{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,1]],"date-time":"2026-06-01T18:12:28Z","timestamp":1780337548606,"version":"3.54.1"},"reference-count":29,"publisher":"Public Library of Science (PLoS)","issue":"6","license":[{"start":{"date-parts":[[2026,6,1]],"date-time":"2026-06-01T00:00:00Z","timestamp":1780272000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS One"],"abstract":"<jats:sec id=\"sec001\">\n                    <jats:title>Purpose\/Objectives<\/jats:title>\n                    <jats:p>The role of postmastectomy radiotherapy (PMRT) in patients with pathologic N1 (pN1) breast cancer, including triple-negative breast cancer (TNBC), remains controversial in the era of modern systemic therapy. We evaluated the association between PMRT and recurrence-free survival (RFS) and overall survival (OS) and identified prognostic factors in a contemporary single-institution pN1 cohort.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"sec002\">\n                    <jats:title>Materials\/Methods<\/jats:title>\n                    <jats:p>We retrospectively reviewed female patients with pT1-2N1M0 breast cancer treated with mastectomy between 1999 and 2023. RFS and OS were estimated using Kaplan-Meier methods and compared by PMRT status with log-rank testing. Univariable Cox proportional hazards models assessed associations between clinical factors\u2014including tumor laterality, receptor subtype (TNBC vs non-TNBC), nodal burden, and adjuvant therapies\u2014and survival outcomes, with subgroup analyses by PMRT status and receptor subtype.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"sec003\">\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Fifty-seven patients were included; 22 (38.6%) received PMRT. With a median follow-up of 85 months, PMRT was not associated with improved RFS (median 133 vs 120 months; p\u2009=\u20090.256) or OS (not reached vs 195 months; p\u2009=\u20090.154). Hormone therapy was significantly associated with improved RFS (HR 0.43; p\u2009=\u20090.026) and OS (HR 0.13; p\u2009=\u20090.003), while having 2\u20133 positive lymph nodes predicted worse RFS (HR 2.86; p\u2009=\u20090.007). No significant differential benefit from PMRT was observed in patients with TNBC or non-TNBC disease.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"sec004\">\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>PMRT was not associated with a survival benefit in this pN1 cohort, including patients with TNBC. Interpretation is limited by modest sample size and statistical power. Outcomes appeared driven by tumor biology, nodal burden, and systemic therapy, supporting individualized PMRT decision-making.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1371\/journal.pone.0341754","type":"journal-article","created":{"date-parts":[[2026,6,1]],"date-time":"2026-06-01T17:54:52Z","timestamp":1780336492000},"page":"e0341754","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":0,"title":["Postmastectomy radiotherapy in pN1 breast cancer: Survival outcomes and prognostic factors from a single-institution cohort"],"prefix":"10.1371","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0009-0009-2380-5681","authenticated-orcid":true,"given":"Raksha M.","family":"Narasimhan","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aren Singh","family":"Saini","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kayla","family":"Samimi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ifeanyichukwu","family":"Ogobuiro","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xuesen","family":"Zhao","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sunwoo","family":"Han","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cristiane","family":"Takita","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Crystal S.","family":"Taswell","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2026,6,1]]},"reference":[{"issue":"14","key":"pone.0341754.ref001","doi-asserted-by":"crossref","first-page":"949","DOI":"10.1056\/NEJM199710023371401","article-title":"Postoperative radiotherapy in high-risk premenopausal women with breast cancer who receive adjuvant chemotherapy. Danish Breast Cancer Cooperative Group 82b Trial","volume":"337","author":"M Overgaard","year":"1997","journal-title":"N Engl J Med"},{"issue":"9165","key":"pone.0341754.ref002","doi-asserted-by":"crossref","first-page":"1641","DOI":"10.1016\/S0140-6736(98)09201-0","article-title":"Postoperative radiotherapy in high-risk postmenopausal breast-cancer patients given adjuvant tamoxifen: Danish Breast Cancer Cooperative Group DBCG 82c randomised trial","volume":"353","author":"M Overgaard","year":"1999","journal-title":"Lancet"},{"issue":"9935","key":"pone.0341754.ref003","doi-asserted-by":"crossref","first-page":"2127","DOI":"10.1016\/S0140-6736(14)60488-8","article-title":"Effect of radiotherapy after mastectomy and axillary surgery on 10-year recurrence and 20-year breast cancer mortality: meta-analysis of individual patient data for 8135 women in 22 randomised trials","volume":"383","author":"EBCTCG (Early Breast Cancer Trialists\u2019 Collaborative Group)","year":"2014","journal-title":"Lancet"},{"issue":"6","key":"pone.0341754.ref004","doi-asserted-by":"crossref","first-page":"594","DOI":"10.6004\/jnccn.2023.0031","article-title":"NCCN Guidelines\u00ae Insights: Breast Cancer, Version 4.2023","volume":"21","author":"WJ Gradishar","year":"2023","journal-title":"J Natl Compr Canc Netw"},{"key":"pone.0341754.ref005","article-title":"Whether adjuvant radiotherapy is desired for postmastectomy patients with T1\u2013T2 tumors and 1\u20133 positive axillary lymph nodes who received modern systemic therapy?","author":"SF Lai","year":"2018","journal-title":"Translational Cancer Research"},{"issue":"5","key":"pone.0341754.ref006","doi-asserted-by":"crossref","first-page":"1337","DOI":"10.1016\/j.ijrobp.2004.08.009","article-title":"Selecting breast cancer patients with T1-T2 tumors and one to three positive axillary nodes at high postmastectomy locoregional recurrence risk for adjuvant radiotherapy","volume":"61","author":"PT Truong","year":"2005","journal-title":"Int J Radiat Oncol Biol Phys"},{"key":"pone.0341754.ref007","doi-asserted-by":"crossref","first-page":"40","DOI":"10.1016\/j.breast.2020.03.003","article-title":"The survival benefit of postmastectomy radiotherapy for breast cancer patients with T1-2N1 disease according to molecular subtype","volume":"51","author":"J Wei","year":"2020","journal-title":"Breast"},{"issue":"11","key":"pone.0341754.ref008","doi-asserted-by":"crossref","first-page":"987","DOI":"10.1056\/NEJMoa1209825","article-title":"Risk of ischemic heart disease in women after radiotherapy for breast cancer","volume":"368","author":"SC Darby","year":"2013","journal-title":"N Engl J Med"},{"issue":"36","key":"pone.0341754.ref009","doi-asserted-by":"crossref","first-page":"4431","DOI":"10.1200\/JCO.2016.69.1188","article-title":"Postmastectomy Radiotherapy: An American Society of Clinical Oncology, American Society for Radiation Oncology, and Society of Surgical Oncology Focused Guideline Update","volume":"34","author":"A Recht","year":"2016","journal-title":"J Clin Oncol"},{"key":"pone.0341754.ref010","volume-title":"No OS benefit at 10 years with post\u2011mastectomy RT in intermediate\u2011risk breast cancer: 10\u2011year overall survival results of the SUPREMO (BIG 2\u201104 MRC) randomized trial. SABCS 2024 Specialisation: Oncology","author":"I Kunkler","year":"2024"},{"issue":"1","key":"pone.0341754.ref011","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1186\/s13058-021-01393-z","article-title":"In modern times, how important are breast cancer stage, grade and receptor subtype for survival: a population-based cohort study","volume":"23","author":"ALV Johansson","year":"2021","journal-title":"Breast Cancer Res"},{"issue":"3","key":"pone.0341754.ref012","doi-asserted-by":"crossref","first-page":"309","DOI":"10.1007\/s10549-007-9556-1","article-title":"An overview of prognostic factors for long-term survivors of breast cancer","volume":"107","author":"I Soerjomataram","year":"2008","journal-title":"Breast Cancer Res Treat"},{"issue":"1","key":"pone.0341754.ref013","doi-asserted-by":"crossref","first-page":"1","DOI":"10.4048\/jbc.2022.25.e6","article-title":"Postmastectomy Radiation Therapy in Patients With Minimally Involved Lymph Nodes: A Review of the Current Data and Future Directions","volume":"25","author":"B-S Jang","year":"2022","journal-title":"J Breast Cancer"},{"issue":"30","key":"pone.0341754.ref014","doi-asserted-by":"crossref","first-page":"49564","DOI":"10.18632\/oncotarget.17318","article-title":"Impact of postmastectomy radiation therapy in T1-2 breast cancer patients with 1-3 positive axillary lymph nodes","volume":"8","author":"H Yin","year":"2017","journal-title":"Oncotarget"},{"issue":"7","key":"pone.0341754.ref015","doi-asserted-by":"crossref","first-page":"489","DOI":"10.21037\/atm.2020.03.49","article-title":"Real-world impact of postmastectomy radiotherapy in T1-2 breast cancer with one to three positive lymph nodes","volume":"8","author":"F-Y Li","year":"2020","journal-title":"Ann Transl Med"},{"issue":"12","key":"pone.0341754.ref016","doi-asserted-by":"crossref","first-page":"9979","DOI":"10.1007\/s00432-023-04908-7","article-title":"Postmastectomy radiotherapy in patients with T1-2N1 breast cancer: a single center experience and a meta-analysis","volume":"149","author":"M Luo","year":"2023","journal-title":"J Cancer Res Clin Oncol"},{"key":"pone.0341754.ref017","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1016\/j.ejca.2022.05.017","article-title":"Prognostic impact of postoperative radiotherapy in patients with breast cancer and with pT1-2 and 1-3 lymph node metastases: A retrospective cohort study based on the Japanese Breast Cancer Registry","volume":"172","author":"A Yamada","year":"2022","journal-title":"Eur J Cancer"},{"issue":"13","key":"pone.0341754.ref018","doi-asserted-by":"crossref","first-page":"4295","DOI":"10.1245\/s10434-015-4528-x","article-title":"Use of Postmastectomy Radiotherapy and Survival Rates for Breast Cancer Patients with T1-T2 and One to Three Positive Lymph Nodes","volume":"22","author":"D Huo","year":"2015","journal-title":"Ann Surg Oncol"},{"issue":"12","key":"pone.0341754.ref019","article-title":"Identification of Risk Factors for Locoregional Recurrence in Breast Cancer Patients with Nodal Stage N0 and N1: Who Could Benefit from Post-Mastectomy Radiotherapy?","volume":"10","author":"E Jwa","year":"2015","journal-title":"PLoS One"},{"issue":"2","key":"pone.0341754.ref020","doi-asserted-by":"crossref","first-page":"141","DOI":"10.1634\/theoncologist.2012-0233","article-title":"Radiotherapy can improve the disease-free survival rate in triple-negative breast cancer patients with T1-T2 disease and one to three positive lymph nodes after mastectomy","volume":"18","author":"X Chen","year":"2013","journal-title":"Oncologist"},{"issue":"35","key":"pone.0341754.ref021","doi-asserted-by":"crossref","first-page":"59800","DOI":"10.18632\/oncotarget.16241","article-title":"Possible benefits from post-mastectomy radiotherapy in node-negative breast cancer patients: a multicenter analysis in Korea (KROG 14-22)","volume":"8","author":"HJ Park","year":"2017","journal-title":"Oncotarget"},{"key":"pone.0341754.ref022","doi-asserted-by":"crossref","first-page":"892","DOI":"10.3389\/fonc.2020.00892","article-title":"Is there a role for post-mastectomy radiotherapy for T1-2N1 breast cancers with node-positive pathology after patients become node-negative pathology following neoadjuvant chemotherapy?","volume":"10","author":"Q Wang","year":"2020","journal-title":"Front Oncol"},{"issue":"16","key":"pone.0341754.ref023","doi-asserted-by":"crossref","first-page":"3878","DOI":"10.1158\/1078-0432.CCR-17-3169","article-title":"21-Gene Recurrence Score Assay Predicts Benefit of Post-Mastectomy Radiotherapy in T1-2 N1 Breast Cancer","volume":"24","author":"CR Goodman","year":"2018","journal-title":"Clin Cancer Res"},{"issue":"13","key":"pone.0341754.ref024","doi-asserted-by":"crossref","first-page":"8335","DOI":"10.1245\/s10434-023-14155-2","article-title":"De-escalation of Post-mastectomy Irradiation in Hormone Receptor-Positive Breast Cancer with One to Three Positive Nodes","volume":"30","author":"GG Halfteck","year":"2023","journal-title":"Ann Surg Oncol"},{"key":"pone.0341754.ref025","doi-asserted-by":"crossref","first-page":"270","DOI":"10.3389\/fonc.2019.00270","article-title":"21-Gene Recurrence Score Assay Could Not Predict Benefit of Post-mastectomy Radiotherapy in T1-2 N1mic ER-Positive HER2-Negative Breast Cancer","volume":"9","author":"W-W Zhang","year":"2019","journal-title":"Front Oncol"},{"issue":"1","key":"pone.0341754.ref026","doi-asserted-by":"crossref","first-page":"13377","DOI":"10.1038\/s41598-022-16749-4","article-title":"Left sided breast cancer is associated with aggressive biology and worse outcomes than right sided breast cancer","volume":"12","author":"Y Abdou","year":"2022","journal-title":"Sci Rep"},{"issue":"5","key":"pone.0341754.ref027","doi-asserted-by":"crossref","first-page":"365","DOI":"10.1093\/jnci\/djk064","article-title":"Long-term risk of cardiovascular disease in 10-year survivors of breast cancer","volume":"99","author":"MJ Hooning","year":"2007","journal-title":"J Natl Cancer Inst"},{"issue":"1","key":"pone.0341754.ref028","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1016\/j.ijrobp.2005.03.047","article-title":"Radiation pneumonitis and pulmonary fibrosis in non-small-cell lung cancer: pulmonary function, prediction, and prevention","volume":"63","author":"V Mehta","year":"2005","journal-title":"Int J Radiat Oncol Biol Phys"},{"issue":"9","key":"pone.0341754.ref029","doi-asserted-by":"crossref","first-page":"864","DOI":"10.1097\/JTO.0b013e318145b2c6","article-title":"Predicting risk of radiation-induced lung injury","volume":"2","author":"I Madani","year":"2007","journal-title":"J Thorac Oncol"}],"container-title":["PLOS One"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0341754","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,6,1]],"date-time":"2026-06-01T17:54:58Z","timestamp":1780336498000},"score":1,"resource":{"primary":{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0341754"}},"subtitle":[],"editor":[{"given":"Satyajeet","family":"Rath","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"editor"}]}],"short-title":[],"issued":{"date-parts":[[2026,6,1]]},"references-count":29,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2026,6,1]]}},"URL":"https:\/\/doi.org\/10.1371\/journal.pone.0341754","relation":{},"ISSN":["1932-6203"],"issn-type":[{"value":"1932-6203","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,6,1]]}}}