{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,7]],"date-time":"2026-09-07T10:10:05Z","timestamp":1788775805669,"version":"build-2803163510"},"reference-count":33,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2026,9,5]],"date-time":"2026-09-05T00:00:00Z","timestamp":1788566400000},"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: Breast\/chest wall (B\/CW) re-irradiation (reRT) is approached cautiously because of concerns regarding late toxicity and uncertain benefit. Contemporary data on mature toxicity and oncologic outcomes after external beam photon reRT are limited. Methods: This retrospective cohort included 113 consecutive patients who completed reRT after resection of locoregionally recurrent breast cancer between 2010 and 2024. The primary endpoint was cumulative incidence of late grade \u2265 2 CTCAE toxicity, analyzed using competing-risks methods. Secondary endpoints were locoregional recurrence-free survival (LRRFS) and local failure (LF), assessed using Kaplan\u2013Meier, Cox regression, and Fine\u2013Gray modeling. Results: Median age at reRT was 66 years. Most recurrences were early-stage (72.6%) and hormone receptor-positive (68.1%). Median cumulative EQD2 was 94.9 Gy, and 25.7% received IMRT. At 67.1 months\u2019 median follow-up, 5-year cumulative incidences of grade \u2265 2 and grade 3 toxicity were 35.4% (95% CI, 25.6\u201345.1) and 3.9% (95% CI, 0.1\u20137.8), respectively. Higher cumulative EQD2 predicted grade \u2265 2 toxicity (SHR, 1.94 per 10 Gy; p &lt; 0.001) and grade 3 toxicity (SHR, 4.32 per 10 Gy; p &lt; 0.001). Longer interval between radiotherapy courses (p = 0.029) and IMRT (SHR, 0.40; p = 0.005) were associated with lower grade \u2265 2 toxicity. Five-year LRRFS was 84.2% (95% CI, 76.7\u201392.4), and LF was 6.8%. Advanced-stage disease and second or subsequent recurrence predicted inferior LRRFS. Partial B\/CW reRT did not compromise disease control in early-stage recurrences. Conclusions: Adjuvant breast and chest wall re-irradiation using external photons achieved durable locoregional control with low rates of severe late toxicity in one of the largest reported cohorts. These findings support individualized curative-intent reRT guided by cumulative dose, technique, and recurrence risk.<\/jats:p>","DOI":"10.3390\/cancers18172878","type":"journal-article","created":{"date-parts":[[2026,9,7]],"date-time":"2026-09-07T09:23:37Z","timestamp":1788773017000},"page":"2878","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["External Beam Breast and Chest Wall Re-Irradiation Following Resection of Ipsilateral Breast Cancer Recurrence: Dose\u2013Toxicity Relationships and Long-Term Oncologic Outcomes"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0009-0004-2585-1650","authenticated-orcid":false,"given":"Suman","family":"Ghosh","sequence":"first","affiliation":[{"name":"Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON M4N 3M5, Canada"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"}]},{"given":"Hany","family":"Soliman","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON M4N 3M5, Canada"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"given":"Edward","family":"Chow","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON M4N 3M5, Canada"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"investigation","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"given":"Hanbo","family":"Chen","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON M4N 3M5, Canada"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"investigation","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"}]},{"given":"Eric","family":"Leung","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON M4N 3M5, Canada"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"investigation","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"given":"Irene","family":"Karam","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON M4N 3M5, Canada"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"investigation","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9647-2851","authenticated-orcid":false,"given":"Eileen","family":"Rakovitch","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON M4N 3M5, Canada"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"investigation","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"given":"Amir H.","family":"Safavi","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON M4N 3M5, Canada"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"investigation","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9714-2782","authenticated-orcid":false,"given":"Danny","family":"Vesprini","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON M4N 3M5, Canada"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"investigation","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"given":"Gregory J.","family":"Czarnota","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON M4N 3M5, Canada"},{"name":"Physical Sciences, Sunnybrook Research Institute, Toronto, ON M4N 3M5, Canada"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"conceptualization","vocabulary":"credit"},{"role":"project-administration","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,5]]},"reference":[{"key":"ref_1","first-page":"229","article-title":"Global Cancer Statistics 2022: GLOBOCAN Estimates of Incidence and Mortality Worldwide for 36 Cancers in 185 Countries","volume":"74","author":"Bray","year":"2024","journal-title":"CA Cancer J. 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