCD19-CARs induced impressive initial response rates, with event-free survival plateauing at 30-50% in long-term follow-up data. During the interval between diagnosis of relapse or refractoriness and CAR T cell infusion, patients require a bridging therapy. To date, this therapy has consisted of highly variable approaches based on local experience. Here, in an European collaborative effort of paediatric and adult haematologists, we summarise current knowledge with the aim of establishing a guidance for bridging therapy. This includes treatment strategies for different patient subgroups, the advantages and disadvantages of low- and highintensity regimens, and the potential impact of bridging therapy on outcome after CAR T cell infusion. This guidance is a step towards a cross-institutional harmonization of bridging therapy, including personalized approaches. This will allow better comparability of clinical data and increase the level of evidence for the treatment of children and young adults with relapsed/refractory B-lineage ALL until CAR T cell infusion.

Immune reconstitution after transplantation of autologous peripheral stem cells in children: a comparison between CD34+ selected and nonmanipulated grafts.

BACKGROUND AND AIMS: High-dose chemotherapy (HDC) followed by autologous stem cell transplantation (ASCT) improves the prognosis in pediatric patients with several solid tumors and lymphomas. Little is known about the reconstitution of the immune system after ASCT and the influence of CD34+ cell selection on the reconstitution in pediatric patients. METHODS: Between 1990 and 2001, 94 pediatric patients with solid tumors and lymphomas received autologous CD34+ selected or unmanipulated peripheral stem cells after HDC. CD34+ selection was carried out with magnetic microbeads. The absolute numbers of T cells, B cells and natural killer (NK) cells were measured and compared in both groups at various time points post-transplant. RESULTS: Recovery of T cells was significantly faster in the unmanipulated group at day 30, with no significant difference later on. Reconstitution of B and NK cells was similar in both groups without significant differences at any time. The CD34+-selected group was divided into patients receiving less or more than 5.385 × 106/kg CD34+ cells. Patients in the CD34+ high-dose group displayed significantly faster reconstitutions of neutrophiles and lymphocyte subsets than the CD34+ low-dose group. CONCLUSIONS: Engraftment and reconstitution of leukocytes, B cells and NK cells after transplantation of CD34+ selected stem cells were comparable to that in patients receiving unmanipulated grafts. T-cell recovery was faster in the unmanipulated group only within the first month. However, this delay could be compensated by transplantation of >5.385 × 106 CD34+ cells/kg. Especially for patients receiving immunotherapy after HDC large numbers of immune effector cells such as NK and T cells are necessary to mediate antibody-dependent cellular cytotoxicity. Therefore, in patients receiving autologous CD34+-selected grafts, our data emphasize the need to administer high stem cell counts.

Survivors of infant atypical teratoid/rhabdoid tumors present with severely impaired cognitive functions especially for fluid intelligence and visual processing: data from the German brain tumor studies.

BACKGROUND: The contribution of tumor type, multimodal treatment, and other patient-related factors upon long-term cognitive sequelae in infant brain tumor survivors remains undefined. We add our retrospective analysis of neuropsychological and quality of survival (QoS) outcome data of survivors of atypical teratoid/rhabdoid tumors (ATRT) and extracranial malignant rhabdoid tumors of the soft tissues (eMRT) and kidneys (RTK) treated within the same framework. Neuropsychological data from children with ATRT were compared to data from children with non-irradiated low-grade glioma (LGG). PATIENTS AND METHODS: Following surgery, patients (0-36 months at diagnosis) had received radio-chemotherapy (up to 54 Gy; ATRT: n = 13; eMRT/RTK: n = 7), chemotherapy only (LGG: n = 4; eMRT/RTK: n = 1) or had been observed (LGG: n = 11). Neuropsychological evaluation employing comparable tests was performed at median 6.8 years (ATRT), 6.6 years (eMRT/RTK), and 5.2 years (LGG) post diagnosis. RESULTS: We detected sequelae in various domains for all tumor types. Group comparison showed impairments, specifically in fluid intelligence (p = .041; d = 1.11) and visual processing (p = .001; d = 2.09) in ATRT patients when compared to LGG patients. Results for psychomotor speed and attention abilities were significantly below the norm for both groups (p < .001-.019; d = 0.79-1.90). Diagnosis predicted impairments of cognitive outcome, while sex- and age-related variables did not. QoS outcome for all rhabdoid patients displayed impairments mainly in social (p = .008; d = 0.74) and school functioning (p = .048; d = 0.67), as well as lower overall scores in psychosocial functioning (p = .023; d = 0.78) and quality of life (p = .006; d = 0.79) compared to healthy controls. CONCLUSION: Survivors of infant ATRT experience various late effects in cognition and QoS following multimodal treatment, while infant LGG patients without radiotherapy demonstrated comparable impairments in psychomotor and attention abilities. Early onset and multimodal treatment of rhabdoid tumors require close monitoring of neuropsychological and QoS sequelae.

Exploiting autophagy balance in T and NK cells as a new strategy to implement adoptive cell therapies.

Autophagy is an essential cellular homeostasis pathway initiated by multiple stimuli ranging from nutrient deprivation to viral infection, playing a key role in human health and disease. At present, a growing number of evidence suggests a role of autophagy as a primitive innate immune form of defense for eukaryotic cells, interacting with components of innate immune signaling pathways and regulating thymic selection, antigen presentation, cytokine production and T/NK cell homeostasis. In cancer, autophagy is intimately involved in the immunological control of tumor progression and response to therapy. However, very little is known about the role and impact of autophagy in T and NK cells, the main players in the active fight against infections and tumors. Important questions are emerging: what role does autophagy play on T/NK cells? Could its modulation lead to any advantages? Could specific targeting of autophagy on tumor cells (blocking) and T/NK cells (activation) be a new intervention strategy? In this review, we debate preclinical studies that have identified autophagy as a key regulator of immune responses by modulating the functions of different immune cells and discuss the redundancy or diversity among the subpopulations of both T and NK cells in physiologic context and in cancer.

[18F]FET-PET in children and adolescents with central nervous system tumors: does it support difficult clinical decision-making?

PURPOSE: Positron emission tomography (PET) with O-(2-[18F]fluoroethyl)-L-tyrosine ([18F]FET) is a well-established tool for non-invasive assessment of adult central nervous system (CNS) tumors. However, data on its diagnostic utility and impact on clinical management in children and adolescents are limited. METHODS: Twenty-one children and young adults (13 males; mean age, 8.6 ± 5.2 years; range, 1-19 at initial diagnosis) with either newly diagnosed (n = 5) or pretreated (n = 16) CNS tumors were retrospectively analyzed. All patients had previously undergone neuro-oncological work-up including cranial magnetic resonance imaging. In all cases, [18F]FET-PET was indicated in a multidisciplinary team conference. The impact of PET imaging on clinical decision-making was assessed. Histopathology (n = 12) and/or clinical and imaging follow-up (n = 9) served as the standard of reference. RESULTS: The addition of [18F]FET-PET to the available information had an impact on further patient management in 14 out of 21 subjects, with avoidance of invasive surgery or biopsy in four patients, biopsy guidance in four patients, change of further treatment in another five patients, and confirmation of diagnosis in one patient. CONCLUSION: [18F]FET-PET may provide important additional information for treatment guidance in pediatric and adolescent patients with CNS tumors.

Risk factors for mixed chimerism in children with hemophagocytic lymphohistiocytosis after reduced toxicity conditioning.

BACKGROUND: Reduced toxicity conditioning for hematopoietic stem cell transplantation of patients with hemophagocyticlymphohistiocytosis (HLH) results in favorable survival, however at the expense of relevant rates of mixed chimerism. Factors predisposing to mixed chimerism remain to be determined. PROCEDURE: Patients with primary HLH transplanted 2009-2016 after treosulfan- or melphalan-based conditioning regimens were analyzed in a retrospective multicenter study for survival, engraftment, chimerism, and adverse events. Mixed chimerism was considered substantial if < 25% donor chimerism occurred and/or if secondary cell therapy was administered. Donor type, graft source, type of alkylating agent, type of serotherapy, and remission status were analyzed as potential risk factors in a multivariable logistic regression model. RESULTS: Among 60 patients, engraftment was achieved in 95%, and the five-year estimated overall survival rate was 75%. Prevalence of any recipient chimerism was 48%. Substantial recipient chimerism was recorded in 32% of patients. Secondary post-HSCT cell therapy was administered in 30% of patients. A human leukocyte antigen (HLA)-mismatched donor (< 10/10) was the only significant risk factor for the occurrence of substantial recipient chimerism (P = 0.01; odds ratio, 5.8; CI 95%, 1.5-26.3). CONCLUSION: The use of an HLA-matched donor is the most important factor to avoid substantial recipient chimerism following treosulfan -or melphalan-based conditioning in primary HLH.

CD34+ selected stem cell boosts can improve poor graft function after paediatric allogeneic stem cell transplantation.

Poor graft function (PGF) is a severe complication of haematopoietic stem cell transplantation (HSCT) and administration of donor stem cell boosts (SCBs) represents a therapeutic option. We report 50 paediatric patients with PGF who received 61 boosts with CD34+ selected peripheral blood stem cells (PBSC) after transplantation from matched unrelated (n = 25) or mismatched related (n = 25) donors. Within 8 weeks, a significant increase in median neutrophil counts (0·6 vs. 1·516 × 109 /l, P < 0·05) and a decrease in red blood cell and platelet transfusion requirement (median frequencies 1 and 7 vs. 0, P < 0·0001 and <0·001), were observed, and 78·8% of patients resolved one or two of their cytopenias. 36·5% had a complete haematological response. Median lymphocyte counts for CD3+ , CD3+ CD4+ , CD19+ and CD56+ increased 8·3-, 14·2-, 22.- and 1·6-fold. The rate of de novo acute graft-versus-host disease (GvHD) grade I-III was only 6% and resolved completely. No GvHD grade IV or chronic GvHD occurred. Patients who responded to SCB displayed a trend toward better overall survival (OS) (P = 0·07). Thus, administration of CD34+ selected SCBs from alternative donors is safe and effective. Further studies are warranted to clarify the impact on immune reconstitution and survival.

Prospective Biomarker Screening for Diagnosis of Invasive Aspergillosis in High-Risk Pediatric Patients.

Combined biomarker screening is increasingly used to diagnose invasive aspergillosis (IA) in high-risk patients. In adults, the combination of galactomannan (GM) and fungal DNA detection has proven to be beneficial in the diagnosis of IA. Data in purely pediatric cohorts are scarce. Here, we monitored 39 children shortly before and after allogeneic stem cell transplantation twice weekly by use of a commercial GM enzyme-linked immunosorbent assay (ELISA) and a PCR assay based on amplification of the pan-Aspergillus ITS1/5.8S ribosomal operon. In addition, clinical data were recorded and classification of IA was performed according to the European Organization for the Research and Treatment of Cancer/Mycoses Study Group (EORTC/MSG) criteria. Among the 39 high-risk children, we identified 4 patients (10.3%) with probable and 2 (5.1%) with possible IA. All patients with probable IA were repeatedly positive for both tests (means of 9.5 and 6.8 positive GM and PCR samples, respectively), whereas both possible IA cases were detected by PCR. The sensitivity and specificity were, respectively, 67% and 89% for GM and 100% and 63% for PCR. Positive and negative predictive values were, respectively, 50% and 100% for GM and 27% and 100% for PCR. For the combined testing approach, both values were 100%. The number of positive samples seemed to be lower in patients undergoing antifungal therapy. Sporadically positive tests occurred in 12% (GM) and 42% (PCR) of unclassified patients. In summary, our data show that combined monitoring for GM and fungal DNA also results in a high diagnostic accuracy in pediatric patients. Future studies have to determine whether combined testing is suitable for early detection of subclinical disease and how antifungal prophylaxis impacts assay performance.

Adoptive T-cell therapy with hexon-specific Th1 cells as a treatment of refractory adenovirus infection after HSCT.

Hematopoietic stem cell transplantation (HSCT) has improved over the last few decades. However, viral infections are often refractory to pharmacologic treatment and require alternative treatment strategies such as immunotherapy. Adenovirus (AdV) is th predominant disease-causing pathogen in pediatric HSCT. In a clinical trial, we analyzed safety and efficacy of ex vivo adoptive T-cell transfer (ACT) with hexon-specific T cells, predominantly of the T-helper cell 1 (Th1) phenotype, in 30 patients with AdV disease or viremia. ACT was feasible with no acute toxicities or significant onset of graft-versus-host disease. ACT led to in vivo antiviral immunity for up to 6 months with viral control, resulting in complete clearance of viremia in 86% of patients with antigen-specific T-cell responses. After ACT and a follow-up of 6 months, overall survival was markedly increased in responders (mean, 122 days; 15 survivors) compared with nonresponders who all died shortly after ACT (mean, 24 days; no survivors). AdV-related mortality was 100% in nonresponders compared with 9.5% in responders (≥1 log reduction of DNA copies per milliliter after ACT). In summary, ex vivo ACT of AdV-specific Th1 cells was well tolerated and led to successful and sustained restoration of T-cell immunity correlated with virologic response and protection from virus-related mortality. This cellular immunotherapy is a short-term available and broadly applicable treatment. The study is registered at European Union Clinical Trials Register as 2005-001092-35.

Pediatric Colorectal Carcinoma is Associated With Excellent Outcome in the Context of Cancer Predisposition Syndromes.

INTRODUCTION: Colorectal carcinoma (CRC) is the second most common adult cancer in Germany, however, it is extremely rare in children and adolescents. In these patients, previous literature describes aggressive behavior and diagnosis at advanced stage. METHOD: Thirty-one patients with CRC age ≤ 18 years and treated between 1990 and 2012 have been identified through the structures and registries of the German Society for Pediatric Oncology and Hematology. RESULTS: The age range was 9-18 years (median 13.5 years); the median follow-up time was 43.9 months (range 1-124 months). Twenty-six patients (84%) were tested for a genetic tumor syndrome (GTS); of these, 11 patients (35% of all patients) tested positive (eight cases of Lynch syndrome, one patient with familial adenomatous polyposis, two patients with constitutional mismatch repair deficiency). An unfavorable histology was reported in 55% of the records (n = 17), a poor differentiation (grade III) in 68% of carcinoma (n = 21). Overall survival (OS) and event-free survival at 5 years was 52.0% and 65.6%, respectively. Five-year survival according to stage was 100% in stage II (n = 2), 100% in stage III (n = 13), and 12.9% in stage IV (n = 15; P < 0.001). Five-year OS in patients with and without a defined GTS was 100% and 36.5% (P = 0.019), respectively. CONCLUSION: Children and adolescents with CRC are frequently diagnosed in advanced stages and have an unfavorable prognosis. In this study, a high percentage of pediatric CRC patients presented with a tumor predisposition syndrome and showed an especially favorable OS.

Formula-feeding is associated with shift towards Th1 cytokines.

PURPOSE: Breast-feeding (BF) versus formula-feeding (FF) may be a factor for the development and differentiation of T-cell subsets and cytokine production in infancy and childhood. We therefore investigated T-cell subpopulations and their cytokine production by flow cytometry as well as cytokine levels in serum samples in breast-fed versus formula-fed infants and children. METHODS: Heparinised blood was taken from 191 healthy infants and children. Peripheral blood mononuclear cells were stimulated with phorbol-mystriate-acetate and ionomycin in the presence of brefeldin. T-cell subsets and cytokines were determined by flow cytometry. Furthermore, serum concentrations of IFNγ and IL4 were measured using ELISA. An IFNγ/IL4 ratio was calculated to estimate the Th1/Th2 balance. RESULTS: Children who were formula-fed show higher numbers of memory T and T helper cells. After stimulation, the number of IFNγ-positive memory T-cells was increased up to the age of 6 years. Breast-fed infants show higher percentages of IL4-positive T helper cells. At ELISA determination, formula-fed children showed higher IFNγ levels than breast-fed children, while IL4 levels did not differ. The IFNγ/IL4 ratio (FACS and ELISA) was elevated in formula-fed infants and children. CONCLUSION: This systematic analysis of cytokine profiles during childhood in dependency of BF allows a better understanding of immune maturation and demonstrates the influence of early feeding on immune function throughout childhood, even after cessation of BF. FF induces a shift towards Th1 cytokines in children. This may have an influence on the development of autoimmune disease in later life.

Osteosarcoma in patients with Rothmund-Thomson syndrome.

BACKGROUND: Rothmund-Thomson syndrome (RTS) is associated with an increased risk of osteosarcoma, but information about affected patients is limited. PROCEDURE: Seven patients with osteosarcoma, treated in the Cooperative Osteosarcoma Study Group-trials, had a diagnosis of RTS. Their patient-, tumor- and treatment-related variables and outcome were reviewed retrospectively. RESULTS: Median age at diagnosis of osteosarcoma was 13 years (range 7-16), five were female, two male. Tumor involved proximal tibia (n = 4), distal tibia (n = 1), distal fibula (n = 1) and proximal ulna (n = 1). Three patients had metastatic disease at diagnosis. All patients received surgery and chemotherapy. Four of seven patients required dose modifications and three of them terminated treatment prematurely. Complete resection of the primary tumor was achieved in all individuals. Two of three affected patients failed to achieve surgical clearance of their primary metastases and died. The third patient relapsed with multiple metastases and died. Two of four patients with localized disease were alive in first complete remission, a third patient in second complete remission after recurrence and a fourth patient died of acute leukemia, while still in first complete remission of osteosarcoma. CONCLUSIONS: Patients with RTS and osteosarcoma may be cured of their cancer with appropriate multimodal therapy. They should be treated like other osteosarcoma patients but preexisting disorders, needs for special support and development of toxicities have to be considered.

Transition to a mesenchymal state in neuroblastoma may be characterized by a high expression of GD2 and by the acquisition of immune escape from NK cells.

Background: Neuroblastoma (NB) is characterized by both adrenergic (ADRN) and undifferentiated mesenchymal (MES) subsets. The ganglioside sialic acid-containing glycosphingolipid (GD2) is widely overexpressed on tumors of neuroectodermal origin promoting malignant phenotypes. MES cells are greatly enriched in post-therapy and relapsing tumors and are characterized by decreased expression of GD2. This event may cause failure of GD2-based immunotherapy. NK cells represent a key innate cell subset able to efficiently kill tumors. However, the tumor microenvironment (TME) that includes tumor cells and tumor-associated (TA) cells could inhibit their effector function. Methods: We studied eight NB primary cultures that, in comparison with commercial cell lines, more faithfully reflect the tumor cell characteristics. We studied four primary NB-MES cell cultures and two pairs of MES/ADRN (691 and 717) primary cultures, derived from the same patient. In particular, in the six human NB primary cultures, we assessed their phenotype, the expression of GD2, and the enzymes that control its expression, as well as their interactions with NK cells, using flow cytometry, RT-qPCR, and cytotoxicity assays. Results: We identified mature (CD105+/CD133-) and undifferentiated (CD133+/CD105-) NB subsets that express high levels of the MES transcripts WWTR1 and SIX4. In addition, undifferentiated MES cells display a strong resistance to NK-mediated killing. On the contrary, mature NB-MES cells display an intermediate resistance to NK-mediated killing and exhibit some immunomodulatory capacities on NK cells but do not inhibit their cytolytic activity. Notably, independent from their undifferentiated or mature phenotype, NB-MES cells express GD2 that can be further upregulated in undifferentiated NB-MES cells upon co-culture with NK cells, leading to the generation of mature mesenchymal GD2bright neuroblasts. Concerning 691 and 717, they show high levels of GD2 and resistance to NK cell-mediated killing that can be overcome by the administration of dinutuximab beta, the anti-GD2 monoclonal antibody applied in the clinic. Conclusions: NB is a heterogeneous tumor representing a further hurdle in NB immunotherapy. However, different from what was reported with NB commercial cells and independent of their MES/ADRN phenotype, the expression of GD2 and its displayed sensitivity to anti-GD2 mAb ADCC indicated the possible effectiveness of anti-GD2 immunotherapy.

Human-Level Differentiation of Medulloblastoma from Pilocytic Astrocytoma: A Real-World Multicenter Pilot Study.

Medulloblastoma and pilocytic astrocytoma are the two most common pediatric brain tumors with overlapping imaging features. In this proof-of-concept study, we investigated using a deep learning classifier trained on a multicenter data set to differentiate these tumor types. We developed a patch-based 3D-DenseNet classifier, utilizing automated tumor segmentation. Given the heterogeneity of imaging data (and available sequences), we used all individually available preoperative imaging sequences to make the model robust to varying input. We compared the classifier to diagnostic assessments by five readers with varying experience in pediatric brain tumors. Overall, we included 195 preoperative MRIs from children with medulloblastoma (n = 69) or pilocytic astrocytoma (n = 126) across six university hospitals. In the 64-patient test set, the DenseNet classifier achieved a high AUC of 0.986, correctly predicting 62/64 (97%) diagnoses. It misclassified one case of each tumor type. Human reader accuracy ranged from 100% (expert neuroradiologist) to 80% (resident). The classifier performed significantly better than relatively inexperienced readers (p < 0.05) and was on par with pediatric neuro-oncology experts. Our proof-of-concept study demonstrates a deep learning model based on automated tumor segmentation that can reliably preoperatively differentiate between medulloblastoma and pilocytic astrocytoma, even in heterogeneous data.

Preemptive immunotherapy in childhood acute myeloid leukemia for patients showing evidence of mixed chimerism after allogeneic stem cell transplantation.

Previous studies have shown that children with acute myeloid leukemia (AML) who developed mixed chimerism (MC) were at high risk for relapse after allogeneic stem-cell transplantation (allo-SCT). We investigated the feasibility of intensified preemptive immunotherapy in children receiving allo-SCT for AML. Eighty-four children were registered in our trial from May 2005 to April 2009; of these, 71 fulfilled the inclusion criteria and were treated according to the study protocol. Serial and semiquantitative analyses of posttransplantation chimerism were performed. Defined immunotherapy approaches were considered in MC patients. Continuous complete chimerism (CC) was observed in 51 of 71 patients. MC was detected in 20 patients and was followed by immunotherapy in 13. Six of 13 MC patients returned to CC without toxicity and remained in long-term remission. Overall, the probability of event-free survival (pEFS) was 66% (95% confidence interval [95% CI] = 53%-76%) for all patients and 46% (95% CI = 19%-70%) in MC patients with intervention; however, this number increased to 71% (95% CI = 26%-92%) in 7 of 13 MC patients on immunotherapy who were in remission at the time of transplantation. All MC patients without intervention relapsed. These results suggest that MC is a prognostic factor for impending relapse in childhood AML, and that preemptive immunotherapy may improve the outcome in defined high-risk patients after transplantation.

Survival following disease recurrence of primary localized alveolar rhabdomyosarcoma.

BACKGROUND: Recurrences in primary localized alveolar rhabdomyosarcoma (RMA) are common. Post-relapse survival is poor. We evaluated prognostic factors including relapse treatment in patients with recurrent RMA. METHODS: Relapses occurred in 115/235 patients with nonmetastatic RMA treated in four consecutive CWS-trials after achievement of a complete remission. Sufficient information about post-relapse treatment and outcome could be obtained in 99 patients and was retrospectively analyzed. RESULTS: Nine of 99 patients received no salvage therapy and died after a median of 2 months. The remaining 90 patients received multimodal relapse treatment including mandatory chemotherapy. Recurrences were grossly resected in 39 patients; 57 patients received radiation. At a median follow-up from relapse of 8 years, 20 patients were alive and disease-free (5-year post-relapse survival [PROS] 21.3 ± 8). All surviving patients apart from a single individual had an isolated, circumscribed recurrence. Sixteen of 20 survivors were treated with adequate local relapse therapy (ALRT, i.e., either complete resection or gross resection + radiation). Survival in the subgroup of 27 individuals with circumscribed recurrences and ALRT was significantly better (PROS 53.7 ± 19) compared with disseminated recurrences and/or tumors treated without ALRT. Absence of primary lymph node involvement, circumscribed relapses, ALRT, and achievement of a second CR were identified as independent favorable risk factors. CONCLUSION: Post-relapse survival for primary localized RMA is generally poor. However, certain patient groups differed significantly in their likelihood of survival and 50% of patients with circumscribed relapses treated with ALRT survived. These findings may form the basis for an evidence-based risk-stratification for recurrent disease including relapse treatment.

Osteosarcoma Arising After Ewing Sarcoma or Vice Versa: A Report of 20 Affected Patients from the Cooperative Osteosarcoma Study Group (COSS).

BACKGROUND/AIM: Ewing sarcoma can arise in patients after osteosarcoma or vice versa. Our aim was to learn more about which patients develop these secondary tumors, which treatments may be effective, and which patients might survive. PATIENTS AND METHODS: The database of the Cooperative Osteosarcoma Study Group (1980-09/2022) was searched for all patients with an osteosarcoma (including undifferentiated pleomorphic sarcoma of the bone) who also suffered from Ewing sarcoma (incl. peripheral neuroectodermal tumor) at any time, previously or thereafter. The identified patients were then analyzed for patient, tumor, and treatment-related variables as well as their disease- and survival-status at the last follow-up. RESULTS: A total of 20 eligible patients [17 Ewing sarcoma prior to osteosarcoma, 3 vice versa; 10 males, 10 females; median age at 1st cancer 10.5 (2.4-20.6), at 2nd cancer 20.5 (9.9-42.4) years] were identified. None of the patients developed a 3rd cancer and none had a known tumor-predisposition syndrome. Sixteen/17 secondary osteosarcomas and no secondary Ewing sarcoma developed in sites that had previously been irradiated. Nineteen/20 (95%) patients received primary multi-agent chemotherapy for their 1st and 2nd cancers. Actuarial overall and event-free survival probabilities at five years after the diagnosis of the secondary cancer were 69% and 42%, respectively. CONCLUSION: Secondary osteosarcoma arising after Ewing sarcoma is almost exclusively associated with radiation. This is not the case vice versa. Either way, long-term survival is a realistic possibility with appropriate multidisciplinary treatment; thus, therapeutic negligence is clearly inadequate.