{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,26]],"date-time":"2026-08-26T16:17:54Z","timestamp":1787761074730,"version":"build-2784847793"},"reference-count":22,"publisher":"Wiley","issue":"9","license":[{"start":{"date-parts":[[2026,7,21]],"date-time":"2026-07-21T00:00:00Z","timestamp":1784592000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"},{"start":{"date-parts":[[2026,7,21]],"date-time":"2026-07-21T00:00:00Z","timestamp":1784592000000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Pediatric Blood &amp; Cancer"],"published-print":{"date-parts":[[2026,9]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Purpose<\/jats:title>\n                    <jats:p>We studied histologic Ewing sarcoma (ES) tumor response at local control surgery to explore associations between histologic response and chemotherapy practice changes over time and confirm its prognostic significance in the modern era.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>We reviewed clinical data for 126 patients with ES treated at Mayo Clinic from 1977 to 2022, analyzing the percentage necrosis as a prognostic factor across chemotherapy regimens (including modern interval\u2010compressed VDC\u2010IE).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      In the historical cohort, 5\u2010year event\u2010free survival (EFS) and overall survival (OS) for patients with \u22645% versus greater than 5% viable tumor were 76% versus 59% (\n                      <jats:italic>p<\/jats:italic>\n                      = 0.01) and 83% versus 62% (\n                      <jats:italic>p<\/jats:italic>\n                      = 0.01). Review of 104 specimens by two pathologists identified the percentage remaining viable tumor as more reproducible than the percentage necrosis and\/or fibrosis. On multivariable analysis of patients with localized disease (\n                      <jats:italic>n<\/jats:italic>\n                      = 87), pelvic tumors and greater than 5% viable tumor remained independent risk factors for poor survival (EFS: hazard ratio [HR] 3.1,\n                      <jats:italic>p<\/jats:italic>\n                      &lt; 0.01; OS: HR 2.1,\n                      <jats:italic>p<\/jats:italic>\n                      = 0.048). The modern cohort consisted of 22 patients. No patients with tumor size less than 8\u00a0cm at diagnosis and 100% necrosis after surgery had events; four of seven with tumors greater than 8\u00a0cm had events despite 100% necrosis.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Our results validate the historical threshold of greater than 5% viable tumor with older chemotherapy regimens but not with modern interval\u2010compressed VDC\u2010IE. In addition, inter\u2010rater reliability for the percentage viable is more reproducible than the percentage necrosis. Although numbers are small, tumors less than 8\u00a0cm with no viable tumor appear to be a favorable subgroup and suggest risk stratification using a combination of tumor size and any viable tumor should be evaluated in ES.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1002\/1545-5017.70420","type":"journal-article","created":{"date-parts":[[2026,7,21]],"date-time":"2026-07-21T10:48:09Z","timestamp":1784630889000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Prognostic Value of Tumor Response in Pediatric and Adult Patients With Ewing Sarcoma"],"prefix":"10.1002","volume":"73","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6142-6310","authenticated-orcid":false,"given":"Roman O.","family":"Kowalchuk","sequence":"first","affiliation":[{"name":"Department of Radiation Oncology Mayo Clinic  Rochester Minnesota USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Melanie A.","family":"Chihak","sequence":"additional","affiliation":[{"name":"Division of Pediatric Hematology\/Oncology Children's Minneapolis  Minneapolis Minnesota USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Michael G.","family":"Keeney","sequence":"additional","affiliation":[{"name":"Department of Laboratory Medicine and Pathology, Mayo Clinic  Rochester Minnesota USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Karen J.","family":"Fritchie","sequence":"additional","affiliation":[{"name":"Department of Laboratory Medicine and Pathology, Mayo Clinic  Rochester Minnesota USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"William S.","family":"Harmsen","sequence":"additional","affiliation":[{"name":"Department of Health Sciences Research Mayo Clinic  Rochester Minnesota USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Taylor M.","family":"Weiskittel","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology Mayo Clinic  Rochester Minnesota USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Katie N.","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology Mayo Clinic  Rochester Minnesota USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8747-692X","authenticated-orcid":false,"given":"Meng","family":"Xu\u2010Welliver","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology Mayo Clinic  Rochester Minnesota USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Michael G.","family":"Haddock","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology Mayo Clinic  Rochester Minnesota USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5656-9568","authenticated-orcid":false,"given":"Wendy A.","family":"Allen\u2010Rhoades","sequence":"additional","affiliation":[{"name":"Division of Pediatric Hematology\/Oncology Department of Pediatrics, Mayo Clinic  Rochester Minnesota USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Peter J.","family":"Schoettler","sequence":"additional","affiliation":[{"name":"Division of Pediatric Hematology\/Oncology Department of Pediatrics, Mayo Clinic  Rochester Minnesota USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Carola A.","family":"Arndt","sequence":"additional","affiliation":[{"name":"Division of Pediatric Hematology\/Oncology Department of Pediatrics, Mayo Clinic  Rochester Minnesota USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kathryn J.","family":"Ruddy","sequence":"additional","affiliation":[{"name":"Division of Medical Oncology Mayo Clinic  Rochester Minnesota USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Peter S.","family":"Rose","sequence":"additional","affiliation":[{"name":"Department of Orthopedic Surgery Mayo Clinic  Rochester Minnesota USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Safia K.","family":"Ahmed","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology Mayo Clinic  Rochester Minnesota USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nadia N.","family":"Laack","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology Mayo Clinic  Rochester Minnesota 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