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Novel effective therapies are urgently needed in recurrent osteosarcoma. GD2 is expressed in human osteosarcoma tumours and cell lines. This study evaluated the disease control rate (DCR) in patients with recurrent osteosarcoma treated with the anti-GD2 antibody dinutuximab plus cytokine therapy as compared to historical outcomes.AOST1421 was a single-arm Phase 2 study for patients with recurrent pulmonary osteosarcoma in complete surgical remission. Patients received up to five cycles of dinutuximab (70 mg/mThirty-nine eligible patients were included in the outcome analysis. Dinutuximab did not demonstrate evidence of efficacy as 11/39 patients remained event free for a DCR of 28.2% (95% CI 15-44.9%). One of 136 administered therapy cycles met criteria for unacceptable toxicity when a patient experienced sudden death of unknown cause. Other ≥ Grade 3 toxicities included pain, diarrhoea, hypoxia, and hypotension. Pharmacokinetic parameters were similar in the two schedules.The combination of dinutuximab with GM-CSF did not significantly improve DCR in recurrent osteosarcoma. Dinutuximab toxicity and pharmacokinetics in adolescent and young adult osteosarcoma patients were similar to younger patients. Other strategies for targeting GD2 in osteosarcoma are being developed.

Supplemental Table 1. Association of clinical features with BM micrometastatic cell burden (CD99+CD45- percent) in flow cytometry cohort. Supplemental Table 2. Total CD99+CD45- percent burden in Ewing sarcoma patients with clinically evident BM metastasis (N=6).

Purpose: Flow cytometry and RT-PCR can detect occult Ewing sarcoma cells in the blood and bone marrow. These techniques were used to evaluate the prognostic significance of micrometastatic disease in Ewing sarcoma.Experimental Design: Newly diagnosed patients with Ewing sarcoma were enrolled on two prospective multicenter studies. In the flow cytometry cohort, patients were defined as “positive” for bone marrow micrometastatic disease if their CD99+/CD45− values were above the upper limit in 22 control patients. In the PCR cohort, RT-PCR on blood or bone marrow samples classified the patients as “positive” or “negative” for EWSR1/FLI1 translocations. The association between micrometastatic disease burden with clinical features and outcome was assessed. Coexpression of insulin-like growth factor-1 receptor (IGF-1R) on detected tumor cells was performed in a subset of flow cytometry samples.Results: The median total bone marrow CD99+CD45− percent was 0.0012% (range 0%–1.10%) in the flow cytometry cohort, with 14 of 109 (12.8%) of Ewing sarcoma patients defined as “positive.” In the PCR cohort, 19.6% (44/225) patients were “positive” for any EWSR1/FLI1 translocation in blood or bone marrow. There were no differences in baseline clinical features or event-free or overall survival between patients classified as “positive” versus “negative” by either method. CD99+CD45− cells had significantly higher IGF-1R expression compared with CD45+ hematopoietic cells (mean geometric mean fluorescence intensity 982.7 vs. 190.9; P < 0.001).Conclusions: The detection of micrometastatic disease at initial diagnosis by flow cytometry or RT-PCR is not associated with outcome in newly diagnosed patients with Ewing sarcoma. Flow cytometry provides a tool to characterize occult micrometastatic tumor cells for proteins of interest. Clin Cancer Res; 22(14); 3643–50. ©2016 AACR.

High dose methotrexate (HDMTX) acute kidney injury (AKI) results in prolonged hospitalization and treatment delays. Using a pharmacologically-based approach, HDMTX was administered with standard combination therapy to patients with osteosarcoma; nephrotoxicity was assessed. Patients were randomized by cycle to 4 h or 12 h HDMTX (12 g/m2) infusions administered with hydration, alkalization and leucovorin rescue. Urinalysis, AKI biomarkers, and estimated glomerular filtration rate using serum creatinine or cystatin C (GFRCr or GFRcysC) were obtained. Serum and urine methotrexate concentrations [MTX] were measured. Patients (n = 12), median (range) age 12.4 (5.7–19.2) years were enrolled; 73 MTX infusions were analyzed. Median (95% Confidence Interval) serum and urine [MTX] were 1309 (1190, 1400) µM and 16.4 (14.7, 19.4) mM at the end of 4 h infusion and 557 (493, 586) µM and 11.1 (9.9, 21.1) mM at the end of 12 h infusion. Time to serum [MTX] 95%. Reducing peak serum and urine MTX concentration by prolonging the infusion duration did not alter risk of acute kidney injury. GFRcysC was decreased at the end of therapy. Proteinuria and elevations in AKI biomarkers indicate that direct tubular damage contributes to HDMTX nephrotoxicity. NCT01848457.

To identify potential clinical prognostic factors associated with a higher risk of local recurrence in localized pelvic Ewing sarcoma (ES) patients treated with radiation therapy.Data for 101 patients treated with definitive radiotherapy (RT) or both surgery and radiation (S+RT) to primary pelvic tumors on INT-0091, INT-0154, and AEWS0031 were analyzed. Imaging data for patients who did not receive radiation were not available for central review, so surgery alone patients were not included. Cumulative incidence rates for local failure at 5-years from time of local control were calculated accounting for competing risks.The most common pelvic subsite was sacrum (44.6%). RT was utilized in 68% of patients and S+RT in 32%. The local failure rate was 25.0% for RT and 6.3% for S+RT (p=0.046). There was no statistically significant difference in local control modality by tumor characteristics. Tumors originating in the ischiopubic-acetabulum region were associated with the highest local failure incidence, 37.5% (p=0.02, vs. sacrum and iliac/buttock tumors), particularly those treated with RT (50.0%, p=0.06). A higher incidence of local failure was seen with each additional 100 mL of tumor at diagnosis (p=0.04). Multivariable analysis demonstrated RT alone (HR 5.1, p=0.04), tumor subsite (particularly ischiopubic-acetabulum tumors, HR 4.6, p=0.02), and increasing volume per 100 mL (HR 1.2, p=0.01) were associated with a higher incidence of local recurrence.Combination surgery and RT is associated with improved local control in patients with pelvic ES compared to definitive RT. Tumors involving the ischiopubic-acetabulum region and increasing tumor volume at diagnosis are associated with inferior local control. Tumor characteristics did not correlate with choice of local therapy modality suggesting an opportunity to develop best local therapy practices guidelines for future studies based on tumor features.

Background The use of radiation therapy to treat metastases in patients with metastatic Ewing sarcoma (MES) has been controversial and variable. The authors report outcomes and patterns of failure after metastatic site irradiation (MSI). Procedure A total of 27 pediatric patients with MES were treated with chemotherapy and received radiation therapy to their primary site. Ten patients additionally received MSI, which consisted of whole-lung irradiation (WLI) in patients with lung metastases. Metastatic sites were followed from diagnosis to the first relapse. Results Median follow-up was 29 months. Seventy-eight percent of patients relapsed. Two-year progression-free survival (PFS) and overall survival with and without MSI were 30 versus 29% (log rank P=0.38) and 60 versus 70% (log rank P=0.11), respectively. The median time to relapse among patients who relapsed was 19.5 versus 12.3 months for those receiving MSI versus those who did not (P=0.04).Seven of 20 (35%) patients with lung metastases received WLI±other MSI. Two-year PFS with and without MSI was 43% versus 23% (log rank P=0.02). Among patients with a complete response to computed tomography, 5 of 14 (36%) patients received MSI. Two-year PFS with and without MSI was 60% versus 33% (log rank P=0.04).In the cohort of patients who relapsed, among all metastatic sites at diagnosis, the disease recurred at 15% of irradiated sites and 31% of unirradiated sites. On logistic regression, no factors were statistically associated with increased risk of recurrence at initial sites of metastases. Conclusions Relapses frequently occur at sites of prior unirradiated disease in patients with MES. WLI may improve 2-year PFS, regardless of chemotherapy response. Further investigation of the role of MSI is warranted.

PURPOSE The primary aim of this phase III randomized trial was to test whether the addition of vincristine, topotecan, and cyclophosphamide (VTC) to interval compressed chemotherapy improved survival outcomes for patients with previously untreated nonmetastatic Ewing sarcoma. METHODS Patients were randomly assigned to receive standard five-drug interval compressed chemotherapy (regimen A) for 17 cycles or experimental therapy with five cycles of VTC within the 17 cycles (regimen B). Patients were stratified by age at diagnosis (< 18 years and ≥18 years) and tumor site (pelvic bone, nonpelvic bone, and extraosseous). Tumor volume at diagnosis was categorized as < 200 mL or ≥ 200 mL. Local control occurred following six cycles. Histologic response was categorized as no viable or any viable tumor. Event-free survival (EFS) and overall survival (OS) were compared between randomized groups with stratified log-rank tests. RESULTS Of 642 enrolled patients, 309 eligible patients received standard and 320 received experimental therapy. The 5-year EFS and OS were 78% and 87%, respectively. There was no difference in survival outcomes between randomized groups (5-year EFS regimen A v regimen B, 78% v 79%; P = .192; 5-year OS 86% v 88%; P = .159). Age and primary site did not affect the risk of an EFS event. However, age ≥ 18 years was associated with an increased risk of death at 5 years (hazard ratio 1.84; 95% CI, 1.15 to 2.96; P = .009). The 5-year EFS rates for patients with pelvic, nonpelvic bone, and extraosseous primary tumors were 75%, 78%, and 85%, respectively. Tumor volume ≥ 200 mL was significantly associated with lower EFS. CONCLUSION While VTC added to five-drug interval compressed chemotherapy did not improve survival, these outcomes represent the best survival estimates to date for patients with previously untreated nonmetastatic Ewing sarcoma.

Background Dexrazoxane protects from lower-cumulative-dose doxorubicin cardiotoxicity, but the effect of dexrazoxane in children with sarcoma treated with higher-cumulative-dose doxorubicin is unknown. Methods We evaluated children with osteosarcoma (OS) on two Children’s Oncology Group trials with higher dose doxorubicin (375–600 mg/m2) preceded by dexrazoxane (10:1 dexrazoxane:doxorubicin dosing). They were evaluated after the minimum expected treatment time (METT), defined as 28 weeks. Cardiotoxicity was identified by echocardiography and serum N-terminal pro-brain natriuretic peptide (NT-proBNP). Second malignant neoplasm (SMN) data was collected. Results All children had normal left ventricular (LV) systolic function as measured by LV fractional shortening and no heart failure. The end-diastolic septal thickness Z-scores (P Z-scores (P Z-scores were significantly smaller for girls (P P = 0.06). Girls had significantly smaller LV end-diastolic dimension Z-scores normalized to BSA (P Conclusions Dexrazoxane prevented LV dysfunction and heart failure in children with OS receiving higher dose doxorubicin. However, LV structural changes were not fully prevented, especially in girls. As a result, hearts become abnormally small for body size, resulting in higher LV stress. Dexrazoxane did not increase the risk of SMN. Dexrazoxane should be used in this population, particularly for girls, to mitigate anthracycline-induced cardiotoxicity. Trial registrations ClinicalTrials.gov: NCT00003937 (P9754) registered 1 Nov 1999, and NCT00023998 (AOST0121) registered 13 Sept 2001.

Purpose Patients with high-risk neuroblastoma (HR-NBL) require radiation to the primary tumor site and sites of persistent metastatic disease. Proton radiation therapy (PRT) may promote organ sparing, but long-term outcomes have not been studied. Methods and Materials Sequential patients with HR-NBL received PRT: 2160 cGy (relative biological effectiveness) to primary tumor bed and persistent metastatic sites, with 3600 cGy (relative biological effectiveness) to gross residual disease. Results From September 2010 through September 2015, 45 patients with HR-NBL received PRT after systemic therapy, primary tumor resection, and high-dose chemotherapy with stem cell rescue. Median age was 46 months at the time of PRT (range, 10 months to 12 years); 23 patients (51%) were male. Primary tumors were adrenal in 40 (89%); 11 (24%) received boost. Ten metastatic sites in 8 patients were radiated. Double scattered proton beams were used for 19 (42%) patients, in combination with x-rays for 2 (5%). The remaining 26 (58%) received pencil beam scanning, available since January 2013. We observed 97% freedom from primary site recurrence at 3, 4, and 5 years. Overall survival rates were 89%, 80%, and 80% and disease-free survival rates were 77%, 70%, and 70%, at 3, 4, and 5 years, respectively. With median follow-up of 48.7 months from diagnosis (range, 11-90 months) for all patients (57.4 months for those alive), 37 (82%) patients are alive, and 32 (71%) are without evidence of disease. One patient experienced locoregional recurrence; the remaining 12 (27%) experienced relapse at distant, nonradiated sites. Acute toxicities during treatment were mainly grade 1. No patient has experienced World Health Organization grade 3 or 4 long-term renal or hepatic toxicity. Pencil beam scanning plans required less planning time and resources than double scattered plans. Conclusions We observe excellent outcomes in patients treated with PRT for HR-NBL from 2010 through 2015, with 82% of patients alive and 97% free of primary site recurrence. No patient has experienced long-term renal or liver toxicity. This treatment maximizes normal tissue preservation and is appropriate for this patient population.

11505 Background: Children’s Oncology Group study AEWS0031 demonstrated superior 5-year event-free survival (EFS) in patients with localized Ewing sarcoma (ES) receiving interval-compressed (IC) chemotherapy (every 2 weeks) compared to standard timing (ST) chemotherapy (every 3 weeks). We assessed the long-term outcome of patients treated on AEWS0031 to determine whether the survival advantage of IC chemotherapy was maintained at 10 years. Methods: AEWS0031 enrolled 568 eligible patients with localized ES. Patients were stratified into four groups by age (

Pediatric histiocytic neoplasms are hematopoietic disorders frequently driven by the BRAF-V600E mutation. Here we identified two BRAF gene fusions (novel MTAP-BRAF and MS4A6A-BRAF) in two aggressive histiocytic neoplasms. In contrast to previously described BRAF fusions, MTAP-BRAF and MS4A6A-BRAF do not respond to the paradox breaker RAF inhibitor (RAFi) PLX8394 due to stable fusion dimerization mediated by the N-terminal fusion partners. This highlights a significant and clinically relevant shift from the current dogma that BRAF-fusions respond similarly to BRAF-inhibitors. As an alternative, we show suppression of fusion-driven oncogenic growth with the pan-RAFi LY3009120 and MEK inhibition.

Pediatric histiocytic neoplasms are hematopoietic disorders frequently driven by the BRAF-V600E mutation. Here, we identified two BRAF gene fusions (novel MTAP-BRAF and MS4A6A-BRAF) in two aggressive histiocytic neoplasms. In contrast to previously described BRAF fusions, MTAP-BRAF and MS4A6A-BRAF do not respond to the paradox breaker RAF inhibitor (RAFi) PLX8394 due to stable fusion dimerization mediated by the N-terminal fusion partners. This highlights a significant and clinically relevant shift from the current dogma that BRAF-fusions respond similarly to BRAF-inhibitors. As an alternative, we show suppression of fusion-driven oncogenic growth with the pan-RAFi LY3009120 and MEK inhibition.

Pediatric histiocytic neoplasms are clonal hematopoietic disorders driven by mutations activating the mitogen-activated protein kinase (MAPK) pathway, such as BRAF-V600E. In non-BRAFV600E cases, we investigated alternative MAPK mutations and found two novel BRAF gene fusions. We investigated the distinct responsiveness of novel BRAF fusions to RAFi therapies and explored the mechanistic basis of such differential responses compared to other BRAF fusions. Two histiocytic patient tumors were analyzed using the CHOP Comprehensive Next-Gen Sequencing Solid Tumor Panel and a targeted RNA-seq panel for 106 fusion partner genes. In the two M- and L-type histiocytic neoplasms assessed, we found novel and rare BRAF gene fusions, MTAP-BRAF and MS4A6A-BRAF, respectively. Both BRAF fusions activated the MAPK/ PI3K pathways and showed homo- and hetero-dimerization with BRAF and the respective N-terminal fusion partner. In contrast to common BRAF fusions, MTAP-BRAF and MS4A6A-BRAF did not respond to PLX8394 due to a lack of disruption of active fusion homo- and hetero-dimers, which was in turn due to the untargeted, stable dimerization mediated by the N-terminal fusion partners. Conversely, we observed robust suppression with LY3009120 that bound fusion dimers and kept them in an inactivate confirmation. MEKi were found to successfully suppress fusion driven signaling and oncogenic phenotypes. Our finding that PLX8394 does not disrupt MTAP-BRAF or MS4A6A-BRAF dimerization due to contribution of N-terminal partners defines a novel paradigm for the distinct mechanisms sought by BRAF fusions in response to RAFi therapy. Overall, this study highlights the unique and differential biology hijacked by BRAF fusions in response to RAFi and further warrants detailed mechanistic classification of BRAF fusions based on their responsiveness to targeted agents.

Kaposiform hemangioendothelioma (KHE) is a rare vascular tumor characterized by aggressive local invasion and a syndrome of platelet trapping known as Kasabach-Merritt phenomenon that, through deposition of platelet derived growth factors, may perpetuate the growth of the tumor. Although many cases of KHE are successfully treated with local control or low-intensity chemotherapy, some cases are often refractory even to aggressive treatment. Herein, we describe a patient with a refractory, recurrent KHE despite multiple attempts at local control and intensive chemotherapy, that ultimately was successfully treated with rationally designed and low-intensity combination therapy of sirolimus and aspirin.

Background Patients with recurrent or refractory osteosarcoma have a poor prognosis with less than 30% surviving two years. Eribulin is a synthetic analog of halichondrin B, has a novel mechanism of action when compared with other microtubule inhibitors, and may have antitumor activity in osteosarcoma. Methods A prospective study was designed to assess the disease control success at four months and objective response rates in patients with recurrent or refractory osteosarcoma treated with eribulin. Eligible patients were between 12 and 50 years of age, had measurable tumor, and met standard organ function requirements. Patients were given eribulin 1.4 mg/m2 /dose on days 1 and 8 of each 3-week cycle for up to 24 months if there was no progressive disease. Response to therapy was assessed using RECIST 1.1 criteria after cycles 2 and 5 and every fourth cycle thereafter. Results Nineteen patients enrolled on the AOST1322 study. The median age of enrollment was 16 years (range, 12-25 years). Twelve patients were male and seven female. Eribulin was well tolerated, with neutropenia identified as the most common toxicity. The median progression-free survival was 38 days and no patients reached the four-month time point without progression. No objective responses were seen in any patient. Conclusion This study rapidly assessed the clinical activity of a novel agent in this patient population. Eribulin was well tolerated, but there were no patients who demonstrated objective response, and all patients had progression prior to four months.

PURPOSE The R2Pulm trial was conducted to evaluate the effect of busulfan-melphalan high-dose chemotherapy with autologous stem-cell rescue (BuMel) without whole-lung irradiation (WLI) on event-free survival (main end point) and overall survival, compared with standard chemotherapy with WLI in Ewing sarcoma (ES) presenting with pulmonary and/or pleural metastases. METHODS From 2000 to 2015, we enrolled patients younger than 50 years of age with newly diagnosed ES and with only pulmonary or pleural metastases. Patients received chemotherapy with six courses of vincristine, ifosfamide, doxorubicin, and etoposide (VIDE) and one course of vincristine, dactinomycin, and ifosfamide (VAI) before either BuMel or seven courses of VAI and WLI (VAI plus WLI) by randomized assignment. The analysis was conducted as intention to treat. The estimates of the hazard ratio (HR), 95% CI, and P value were corrected for the three previous interim analyses by the inverse normal method. RESULTS Of 543 potentially eligible patients, 287 were randomly assigned to VAI plus WLI (n = 143) or BuMel (n = 144). Selected patients requiring radiotherapy to an axial primary site were excluded from randomization to avoid excess organ toxicity from interaction between radiotherapy and busulfan. Median follow-up was 8.1 years. We did not observe any significant difference in survival outcomes between treatment groups. Event-free survival was 50.6% versus 56.6% at 3 years and 43.1% versus 52.9% at 8 years, for VAI plus WLI and BuMel patients, respectively, resulting in an HR of 0.79 (95% CI, 0.56 to 1.10; P = .16). For overall survival, the HR was 1.00 (95% CI, 0.70 to 1.44; P = .99). Four patients died as a result of BuMel-related toxicity, and none died after VAI plus WLI. Significantly more patients in the BuMel arm experienced severe acute toxicities than in the VAI plus WLI arm. CONCLUSION In ES with pulmonary or pleural metastases, there is no clear benefit from BuMel compared with conventional VAI plus WLI.

Purpose: Flow cytometry and RT-PCR can detect occult Ewing sarcoma cells in the blood and bone marrow. These techniques were used to evaluate the prognostic significance of micrometastatic disease in Ewing sarcoma. Experimental Design: Newly diagnosed patients with Ewing sarcoma were enrolled on two prospective multicenter studies. In the flow cytometry cohort, patients were defined as “positive” for bone marrow micrometastatic disease if their CD99+/CD45− values were above the upper limit in 22 control patients. In the PCR cohort, RT-PCR on blood or bone marrow samples classified the patients as “positive” or “negative” for EWSR1/FLI1 translocations. The association between micrometastatic disease burden with clinical features and outcome was assessed. Coexpression of insulin-like growth factor-1 receptor (IGF-1R) on detected tumor cells was performed in a subset of flow cytometry samples. Results: The median total bone marrow CD99+CD45− percent was 0.0012% (range 0%–1.10%) in the flow cytometry cohort, with 14 of 109 (12.8%) of Ewing sarcoma patients defined as “positive.” In the PCR cohort, 19.6% (44/225) patients were “positive” for any EWSR1/FLI1 translocation in blood or bone marrow. There were no differences in baseline clinical features or event-free or overall survival between patients classified as “positive” versus “negative” by either method. CD99+CD45− cells had significantly higher IGF-1R expression compared with CD45+ hematopoietic cells (mean geometric mean fluorescence intensity 982.7 vs. 190.9; P < 0.001). Conclusions: The detection of micrometastatic disease at initial diagnosis by flow cytometry or RT-PCR is not associated with outcome in newly diagnosed patients with Ewing sarcoma. Flow cytometry provides a tool to characterize occult micrometastatic tumor cells for proteins of interest. Clin Cancer Res; 22(14); 3643–50. ©2016 AACR.

Background The prognostic significance of having extraskeletal (EES) versus skeletal Ewing sarcoma (ES) in the setting of modern chemotherapy protocols is unknown. The purpose of this study was to compare the clinical characteristics, biologic features, and outcomes for patients with EES and skeletal ES. Methods Patients had localized ES and were treated on two consecutive protocols using five-drug chemotherapy (INT-0154 and AEWS0031). Patients were analyzed based on having an extraskeletal (n = 213) or skeletal (n = 826) site of tumor origin. Event-free survival (EFS) was estimated using the Kaplan–Meier method, compared using the log-rank test, and modeled using Cox multivariate regression. Results Patients with extraskeletal ES (EES) were more likely to have axial tumors (72% vs. 55%; P 8 cm (9% vs. 17%; P < 0.01), and less likely to be white (81% vs. 87%; P < 0.001) compared to patients with skeletal ES. There was no difference in key genomic features (type of EWSR1 translocation, TP53 mutation, CDKN2A mutation/loss) between groups. After controlling for age, race, and primary site, EES was associated with superior EFS (hazard ratio = 0.69; 95% confidence interval: 0.50–0.95; P = 0.02). Among patients with EES, age ≥18, nonwhite race, and elevated baseline erythrocyte sedimentation rate were independently associated with inferior EFS. Conclusion Clinical characteristics, but not key tumor genomic features, differ between EES and skeletal ES. Extraskeletal origin is a favorable prognostic factor, independent of age, race, and primary site.

BackgroundThe choice of a local control (LC) modality for Ewing sarcoma (EWS) of the femur is controversial. This study aimed to determine the effect of LC modality on tumor LC and patient outcomes.MethodsThe study reviewed the treatment and outcomes for 115 patients who had EWS of the femur treated with similar chemotherapy in three cooperative group trials. Patient outcomes were analyzed according to the LC modality using the log-rank test and the cumulative incidence of local or distant failure using competing risks regression.ResultsThe median age of the patients was 13 years. The most common tumor location was the proximal femur followed by the mid femur. For 55 patients with available data, the tumor was larger than 8 cm in 29 patients and 8 cm or smaller in 26 patients. For 84 patients (73 %), surgery only was performed, whereas 17 patients (15 %) had surgery plus radiation, and 14 patients (12 %) had radiation only. The 5-year event-free survival (EFS) rate was 65 % (95 % confidence interval [CI], 55-73 %), and the 5-year overall survival (OS) rate was 70 % (95 % CI, 61-78 %). Patient outcomes did not differ significantly according to tumor location within the femur (proximal, mid or distal) or tumor size (

Introduction: Pediatric histiocytic neoplasms are clonal hematopoietic disorders driven by mutations activating the mitogen-activated protein kinase (MAPK) pathway, such as BRAF- V600E. In non-BRAFV600E cases, we investigated alternative MAPK mutations and found two novel BRAF gene fusions. We have previously shown effective targeting of BRAF fusions (KIAA1549-BRAF) in pediatric low-grade gliomas (PLGGs) with paradox breaker RAF inhibitor (RAFi), PLX8394 and MEK inhibitors (MEKi). Here, we investigate the distinct responsiveness of novel BRAF fusions to RAFi therapies and explore the mechanistic basis of such differential responses compared to other BRAF fusions. Method: Two histiocytic patient tumors were analyzed using the CHOP Comprehensive Next- Gen Sequencing Solid Tumor Panel and a targeted RNA-seq panel for 106 fusion partner genes. Novel BRAF fusions identified were sub-cloned to create heterologous cell models. Immunoblotting of serum starved cells measured MAPK and PI3K pathway activation and soft agar assay tested for oncogenic phenotypes driven by BRAF fusions, along with response to PLX8394, LY3009120 (pan-RAF dimer inhibitor), and MEKi. Co-immunoprecipitation assays using Myc- and Flag-tagged BRAF fusion constructs assessed dimerization profiles, with or without inhibitors. Result: In the two M- and L-type histiocytic neoplasms assessed, we found novel and rare BRAF gene fusions, MTAP-BRAF and MS4A6A-BRAF, respectively. Both BRAF fusions activated the MAPK/ PI3K pathways and showed homo- and hetero-dimerization with BRAF and the respective N-terminal fusion partner. Compared to common BRAF fusions, MTAP-BRAF and MS4A6A- BRAF did not respond to PLX8394 due to no disruption of active fusion homo- and hetero-dimers, which was in turn was due to the untargeted, stable dimerization mediated by the N-terminal fusion partners. Conversely, we observed robust suppression with LY3009120 that bound fusion dimers and kept them in an inactivate confirmation. MEKi selumetinib and trametinib also suppressed fusion driven signaling and oncogenic phenotypes. Conclusion: We show that novel MTAP-BRAF and MS4A6A-BRAF fusions, found in histiocytic tumors, do not respond to RAFi PLX8394 but are targeted by LY3009120 or MEKi. Our finding that PLX8394 does not disrupt MTAP-BRAF or MS4A6A-BRAF dimerization due to contribution of N-terminal partners defines a novel paradigm for the distinct mechanisms sought by BRAF fusions in response to RAFi therapy. We show potent suppression of these mechanistically distinct BRAF fusions with MEKi or LY3009120 which function independent of vulnerability to fusion dimerization. Overall, this study highlights the unique and differential biology hijacked by BRAF fusions in response to RAFi and further warrants detailed mechanistic classification of BRAF fusions based on their responsiveness to targeted agents. Citation Format: Payal Jain, Lea F. Surrey, Joshua Straka, Pierre Russo, Richard Womer, Marilyn Li, Phillip B. Storm, Angela J. Waanders, Michael Hogarty, Jennifer Picarsic, Adam C. Resnick. Novel BRAF gene fusions in pediatric histiocytic neoplasms respond differentially to RAF targeted therapies based on dimerization profiles [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 632.

11529 Background: Maximum tumor dimension > 8 cm. and large tumor volume have been reported to be adverse prognostic factors in patients with ES but have not been prospectively evaluated in the context of a phase 3 clinical trial with interval compressed chemotherapy. Methods: COG AEWS1031 (NCT01231906) was a randomized phase 3 clinical trial comparing interval compressed chemotherapy regimens in patients with newly diagnosed localized ES of bone and soft tissue. A correlative objective of AEWS1031 was to evaluate tumor size and volume as prognostic factors. Institution-reported dimensions of the primary tumor from baseline imaging were prospectively collected. For inclusion in this analysis, patients had to have at least 1 tumor dimension reported for tumor size analyses and dimensions in 3 axes for tumor volume analyses. Maximum dimension was dichotomized as less than vs. > / = 8cm. Tumor volume was dichotomized as less than vs. > / = 200 mL. Event-free (EFS) and overall survival (OS) from enrollment were calculated using Kaplan-Meier methods and compared between groups using a two-sided log-rank test. Hazard ratios (HR) and confidence intervals (CI) were calculated using the Cox model. Results: The 5-year EFS and OS of the 629 eligible patients was 78% (95% CI: 75-81%) and 87% (95% CI: 84-90%) respectively and there was no significant difference in both EFS and OS between the randomized interval compressed chemotherapy arms of AEWS1031. 590 of 629 (94%) patients were evaluable for maximum tumor dimension and 307 (52%) had tumors > / = 8 cm. Patients with tumors > / = 8 cm were at significantly increased risk for EFS events (p = 0.016) with estimated 5-year EFS of 73.7% (95% CI: 68.1 vs.78.4%) vs. 82.9% (95% CI 77.7-87.1%) for patients with tumors < 8 cm [HR: 1.53 (1.08-2.17)]. For tumor volume, 586 of 629 patients (93%) were evaluable and 180 (31%) had tumors > / = 200 mL. Patients with tumor volume > / = 200 mL were at significantly increased risk for EFS events (p = 0.003) with estimated 5-year EFS of 70% (95% CI: 62.3-76.4%) vs. 81.6% (95% CI: 77.2-85.2%) for patients with tumors < 200 mL [HR: 1.69 (1.2-2.39)]. Conclusions: Maximum tumor dimension and tumor volume as defined are both prognostic in patients with newly diagnosed localized ES treated with interval compressed chemotherapy. Clinical trial information: NCT01231906 .

Background Carboplatin is often adaptively dosed based on glomerular filtration rate (GFR), usually estimated by nuclear medicine tests. At least five pediatric adaptive dosing formulas have been developed. In an effort to standardize dosing in Children's Oncology Group protocols, we explored methodologic variation in GFR estimation and adaptive-dosing formula performance. Procedure Nuclear medicine GFR data from published series of ≥100 children with cancer were compared. Data from patients for whom body surface area, weight, GFR, and tracer half-life were available were used to compare formulas. Results Differences in methods used to estimate GFR in children with cancer resulted in highly variable population results, with median GFRs ranging from 96 to 150 mL/min/1.73m2 . The choice of adaptive formula had a major impact on calculated dose. When targeting an area under the curve of 7.9 mg/mL • min, the median difference between the formula yielding the lowest and highest carboplatin dose for individual subjects was 289 (range 96-1 737) mg/m2 . Conclusions Wide variation in GFR obtained with nuclear-medicine-based tests in children with cancer primarily results from systematic methodologic errors. Formulas for calculating carboplatin dose produce additional and substantial variation that may place children with cancer at unnecessary risk for excessive toxicity or underdosing. These findings indicate a need for the development of a uniform, validated method for GFR determination in children that should be utilized in all centers. Currently, adaptive dosing of carboplatin based on GFR has serious limitations and in most clinical settings should arguably not be used in place of body-surface-area-based dosing.

Introduction: Pelvic sarcomas may present with vague symptoms. The aim of this study was to examine the characteristics and clinical presentations of different types of pelvic sarcoma in children. Methods: This is a retrospective cohort study of patients up to 21 years of age with the diagnosis of pelvic sarcoma between January 2000 and June 2013. Data on demographics, tumor type and location, and clinical presentation were collected from the medical records. Results: A total of 59 patients [37 males (62.7%) and 22 females (37.3%)] were examined in this study. Mean age at presentation was 11.3 ± 5 years (range 0.8–21 years). Thirty-six patients had Ewing sarcoma (61%), 9 osteosarcoma (6.8%), 4 undifferentiated sarcoma (6.8%), 2 (3.4%) rhabdomyosarcoma, 2 synovial cell sarcoma, and one (1.7%) of each fibrosarcoma, dermatofibrosarcoma, fibromyxoid sarcoma, chondrosarcoma, chordoma, and epithelioid sarcoma. Pain at presentation was reported in 41 patients, 13 mass, 8 limping, and 5 neurologic symptoms. Most of the bony tumors were painful (77%), while most of the soft tissue tumors were painless (70%). Nine patients presented with constitutional symptoms. Most patients presented within 4–12 months from symptoms beginning. Twenty-one patients (35.6%) presented with metastases (14 Ewing sarcoma, 6 osteosarcoma, and 1 synovial cell sarcoma). Pelvic radiographs showed lytic lesion in 11 patients, 4 sclerotic lesions, 6 mixed lesion, 6 had only soft tissue mass, 1 radiograph showed osteopenia, and 2 radiographs were reported normal. Conclusion: Ewing sarcoma was the most common pelvic sarcoma tumor in children. In most cases, pelvic sarcoma in children presented with pain mimicking other benign conditions. Some patients presented with metastatic disease with no prognostic clinical or radiographical signs or symptoms. Pelvic sarcoma should be considered a differential diagnosis as part of children work up.

Background The combination of topotecan and cyclophosphamide is active in relapsed Ewing sarcoma family of tumors (ESFT). The feasibility of adding these agents combined with vincristine (vincristine–topotecan–cyclophosphamide [VTc]) to standard five-drug chemotherapy with vincristine–doxorubicin–cyclophosphamide (VDC) and ifosfamide–etoposide (IE) administered in an interval-compressed (2-week instead of 3-week intervals) schedule was investigated. Procedure Newly diagnosed patients with localized ESFT < 31 years, with good performance status and adequate organ function were eligible. Seventeen alternating cycles of chemotherapy with VTc, VDC, and IE were administered at 2-week intervals. Local control (LC) of the primary tumor occurred following six cycles. Primary endpoints were the ability to deliver chemotherapy in an interval-compressed schedule, and the rate of grade 3 or greater nonhematologic toxicity and grade 4 hematologic toxicity, which delayed chemotherapy by ≥2 weeks. Secondary endpoints were event-free survival (EFS) and overall survival (OS). Results Thirty-five patients with a median age of 11 years were enrolled. The mean time to last dose of chemotherapy prior to LC was 12.6 ± 1.4 weeks and 45.5% of patients received intended chemotherapy without any delay prior to LC. There were no toxic deaths or unexpected toxicities. Five-year EFS was 79.6% (95% confidence interval [CI]: 61.8–89.7%) and 5-year OS was 88% (95% CI: 71.4–95.3%). Conclusions The addition of VTc to standard therapy was tolerable with sufficient interval compression compared to historical standard 3-week cycles.

Ewing sarcoma (ES) is an aggressive sarcoma of bone and soft tissue occurring at any age with a peak incidence in adolescents and young adults. The treatment of ES relies on a multidisciplinary approach, coupling risk-adapted intensive neoadjuvant and adjuvant chemotherapies with surgery and/or radiotherapy for control of the primary site and possible metastatic disease. The optimization of ES multimodality therapeutic strategies has resulted from the efforts of several national and international groups in Europe and North America and from cooperation between pediatric and medical oncologists. Successive first-line trials addressed the efficacy of various cyclic combinations of drugs incorporating doxorubicin, vincristine, cyclophosphamide, ifosfamide, etoposide, and dactinomycin and identified prognostic factors now used to tailor therapies. The role of high-dose chemotherapy is still debated. Current 5-year overall survival for patients with localized disease is 65% to 75%. Patients with metastases have a 5-year overall survival

Background Although multiple prognostic variables have been proposed for Ewing sarcoma (EWS), little work has been done to further categorize these variables into prognostic groups for risk classification. Procedure We derived initial prognostic groups from 2,124 patients with EWS in the SEER database. We constructed a multivariable recursive partitioning model of overall survival using the following covariates: age; stage; race/ethnicity; sex; axial primary; pelvic primary; and bone or soft tissue primary. Based on this model, we identified risk groups and estimated 5-year overall survival for each group using Kaplan–Meier methods. We then applied these groups to 1,680 patients enrolled on COG clinical trials. Results A multivariable model identified five prognostic groups with significantly different overall survival: (i) localized, age

Relapse of Ewing sarcoma (ES) can occur months or years after initial remission and salvage therapy for relapsed disease is usually ineffective. Thus, there is great need to develop biomarkers that can predict which patients are at risk for relapse so that therapy and post-therapy evaluation can be adjusted accordingly. For the current study we performed whole genome expression profiling on two independent cohorts of clinically annotated ES tumors in an effort to identify and validate prognostic gene signatures. ES specimens were obtained from the Children's Oncology Group (COG) and whole genome expression profiling performed using Affymetrix Human Exon 1.0 ST arrays. Lists of differentially expressed genes between survivors and non-survivors were used to identify prognostic gene signatures. An independent cohort of tumors from the Euro-Ewing cooperative group was similarly analyzed as a validation cohort. Unsupervised clustering of gene expression data failed to segregate tumors based on outcome. Supervised analysis of survivors vs. non-survivors revealed a small number of differentially expressed genes and several statistically significant gene signatures. Gene specific enrichment analysis (GSEA) demonstrated that integrin and chemokine genes were associated with survival in tumors where stromal contamination was present. Tumors that did not harbor stromal contamination showed no association of any genes or pathways with clinical outcome. Our results reflect the challenges of performing RNA-based assays on archived bone tumor specimens. In addition, they reveal a key role for tumor stroma in determining ES prognosis. Future biologic and clinical investigations should focus on elucidating the contribution of tumor:microenvironment interactions on ES progression and response to therapy. Key words: ES, gene expression profiling, prognostic signature.

Purpose. To associate baseline patient characteristics and relapse across consecutive COG studies.Methods. We analyzed risk factors for LESFT patients in three randomized COG trials. We evaluated age at enrollment, primary site, gender, tumor size, and treatment (as randomized). We estimated event-free survival (EFS, Kaplan-Meier) and compared risk across groups (log-rank test). Characteristics were assessed by proportional hazards regression with the characteristic of interest as the only component. Confidence intervals (CI) for RR were derived. Factors related to outcome at level 0.05 were included in a multivariate regression model.Results. Between 12/1988 and 8/2005, 1444 patients were enrolled and data current to 2001, 2004, or 2008 were used. Patients were with a median age of 12 years (0–45), 55% male and 88% Caucasian. The 5-year EFS was 68.3% ± 1.3%. In univariate analysis age, treatment, and tumor location were identified for inclusion in the multivariate model, and all remained significant (p< 0.01). Since tumor size was not collected in the last study, the other two were reanalyzed. This model identified age, treatment, tumor location, and tumor size as significant predictors.Conclusion. Age > 18 years, pelvic tumor, size > 8 cms, and chemotherapy without ifosfamide/etoposide significantly predict worse outcome. AEWS0031 isNCT00006734, INT0091 and INT0054 designed before 1993 (unregistered).

To identify clinical and treatment variables associated with a higher risk of local failure in Ewing sarcoma patients treated on recent Children's Oncology Group protocols.Data for 956 patients treated with ifosfamide and etoposide-based chemotherapy on INT-0091, INT-0154, and AEWS0031 were analyzed. Local treatment modalities were defined as surgery, definitive radiation therapy (RT), or surgery plus radiation (S+RT). Five-year cumulative incidence of local failure was determined.The local failure rate for the entire cohort was 7.3%, with a 3.9% rate for surgery, 15.3% for RT (P.01), and 6.6% for S+RT (P=.12). The local failure incidence was 5.4% for extremity tumors, 13.2% for pelvis tumors (P.01), 5.3% for axial non-spine tumors (P=.90), 9.1% for extraskeletal tumors (P=.08), and 3.6% for spine tumors (P=.49). The incidence of local failure was 14.8% for extremity tumors and 22.4% for pelvis tumors treated with RT, compared with 3.7% for extremity tumors and 3.9% for pelvis tumors treated with surgery (P≤.01). There was no difference in local failure incidence by local treatment modality for axial non-spine, spine, and extraskeletal tumors. The local failure incidence was 11.9% in patients aged ≥18 years versus 6.7% in patients aged18 years (P=.02). Age ≥18 years (hazard ratio 1.9, P=.04) and treatment with RT (hazard ratio 2.40, P.01) remained independent prognostic factors for higher local failure incidence on multivariate analysis. Tumor size (/≥ 8 cm) was available in 40% of patients and did not correlate with local failure incidence.Local tumor control is excellent and similar between surgery and RT for axial non-spine, spine, and extraskeletal tumors. Age ≥18 years and use of RT, primarily for pelvis and extremity tumors, are associated with the highest risk of local failure. Further efforts should focus on improving outcomes for these patients.

An analysis of dose modifications for infants in 29 Children's Oncology Group protocols across 10 cancer types revealed 11 sets of criteria defining the infant population using age, weight, body surface area (BSA), or a combination of these parameters and eight dose modification methods. A new method of dosing anticancer drugs in infants was developed based on the rationale that prior modifications were implemented to reduce toxicity, which is not cancer-specific. The new method uses BSA dose banding in dosing tables for infants and children with a BSA

Purpose: Pediatric head and neck malignancies are managed with intensive multimodality therapy. Proton beam therapy (PBT) may reduce toxicity by limiting exposure of normal tissue to radiation. In this study, we report acute toxicities and early outcomes following PBT for pediatric head and neck malignancies.Materials and methods: Between 2010 and 2016, pediatric patients with nonhematologic malignancies of the head and neck were treated with PBT. Clinical and dosimetric data were abstracted from the medical record and treatment planning system with institutional review board approval.Results: Sixty-nine consecutive pediatric patients were treated with proton-based radiotherapy for head and neck malignancies. Thirty-five were treated for rhabdomyosarcoma to a median dose of 50.4 Gy relative biological effectiveness [RBE]. Ten patients were treated for Ewing sarcoma to a median dose of 55.8 Gy[RBE]. Twenty-four patients were treated for other histologies to a median dose of 63.0 Gy[RBE]. Grade 3 oral mucositis, anorexia, and dysphagia were reported to be 4, 22, and 7%, respectively. Actuarial 1-year freedom from local recurrence was 92% (95% CI 80–97). Actuarial 1-year overall survival was 93% (95% CI 79–98) in the entire cohort. Oral cavity mucositis was significantly correlated with oral cavity dose (D80 and D50 [P Conclusions: In this study, we report low rates of acute toxicity in a cohort of pediatric patients with head and neck malignancies. PBT appears safe for this patient population, with local control rates similar to historical reports. Longer follow-up will be required to evaluate late toxicity and long-term disease control.

Pelvic sarcoma is uncommon in children and challenging to treat. This study examined different surgical approaches to treat pelvic sarcoma with the aim of assessing the oncologic, and functional outcomes. We retrospectively examined the medical records of patients younger than 21 years of age who underwent surgery for pelvic sarcoma at our institution from 1992 to 2010. The functional status of the patients was examined after a minimum follow-up of two years. Twenty-six patients were included in the analysis. Nineteen (73%) patients were male and seven (27%) were female. Mean age at presentation was 12.0 ± 3.9 years. Nineteen patients had Ewing sarcoma (73%), five had osteosarcoma (19%), one had chondrosarcoma (4%) and one had rhabdomyosarcoma (4%). Iliac wing resection with no reconstruction was done in three patients. Reconstruction with free fibular graft A-frame was performed in four patients, saddle endoproshtesis in five patients, iliac autoclave in one patient, and internal hemipelvectomy in nine patients. Hindquarter amputation was performed in five patients. Median follow-up was 4.6 years (range, 2.6–16 years). Nineteen patients were alive (73%); of those, 13 were known to be without disease, three were with disease and three did not have known tumor status. Six patients were reported deceased, three had osteosarcoma and three had Ewing sarcoma. Function was assessed in 17 patients; 64% were asymptomatic and ambulatory and 36% were symptomatic and ambulatory. Salvage reconstruction for pelvic sarcoma can be performed through various procedures on the extent of necessary bony resection. Survival rate and functional outcomes were promising in the performed study.

Background A growing collection of retrospective studies have suggested that TP53 mutations and/or CDKN2A deletions have prognostic significance in Ewing sarcoma. We sought to evaluate these variables in patients with localized disease treated prospectively on a single Children’s Oncology Group protocol.

Background Patients with Ewing sarcoma require local primary tumor control with surgery, radiation, or both. Optimal choice of local control for overall and local disease control remains unclear.

ObjectiveWe sought to determine how sex and dexrazoxane therapy influence cardiac remodelling in children with sarcoma receiving high-dose doxorubicin.MethodsIn a retrospective cohort of 85 children with sarcoma receiving high-dose doxorubicin, echocardiography measures prior to, early after (within 6 months of doxorubicin completion) and 1 – 2 years after doxorubicin completion were quantified. At each follow-up visit, multivariable, propensity-adjusted linear regression models evaluated dexrazoxane’s effects on changes in left ventricular (LV) shortening fraction (SF), structure, strain and wall stress for subgroups divided by sex. Likelihood ratio tests assessed the interaction between sex and dexrazoxane in determining these changes.ResultsEarly after doxorubicin completion, males not treated with dexrazoxane (n = 15) developed increased cavity size and diminished circumferential strain; females (n = 8) developed diminished SF and strain indices, and increased cavity size and wall stress. With dexrazoxane, males (n = 33) demonstrated less deterioration in circumferential strain by 3.4% (95% CI 0.01 to 6.8), and females (n = 29) demonstrated less reduction in SF by 5.7% (95% CI 2.1 to 9.3), and had mitigation of increases in cavity size and wall stress. In interaction analyses, females had greater protection with dexrazoxane with regard to SF (p = 0.019) and cavity size in diastole (p = 0.002) and systole (p ≤ 0.001). These findings largely persisted 1 – 2 years after doxorubicin therapy.ConclusionsEarly, sustained alterations in LV structure and function occur in children with sarcoma after high-dose doxorubicin, with adverse changes and protective effects of dexrazoxane more pronounced in females as compared with males. Dexrazoxane may have sex-specific cardioprotective effects.

Purpose To simplify the recommended staging evaluation by correlating tumor and clinical features with patterns of distant metastasis in newly diagnosed patients with embryonal rhabdomyosarcoma (ERMS) or alveolar rhabdomyosarcoma (ARMS). Patients and Methods Patient data from the Intergroup Rhabdomyosarcoma Study Group and the Children's Oncology Group over two periods were analyzed: 1991 to 1997 and 1999 to 2004. We used recursive partitioning analyses to identify factors (including histology, age, regional nodal and distant metastatic status, tumor size, local invasiveness, and primary site) that divided patients into subsets with the most different rates of metastatic disease. Results Of the 1,687 patients analyzed, 5.7% had lung metastases, 4.8% had bone involvement, and 6% had bone marrow (BM) involvement. Rhabdomyosarcoma (RMS) without local invasion (T1) had a low rate of metastasis for all distant sites, especially ERMS (0% bone, 0% BM). ARMS with local invasion (T2) had a higher rate of metastasis for all distant sites (13% lung, 18% bone, 23% BM). ERMS, T2 also had a higher rate of metastatic lung involvement (9%). The likelihood of bone or BM involvement increased in the presence of lung metastases (41% with, 6% without). Regional nodal metastases (N1) predicted a high rate of metastasis in all distant sites (14% lung, 14% bone, 18% BM). A staging algorithm was developed. Conclusion Staging studies in childhood RMS can be tailored to patients' presenting characteristics. Bone marrow aspirate and biopsy and bone scan are unnecessary in at least one third of patients with RMS.

Background To determine feasibility and safety of proactive enteral tube feeding (ETF) in pediatric oncology patients. Methods Pediatric patients with newly diagnosed brain tumors, myeloid leukemia or high-risk solid tumors were eligible. Subjects agreeing to start ETF before cycle 2 chemotherapy were considered proactive participants (PPs). Those who declined could enroll as chart collection receiving nutritional standard of care. Nutritional status was assessed using standard anthropometric measurements. Episodes of infection and toxicity related to ETF were documented from diagnosis to end of therapy. A descriptive comparison between PPs and controls was conducted. Results One hundred four eligible patients were identified; 69 enrolled (20 PPs and 49 controls). At diagnosis, 17% of all subjects were underweight and 26% overweight. Barriers to enrollment included physician, subject and/or family refusal, and inability to initiate ETF prior to cycle 2 of chemotherapy. Toxicity of ETF was minimal, but higher percentage of subjects in the proactive group had episodes of infection than controls. Thirty-nine percent of controls eventually started ETF and were twice as likely to receive parenteral nutrition. PPs experienced less weight loss at ETF initiation than controls receiving ETF and were the only group to demonstrate improved nutritional status at end of study. Conclusions Proactive ETF is feasible in children with cancer and results in improved nutritional status at end of therapy. Episodes of infection in this study are concerning; therefore, a larger randomized trial is required to further delineate infectious risks and toxicities that may be mitigated by improved nutritional status. Pediatr Blood Cancer 2014;61:281–285. © 2013 Wiley Periodicals, Inc.

BACKGROUND Proton therapy for treatment for high-risk neuroblastoma may offer sparing of organs at risk (OAR) when compared to intensity-modulated X-ray therapy (IMXT). PROCEDURE Double-scattered proton plans and IMXT plans delivering 2,160 cGy to the primary tumor site and other residual disease were developed for 13 consecutive HR-NBL patients. Radiation doses to target volumes and OAR were calculated to determine the optimal modality for each. RESULTS All patients received radiation (5/13 ≥ 2 sites). No patient has experienced local recurrence or clinical organ toxicity. Coverage was excellent using both protons and IMXT: median % dose delivered to 95% clinical target volume was 99% and 100%, respectively. For nine patients with lateralized disease, proton therapy offered sparing of the contralateral kidney both with regard to median dose and dose to 20% (median

Purpose Chemotherapy with alternating vincristine-doxorubicin-cyclophosphamide and ifosfamide-etoposide cycles and primary tumor treatment with surgery and/or radiation therapy constitute the usual approach to localized Ewing sarcoma in North America. We tested whether chemotherapy intensification through interval compression could improve outcome. Patients and Methods This was a prospective, randomized controlled trial for patients younger than 50 years old with newly diagnosed localized extradural Ewing sarcoma. Patients assigned to standard and intensified treatment were to begin chemotherapy cycles every 21 and 14 days, respectively, provided an absolute neutrophil count greater than 750 × 106/L and a platelet count greater than 75 × 109/L. Patients received vincristine (2 mg/m2), doxorubicin (75 mg/m2), and cyclophosphamide (1.2 g/m2) alternating with ifosfamide (9 g/m2) and etoposide (500 mg/m2) for 14 cycles, with filgrastim (5 mg/kg per day; maximum, 300 mg) between cycles. Primary tumor treatment (surgery, radiation, or both) was to begin at week 13 (after four cycles in the standard arm and six cycles in the intensified arm). The primary end point was event-free survival (EFS). The study is registered at ClinicalTrials.gov (identifier: NCT00006734). Results Five hundred eighty-seven patients were enrolled and randomly assigned, and 568 patients were eligible, with 284 patients in each regimen. For all cycles, the median cycle interval for standard treatment was 21 days (mean, 22.45 days); for intensified treatment, the median interval was 15 days (mean, 17.29 days). EFS at a median of 5 years was 65% in the standard arm and 73% in the intensified arm (P = .048). The toxicity of the regimens was similar. Conclusion For localized Ewing sarcoma, chemotherapy administered every 2 weeks is more effective than chemotherapy administered every 3 weeks, with no increase in toxicity.

Purpose Ewing sarcoma family tumors (ESFTs) exhibit chromosomal translocations that lead to the creation of chimeric fusion oncogenes. Combinatorial diversity among chromosomal breakpoints produces varying fusions. The type 1 EWS-FLI1 transcript is created as a result of fusion between exons 7 of EWS and 6 of FLI1, and retrospective studies have reported that type 1 tumors are associated with an improved outcome. We have re-examined this association in a prospective cohort of patients with ESFT treated according to current Children's Oncology Group (COG) treatment protocols. Methods Frozen tumor tissue was prospectively obtained from patients diagnosed with ESFT, and reverse transcriptase polymerase chain reaction (RT-PCR) was used to determine translocation status. Analysis was confined to patients with localized tumors who were diagnosed after 1994 and treated according to COG protocols. Translocation status was correlated with disease characteristics, event-free survival (EFS), and overall survival (OS). Results RT-PCR identified chimeric fusion oncogenes in 119 of 132 ESFTs. Eighty-nine percent of identified transcripts were EWS-FLI1, and of these, 58.8% were type 1. Five-year EFS and OS rates for patients with type 1 and non–type 1 fusions diagnosed between 2001 and 2005 were equivalent (type 1: EFS, 63% ± 7%; OS, 83% ± 6%; non–type 1: EFS, 71% ± 9%; OS, 79% ± 8%). Conclusion Current intensive treatment protocols for localized ESFT have erased the clinical disadvantage that was formerly observed in patients with non–type 1 EWS-FLI1 fusions.

Summary Progress in the treatment of Ewing's sarcoma, the second most common bone tumour in children and adolescents, has improved survival from about 10% in the period before chemotherapy was introduced to about 75% today for patients with localised tumours. However, patients with metastases still fare badly, and the therapy carries short-term and long-term toxicities. Multidisciplinary care is indispensable for these patients. Molecular techniques and new imaging modalities are affecting the diagnosis and classification of patients with Ewing's sarcoma. Cooperative group studies have led to chemotherapy regimens using the same drugs (vincristine, doxorubicin, cyclophosphamide, ifosfamide, and etoposide), although the exact regimens differ in Europe and North America. The EWS–ETS family of gene fusions and their downstream effects in Ewing's sarcomas provide opportunities for new approaches to treatment. These include the inhibition of the fusion gene or its protein product, and pathways related to IGF1 and mTOR. Inhibition of tyrosine kinases, exploitation of non-apoptotic cell death, and interference with angiogenesis are promising new approaches. With many new approaches and relatively few patients, it will be challenging to integrate new and established treatments through clinical trials.

Objective To review the current management of pediatric genitourinary rhabdomyosarcoma (RMS). Methods Studies performed by the Intergroup Rhabdomyosarcoma Study Group, Children's Oncology Group (COG), International Society of Paediatric Oncology (SIOP) and others over the past 10 years were reviewed to compare the use of surgery, chemotherapy, and radiotherapy for treatment of RMS and their associated outcomes. Results Equivalent overall survival rates were reported in the last COG and SIOP trials, with worse event-free survival rates for bladder/prostate RMS in SIOP trials. The use of radiotherapy for local control was the main difference between current COG and SIOP protocols. Surgery is used to diagnose RMS, and for local control after chemotherapy. Chemotherapy is used for systemic control of RMS, but metastatic RMS will require new approaches. Conclusion Risk stratification and risk-based therapy are being studied to decrease morbidity from treatment of RMS. The proper role of surgery vs radiotherapy for local control and whether additional treatment with second-line chemotherapy outweighs the avoidance of radiotherapy remain to be defined.

In the field of sarcoma molecular diagnosis, the "test" most frequently requested is for the gene fusions generated by the chromosomal translocations in Ewing family tumors (EFTs). Of note, this test is perhaps the most complicated of all of the molecular assays in the sarcoma diagnostic toolbox. Starting with the frequent 11;22 translocation involving the EWS gene on chromosome 22 and the FLI1 gene on chromosome 11, the chromosome breakpoints are spread among four introns in the EWS gene and six introns in the FLI1 gene to give a large number of possible EWS-FLI1 fusion products.1 The size of the fusion transcripts can vary over a 700-bp range, thereby necessitating cautious investigation of a large range of product sizes in diagnostic reverse transcription-polymerase chain reaction (RT-PCR) assays. To increase the complexity further, a relatively frequent variant 21;22 chromosomal translocation generates a fusion of EWS to ERG, which encodes an ETS domain-containing transcription factor highly related to FLI1 with a comparable distribution of chromosomal breakpoints.1 Next, as described in the article by Wang and associates in this issue of The Journal of Molecular Diagnostics,2 the complexity continues to rise as there are three additional translocations [t(2;22), t(7;22), and t(17;22)] that juxtapose EWS to genes, encoding three additional members of the ETS transcription factor family (FEV, ETV1, and E1AF, respectively) in small numbers of EFT cases. In addition to these rare variant fusions, there is also a second set of rare variants involving the FUS gene, which encodes an RNA-binding protein highly related to EWS. This second set includes a 16;21 translocation in which FUS is juxtaposed to ERG,3 which was found in a small group of cases and, as described by Ng and colleagues4 also in this issue of the JMD, a FUS-FEV fusion resulting from a novel 2;16 translocation found in a single case. Based on these collective findings, a definitive investigation of the gene fusions associated with EFT is, to put it simply, a daunting task.

Morphologically, the distinction between undifferentiated embryonal sarcoma of the liver (UESL) and biliary tract rhabdomyosarcoma (RMS) can be uncertain because of some shared pathologic similarities. Patients with UESL have been consistently but erroneously enrolled in Children's Oncology Group (COG) treatment protocols because UESL was equated with RMS, despite the differing primary treatment modalities of these entities. Review of COG pathology files yielded 20 cases of UESL that were compared to 25 cases of biliary tract RMS. Clinicopathologic features including immunohistochemical staining were examined. In the UESL cases, the male:female ratio was 1:1 and the median age was 10.5 years. Histologically, hyaline globules and diffuse anaplasia were consistently present. The cases of RMS had a male:female ratio of 1.8:1 with a median age of 3.4 years and routinely lacked diffuse anaplasia and hyaline globules. Polyclonal desmin and muscle-specific actin were variably immunoreactive in UESL and RMS; however, myogenin and myogenic regulatory protein D1 (MyoD1) were uniformly negative in UESL and routinely positive in the majority of biliary tract RMS. Myogenin, in particular, was highly significant ( P = 0.0003) in distinguishing RMS from UESL. With a median follow-up of 8 months, 11 of 18 patients with UESL were still alive. The estimated 5-year survival for biliary tract RMS was 66%. Establishing the correct diagnosis of these distinct clinical and pathologic entities is important, as surgery alone may be curative in UESL, whereas initial chemotherapy is often recommended for the treatment of biliary tract RMS.

Relapse of Ewing sarcoma (ES) can occur months or years after initial remission, and salvage therapy for relapsed disease is usually ineffective. Thus, there is great need to develop biomarkers that can predict which patients are at risk for relapse so that therapy and post‐therapy evaluation can be adjusted accordingly. For this study, we performed whole genome expression profiling on two independent cohorts of clinically annotated ES tumours in an effort to identify and validate prognostic gene signatures. ES specimens were obtained from the Children's Oncology Group and whole genome expression profiling performed using Affymetrix Human Exon 1.0 ST arrays. Lists of differentially expressed genes between survivors and non‐survivors were used to identify prognostic gene signatures. An independent cohort of tumours from the Euro‐Ewing cooperative group was similarly analysed as a validation cohort. Unsupervised clustering of gene expression data failed to segregate tumours based on outcome. Supervised analysis of survivors versus non‐survivors revealed a small number of differentially expressed genes and several statistically significant gene signatures. Gene‐specific enrichment analysis demonstrated that integrin and chemokine genes were associated with survival in tumours where stromal contamination was present. Tumours that did not harbour stromal contamination showed no association of any genes or pathways with clinical outcome. Our results reflect the challenges of performing RNA‐based assays on archived bone tumour specimens. In addition, they reveal a key role for tumour stroma in determining ES prognosis. Future biological and clinical investigations should focus on elucidating the contribution of tumour:micro‐environment interactions on ES progression and response to therapy.