Survival In Ewing Sarcoma Research Articles

One Hundred Percent Tumor Necrosis is Associated with Survival in Ewing Sarcoma

Background and Objectives:Ewing sarcoma is a primary malignancy affecting both bone and soft tissue. Following preoperative chemotherapy and surgical resection, histologic response (tumor necrosis) is correlated with patient survival. The most prognostic cutoff for tumor necrosis continues to be debated. The objective of this study was to explore several cutoffs and determine their prognostic value in a contemporary cohort of Ewing sarcoma patients.
 Methods:The National Cancer Database was used to identify 564 patients with osseous and soft tissue tumors in the Ewing sarcoma family from 2010 to 2015. All patients had documented preoperative chemotherapy, surgical resection, and vital status. Survival was stratified by tumor necrosis using Kaplan Meier analysis. 356 patients with osseous tumors were included in multivariate logistic and cox regression analyses to identify predictors of histologic response and survival, respectively.
 Results:In a combined soft tissue and osseous tumor cohort, there was a significant difference (p = 0.01, log-rank test) in overall survival between patients with 100% necrosis and patients with less than 100% necrosis. This was observed over the 5-year study period. Other cutoffs were not statistically different. In patients with osseous tumors, less than 100% necrosis was negatively associated with survival (HR 3.48 [95% CI 1.19-10.13]; p< 0.05), with only skip metastasis having a stronger negative association (HR 4.31 [95% CI 1.22-15.29]; p< 0.05). Male sex (OR 0.50 [95% CI 0.28-0.90]; p<0.05), tumors located in the axial skeleton (OR 0.30 [95% CI 0.12- 0.77]; p<0.05), and positive surgical margins (OR 0.28 [95% CI 0.08-0.95]; p<0.05) were negatively associated with 100% necrosis.
 Conclusion and Implications:A cutoff of 100% tumor necrosis was associated with improved survival in Ewing sarcoma. This association was strong relative to other commonly used prognostic factors in osseous cases and is a valuable tool to counsel patients and guide future clinical trials.

Abstract PR002: Identification of metabolic adaptation mechanisms that drive anoikis suppression and metastasis in Ewing sarcoma

Abstract Metastasizing cancer cells must overcome anoikis (detachment-induced death) prior to colonization in distant organs. Ewing sarcoma (EwS) is a highly aggressive bone and soft tissue cancer that mainly occurs in children, adolescents, and young adults. EwS patients with metastatic disease have a 5-year survival rate of only 15-20%, which has not changed for decades. Our recent study identified that EwS cells are highly dependent on augmented cysteine metabolism and glutathione biogenesis in anoikis suppression and metastasis through the IL1RAP protein. Mechanistically, IL1RAP binds the cell surface system Xc- transporter to enhance exogenous cystine uptake, thereby replenishing cysteine and glutathione antioxidant pools. Moreover, under cystine depletion, IL1RAP induces cystathionine gamma lyase (CTH) to activate the transsulfuration pathway for de novo cysteine synthesis. Furthermore, we show that inhibitors of Glutaminase (GLS) and Glutamate cysteine ligase (GCL), two critical enzymes for glutamate and glutathione synthesis, synergistically induce massive anoikis and ferroptosis in EwS cells. However, as a single agent, GLSi or GCLi only had moderate effects on EwS survival. Our global proteomic analysis identified dramatic adaptive changes in response to GLSi and GCLi, which may facilitate EwS cell survival and metastasis upon blockade of these metabolic processes. To further pinpoint critical regulators of anoikis and metastasis, we found that anokis suppression is governed by EWS-FLI1, a driver oncogene in EwS, and depletion of EWS-FLI1 triggered anoikis and led to cell death of EwS tumor spheroids formed in 3D cultures, whereas only a mild cytostatic effect was induced in 2D cultures. Given the predominant role of oncogenic EWS-FLI1 in anoikis suppression, we performed proteomic analysis in EwS cells +/- EWS-FLI1 depletion or gene rescue cultured under either 2D or 3D conditions prior to anoikis onset. We found that the 2D-to-3D transition induced marked global proteomic changes, suggesting a molecular reprogramming in response to 3D-induced anoikis stress that might be crucial for anoikis suppression. Moreover, a significant subset of these adaptive proteomic changes was driven by EWS-FLI1. Among these proteins, we validated that CDH11 is highly expressed in EwS compared with >1000 other human cancer cell lines, and localized on the EwS cell surface, which might be targeted via immunotherapeutic strategies. Thus, these studies provide insights into adaptive mechanisms upon perturbation of glutathione metabolism and oncogenes that drive anoikis suppression and metastasis in EwS. Citation Format: Hai-Feng Zhang, Christopher S. Hughes, Alberto Delaidelli, Yue Zhou Huang, Taras Shyp, Xiaqiu Yang, Poul H. Sorensen. Identification of metabolic adaptation mechanisms that drive anoikis suppression and metastasis in Ewing sarcoma [abstract]. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr PR002.

3D vs. 2D MRI radiomics in skeletal Ewing sarcoma: Feature reproducibility and preliminary machine learning analysis on neoadjuvant chemotherapy response prediction.

The extent of response to neoadjuvant chemotherapy predicts survival in Ewing sarcoma. This study focuses on MRI radiomics of skeletal Ewing sarcoma and aims to investigate feature reproducibility and machine learning prediction of response to neoadjuvant chemotherapy. This retrospective study included thirty patients with biopsy-proven skeletal Ewing sarcoma, who were treated with neoadjuvant chemotherapy before surgery at two tertiary sarcoma centres. 7 patients were poor responders and 23 were good responders based on pathological assessment of the surgical specimen. On pre-treatment T1-weighted and T2-weighted MRI, 2D and 3D tumour segmentations were manually performed. Features were extracted from original and wavelet-transformed images. Feature reproducibility was assessed through small geometrical transformations of the regions of interest mimicking multiple manual delineations, and intraclass correlation coefficient >0.75 defined feature reproducibility. Feature selection also consisted of collinearity and significance analysis. After class balancing in the training cohort, three machine learning classifiers were trained and tested on unseen data using hold-out cross-validation. 1303 (77%) 3D and 620 (65%) 2D radiomic features were reproducible. 4 3D and 4 2D features passed feature selection. Logistic regression built upon 3D features achieved the best performance with 85% accuracy (AUC=0.9) in predicting response to neoadjuvant chemotherapy. Compared to 2D approach, 3D MRI radiomics of Ewing sarcoma had superior reproducibility and higher accuracy in predicting response to neoadjuvant chemotherapy, particularly when using logistic regression classifier.

Surgical subtypes and survival in Ewing sarcoma: A National Cancer Database (NCDB) analysis.

e23511 Background: Ewing sarcoma (EWS) is the one of the most common primary malignancies of bone, more commonly affecting the pediatric population Standard of care for EWS currently involves surgical intervention in combination with chemotherapy, in addition to the potential use of preoperative and/or postoperative radiation on a case by case basis. To date, there is not much in the literature reported regarding different surgical subtypes in these patients. Thus, this study aims to analyze survival outcomes amongst the different surgical subtypes in EWS patients. Methods: Using the NCDB, patients diagnosed with EWS between 2004-2018 were identified using ICD-O-3 histology code 9260. The cohort was analyzed to determine if they received any surgical intervention and, if so, which surgical subtype was used. Univariate analysis was then performed assessing patient length of survival for each surgical subtype. Data was analyzed using SPSS and statistical significance was set at α = 0.05. Results: A total of 2208 patients were included that had survival data and had received surgical intervention. The mean survival time of all patients was 118.1 months. Surgical patients survived an average of 137.2 months while nonsurgical patients survived 96.0 months on average (p < .00001). Analysis of surgical subtypes revealed significantly longer survival in patients who underwent radical excision with limb salvage compared to patients who underwent partial resection (p < .05). Patients who received a partial limb amputation survived significantly longer than patients who received a total limb amputation (p < .01). Patients who underwent local tumor excision or radial excision with limb salvage also survived significantly longer than patients with total limb amputation (p < .05 and p < .01, respectively). Conclusions: This study found that receipt of surgery is associated with longer survival in Ewing sarcoma patients. Further, different surgical interventions may influence survival in Ewing sarcoma as patients receiving radical excision with limb salvage fared better than partial resection and partial limb amputation better than total limb amputation. Future studies would benefit from investigating additional variables that may influence receipt of surgical interventions including patient demographics, socioeconomic status, and surgical center type.[Table: see text]

Primary site and survival in ewing sarcoma: A National Cancer Database (NCDB) analysis.

e23510 Background: Ewing sarcoma is the one of the most common primary malignancies of bone, with an incidence of about 1 case per million in the United States. Ewing sarcoma typically affects the pelvis, axial skeleton, and femur. However, this cancer can affect other bony regions and, to the author’s knowledge, all possible primary sites have not been investigated in-depth in regards to tumor location and the effect it may have on outcomes. The aim of this study is to conduct such an investigation to see whether or not the primary site of the tumor in osteosarcoma patients may have an effect on survival. Methods: Using the NCDB, patients diagnosed with Ewing sarcoma between 2004-2018 were identified using ICD-O-3 histology code 9260. The cohort was analyzed to investigate survival outcomes in different primary sites. Univariate analysis was then performed assessing patient length of survival for each primary site subtype. Data was analyzed using SPSS and statistical significance was set at α = 0.05. Results: A total of 4284 patients with known primary site that had survival data were included. The sites with the best survival were the skull, face, and mandible and upper limb. Patients with primary tumor of the skull, face, and mandible survived significantly longer than all groups other than the upper limb (all p < .01). Upper limb patients survived significantly longer than all groups other than the skull, face, and mandible and lower limb (all p < .05). The labeled primary site with the lowest survival was the pelvis, sacrum, and coccyx and significantly lower than the lower limb, vertebral column, and ribs, sternum, and clavicle (all p < .01). Survival of patients with primary site of the upper limb versus lower limb, and vertebral column versus ribs, sternum, and clavicle did not differ (each p > .05). Conclusions: This study found numerous survival differences between patients diagnosed with Ewing sarcoma of different primary sites. Labeled primary sites of the skull, face, and mandible and upper limb were associated with best survival while the pelvis, sacrum, and coccyx were associated with worst survival. Future studies may benefit from investigations into variables that may impact the survival differences we have presented including staging, treatments, time from diagnosis to treatment, and insurance status.[Table: see text]

What Do We Know about Survival in Skeletally Premature Children Aged 0 to 10 Years with Ewing Sarcoma? A Multicenter 10-Year Follow-Up Study in 60 Patients.

Simple SummaryYounger age has been associated with better overall survival in Ewing sarcoma, especially under the age of 10. Our study aimed at describing long-term outcomes of a cohort of 60 patients aged 0–10 with Ewing sarcoma, treated with chemotherapy, surgery and/or radiotherapy. Overall survival of these youngest patients with ES was very good. After 10 years, 81% of patients were still alive, 89% did not have a local recurrence and 81% did not have distant metastasis (in lungs and/or bone). Limb salvage surgery was achieved in >90% of patients. Wide resection margin was the only factor significantly associated with better survival, but age < 6 years, smaller tumors, no metastases at diagnosis and treatment after 2000 also seemed to result in better overall survival.(1) Background: Younger age has been associated with better overall survival (OS) in Ewing sarcoma (ES), especially under the age of 10. The favorable survival in younger patients underlines the need for minimizing treatment burden and late sequelae. Our study aimed at describing clinical characteristics, treatment and outcome of a cohort of ES patients aged 0–10. (2) Methods: In this retrospective multicenter study, all consecutive ES patients aged 0–10, treated in four sarcoma centers in the Netherlands (n = 33) and one in Spain (n = 27) between 1982 and 2008, with a minimum follow-up of 10 years, were included. OS, local recurrence-free survival (LRFS) and distant metastasis-free survival (DMFS) were calculated. Potential factors of influence on OS (risk and protective factors) were analyzed. (3) Results: 60 patients with median follow-up 13.03 years were included. All patients were treated with chemotherapy in combination with local treatment, being surgery alone in 30 (50%) patients, radiotherapy (RT) alone in 12 (20%) patients or surgery plus RT in 18 (30%) patients (12 pre- and 6 postoperative). Limb salvage was achieved in 93% of patients. The 10-OS, -LRFS and -DMFS are 81% (95% CI: 71–91%), 89% (95% CI: 85–93%) and 81% (95% CI: 71–91%), respectively. Six patients developed LR, of which two developed subsequent DM; all had axial ES (pelvis, spine or chest wall), and these patients all died. Ten patients developed DM; eight died due to progressive disease, and two are currently in remission, both with pulmonary metastasis only. Negative or wide resection margin was significantly associated with better OS. Age < 6 years, tumor volume < 200 mL, absence of metastatic disease and treatment after 2000 showed trends towards better OS. Two patients developed secondary malignancy; both had chemotherapy combined with definitive RT for local treatment. (4) Conclusions: Overall survival of these youngest patients with ES was very good. Limb salvage surgery was achieved in >90% of patients. Wide resection margin was the only factor significantly associated with better survival.

Ewing sarcoma of the pelvis: Clinical features and overall survival,

IntroductionPrimary Ewing Sarcoma of Bone is a malignancy whose treatment requires both systemic chemotherapy and local control through surgical resection and/or radiation. Ewing Sarcoma of the pelvis has been noted to confer a worse prognosis relative to other anatomic sites of Ewing Sarcoma. This study explores the presenting features, treatment modalities for local control, and overall survival of primary Ewing sarcoma of the pelvis in comparison to other commonly affected anatomic sites. MethodsThe National Cancer Institute Surveillance, Epidemiology, and End-Results (SEER) database was used to identify cases of pelvic Ewing sarcoma diagnosed between years 2004 and 2015. Demographic variables including sex, race, and age at diagnosis were described for each case, as well as therapeutic modalities including surgery and radiation. Bone-specific Collaborative Staging variables, including tumor size, tumor extension, and metastasis at diagnosis, were described for the same cohort. Univariate and multivariate assessments were performed for statistical comparison between presenting factors, treatment modalities, and between anatomic locations of presentation. ResultsWithin the database, 296 patients with Ewing sarcoma of the pelvic bones were available for review, which represented 25.7% of the 1152 cases surveyed across all anatomic sites. In the subset of patients with Ewing Sarcoma of the pelvis, 63.5% were male; the median age of diagnosis was 17 years; extra-compartmental tumor extension was noted in 82.1%; average tumor size was 9.7 cm; and metastasis at diagnosis was noted in 46.1% of the cohort. Only 28.6% of the pelvis sarcoma patients received surgical resection as part or all of their local control treatment, while 67.6% received some form of radiation therapy. When compared to the presenting features of Ewing Sarcoma from other anatomic sites, patients with pelvic tumors had larger tumors at time of diagnosis, higher rates of metastatic disease, and were less likely to undergo surgical intervention. The 2-, 5-, and 10-year overall survival rates for the patients presenting with Ewing Sarcoma of the pelvis was 70.3%, 49.7%, and 41.9%, respectively, which were significantly lower across all time-points than any other anatomic site. Discussion and ConclusionEwing Sarcoma of the pelvis is an aggressive malignancy that presents with relatively large tumors and a high rate of metastatic dissemination. Surgical intervention is less frequent when Ewing Sarcoma presents in the pelvis than when it presents in other anatomic locations. These factors may contribute to the worse overall survival of Ewing Sarcoma when compared to the same diagnosis originating in other anatomic sites. Prospective, randomized study is required to determine the true causal effects of these factors on survival.

TRIM8 modulates the EWS/FLI oncoprotein to promote survival in Ewing sarcoma.

SummaryFusion-transcription factors (fusion-TFs) represent a class of driver oncoproteins that are difficult to therapeutically target. Recently, protein degradation has emerged as a strategy to target these challenging oncoproteins. The mechanisms that regulate fusion-TF stability, however, are generally unknown. Using CRISPR-Cas9 screening, we discovered tripartite motif-containing 8 (TRIM8) as an E3 ubiquitin ligase that ubiquitinates and degrades EWS/FLI, a driver fusion-TF in Ewing sarcoma. Moreover, we identified TRIM8 as a selective dependency in Ewing sarcoma compared with >700 other cancer cell lines. Mechanistically, TRIM8 knockout led to an increase in EWS/FLI protein levels that was not tolerated. EWS/FLI acts as a neomorphic substrate for TRIM8, defining the selective nature of the dependency. Our results demonstrate that fusion-TF protein stability is tightly regulated and highlight fusion oncoprotein-specific regulators as selective therapeutic targets. This study provides a tractable strategy to therapeutically exploit oncogene overdose in Ewing sarcoma and potentially other fusion-TF-driven cancers.

PO-1426 Role of 22q12 translocation as a predictor of metastasis and decreased survival in Ewing sarcoma

PO-1426 Role of 22q12 translocation as a predictor of metastasis and decreased survival in Ewing sarcoma

Using machine learning techniques predicts prognosis of patients with Ewing sarcoma.

Ewing sarcoma is one of the most common types of malignant bone tumor in children and adolescents. However, to our limited knowledge, no study exists that uses machine learning to create algorithms for the prediction of survivorship for Ewing sarcoma. About 2332 patients with Ewing sarcoma between 1975 and 2016 in the United States were identified from Surveillance, Epidemiology, and End Results (SEER) program. All patients in the data set were randomly assigned into the training set and the testing set, at a 2:8 ratio. In the training set, boosted decision tree, support vector machine, nonparametric random forest method, and neural network models were developed to predict the 5-year survivorship. The overall survival rate in 5-year follow-up of this patient cohort is 60.72%. With respect to the algorithms for both cancer specific survival and overall survival, there was slight superiority in our performance metrics favoring the random forest method over the other models for survival prediction, with 77/83% sensitivity and 91/94% specificity, respectively. The random forest method was incorporated into a freely available web-based application. This application can be accessed through https://zryan.shinyapps.io/EwingSarcoma/. Clinical Significance: To the best of our knowledge, this is the first available predictive model for predicting survival in Ewing sarcoma based on machine-learning algorithms. This study may provide orthopedic surgeons with an easily accessible prediction tool when dealing with patients suffering from Ewing sarcoma.

Indeterminate pulmonary nodules are not associated with worse overall survival in Ewing Sarcoma

AimLung metastases are a negative prognostic factor in Ewing sarcoma, however, the incidence and significance of sub-centimetre pulmonary nodules at diagnosis is unclear. The aims of this study were to (1): determine the incidence of indeterminate pulmonary nodules (IPNs) in patients diagnosed with Ewing sarcoma (2); establish the impact of IPNs on overall and metastasis-free survival and (3) identify patient, oncological and radiological factors that correlate with poorer prognosis in patients that present with IPNs on their staging chest CT. Materials & methodsBetween 2008 and 2016, 173 patients with a first presentation of Ewing sarcoma of bone were retrospectively identified from an institutional database. Staging and follow-up chest CTs for all patients with IPN were reviewed by a senior radiologist. Clinical and radiologic course were examined to determine overall- and metastasis-free survival for IPN patients and to identify demographic, oncological or nodule-specific features that predict which IPN represent true lung metastases. ResultsFollowing radiologic re-review, IPN were found in 8.7% of patients. Overall survival for IPN patients was comparable to those with a normal staging chest CT (2-year overall survival of 73.3% [95% CI 43.6–89] and 89.4% [95% CI 81.6–94], respectively; p = 0.34) and was significantly better than for patients with clear metastases (46.0% [95% CI 31.9–59]; p < 0.0001). Similarly, there was no difference in metastasis-free survival between ‘No Metastases’ and ‘IPN’ patients (p = 0.16). Lung metastases developed in 40% of IPN patients at a median 9.6 months. Reduction of nodule size on neoadjuvant chemotherapy was associated with worse overall survival in IPN patients (p = 0.0084). ConclusionIPN are not uncommon in patients diagnosed with Ewing sarcoma. In this study, we were unable to detect a difference in overall- or metastasis-free survival between patients with IPN at diagnosis and patients with normal staging chest CTs.

Abstract 6594: Targeting Ewing sarcoma and osteosarcoma with anti-MCAM chimeric antigen receptor modified NK cells

Abstract Ewing sarcoma and osteosarcoma are the two most common pediatric malignant bone tumors. Patients who present with metastatic disease or relapse have a dismal average 5-year survival of only 20%. Novel therapeutic approaches are desperately needed. The melanoma cell adhesion molecule (MCAM/CD146/MUC18) is highly expressed in sarcoma and metastatic pediatric tumors. MCAM depletion inhibits Ewing sarcoma cell migration in vitro and tumor metastasis in vivo. High MCAM levels in patient tumors are associated with poor survival in Ewing sarcoma. MCAM therefore constitutes a unique and novel target for immunotherapy against MCAM+ sarcomas. We previously demonstrated that natural killer (NK) cell engineered to express chimeric antigen receptor (CAR) against CD20 significantly reduced tumor burden, prevented tumor dissemination, and extended survival of treated mice compared to mock NK treatment in humanized Burkitt lymphoma xenograft mouse model. We hypothesize that anti-MCAM CAR NK cell will enhance the inherent NK-sarcoma cytotoxicity by better targeting sarcoma cells. Here we develop an anti-MCAM CAR NK cell and investigate its efficacy in promoting NK cell cytotoxicity against Ewing sarcoma and osteosarcoma. MCAM expression in sarcoma cell lines and tumor samples were validated by flow cytometry and western blotting. Peripheral blood mononuclear cells (PBMCs) are expanded into NK cells ex vivo using K562-mbIL21-41BBL artificial antigen presenting cells (aAPC). Anti-MCAM CAR NK cells are generated by non-viral electroporation of anti-MCAM CAR mRNA into expanded NK cells. Anti-MCAM CAR NK cytotoxicity is evaluated in vitro by luciferase based cytotoxicity assay. We detected various levels of MCAM expression in Ewing sarcoma and osteosarcoma cell lines and tumors. In addition, we noticed an interesting patchy expression pattern of MCAM in the Ewing sarcoma tumor sample. Importantly, we found a significantly increased cytotoxicity of anti-MCAM CAR NK cells compared to mock NK cells (59.9±10 vs 13.3±3.7 at E:T ratio of 5:1, p=0.006; and 65.6±7 vs 13.7±3.4 at 10:1, p=0.004) against Ewing sarcoma TC71 cells after co-culturing for 4 hours. A similar result was observed at the time point of 48 hours (91.5±8 vs 59±0.5 at E:T of 5:1, p=0.018). Anti-MCAM CAR NK cells also showed significantly enhanced cytotoxicity against U2OS osteosarcoma cells compared to mock NK cells (32.6±23.2 vs 0.5±19.5 at E:T of 0.5:1, p=0.004; 47.1±27.4 vs 10.2±24 at E:T of 1:1, p=0.001) at the time point of 48 hours. In summary, these findings demonstrated enhanced efficacy of anti-MCAM CAR NK cells compared to mock NK cells against Ewing sarcoma and osteosarcoma cells and support a further preclinical investigation whether targeting MCAM by CAR NK will limit sarcoma growth and/or metastasis and increase survival in vivo. Citation Format: Aliza Gardenswartz, Wen Luo, Jeremy M. Rosenblum, Janet Ayello, Mitchell S. Cairo. Targeting Ewing sarcoma and osteosarcoma with anti-MCAM chimeric antigen receptor modified NK cells [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 6594.

Timing of Local Therapy Affects Survival in Ewing Sarcoma

Timing of Local Therapy Affects Survival in Ewing Sarcoma

A nomogram for determining the disease-specific survival in Ewing sarcoma: a population study

BackgroundWe aimed to develop and validate a nomogram for predicting the disease-specific survival of Ewing sarcoma (ES) patients.MethodsThe Surveillance, Epidemiology, and End Results (SEER) program database was used to identify ES from 1990 to 2015, in which the data was extracted from 18 registries in the US. Multivariate analysis performed using Cox proportional hazards regression models was performed on the training set to identify independent prognostic factors and construct a nomogram for the prediction of the 3-, 5-, and 10-year survival rates of patients with ES. The predictive values were compared by using concordance indexes (C-indexes), calibration plots, integrated discrimination improvement (IDI), net reclassification improvement (NRI), and decision curve analysis (DCA).ResultsA total of 2,643 patients were identified. After multivariate Cox regression, a nomogram was established based on a new model containing the predictive variables of age, race, extent of disease, tumor size, and therapy of surgery. The new model provided better C-indexes (0.684 and 0.704 in the training and validation cohorts, respectively) than the model without therapy of surgery (0.661 and 0.668 in the training and validation cohorts, respectively). The good discrimination and calibration of the nomogram were demonstrated for both the training and validation cohorts. NRI and IDI were also improved. Finally, DCA demonstrated that the nomogram was clinically useful.ConclusionWe developed a reliable nomogram for determining the prognosis and treatment outcomes of patients with ES in the US. However, the proposed nomogram still requires external data verification in future applications, especially for regions outside the US.

The Ewing Family of Tumors Relies on BCL-2 and BCL-XL to Escape PARP Inhibitor Toxicity.

It was recently demonstrated that the EWSR1-FLI1 t(11;22)(q24;12) translocation contributes to the hypersensitivity of Ewing sarcoma to PARP inhibitors, prompting clinical evaluation of olaparib in a cohort of heavily pretreated Ewing sarcoma tumors. Unfortunately, olaparib activity was disappointing, suggesting an underappreciated resistance mechanism to PARP inhibition in patients with Ewing sarcoma. We sought to elucidate the resistance factors to PARP inhibitor therapy in Ewing sarcoma and identify a rational drug combination capable of rescuing PARP inhibitor activity. We employed a pair of cell lines derived from the same patient with Ewing sarcoma prior to and following chemotherapy, a panel of Ewing sarcoma cell lines, and several patient-derived xenograft (PDX) and cell line xenograft models. We found olaparib sensitivity was diminished following chemotherapy. The matched cell line pair revealed increased expression of the antiapoptotic protein BCL-2 in the chemotherapy-resistant cells, conferring apoptotic resistance to olaparib. Resistance to olaparib was maintained in this chemotherapy-resistant model in vivo, whereas the addition of the BCL-2/XL inhibitor navitoclax led to tumor growth inhibition. In 2 PDXs, olaparib and navitoclax were minimally effective as monotherapy, yet induced dramatic tumor growth inhibition when dosed in combination. We found that EWS-FLI1 increases BCL-2 expression; however, inhibition of BCL-2 alone by venetoclax is insufficient to sensitize Ewing sarcoma cells to olaparib, revealing a dual necessity for BCL-2 and BCL-XL in Ewing sarcoma survival. These data reveal BCL-2 and BCL-XL act together to drive olaparib resistance in Ewing sarcoma and reveal a novel, rational combination therapy that may be put forward for clinical trial testing.

Timing of Local Therapy Affects Survival in Ewing Sarcoma

We aimed to investigate the relationship between survival and time to local therapy after initiation of up-front chemotherapy in the treatment of patients with localized Ewing sarcoma. The National Cancer Database was queried for patients with localized Ewing sarcoma treated with primary chemotherapy and subsequent local therapy. Kaplan-Meier survival curves were generated for patients initiating local therapy 6 to 15weeks and ≥16weeks after chemotherapy initiation. Multivariable binomial logistic regression was used to identify factors associated with prolonged time to local therapy. A multivariable Cox proportional hazards model was used to identify factors associated with overall survival (OS). The final cohort included 1318 patients. A higher proportion of patients initiating local therapy 6 to 15weeks after chemotherapy initiation versus ≥16weeks after chemotherapy initiation were ≤21years old (79.5% vs 72.0%; P=.004). Age >21years (P<.001; hazard ratio, 1.65; 95% confidence interval, 1.28-2.12), tumor size >8cm(P=.016), and time to local therapy ≥16weeks (P=.005; hazard ratio, 1.41; 95% confidence interval, 1.11-1.80) were associated with reduced OS; after review of margin status, negative margins were associated with improved OS compared with gross disease (P=.029). Patients initiating local therapy at 6 to 15weeks versus ≥16weeks had a 5-year OS of 78.7% versus 70.4% and a 10-year OS of 70.3% versus 57.1%, respectively (P<.001). The difference in OS according to time to local therapy was particularly more important in patients receiving radiation therapy alone. Age >21years and treatment by radiation therapy alone were associated with delayed time (>16weeks) to local therapy, whereas private insurance and income >$48,000 were less likely to be associated with delayed local therapy. Delayed time to local therapy ≥16weeks after chemotherapy initiation was independently associated with worse survival in patients with localized Ewing sarcoma.

EWS-FLI1 regulates a transcriptional program in cooperation with Foxq1 in mouse Ewing sarcoma.

EWS‐FLI1 constitutes an oncogenic transcription factor that plays key roles in Ewing sarcoma development and maintenance. We have recently succeeded in generating an ex vivo mouse model for Ewing sarcoma by introducing EWS‐FLI1 into embryonic osteochondrogenic progenitors. The model well recapitulates the biological characteristics, small round cell morphology, and gene expression profiles of human Ewing sarcoma. Here, we clarified the global DNA binding properties of EWS‐FLI1 in mouse Ewing sarcoma. GGAA microsatellites were found to serve as binding sites of EWS‐FLI1 albeit with less frequency than that in human Ewing sarcoma; moreover, genomic distribution was not conserved between human and mouse. Nevertheless, EWS‐FLI1 binding sites within GGAA microsatellites were frequently associated with the histone H3K27Ac enhancer mark, suggesting that EWS‐FLI1 could affect global gene expression by binding its target sites. In particular, the Fox transcription factor binding motif was frequently observed within EWS‐FLI1 peaks and Foxq1 was identified as the cooperative partner that interacts with the EWS portion of EWS‐FLI1. Trib1 and Nrg1 were demonstrated as target genes that are co‐regulated by EWS‐FLI1 and Foxq1, and are important for cell proliferation and survival of Ewing sarcoma. Collectively, our findings present novel aspects of EWS‐FLI1 function as well as the importance of GGAA microsatellites.

18F-FDG PET/CT as an Indicator of Survival in Ewing Sarcoma of Bone.

Objective: The existing literature of 18 F-FDG PET/CT in Ewing sarcoma investigates mixed populations of patients with both soft tissue and bone primary tumors. The aim of our study was to evaluate whether the maximum standardized uptake value (SUVmax) obtained with 18F-FDG PET/CT before and after induction chemotherapy can be used as an indicator of survival in patients with Ewing sarcoma originating exclusively in the skeleton.Materials and Methods: A retrospective database search from 2004-2011 identified 28 patients who underwent 18 F-FDG PET/CT before (SUV1, n= 28) and after (SUV2, n=23) induction chemotherapy. Mean follow up was 3.3 years and median follow up for survivors was 6.3 years (range: 2.6-9.8 years). Multivariate and univariate Cox proportional hazard model was used to assess for correlation of SUV1, SUV2, and the change in SUVmax with overall survival (OS) and progression-free survival (PFS).Results: Mean SUVmax was 10.74 before (SUV1) and after 4.11 (SUV2) induction chemotherapy. High SUV1 (HR = 1.05, 95% CI: 1.0-1.1, P = 0.01) and SUV2 (HR =1.2, 95% CI: 1.0-1.4, P = 0.01) were associated with worse OS. A cut off point of 11.6 was identified for SUV1. SUV1 higher than 11.6 had significantly worse OS (HR = 5.71, 95% CI: 1.85 - 17.61, P = 0.003) and PFS (HR = 3.16, 95% CI: 1.13 - 8.79, P = 0.03, P < 0.05 is significant).Conclusion: 18F-FDG PET/CT can be used as a prognostic indicator for survival in primary Ewing sarcoma of bone.

What's New in Primary Bone Tumors.

This Update provides a review of work published in the area of primary musculoskeletal tumors between May 2015 and June 2016. The studies are largely Level III and IV, in part due to the rarity and varied nature of such tumors. The articles were identified by searching PubMed and reviewing prominent journals. Margins and local recurrence were the focus of several osteosarcoma studies. Bertrand et al. reviewed 51 high-grade extremity sarcomas with localized disease at presentation and found that a positive margin compared with a negative margin of >1 mm was the only factor that independently predicted local recurrence1. They confirmed that patients with a positive surgical margin had an increased risk of death from disease compared with those with negative margins. In another study, no local recurrences were noted among 11 patients followed for a minimum of 37 months who had undergone joint-sparing surgery for proximal tibial osteosarcoma that invaded the physis2. The proximal edge of the tumors was treated with intraoperative microwave ablation prior to tumor resection. The proximal osteotomies were planned at the edge of the tumor, but there were no positive margins. As Ewing sarcoma survival has improved, the factors influencing long-term outcomes have become more important. Stish et al. analyzed scores of the Toronto Extremity Salvage Score (TESS) and Pediatric Quality of Life Inventory (PedsQL) for 74 patients at an average duration of follow-up of 17.8 years3. They found that TESS results were better for those diagnosed at <18 years of age and that PedsQL scores were better for male patients than for female patients. Pelvic tumors were associated with decreased functional outcomes but not lower quality-of-life scores compared with tumors from other sites. The authors were not able to measure an effect of local therapy modality. Survival among …

In silico and in vitro drug screening identifies new therapeutic approaches for Ewing sarcoma

The long-term overall survival of Ewing sarcoma (EWS) patients remains poor; less than 30% of patients with metastatic or recurrent disease survive despite aggressive combinations of chemotherapy, radiation and surgery. To identify new therapeutic options, we employed a multi-pronged approach using in silico predictions of drug activity via an integrated bioinformatics approach in parallel with an in vitro screen of FDA-approved drugs. Twenty-seven drugs and forty-six drugs were identified, respectively, to have anti-proliferative effects for EWS, including several classes of drugs in both screening approaches. Among these drugs, 30 were extensively validated as mono-therapeutic agents and 9 in 14 various combinations in vitro. Two drugs, auranofin, a thioredoxin reductase inhibitor, and ganetespib, an HSP90 inhibitor, were predicted to have anti-cancer activities in silico and were confirmed active across a panel of genetically diverse EWS cells. When given in combination, the survival rate in vivo was superior compared to auranofin or ganetespib alone. Importantly, extensive formulations, dose tolerance, and pharmacokinetics studies demonstrated that auranofin requires alternative delivery routes to achieve therapeutically effective levels of the gold compound. These combined screening approaches provide a rapid means to identify new treatment options for patients with a rare and often-fatal disease.