Predictors of Recurrence and Patterns of Initial Failure in Localized Ewing Sarcoma: A Contemporary 20-Year Experience

Consensus recommendations regarding local and metastasis-directed therapies in the management of relapsed/recurrent Ewing sarcoma

Limited randomized or prospective data are available to guide local/metastasis directed therapy (LMDT) in relapsed/recurrent Ewing sarcoma (RR-ES), resulting in uncertainty regarding best clinical practice for these patients. This report reviews the available literature on LMDT approaches and provides consensus recommendations regarding therapeutic decision making, timing, and indications for the use of LMDT in the management of RR-ES. LMDT should be considered on a case-by-case basis to assess appropriateness, optimal timing/modality, palliative versus curative intent, and its role in relation to chemotherapy. One commonly used LMDT is radiotherapy (RT), which can be delivered through standard, hypofractionated, or stereotactic techniques based on factors including prior RT, tumor size, and/or location. Chemotherapy can be combined with RT, although prospective data are limited in the relapse setting. Surgery for LMDT not only addresses the tumor but also provides tissue for analysis, though the potential surgical morbidity based on location, extent of resection, and recovery complications should be considered. Interventional radiology approaches also can procure tumor tissue while delivering LMDT; there are several different procedures available based on the location, size, and extent of disease. Finally, a combination of LMDT approaches can be used for patients with RR-ES. Decisions regarding the management of RR-ES should involve a multidisciplinary team and factor in the burden of disease, progression-free interval, life expectancy, toxicity profiles of LMDT, and quality of life. In such patients, informed and shared decision making with patients and their families is paramount.

Inhibition Of One-Carbon Metabolism In Ewing Sarcoma Results In Profound And Prolonged Growth Suppression Associated With Purine Depletion

Ewing sarcoma (EWS) is the second most common primary bone malignancy in adolescents and young adults. Patients who present with localized disease have experienced a steadily improving survival rate over the years, whereas those who present with metastatic disease have the same dismal prognosis as 30 years ago, with long term survival rates less than 20%, despite maximal intensification of chemotherapy. Thus, novel treatment approaches are a significant unmet clinical need. Targeting metabolic differences between EWS and normal cells offers a promising approach to improve outcomes for these patients. One-carbon metabolism utilizes serine and folate to generate glycine and tetrahydrofolate (THF)-bound one-carbon units required for de novo nucleotide biosynthesis. Elevated expression of several one-carbon metabolism genes is significantly associated with reduced survival in EWS patients. We show that both genetic and pharmacological inhibition of a key enzyme of the mitochondrial arm of the one-carbon metabolic pathway, serine hydroxymethyltransferase 2 (SHMT2), leads to substantial inhibition of EWS cell proliferation and colony-forming ability, and that this effect is primarily caused by depletion of glycine and one-carbon units required for synthesis of purine nucleotides. Inhibition of one-carbon metabolism at a different node, using the clinically relevant dihydrofolate reductase inhibitor Pralatrexate, similarly yields a profound growth inhibition, with depletion of thymidylate and purine nucleotides. Genetic depletion of SHMT2 dramatically impairs tumor growth in a xenograft model of EWS. Together, these data establish the upregulation of the one-carbon metabolism as a novel and targetable vulnerability of EWS cells, which can be exploited for therapy.

Statement of Significance

Using both genetic and pharmacologic approaches, this study identifies Ewing sarcoma's dependence on the mitochondrial arm, but not the cytoplasmic arm, of one-carbon metabolism as a targetable vulnerability that can be effectively harnessed for therapy.

Open-Label, Multicenter, Phase I/II, First-in-Human Trial of TK216: A First-Generation EWS::FLI1 Fusion Protein Antagonist in Ewing Sarcoma

PURPOSE

Ewing Sarcoma (ES), a rare cancer with a pathognomonic translocation resulting in the Ewing sarcoma gene (EWS)::FLI1 oncoprotein, has a poor prognosis in the relapsed/refractory (R/R) setting. Tokalas (TK)216 was designed to bind EWS::FLI1 proteins directly, disrupt protein-protein interactions, and inhibit transcription factor function. TK216 plus vincristine showed synergistic activity in preclinical tumor models. To our knowledge, we report the results of a first-in-class, first-in-human phase I/II trial of TK216 in R/R ES.

PATIENTS AND METHODS

TK216 was administered intravenously as a continuous infusion to patients with R/R ES in 11 cohorts. The dosing duration of 7 days was later extended to 10, 14, and 28 days. Vincristine could be added on day 1 after cycle 2, per investigators' choice. The trial used a 3 + 3 design with an expansion cohort at the recommended phase II dose (RP2D).

RESULTS

A total of 85 patients with a median age of 27 years (range, 11-77) were enrolled. The maximum tolerated dose for the 14-day infusion of TK216, 200 mg/m2 once daily, was determined in cohort 9 and selected as the RP2D. The median previous number of systemic therapies regimens was three (range, 1-10). The most frequent-related adverse events in patients treated at the RP2D included neutropenia (44.7%), anemia (29.4%), leukopenia (29.4%), febrile neutropenia (15.3%), thrombocytopenia (11.8%), and infections (17.6%). In cohorts 9 and 10, two patients had a complete response, one had a partial response, and 14 had stable disease; the 6-month progression-free survival was 11.9%. There were no responses among the eight patients in cohort 11.

CONCLUSION

TK216 administered as 14-day continuous infusion with or without vincristine was well tolerated and showed limited activity at the RP2D in R/R ES.

Orthopedic approaches for bone sarcoma: A bibliometric review of the 50 most cited papers

Background

Curative treatment of bone sarcoma is primarily based on operative management. The Orthopedic Oncology approach towards this disease has evolved greatly to the breakthrough in systemic treatment options as well as unique implant designs favoring limb salvage over amputations. The purpose of this study was to perform a bibliometric analysis of the top 50 most cited papers related to the orthopedic the approach to bone sarcomas.

Methods

We queried the ISI Web of Knowledge database in July 2022. Keywords utilized were: ""Bone Sarcoma" OR "Osteosarcoma" OR "Ewing Sarcoma" OR "Chondrosarcoma" OR "Chordoma". The top 50 articles pertaining to the orthopedic approach to bone sarcoma were included for analysis and included manuscript title, authors, citation count, journal and publication year.

Results

The mean number of citations are 187.06 (Range 125-400; SD 67.83). The average citations per year is 10.03 (Range 47.86-3.43; SD 8.05). Many articles were published from 2000 to 2009 (n = 20) and 1990-1999 (n = 13). The majority of the articles were published by institutions within the United States (n = 32). The most common level of evidence was level IV (n = 37). Majority of the articles focused on treatment outcome (n = 22).

Conclusion

This study offers a comprehensive review of the most cited literature regarding orthopedic approaches to bony sarcomas. Modern treatment approaches for bone sarcoma has resulted in an increased focus within the literature on achieving disease free survival wide tissue margins. Understanding the trends of available studies allows for physicians and researchers to target and innovate future areas of study.

Impact of locus of care on outcomes in adolescents and young adults with osteosarcoma and Ewing sarcoma treated at pediatric versus adult cancer centers: An IMPACT cohort study

BACKGROUND

Location of cancer care (LOC; pediatric vs. adult center) impacts outcomes in adolescents and young adults (AYA) with some cancer types. Data on the impact of LOC on survival in AYA with osteosarcoma (OSS) and Ewing sarcoma (EWS) are limited OBJECTIVES: To compare differences in demographics, disease/treatment characteristics, and survival in a population-based cohort of AYA with OSS or EWS treated at pediatric versus adult centers METHODS: The Initiative to Maximize Progress in Adolescent Cancer Therapy (IMPACT) cohort captured demographic, disease, and treatment data for all AYA (15-21 years old) diagnosed with OSS and EWS in Ontario, Canada between 1992 and 2012. Patients were linked to provincial administrative health care databases. Outcomes were compared between patients treated in pediatric versus adult centers.

RESULTS

One hundred thirty-seven AYA were diagnosed with OSS (LOC: 47 pediatric, 90 adult) and 84 with EWS (38 pediatric, 46 adult). AYA treated at pediatric centers were more likely to be enrolled in a clinical trial (OSS 55% vs. 1%, p < .001; EWS 53% vs. 2%, p < .001) and received higher cumulative chemotherapy doses. Five-year event-free survival (EFS ± standard error) in OSS and EWS were 47% ± 4% and 43% ± 5%, respectively. In multivariable analysis, the impact of LOC (pediatric vs. adult center) on EFS in OSS (adjusted hazard ratio [HR] 1.15, 95% confidence interval [CI]: 0.58-2.27, p = .69) and EWS (adjusted HR 1.82, 95% CI: 0.97-3.43, p = .06) was not statistically significant.

CONCLUSION

Despite disparities in trial participation and chemotherapy doses, outcomes did not differ by LOC suggesting that AYA with bone tumors can be treated at either pediatric or adult centers.

Age as a Prognostic Factor in Patients with Ewing Sarcoma-The Polish Sarcoma Group Experience

Ewing sarcoma (ES) is a rare and aggressive disease that requires multidisciplinary treatment with the use of chemotherapy, radiotherapy, and surgery. Our retrospective study aimed to analyze the prognostic factors and treatment results in different age groups of patients. Between 1998 and 2018, 569 patients with ES were treated in two referral centers. The patients were divided into four age groups (≤10 years; 11–18 years; 19–25, and >25). The treatment results and prognostic factors were assessed for each group. For statistical analyses, we used the Chi2 test, the Kaplan–Meier estimator with a log-rank test, and the multivariate Cox model. Five-year overall survival (OS) rate was 56%. In the age subgroups: ≤10 years, 11–18 years, 19–25 years, and >25 years, the 5-year OS rates were 75%, 58%, 41%, and 52%, respectively. Favorable prognostic factors: female gender (p = 0.024), non-axial localization (p = 0.005), VIDE regimen (p < 0.001), and surgery as a local treatment (p < 0.001) dominated in the group ≤10 years. In multivariate analysis, male (HR = 1.53), axial localization (HR = 1.46), M1 status at presentation (HR = 2.64), and age > 10 years (HR = 2.29) were associated with shorter OS. The treatment results in ES are significantly better in children aged ≤10 years; the challenge is to provide therapy for adolescents and young adults. The diagnostics and treatment of ES patients must be provided in referral centers.