{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T11:10:01Z","timestamp":1790334601820,"version":"4.1.0"},"reference-count":33,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T00:00:00Z","timestamp":1790294400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Cancers"],"abstract":"<jats:p>Background: Retroperitoneal sarcomas (RPS) are rare malignancies that pose challenges due to their large size and proximity to organs-at-risk (OARs). Compared to conventional 5-week radiation therapy (RT), hypofractionated RT (HFRT) offers a shorter alternative with potential biologic benefit, and simultaneous integrated boost (SIB) can increase delivered dose. We evaluated the dosimetric feasibility of HFRT with a central tumor SIB for bulky RPS. Methods: Fifteen patients with RPS previously treated with preoperative conventionally fractionated RT were replanned using HFRT with a central SIB. Volumetric modulated arc therapy (VMAT) plans were created to deliver 42.75 Gy in 15 fractions to the planning target volume (PTV), 45 Gy to the internal gross tumor volume (iGTV), and 52.5 Gy to the SIB volume (1 cm contraction of iGTV). OAR planning objectives were prioritized during optimization. Dosimetric plan-generation feasibility was defined as generation of a treatment plan meeting prespecified target-coverage criteria; compliance with each OAR objective was assessed separately. Results: Mean tumor size was 18.3 cm (range 5.8\u201328.2 cm), with mean volumes for iGTV, SIB, and PTV of 1633.8 cc, 926.9 cc, and 3323.2 cc, respectively. All plans met the prespecified target coverage criteria for iGTV, SIB, and PTV. Ten of 15 plans met all target-coverage criteria and all prespecified OAR objectives; five met the target coverage criteria and non-bowel OAR objectives but exceeded at least one bowel objective by &lt;1% of the specified constraint. All non-bowel OAR objectives were met except that the bilateral kidney objective was exceeded in 4 of 11 evaluable patients. The average homogeneity index for the iGTV and SIB were 0.21 (range 0.18\u20130.25) and 0.05 (range 0.04\u20130.06), respectively. The PTV 95% conformality index was 0.99 (range 0.97\u20131.0), indicating excellent target conformation with minimal normal tissue spillage. Conclusions: These findings support the dosimetric feasibility of generating hypofractionated radiation therapy plans with a central SIB for large retroperitoneal sarcomas. However, one-third of plans exceeded at least one bowel objective, and these planning results do not establish clinical deliverability, safety, or efficacy.<\/jats:p>","DOI":"10.3390\/cancers18193114","type":"journal-article","created":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T10:34:10Z","timestamp":1790332450000},"page":"3114","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Dosimetric Feasibility of Hypofractionated Radiation Therapy with Simultaneously Integrated Central Boost for Retroperitoneal Sarcoma"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1266-6785","authenticated-orcid":false,"given":"Zoe L.","family":"Cosner","sequence":"first","affiliation":[{"name":"Department of Radiation Oncology, Brigham and Women\u2019s Hospital and Dana-Farber Cancer Institute, Boston, MA 02115, USA"},{"name":"Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA 02114, USA"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"visualization","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0009-0000-7982-5440","authenticated-orcid":false,"given":"Katie","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, Mayo Clinic, Rochester, MN 55905, USA"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"given":"Yaguang","family":"Pei","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, Brigham and Women\u2019s Hospital and Dana-Farber Cancer Institute, Boston, MA 02115, USA"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"software","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2071-5137","authenticated-orcid":false,"given":"Kevin X.","family":"Liu","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, Brigham and Women\u2019s Hospital and Dana-Farber Cancer Institute, Boston, MA 02115, USA"},{"name":"Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA 02114, USA"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"given":"Elizabeth H.","family":"Baldini","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, Brigham and Women\u2019s Hospital and Dana-Farber Cancer Institute, Boston, MA 02115, USA"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7885-6317","authenticated-orcid":false,"given":"Miranda B.","family":"Lam","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, Brigham and Women\u2019s Hospital and Dana-Farber Cancer Institute, Boston, MA 02115, USA"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"project-administration","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"89","DOI":"10.1102\/1470-7330.2005.0019","article-title":"Retroperitoneal sarcomas","volume":"5","author":"Francis","year":"2005","journal-title":"Cancer Imaging"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"215","DOI":"10.1007\/s13193-012-0152-4","article-title":"Retroperitoneal sarcomas- a challenging problem","volume":"3","author":"Kumar","year":"2012","journal-title":"Indian J. Surg. Oncol."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Schmitz, E., and Nessim, C. (2022). Retroperitoneal Sarcoma Care in 2021. Cancers, 14.","DOI":"10.3390\/cancers14051293"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"2489","DOI":"10.1111\/ans.70249","article-title":"Defining an Unresectable Primary Retroperitoneal Sarcoma","volume":"95","author":"Tai","year":"2025","journal-title":"ANZ J. Surg."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"2761","DOI":"10.3390\/curroncol30030209","article-title":"Management of Recurrent Retroperitoneal Sarcoma","volume":"30","author":"Jolissaint","year":"2023","journal-title":"Curr. Oncol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"598","DOI":"10.3390\/curroncol30010047","article-title":"Radiation Therapy for Retroperitoneal Sarcomas: A Strass-Ful Situation","volume":"30","author":"Farooqi","year":"2023","journal-title":"Curr. Oncol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1366","DOI":"10.1016\/S1470-2045(20)30446-0","article-title":"Preoperative radiotherapy plus surgery versus surgery alone for patients with primary retroperitoneal sarcoma (EORTC-62092: STRASS): A multicentre, open-label, randomised, phase 3 trial","volume":"21","author":"Bonvalot","year":"2020","journal-title":"Lancet Oncol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"127","DOI":"10.1097\/SLA.0000000000005492","article-title":"Preoperative Radiotherapy in Patients with Primary Retroperitoneal Sarcoma: EORTC-62092 Trial (STRASS) Versus Off-trial (STREXIT) Results","volume":"278","author":"Callegaro","year":"2023","journal-title":"Ann. Surg."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"85","DOI":"10.1016\/j.adro.2016.12.003","article-title":"Phase 1 trial of preoperative image guided intensity modulated proton radiation therapy with simultaneously integrated boost to the high risk margin for retroperitoneal sarcomas","volume":"2","author":"DeLaney","year":"2017","journal-title":"Adv. Radiat. Oncol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"123","DOI":"10.1016\/j.ijrobp.2023.03.037","article-title":"Neoadjuvant Simultaneous Integrated Boost Radiation Therapy Improves Clinical Outcomes for Retroperitoneal Sarcoma","volume":"117","author":"Liveringhouse","year":"2023","journal-title":"Int. J. Radiat. Oncol. Biol. Phys."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"6","DOI":"10.3857\/roj.2024.00297","article-title":"Feasibility and safety study of ultra-hypofractionated neoadjuvant radiotherapy to margins-at-risk in retroperitoneal sarcoma","volume":"43","author":"Wong","year":"2025","journal-title":"Radiat. Oncol. J."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1375","DOI":"10.1016\/j.adro.2020.05.012","article-title":"Response to Central Boost Radiation Therapy in an Unresectable Retroperitoneal Sarcoma: A Case Report","volume":"5","author":"Lee","year":"2020","journal-title":"Adv. Radiat. Oncol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"101689","DOI":"10.1016\/j.adro.2024.101689","article-title":"Response to Central Boost Radiation Therapy in Unresectable Retroperitoneal Sarcoma: A Case Series","volume":"10","author":"Burner","year":"2025","journal-title":"Adv. Radiat. Oncol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1547","DOI":"10.1016\/S1470-2045(22)00638-6","article-title":"Hypofractionated, 3-week, preoperative radiotherapy for patients with soft tissue sarcomas (HYPORT-STS): A single-centre, open-label, single-arm, phase 2 trial","volume":"23","author":"Guadagnolo","year":"2022","journal-title":"Lancet Oncol."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Zerey, M.M., Gul, A., Kalman, N.S., and Hall, M.D. (2025). Hypofractionated Radiotherapy for Soft Tissue Sarcomas. Cancers, 17.","DOI":"10.3390\/cancers17071170"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"e2400488","DOI":"10.1200\/GO-24-00488","article-title":"Impact of Hypofractionated Radiation Protocols on Reducing Travel Burden and Improving Patient Satisfaction: When Less Is More","volume":"11","author":"Mulla","year":"2025","journal-title":"JCO Glob. Oncol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"239","DOI":"10.2217\/fon.15.300","article-title":"Immunomodulatory effects of radiation: What is next for cancer therapy?","volume":"12","author":"Kumari","year":"2016","journal-title":"Future Oncol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"100913","DOI":"10.1016\/j.adro.2022.100913","article-title":"Hypofractionated Radiation Therapy for Unresectable or Metastatic Sarcoma Lesions","volume":"7","author":"Damron","year":"2022","journal-title":"Adv. Radiat. Oncol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"110185","DOI":"10.1016\/j.radonc.2024.110185","article-title":"Partially Ablative Body Radiotherapy (PABR): A novel approach for palliative radiotherapy of locally advanced bulky unresectable sarcomas","volume":"194","author":"Yu","year":"2024","journal-title":"Radiother. Oncol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"305","DOI":"10.1016\/j.radcr.2023.10.024","article-title":"Complete metabolic response after Partially Ablative Radiotherapy (PAR) for bulky retroperitoneal liposarcoma: A case report","volume":"19","author":"Medici","year":"2024","journal-title":"Radiol. Case Rep."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"602","DOI":"10.1016\/j.ijrobp.2015.02.013","article-title":"Treatment Guidelines for Preoperative Radiation Therapy for Retroperitoneal Sarcoma: Preliminary Consensus of an International Expert Panel","volume":"92","author":"Baldini","year":"2015","journal-title":"Int. J. Radiat. Oncol. Biol. Phys."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"108612","DOI":"10.1016\/j.ejso.2023.107354","article-title":"Learning curve in retroperitoneal sarcoma surgery","volume":"50","author":"Kumar","year":"2024","journal-title":"Eur. J. Surg. Oncol."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Sam\u00e0, L., Rodda, G.A., Ruspi, L., Sicoli, F., D\u2019Amato, V., Renne, S.L., Laffi, A., Baldaccini, D., Clerici, E., and Navarria, P. (2024). Mesenchymal Tumor Management: Integrating Surgical and Non-Surgical Strategies in Different Clinical Scenarios. Cancers, 16.","DOI":"10.3390\/cancers16172965"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"50","DOI":"10.1002\/acm2.12739","article-title":"A new homogeneity index definition for evaluation of radiotherapy plans","volume":"20","author":"Yan","year":"2019","journal-title":"J. Appl. Clin. Med. Phys."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"333","DOI":"10.1016\/j.ijrobp.2005.09.028","article-title":"Conformity index: A review","volume":"64","author":"Feuvret","year":"2006","journal-title":"Int. J. Radiat. Oncol. Biol. Phys."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"668","DOI":"10.1093\/jrr\/rrw037","article-title":"Dose-volume analysis of predictors for chronic gastrointestinal complications in patients with cervical cancer treated with postoperative concurrent chemotherapy and whole-pelvic radiation therapy","volume":"57","author":"Isohashi","year":"2016","journal-title":"J. Radiat. Res."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"360","DOI":"10.1016\/j.prro.2015.12.005","article-title":"Acute gastrointestinal toxicity and bowel bag dose-volume parameters for preoperative radiation therapy for retroperitoneal sarcoma","volume":"6","author":"Mak","year":"2016","journal-title":"Pract. Radiat. Oncol."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1053","DOI":"10.1016\/j.ijrobp.2015.04.039","article-title":"Retroperitoneal Sarcoma Target Volume and Organ at Risk Contour Delineation Agreement Among NRG Sarcoma Radiation Oncologists","volume":"92","author":"Baldini","year":"2015","journal-title":"Int. J. Radiat. Oncol. Biol. Phys."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"e15","DOI":"10.1016\/j.prro.2013.04.003","article-title":"Limitations of the bowel bag contouring technique in the definitive treatment of cervical cancer","volume":"4","author":"Dominello","year":"2014","journal-title":"Pract. Radiat. Oncol."},{"key":"ref_30","first-page":"100926","article-title":"Acute enteritis with pelvic SBRT: Influence of bowel delineation methods","volume":"52","author":"Dinesan","year":"2025","journal-title":"Clin. Transl. Radiat. Oncol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"101953","DOI":"10.1016\/j.adro.2025.101953","article-title":"The impact of radiation dose to bowel on the risk of developing gastrointestinal toxicities when treating abdominopelvic soft tissue sarcomas with preoperative radiation therapy","volume":"11","author":"Yoder","year":"2025","journal-title":"Adv. Radiat. Oncol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"e514","DOI":"10.1016\/j.prro.2020.06.012","article-title":"Long-Term Results of Moderate Hypofractionation to Prostate and Pelvic Nodes Plus Androgen Suppression in High-Risk Prostate Cancer","volume":"10","author":"Faria","year":"2020","journal-title":"Pract. Radiat. Oncol."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"12","DOI":"10.1186\/s13014-021-01976-2","article-title":"Safety of accelerated hypofractionated whole pelvis radiation therapy prior to high dose rate brachytherapy or stereotactic body radiation therapy prostate boost","volume":"17","author":"Phuong","year":"2022","journal-title":"Radiat. Oncol."}],"container-title":["Cancers"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-6694\/18\/19\/3114\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T10:40:09Z","timestamp":1790332809000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-6694\/18\/19\/3114"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,25]]},"references-count":33,"journal-issue":{"issue":"19","published-online":{"date-parts":[[2026,10]]}},"alternative-id":["cancers18193114"],"URL":"https:\/\/doi.org\/10.3390\/cancers18193114","relation":{},"ISSN":["2072-6694"],"issn-type":[{"value":"2072-6694","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,25]]}}}