Real-world experiences in patients with Ewing sarcoma treated at a specialist centre in Turkey.

Objectives: The present study evaluates the clinical outcomes of children, adolescents and adults with Ewing sarcoma and identifies the prognostic factors. Methods: Included in the study were 222 pediatric and adult patients diagnosed with Ewing sarcoma (EwS) who were followed up between 1992 and 2019, and whose data were analyzed retrospectively. Results: The median age of 131 male and 91 female patients included in the study was 13 (1-64). The median follow-up duration of the survivors was 79 months (range, 11-182 months). The 3-year EFS rate of the 222 patients was 34 % (Confidence Interval (CI) (0.158-0.242 %) and the OS rate was 54 % (CI, 0.289-0.590 %). For the non-metastatic patients, the 3-year EFS rate was 47 % and the OS was 68 %, while for the metastatic patients the 3-year EFS rate was 13 % and the OS was 30 %. Of the patient sample, 81 (36, 5 %) survived, of whom 72 were continuously free of disease while the disease persisted in nine, and three developed a secondary neoplasm (2 of whom subsequently died while one survived disease-free). Of the 129 patients who relapsed with metastases and/or local recurrence, eight survived and are disease-free, nine are alive with uncontrolled disease; five were lost to follow-up and 107 died. Conclusion: The findings of the present study suggest metastatic disease at presentation and positive margins after surgery to be of prognostic significance in EwS. Disruptions in aggressive local treatments may reduce the chances of cure in EwS.

Ewing sarcoma among children 5 years of age or younger: Is it a different disease?

INTRODUCTION: Children ≤5 years of age with Ewing's sarcoma (ES) possibly have a distinct disease biology, data on which are scarce. We evaluated clinical features, outcomes, and prognostic factors of ES among children with age ≤5 years. METHODS: Children with ES registered between 2003 and 2019 were included. Baseline clinical and treatment details were retrieved from medical records. Prognostic factors were identified using multivariable Cox regression. Clinical features and outcomes of children ≤5 years were compared with those greater than 5 years by chi-square and log-rank tests. Propensity score-matched (PSM) analysis was done to evaluate the impact of age on survival in the metastatic and localized subgroups. RESULTS: Out of the 859 patients, 86 (10%) were ≤5 years of age (median age 4 years, 60 males [69.8%]). The most common location was the extremities (37.2%), followed by thorax (27.9%) and head and neck (H&N) (22.1%); baseline metastases were seen in 25 patients (29.8%). The median event-free-survival (EFS) and overall survival (OS) were 25.6 and 68.7 months, respectively. Metastatic disease predicted inferior OS (hazard ratio [HR] = 2.54, p = .018) and EFS (HR = 2.47, p = .007], symptom duration ≤3 months predicted an inferior OS (HR = 2.17, p = .048). Compared to age greater than 5 years, younger children had more H&N and less pelvic primaries (p < .001) and lesser baseline metastases (p = .037). PSM analysis did not reveal any significant impact of age on OS in the metastatic (HR = 1.59, p = .29) or localized cohort (HR = 1.77, p = .09). CONCLUSIONS: Children with ES ≤5 years of age have a distinct favorable clinical presentation. However, age is not an independent prognostic factor for survival outcomes when adjusted for confounders.

Preclinical models for the study of pediatric solid tumors: focus on bone sarcomas.

Sarcomas comprise between 10-15% of all pediatric malignancies. Osteosarcoma and Ewing sarcoma are the two most common pediatric bone tumors diagnosed in children and young adults. These tumors are commonly treated with surgery and/or radiation therapy and combination chemotherapy. However, there is a strong need for the development and utilization of targeted therapeutic methods to improve patient outcomes. Towards accomplishing this goal, pre-clinical models for these unique malignancies are of particular importance to design and test experimental therapeutic strategies prior to being introduced to patients due to their origination site and propensity to metastasize. Pre-clinical models offer several advantages for the study of pediatric sarcomas with unique benefits and shortcomings dependent on the type of model. This review addresses the types of pre-clinical models available for the study of pediatric solid tumors, with special attention to the bone sarcomas osteosarcoma and Ewing sarcoma.

Extraosseous Ewing Sarcoma in a 28-Year-Old Male: A Case Report and Literature Review.

Ewing sarcoma (ES) is an uncommon and highly aggressive bone malignancy that predominantly occurs in children and young adults. Extraosseous Ewing sarcoma (EES), an even rarer variant, can present in the soft tissues instead of bone. In this case report, we detail a previously healthy 28-year-old male presenting with an isolated enlarged left inguinal lymph node, subsequently diagnosed as EES. The patient presented with a three-month history of a non-tender, gradually enlarging lump in the left groin. Fine needle aspiration revealed a small round blue cell tumor with a high Ki-67 score, and subsequent excisional biopsy identified a rare genetic fusion mutation. Postoperative positron emission tomography (PET)/computed tomography (CT) scan did not show any fludeoxyglucose F18 (FDG) uptake lesions to suggest residual malignancy. The patient is currently awaiting chemotherapy. Throughout the discussion of this case, we highlight the importance of considering EES in the differential diagnosis of isolated lymph node enlargement, the role of genetic testing in diagnosis, and the treatment modalities offered.

Primary Ewing's sarcoma of the intestine: case report and literature review.

Ewing sarcoma (ES)/peripheral primitive neuroectodermal tumor is a highly aggressive malignant tumor that typically presents in bone and soft tissue. Primary ES of the intestine is relatively rare, which poses a challenge in distinguishing it from other primary tumors of the small intestine through imaging. This article details a case study of ES originating in the intestine. Computed tomography (CT) imaging suggested a small intestinal stromal tumor, and so the patient underwent resection of the small bowel and omental tumor. Pathology results confirmed the diagnosis of ES of the small intestine. Following surgery, the patient underwent six cycles of chemotherapy, and a follow-up positron emission tomography-CT revealed widespread dissemination of the disease with intraperitoneal metastasis, ultimately resulting in the death of the patient.

Gene signatures of copper metabolism related genes may predict prognosis and immunity status in Ewing's sarcoma.

Background: Cuproptosis is copper-induced cell death. Copper metabolism related genes (CMRGs) were demonstrated that used to assess the prognosis out of tumors. In the study, CMRGs were tested for their effect on TME cell infiltration in Ewing's sarcoma (ES). Methods: The GEO and ICGC databases provided the mRNA expression profiles and clinical features for downloading. In the GSE17674 dataset, 22prognostic-related copper metabolism related genes (PR-CMRGs) was identified by using univariate regression analysis. Subsequently, in order to compare the survival rates of groups with high and low expression of these PR-CMRGs,Kaplan-Meier analysis was implemented. Additionally, correlations among them were examined. The study employed functional enrichment analysis to investigate probable underlying pathways, while GSVA was applied to evaluate enriched pathways in the ES (Expression Set). Through an unsupervised clustering algorithm, samples were classified into two clusters, revealing significant differences in survival rates and levels of immune infiltration. Results: Using Lasso and step regression methods, five genes (TFRC, SORD, SLC11A2, FKBP4, and AANAT) were selected as risk signatures. According to the Kaplan-Meier survival analysis, the high-risk group had considerably lower survival rates than the low-risk group(p=6.013e-09). The area under the curve (AUC) values for the receiver operating characteristic (ROC) curve were 0.876, 0.883, and 0.979 for 1, 3, and 5 years, respectively. The risk model was further validated in additional datasets, namely GSE63155, GSE63156, and the ICGC datasets. To aid in outcome prediction, a nomogram was developed that incorporated risk levels and clinical features. This nomogram's performance was effectively validated through calibration curves.Additionally, the study evaluated the variations in immune infiltration across different risk groups, as well as high-expression and low-expression groups. Importantly, several drugs were identified that displayed sensitivity, offering potential therapeutic options for ES. Conclusion: The findings above strongly indicate that CMRGs play crucial roles in predicting prognosis and immune status in ES.

Askin's Tumour: A Report of a Rare Case.

Primitive neuroectodermal tumours (PNETs) are rare, malignant tumours arising from primitive nerve cells. PNET of the chest wall is rare and is observed in children and young adults. Askin defined Askin's tumour as a PNET of the thoracopulmonary area. It develops from the soft tissues of the chest wall, particularly in the paravertebral region. Here, we report a case of Askin's tumour, a rare neoplasm occurring in the thoracopulmonary region in a 13-year-old girl. She came with complaints of fever, cold, cough with mucoid expectoration, breathlessness for 15 days, and generalized weakness for three months. A high-resolution computed tomography (HRCT) thorax scan was also done, which suggested a large right pleural-based mass with vertebral metastasis. Through diligent diagnostic evaluation involving imaging studies and histopathological examination, the tumour was accurately identified.

Preserved walking function without postoperative reconstruction for pelvic Ewing's sarcoma: a case report.

BACKGROUND: Ewing's sarcoma is a primary bone tumor predominantly observed in children and adolescents, necessitating a multidisciplinary treatment approach. While localized cases have a 5-year survival rate of 60-70%, the prognosis is significantly worse in pelvic advanced cases with metastasis. Moreover, pelvic Ewing's sarcoma has the unique problem of leading to high rates of postoperative infection. CASE PRESENTATION: We present the case of a Japanese 14-year-old boy with left iliac Ewing's sarcoma and multiple metastases. At the initial visit, imaging revealed a large tumor in the left iliac bone with extraosseous extension and metastasis to multiple sites. Neoadjuvant chemotherapy resulted in significant tumor reduction. Surgical resection was performed without pelvic ring reconstruction to enable early postoperative chemotherapy and minimize postoperative infection risk. Despite complete abductor muscle removal, the patient achieved a stable gait postoperatively by centering the load axis. CONCLUSION: Our case highlights the successful management of a left iliac Ewing's sarcoma with multiple metastases, with a focus on functional preservation and infection risk reduction. Pelvic ring reconstruction was not performed to avoid postoperative complications, emphasizing the importance of early postoperative chemotherapy. The patient achieved a stable gait postoperatively, demonstrating the potential benefits of this approach in similar cases.

Extraskeletal Ewing Sarcoma Disguised as a Vascular Malformation.

Extraskeletal Ewing sarcoma (EES) is a rare entity, accounting for only 3% of lesions encountered in upper extremity. We present two paediatric patients, who were initially diagnosed with a vascular malformation based on clinical assessment and imaging. Final histopathology revealed Ewing sarcoma of soft tissue origin, confirmed by immunohistochemical analysis. Hand surgeons, who are routinely approached for a myriad of hand pathologies, should be wary and consider EES as a differential when treating such lesions. A multidisciplinary approach with an appropriate treatment algorithm can help in a speedy diagnosis, improving the long-term prognosis of the disease. Level of Evidence: Level V (Therapeutic).

[Experience in diagnosis and treatment of 6 cases of renal Ewing's sarcoma with venous thrombus].

OBJECTIVE: To review and analyze the clinical diagnosis and treatment of renal Ewing's sarcoma with venous tumor embolus, to follow up the survival and prognosis of the patients, and to provide help for the diagnosis and treatment of the disease. METHODS: Clinical data (including general data, surgical data and postoperative pathological data) of patients diagnosed with renal Ewing's sarcoma with venous tumor embolus in Peking University Third Hospital from June 2016 to June 2022 were collected, and the prognosis of the patients was followed up to analyze the influence of diagnosis and treatment process on the prognosis of the disease. RESULTS: There were 6 patients, including 1 male and 5 females. There were 4 cases of left renal tumor and 2 cases of right renal tumor. The median age at diagnosis was 28 years (16-52 years). The imaging findings were all exogenous tumors with internal necrotic tissue and hemorrhage. The mean maximum tumor diameter was 12.6 cm, and the mean tumor thrombus length was 7.8 cm. Four patients underwent open surgery and 2 patients underwent laparoscopic surgery. The postoperative pathological results were renal Ewing sarcoma. Immunohistochemical results showed 3 cases of CD99 (+), 2 cases of FLI-1 (+), and 1 case of CD99, FLI-1 (-). 3 patients received chemotherapy (cyclophosphamide, doxorubicin, vincristine/ifosfamide, etoposide), 1 case received chemotherapy combined with radiotherapy, and 2 cases received no adjuvant therapy. The mean overall survival (OS) of the 6 patients was 37 months, and the mean OS of the 4 patients (47 months) who received chemotherapy was significantly higher than that of the 2 patients (16 months) who did not receive chemotherapy (P=0.031). CONCLUSION: Renal Ewing's sarcoma with venous tumor embolus is rare in clinic, and it is common in young female patients. The operation is difficult and the prognosis is poor. Surgical resection, adjuvant radiotherapy and chemotherapy can improve the overall survival rate of the patients.

Unusual Presentation of Thoracic Epidural Ewing Sarcoma in a 20-Year-Old Patient: A Case Report.

The aim of this case report is to present a rare case of epidural Ewing sarcoma with spinal cord compression, which is an uncommon presentation of this tumor. Ewing's sarcoma is a primary malignant tumor predominantly affecting individuals in their second decade of life, primarily impacting those aged 10 to 25, with the average age of onset being around 20 years. Epidemiological studies reveal that this cancer most commonly arises in the diaphyses of the long tubular bones in the lower extremities. Spinal involvement, however, is exceedingly uncommon. A case of sacral type of Ewing's sarcoma, with the most common localization of the primary spinal sarcomas and an extremely aggressive course, has been described in the literature. Other localizations of Ewing's sarcoma located in other areas of the spine are also presented. Even rarer are cases in which the tumor formation is located epidurally and exhibits marked medullary compression and absent neurological symptoms. We present the case of a 20-year-old patient who was admitted to the neurology department with symptoms of lower flaccid paraparesis and pelvic-reservoir dysfunction, specifically urinary retention for 16-17 hours, after which a catheter was added. MRI revealed an epidural tumor spanning TH5-TH7 vertebral levels, causing significant spinal cord compression. A CT scan of the chest identified a tumor on the left side at the level of the sixth rib, featuring soft tissue involvement, rib destruction, lung invasion, and a small pleural effusion. Due to the critical neurological symptoms, the patient underwent emergency surgery in the neurosurgical department, which included thoracic laminectomies, maximal possible tumor resection, and effective spinal cord decompression. Postoperative period was uneventful. Histopathological examination confirmed the diagnosis of Ewing's epidural sarcoma. The patient subsequently received adjuvant chemotherapy and radiotherapy. Six months post-treatment, the patient demonstrated a satisfactory overall condition with significant improvement in gait and continues to undergo chemotherapy courses.

The Landscape of microRNAs in Bone Tumor: A Comprehensive Review in Recent Studies.

Cancer, the second greatest cause of mortality worldwide, frequently causes bone me-tastases in patients with advanced-stage carcinomas such as prostate, breast, and lung cancer. The existence of these metastases contributes to the occurrence of skeletal-related events (SREs), which are defined by excessive pain, pathological fractures, hypercalcemia, and spinal cord com-pression. These injurious incidents leave uncomfortably large holes in each of the cancer patient's life quality. Primary bone cancers, including osteosarcoma (OS), chondrosarcoma (CS), and Ewing's sarcoma (ES), have unclear origins. MicroRNA (miRNA) expression patterns have been changed in primary bone cancers such as OS, CS, and ES, indicating a role in tumor development, invasion, metastasis, and treatment response. These miRNAs are persistent in circulation and ex-hibit distinct patterns in many forms of bone tumors, making them potential biomarkers for early detection and treatment of such diseases. Given their crucial regulatory functions in various bio-logical processes and conditions, including cancer, this study aims to look at miRNAs' activities and possible contributions to bone malignancies, focusing on OS, CS, and ES. In conclusion, miRNAs are valuable tools for diagnosing, monitoring, and predicting OS, CS, and ES outcomes. Further research is required to fully comprehend the intricate involvement of miRNAs in these bone cancers and to develop effective miRNA-based treatments.

Combinatorial macrophage induced innate immunotherapy against Ewing sarcoma: Turning "Two Keys" simultaneously.

BACKGROUND: Macrophages play important roles in phagocytosing tumor cells. However, tumors escape macrophage phagocytosis in part through the expression of anti-phagocytic signals, most commonly CD47. In Ewing sarcoma (ES), we found that tumor cells utilize dual mechanisms to evade macrophage clearance by simultaneously over-expressing CD47 and down-regulating cell surface calreticulin (csCRT), the pro-phagocytic signal. Here, we investigate the combination of a CD47 blockade (magrolimab, MAG) to inhibit the anti-phagocytic signal and a chemotherapy regimen (doxorubicin, DOX) to enhance the pro-phagocytic signal to induce macrophage phagocytosis of ES cells in vitro and inhibit tumor growth and metastasis in vivo. METHODS: Macrophages were derived from human peripheral blood monocytes by granulocyte-macrophage colony-stimulating factor (GM-CSF) and macrophage colony-stimulating factor (M-CSF). Flow cytometry- and microscopy-based in-vitro phagocytosis assays were performed to evaluate macrophage phagocytosis of ES cells. Annexin-V assay was performed to evaluate apoptosis. CD47 was knocked out by CRISPR/Cas9 approach. ES cell-based and patient-derived-xenograft (PDX)-based mouse models were utilized to assess the effects of MAG and/or DOX on ES tumor development and animal survival. RNA-Seq combined with CIBERSORTx analysis was utilized to identify changes in tumor cell transcriptome and tumor infiltrating immune cell profiling in MAG and/or DOX treated xenograft tumors. RESULTS: We found that MAG significantly increased macrophage phagocytosis of ES cells in vitro (p < 0.01) and had significant effect on reducing tumor burden (p < 0.01) and increasing survival in NSG mouse model (p < 0.001). The csCRT level on ES cells was significantly enhanced by DOX in a dose- and time-dependent manner (p < 0.01). Importantly, DOX combined with MAG significantly enhanced macrophage phagocytosis of ES cells in vitro (p < 0.01) and significantly decreased tumor burden (p < 0.01) and lung metastasis (p < 0.0001) and extended animal survival in vivo in two different mouse models of ES (p < 0.0001). Furthermore, we identified CD38, CD209, CD163 and CD206 as potential markers for ES-phagocytic macrophages. Moreover, we found increased M2 macrophage infiltration and decreased expression of Cd209 in the tumor microenvironment of MAG and DOX combinatorial therapy treated tumors. CONCLUSIONS: By turning "two keys" simultaneously to reactivate macrophage phagocytic activity, our data demonstrated an effective and highly translatable alternative therapeutic approach utilizing innate (tumor associated macrophages) immunotherapy against high-risk metastatic ES.

Unlocking epigenetics for precision treatment of Ewing's sarcoma.

Ewing's sarcoma (EWS) is a highly aggressive malignant bone tumor primarily affecting adolescents and young adults. Despite the efficacy of chemoradiotherapy in some cases, the cure rate for patients with metastatic and recurrent disease remains low. Therefore, there is an urgent need for innovative therapeutic approaches to address the challenges associated with EWS treatment. Epigenetic regulation, a crucial factor in physiological processes, plays a significant role in controlling cell proliferation, maintaining gene integrity, and regulating transcription. Recent studies highlight the importance of abnormal epigenetic regulation in the initiation and progression of EWS. A comprehensive understanding of the intricate interactions between EWS and aberrant epigenetic regulation is essential for advancing clinical drug development. This review aims to provide a comprehensive overview of both epigenetic targets implicated in EWS, integrating various therapeutic modalities to offer innovative perspectives for the clinical diagnosis and treatment of EWS.

Extraosseous Ewing Sarcoma With Upper Gastrointestinal Bleeding.

Ewing sarcoma/primitive neuroectodermal tumor (ES/PNET) is a type of malignancy that usually appears as a tumor in the bone. However, in a few patients with ES/PNET, it can occur outside of the bone. Although extraosseous ES/PNET can appear in various parts of the body, involvement of small bowel is rare. If it does, it can present with vague abdominal pain and gastrointestinal bleeding. This case report presents a 28-year-old gentleman with extraosseous ES/PNET in the duodenum who experienced gastrointestinal bleeding as a presenting symptom.

ISLET-1 expression in soft tissue neoplasms reveals high sensitivity but moderate specificity for desmoplastic small round cell tumors and potential utility as a diagnostic biomarker.

ISLET-1 (ISL1) is a LIM-homeodomain transcription factor. Selective ISL1 expression is shown in neuroendocrine, non-neuroendocrine, and some soft tissue tumors including desmoplastic small round cell tumor (DSRCT). We assessed the specificity of ISL1 (clone EP283, 1:500, Cell Marque) in 288 soft tissue tumors, which included 17 DSRCTs and other histologic mimics. Positive staining threshold for ISL1 was set to >10 % of neoplastic cell nuclei at moderate intensity. ISL1 IHC was positive in 15/16 (94 %) DSRCTs with 75 % showing diffuse (>50 %) expression. ISL1 was positive in 1/10 (10 %) Ewing sarcomas (EWS), 7/13 (54 %) alveolar rhabdomyosarcoma (RMS), 14/22 (63 %) embryonal RMS, 7/14 (50 %) synovial sarcomas, 15/16 (93 %) neuroblastoma, 1/5 (20 %) Wilms tumor, 2/4 (50 %) olfactory neuroblastoma, and all 9 Merkel cell carcinomas. Other tumors, including all CIC::DUX4 sarcomas, were negative except 3/27 leiomyosarcomas, and 1 each of angiosarcoma, myxoid liposarcomas, inflammatory myofibroblastic tumor, malignant peripheral nerve sheath tumor, tenosynovial giant cell tumor, dedifferentiated LPS, and 1 ectomesenchymoma. In summary, among the soft tissue tumors tested, ISL1 is a highly sensitive but moderately specific marker for DSRCT and may be useful to distinguish from round cell mimics including EWS and CIC::DUX4 sarcomas. The oncogenic role of ISL1 in these tumors warrants further investigation.

A rare case of Ewing's sarcoma primary of the cervical spine in a 1-year-old child: A case report and literature review.

INTRODUCTION AND SIGNIFICANCE: Ewing sarcoma is a rare and malignant bone tumor that can primarily affect the cervical spine. Symptoms may not always be present, but muscle weakness is a critical indicator of disease progression and necessitates urgent surgical intervention to relieve pressure on the spinal cord. CASE PRESENTATION: We present a case of a child who experienced sudden muscle weakness in the left upper limb. An MRI of the spine revealed a tumor in the cervical spine compressing the spinal cord. Urgent surgical intervention was performed, successfully removing most of the tumor. This was followed by complementary chemotherapy. CLINICAL DISCUSSION: Tumors located in the cervical spine are challenging to treat due to their location. Urgent surgery may be crucial when muscle weakness is present. This case demonstrates a novel surgical approach through the spinous processes of the vertebrae, avoiding laminectomy and the need for spinal fixation, which can be difficult in children. CONCLUSION: Our case highlights a rare presentation of Ewing sarcoma in the cervical spine, infrequently reported in medical literature. It also demonstrates the success of a novel surgical approach that avoids spinal fixation in children.

Human EWS-FLI protein levels and neomorphic functions show a complex, function-specific dose-response relationship in Drosophila.

Ewing sarcoma (EwS) is a cancer that arises in the bones and soft tissues, typically driven by the Ewing's sarcoma breakpoint region 1-Friend leukemia virus integration 1 (EWS-FLI) oncogene. Implementation of genetically modified animal models of EwS has proved difficult largely owing to EWS-FLI's high toxicity. The EWS-FLI1FS frameshift variant that circumvents toxicity but is still able to perform key oncogenic functions provided the first study model in Drosophila. However, the quest for Drosophila lines expressing full-length, unmodified EWS-FLI remained open. Here, we show that EWS-FLI1FS's lower toxicity is owed to reduced protein levels caused by its frameshifted C-terminal peptide, and report new strategies through which we have generated Drosophila lines that express full-length, unmodified EWS-FLI. Using these lines, we have found that the upregulation of transcription from GGAA-microsatellites (GGAAµSats) presents a positive linear correlation within a wide range of EWS-FLI protein concentrations. In contrast, rather counterintuitively, GGAAµSats-independent transcriptomic dysregulation presents relatively minor differences across the same range, suggesting that GGAAµSat-dependent and -independent transcriptional upregulation present different kinetics of response with regards to changing EWS-FLI protein concentration. Our results underpin the functional relevance of varying EWS-FLI expression levels and provide experimental tools to investigate, in Drosophila, the effect of the EWS-FLI 'high' and 'low' states that have been reported and are suspected to be important for EwS in humans.

Impact of age on safety of Busulfan-Melphalan followed by autologous hematopoietic stem-cell transplantation versus standard chemotherapy in the patients of the EURO-E.W.I.N.G. 99 and Ewing 2008 clinical trials.

INTRODUCTION: Ewing sarcoma (ES), is a rare cancer affecting children, adolescents and adults. After VIDE (vincristine-ifosfamide-doxorobucin-etoposide) induction chemotherapy, Busulfan-Melphalan (BuMel) high-dose chemotherapy followed by autologous hematopoietic stem cells transplantation improved outcomes in unfavourable localized ES, but with more toxicities than conventional chemotherapy (VAI: Vincristine-dactinomycin-Ifosfamide). We evaluated whether the risk of acute toxicity associated with BuMel compared to VAI varied according to age in patients recruited in the R2Loc and R2Pulm randomised trials of the Euro-E.W.I.N.G.99 and Ewing-2008 trials. METHODS: We included patients with a localized high-risk disease, or pulmonary or pleural metastasis. We analysed the risk of severe toxicity according to randomised treatment group (VAI versus BuMel) and age group (<12 years, 12-17 years, 18-24 years, ≥25 years). We evaluated the heterogeneity of treatment effects by age group using interaction terms in logistic multivariable models. RESULTS: The analysis included 243 patients treated with VAI and 205 with BuMel. Overall, BuMel was associated with a higher risk of severe acute toxicity than VAI particularly haematological, gastrointestinal, liver, sinusoidal occlusive syndrome, and infections. Severe haematological toxicity and lower general condition were significantly more frequent in younger patients, whatever treatment. We did not observe any significant heterogeneity in terms of the excess risk of severe toxicities associated with BuMel compared to VAI according to age group. CONCLUSION: The excess of acute toxicity associated with BuMel compared to VAI does not vary significantly with age, suggesting the feasibility of BuMel across all age groups.

The survival disparity between children and adolescents and young adults (AYAs) with Ewing sarcoma in the Netherlands did not change since the 1990s despite improved survival: A population-based study.

BACKGROUND: Adolescents and young adults (AYAs) with Ewing sarcoma have a worse prognosis than children. Population-based survival evaluations stratifying findings by important clinical factors are, however, limited. This Dutch population study comprehensively compared survival of children and AYAs with Ewing sarcoma over three decades considering diagnostic period, tissue of origin, tumor site, and disease stage. METHODS: Data on all children (0-17 years, N = 463) and AYAs (18-39 years, N = 379) diagnosed with Ewing sarcoma in the Netherlands between 1990-2018 were collected from the Netherlands Cancer Registry with follow-up until February 2023. Five-year relative survival was calculated using the cohort method. Multivariable analyses were conducted through Poisson regression. RESULTS: Children with Ewing sarcoma had a significantly higher 5-year relative survival than AYAs (65 % vs. 44 %). An increasing trend in survival was noted reaching 70 % in children and 53 % in AYAs in 2010-2018. Results were similar for Ewing bone sarcoma and extraosseous Ewing sarcoma. AYAs had a poorer prognosis than children for most tumor sites and regardless of disease stage. Survival probabilities were 60 % vs. 78 % for localized disease and 20 % vs. 33 % for metastatic disease. Multivariable-regression analysis, adjusted for follow-up time, diagnostic period, sex, disease stage, and tumor site, confirmed increased excess mortality among AYAs compared with children (excess HR: 1.7, 95 % CI: 1.3-2.1). CONCLUSIONS: Despite survival improvements since the 1990s, AYAs with Ewing sarcoma in the Netherlands continue to fare considerably worse than children. This survival disparity was present irrespective of tissue of origin, tumor site, and disease stage.