{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,18]],"date-time":"2026-09-18T11:37:45Z","timestamp":1789731465679,"version":"4.0.1"},"reference-count":28,"publisher":"MDPI AG","issue":"22","license":[{"start":{"date-parts":[[2025,11,10]],"date-time":"2025-11-10T00:00:00Z","timestamp":1762732800000},"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: One of the challenges in treating pancreatic ductal adenocarcinoma (PDAC) with stereotactic radiotherapy (SRT) is to manage lesions abutted to the duodenum, bowel and stomach. Simultaneous integrated protection (SIP) is one of the proposed approaches to increase plan reproducibility and quality. However, no clinical data are available regarding the dosimetric objectives impacting local control probability. Methods: This is a prospective, single-arm study. Key inclusion criteria were as follows: PDAC histology; tumor abutment with duodenum, stomach, or small bowel; and SRT schedule consisting of 45 Gy in six fractions. Delineation of the PTV overlapped with critical OARs (PTV_SIP) and PTV outside critical OARs (PTV_Dominant) was mandatory. Dose constraints were as follows: (near) maximum dose, D2cc, and D20cc to critical OARs 38 Gy, 32 Gy, and 24 Gy, respectively. This study was designed to prospectively investigate the main clinical and dosimetric parameters impacting freedom from local recurrence (FFLR). Results: From June 2019 to January 2024, 104 patients were enrolled. One-year FFLR was 91.7%. Fifteen events of local failure occurred (17.6%). Mapping of local relapses showed a relapse inside the PTV_SIP area in nine patients and outside the PTV_SIP in six cases (NS). Whole PTV &gt; 69 cc, PTV_SIP &gt; 4 cc, PTV-SIP\/whole PTV ratio &gt; 7%, (near) Dmin to PTV_SIP &lt; 25 Gy, mean dose to PTV_SIP &lt; 28 Gy, and (near) Dmin to PTV_Dominant &lt; 29 Gy were associated with worse FFLR. Multivariable analysis showed PTV_SIP absolute volume of more than 4 cc, mean dose to PTV_SIP &lt; 28 Gy and whole PTV &gt; 69 cc were independently related to worse FFLR. One case of acute G4 toxicity and two cases of acute G3 toxicity occurred, with two late toxicity deaths not certainly due to treatment. Conclusions: In this prospective study, SIP planning strategy with six fractions is safe and effective in pancreatic targets with critical contact with critical OARs. Given its potential advantages, SIP planning is a potential innovative strategy that should be compared to standard SRT planning in an ad hoc trial design.<\/jats:p>","DOI":"10.3390\/cancers17223617","type":"journal-article","created":{"date-parts":[[2025,11,10]],"date-time":"2025-11-10T11:47:27Z","timestamp":1762775247000},"page":"3617","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Impact of Dosimetric Parameters on Tumor Control in Stereotactic Radiotherapy for Pancreatic Cancer: A Prospective Study on 104 Patients Treated with Simultaneous Integrated Protection (SIP)"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5455-3335","authenticated-orcid":false,"given":"Marco Lorenzo","family":"Bon\u00f9","sequence":"first","affiliation":[{"name":"Radiation Oncology Unit, Istituto del Radio O. Alberti, Spedali Civili Hospital, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jacopo","family":"Balduzzi","sequence":"additional","affiliation":[{"name":"Radiation Oncology Unit, Istituto del Radio O. Alberti, Spedali Civili Hospital, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gloria","family":"Pedersoli","sequence":"additional","affiliation":[{"name":"Radiation Oncology Unit, Istituto del Radio O. Alberti, Spedali Civili Hospital, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dario","family":"Moneghini","sequence":"additional","affiliation":[{"name":"Department of Digestive Endoscopy, Spedali Civili Hospital, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marco","family":"Ramera","sequence":"additional","affiliation":[{"name":"Department of Surgery, Spedali Civili Hospital and Brescia University, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nazario","family":"Portolani","sequence":"additional","affiliation":[{"name":"Department of Surgery, Spedali Civili Hospital and Brescia University, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jacopo","family":"Andreuccetti","sequence":"additional","affiliation":[{"name":"Department of Surgery, Spedali Civili Hospital, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Luigi","family":"Grazioli","sequence":"additional","affiliation":[{"name":"Department of Radiology, Spedali Civili Hospital, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Barbara","family":"Frittoli","sequence":"additional","affiliation":[{"name":"Department of Radiology, Spedali Civili Hospital, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sarah","family":"Molfino","sequence":"additional","affiliation":[{"name":"Department of Surgery, Spedali Civili Hospital, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anna Maria","family":"Bozzola","sequence":"additional","affiliation":[{"name":"Department of Pathology, Spedali Civili Hospital, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maria Teresa","family":"Cefaratti","sequence":"additional","affiliation":[{"name":"Radiation Oncology Unit, Istituto del Radio O. Alberti, Spedali Civili Hospital, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eneida","family":"Mataj","sequence":"additional","affiliation":[{"name":"Radiation Oncology Unit, Istituto del Radio O. Alberti, Spedali Civili Hospital, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7092-0265","authenticated-orcid":false,"given":"Giulia","family":"Volpi","sequence":"additional","affiliation":[{"name":"Radiation Oncology Unit, Azienda Ospedaliera Universitaria Integrata di Verona, 37126 Verona, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8635-7411","authenticated-orcid":false,"given":"Luigi","family":"Spiazzi","sequence":"additional","affiliation":[{"name":"Department of Medical Physics, Spedali Civili Hospital, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Federica","family":"Saiani","sequence":"additional","affiliation":[{"name":"Department of Medical Physics, Spedali Civili Hospital, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alfredo","family":"Fiume","sequence":"additional","affiliation":[{"name":"Department of Medical Physics, Spedali Civili Hospital, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3699-8744","authenticated-orcid":false,"given":"Cesare","family":"Tomasi","sequence":"additional","affiliation":[{"name":"Radiation Oncology Unit, Istituto del Radio O. Alberti, Spedali Civili Hospital, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vittorio","family":"Morelli","sequence":"additional","affiliation":[{"name":"Radiation Oncology Unit, Istituto del Radio O. Alberti, Spedali Civili Hospital, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Paola","family":"Vitali","sequence":"additional","affiliation":[{"name":"Radiation Oncology Unit, Istituto del Radio O. Alberti, Spedali Civili Hospital, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Francesco","family":"Frassine","sequence":"additional","affiliation":[{"name":"Radiation Oncology Unit, Istituto del Radio O. Alberti, Spedali Civili Hospital, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0168-3432","authenticated-orcid":false,"given":"Luca","family":"Triggiani","sequence":"additional","affiliation":[{"name":"Radiation Oncology Unit, Spedali Civili Hospital and Brescia University, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andrea","family":"Guerini","sequence":"additional","affiliation":[{"name":"Radiation Oncology Unit, Spedali Civili Hospital and Brescia University, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Davide","family":"Tomasini","sequence":"additional","affiliation":[{"name":"Radiation Oncology Unit, Istituto del Radio O. Alberti, Spedali Civili Hospital, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fabrizia","family":"Terraneo","sequence":"additional","affiliation":[{"name":"Radiation Oncology Unit, Istituto del Radio O. Alberti, Spedali Civili Hospital, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-5795-6334","authenticated-orcid":false,"given":"Domenico","family":"Della Casa","sequence":"additional","affiliation":[{"name":"Department of Digestive Endoscopy, Spedali Civili Hospital, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fernando","family":"Barbera","sequence":"additional","affiliation":[{"name":"Radiation Oncology Unit, Istituto del Radio O. Alberti, Spedali Civili Hospital, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4126-733X","authenticated-orcid":false,"given":"Stefano Maria","family":"Magrini","sequence":"additional","affiliation":[{"name":"Radiation Oncology Unit, Spedali Civili Hospital and Brescia University, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5485-1260","authenticated-orcid":false,"given":"Michela","family":"Buglione","sequence":"additional","affiliation":[{"name":"Radiation Oncology Unit, Spedali Civili Hospital and Brescia University, 25123 Brescia, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,11,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"193","DOI":"10.1007\/s00066-018-1416-x","article-title":"Icru report 91 on prescribing, recording, and reporting of stereotactic treatments with small photon beams: Statement from the degro\/dgmp working group stereotactic radiotherapy and radiosurgery","volume":"195","author":"Wilke","year":"2019","journal-title":"Strahlenther. 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