{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,8]],"date-time":"2026-07-08T05:13:33Z","timestamp":1783487613954,"version":"3.55.0"},"reference-count":33,"publisher":"MDPI AG","issue":"13","license":[{"start":{"date-parts":[[2026,6,30]],"date-time":"2026-06-30T00:00:00Z","timestamp":1782777600000},"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\/Objectives: To evaluate the dosimetric performance and early clinical outcomes of five-fraction accelerated partial breast irradiation (APBI) delivered with helical tomotherapy (HT), and to identify volumetric parameters associated with ipsilateral breast dose exposure. Methods: We retrospectively reviewed early-stage breast cancer patients treated with APBI using HT (30 Gy in five fractions) between January 2024 and June 2025. Dosimetric parameters, acute toxicity, and early oncologic outcomes were analyzed. Correlation and receiver operating characteristic (ROC) analyses were performed to assess the association between volumetric parameters and ipsilateral breast V15Gy. Results: Sixteen patients were included with a median follow-up of 17.7 months. Mean PTV volume was 179.1 \u00b1 53.9 mL, and mean PTV V95% was 98.0 \u00b1 2.7%. Organ-at-risk sparing was favorable, with a mean heart dose of 0.82 \u00b1 0.59 Gy and ipsilateral lung mean dose of 2.91 \u00b1 0.45 Gy. The PTV-to-whole-breast volume ratio showed a significant correlation with ipsilateral breast V15Gy (\u03b2 = 30.06, R2 = 0.34, p = 0.019) with a cutoff value of approximately 0.33 to predict ipsilateral breast V15Gy \u2265 50%. Acute toxicity was mild with no grade \u2265 2 dermatitis observed. Conclusions: Five-fraction APBI delivered with HT is dosimetrically feasible with favorable early toxicity profiles. The PTV-to-whole-breast volume ratio may serve as a simple and clinically applicable planning metric for anticipating ipsilateral breast dose.<\/jats:p>","DOI":"10.3390\/cancers18132122","type":"journal-article","created":{"date-parts":[[2026,6,30]],"date-time":"2026-06-30T16:56:55Z","timestamp":1782838615000},"page":"2122","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Accelerated Partial Breast Irradiation Delivered with Helical Tomotherapy: Dosimetry and Volumetric Predictors of Ipsilateral Breast Dose"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8219-582X","authenticated-orcid":false,"given":"Eva Yu-Hsuan","family":"Chuang","sequence":"first","affiliation":[{"name":"Division of Radiation Oncology, Department of Radiology, Far Eastern Memorial Hospital, New Taipei City 220, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chen-Hsi","family":"Hsieh","sequence":"additional","affiliation":[{"name":"Division of Radiation Oncology, Department of Radiology, Far Eastern Memorial Hospital, New Taipei City 220, Taiwan"},{"name":"School of Medicine, College of Medicine, National Yang Ming Chiao Tung University, Taipei 112, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pei-Wei","family":"Shueng","sequence":"additional","affiliation":[{"name":"Division of Radiation Oncology, Department of Radiology, Far Eastern Memorial Hospital, New Taipei City 220, Taiwan"},{"name":"School of Medicine, College of Medicine, National Yang Ming Chiao Tung University, Taipei 112, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chen-Xiong","family":"Hsu","sequence":"additional","affiliation":[{"name":"Division of Radiation Oncology, Department of Radiology, Far Eastern Memorial Hospital, New Taipei City 220, Taiwan"},{"name":"Department of Computer Science and Engineering, Yuan Ze University, Taoyuan 320, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7407-6284","authenticated-orcid":false,"given":"Deng-Yu","family":"Kuo","sequence":"additional","affiliation":[{"name":"Division of Radiation Oncology, Department of Radiology, Far Eastern Memorial Hospital, New Taipei City 220, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yueh-Feng","family":"Lu","sequence":"additional","affiliation":[{"name":"Division of Radiation Oncology, Department of Radiology, Far Eastern Memorial Hospital, New Taipei City 220, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hsin-Pei","family":"Yeh","sequence":"additional","affiliation":[{"name":"Division of Radiation Oncology, Department of Radiology, Far Eastern Memorial Hospital, New Taipei City 220, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9073-6414","authenticated-orcid":false,"given":"Pei-Yu","family":"Hou","sequence":"additional","affiliation":[{"name":"Division of Radiation Oncology, Department of Radiology, Far Eastern Memorial Hospital, New Taipei City 220, Taiwan"},{"name":"Department of Computer Science and Engineering, Yuan Ze University, Taoyuan 320, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,30]]},"reference":[{"key":"ref_1","first-page":"287","article-title":"Global burden of female breast cancer: New estimates in 2022, temporal trend and future projections up to 2050 based on the latest release from GLOBOCAN","volume":"5","author":"Zhang","year":"2025","journal-title":"J. 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