{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,21]],"date-time":"2026-10-21T02:18:13Z","timestamp":1792549093333,"version":"4.5.0"},"reference-count":15,"publisher":"Wiley","issue":"3","license":[{"start":{"date-parts":[[2025,1,30]],"date-time":"2025-01-30T00:00:00Z","timestamp":1738195200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":["acsjournals.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Cancer"],"published-print":{"date-parts":[[2025,2]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Background<\/jats:title><jats:p>The risk of recurrence in patients with small, lymph node\u2010negative, human epidermal growth factor receptor 2 (HER2)\u2010positive breast cancers untreated with adjuvant chemotherapy\/HER2\u2010directed therapy is uncertain. To investigate this, the authors conducted a retrospective, population\u2010based study of chemotherapy use and breast cancer\u2010specific survival (BCSS) among patients with stage IA HER2\u2010positive breast cancer.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>The authors analyzed Surveillance, Epidemiology, and End Results data from patients diagnosed with stage IA HER2\u2010positive breast cancer from 2010 to 2019. They examined the frequency of chemotherapy use by tumor size and hormone receptor (HR) status and applied multivariate logistic regression to assess the factors associated with receipt of chemotherapy. BCSS was evaluated and performed multivariable Cox regression was performed to evaluate the association between chemotherapy receipt and BCSS.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Among 12,896 patients, 74.0% had HR\u2010positive\/HER2\u2010positive breast cancer, and 26.0% had HR\u2010negative\/HER2\u2010positive breast cancer. Adjuvant chemotherapy was received by to 58.9% of patients, with lower utilization for those who were older, Hispanic or Asian\/Pacific Islander, separated\/divorced\/widowed, or had a lower median household income. The median follow\u2010up was 46 months. Among the patients who had pathologic T1 (pT1) microscopic, pT1a, or pT1b tumors, the 5\u2010year BCSS rate was 97.6%\u201399.6% in those who had no evidence of chemotherapy receipt in the medical record versus 98.4%\u2013100.0% in those who did receive chemotherapy. Among patients who had pT1c tumors and had no evidence of chemotherapy receipt, the 5\u2010year BCSS rate was 92.1% for those with HR\u2010negative\/HER2\u2010positive breast cancer and 96.0% for those with HR\u2010positive\/HER2\u2010positive breast cancer. Patients who had pT1c tumors and received chemotherapy had a 5\u2010year BCSS rate of 96.7% in those with HR\u2010negative\/HER2\u2010positive breast cancer and 98.7% in those with HR\u2010positive\/HER2\u2010positive breast cancer.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>In this large, population\u2010based study of patients with stage IA HER2\u2010positive breast cancer, patients who had tumors \u22641 cm had excellent outcomes with or without chemotherapy. Patients with pT1c tumors had a greater increase in BCSS with the receipt chemotherapy.<\/jats:p><\/jats:sec>","DOI":"10.1002\/cncr.35729","type":"journal-article","created":{"date-parts":[[2025,1,30]],"date-time":"2025-01-30T06:05:51Z","timestamp":1738217151000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Outcomes and treatment patterns for stage I human epidermal growth factor receptor 2\u2010positive breast cancer in the Surveillance, Epidemiology, and End Results database, 2010\u20132019"],"prefix":"10.1002","volume":"131","author":[{"given":"Adrienne G.","family":"Waks","sequence":"first","affiliation":[{"name":"Department of Medical Oncology Dana\u2010Farber Cancer Institute  Boston Massachusetts USA"},{"name":"Breast Oncology Program Dana\u2010Farber Brigham Cancer Center  Boston Massachusetts USA"},{"name":"Harvard Medical School  Boston Massachusetts USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Paolo","family":"Tarantino","sequence":"additional","affiliation":[{"name":"Department of Medical Oncology Dana\u2010Farber Cancer Institute  Boston Massachusetts USA"},{"name":"Breast Oncology Program Dana\u2010Farber Brigham Cancer Center  Boston Massachusetts USA"},{"name":"Harvard Medical School  Boston Massachusetts USA"},{"name":"Department of Oncology and Onco\u2010Hematology University of Milan  Milan Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Emily L.","family":"Chen","sequence":"additional","affiliation":[{"name":"Brigham and Women\u2019s Hospital  Boston Massachusetts USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rachel A.","family":"Freedman","sequence":"additional","affiliation":[{"name":"Department of Medical Oncology Dana\u2010Farber Cancer Institute  Boston Massachusetts USA"},{"name":"Breast Oncology Program Dana\u2010Farber Brigham Cancer Center  Boston Massachusetts USA"},{"name":"Harvard Medical School  Boston Massachusetts USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nancy U.","family":"Lin","sequence":"additional","affiliation":[{"name":"Department of Medical Oncology Dana\u2010Farber Cancer Institute  Boston Massachusetts USA"},{"name":"Breast Oncology Program Dana\u2010Farber Brigham Cancer Center  Boston Massachusetts USA"},{"name":"Harvard Medical School  Boston Massachusetts USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nabihah","family":"Tayob","sequence":"additional","affiliation":[{"name":"Department of Medical Oncology Dana\u2010Farber Cancer Institute  Boston Massachusetts USA"},{"name":"Harvard Medical School  Boston Massachusetts USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Carlos T.","family":"Vallejo","sequence":"additional","affiliation":[{"name":"Grupo Oncol\u00f3gico Cooperativo del Sur  Neuqu\u00e9n Argentina"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Julieta","family":"Leone","sequence":"additional","affiliation":[{"name":"Grupo Oncol\u00f3gico Cooperativo del Sur  Neuqu\u00e9n Argentina"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5940-8671","authenticated-orcid":false,"given":"Sara M.","family":"Tolaney","sequence":"additional","affiliation":[{"name":"Department of Medical Oncology Dana\u2010Farber Cancer Institute  Boston Massachusetts USA"},{"name":"Breast Oncology Program Dana\u2010Farber Brigham Cancer Center  Boston Massachusetts USA"},{"name":"Harvard Medical School  Boston Massachusetts USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8537-652X","authenticated-orcid":false,"given":"Jose Pablo","family":"Leone","sequence":"additional","affiliation":[{"name":"Department of Medical Oncology Dana\u2010Farber Cancer Institute  Boston Massachusetts USA"},{"name":"Breast Oncology Program Dana\u2010Farber Brigham Cancer Center  Boston Massachusetts USA"},{"name":"Harvard Medical School  Boston Massachusetts USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2025,1,30]]},"reference":[{"key":"e_1_2_9_2_1","doi-asserted-by":"publisher","DOI":"10.1126\/science.3798106"},{"key":"e_1_2_9_3_1","doi-asserted-by":"publisher","DOI":"10.1200\/JCO.19.00066"},{"key":"e_1_2_9_4_1","doi-asserted-by":"publisher","DOI":"10.1158\/1538\u20107445.sabcs22\u2010pd18\u201001"},{"key":"e_1_2_9_5_1","unstructured":"NCCN Guidelines Version 3.2024. Invasive Breast Cancer. NCCN;2024."},{"key":"e_1_2_9_6_1","doi-asserted-by":"publisher","DOI":"10.1002\/sim.4780040112"},{"key":"e_1_2_9_7_1","doi-asserted-by":"publisher","DOI":"10.2217\/fon.15.240"},{"key":"e_1_2_9_8_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.critrevonc.2018.03.010"},{"key":"e_1_2_9_9_1","doi-asserted-by":"publisher","DOI":"10.1200\/JCO.2007.15.8659"},{"key":"e_1_2_9_10_1","doi-asserted-by":"publisher","DOI":"10.1200\/JCO.2009.22.0962"},{"key":"e_1_2_9_11_1","doi-asserted-by":"publisher","DOI":"10.1200\/JCO.2013.52.0858"},{"key":"e_1_2_9_12_1","doi-asserted-by":"publisher","DOI":"10.1200\/JCO.2009.23.2025"},{"key":"e_1_2_9_13_1","doi-asserted-by":"publisher","DOI":"10.1200\/JCO.2013.53.1608"},{"key":"e_1_2_9_14_1","doi-asserted-by":"publisher","DOI":"10.1038\/s41523\u2010024\u201000652\u20104"},{"key":"e_1_2_9_15_1","doi-asserted-by":"publisher","DOI":"10.1200\/cci.20.00064"},{"key":"e_1_2_9_16_1","doi-asserted-by":"publisher","DOI":"10.6004\/jnccn.2018.7058"}],"container-title":["Cancer"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/acsjournals.onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/cncr.35729","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T20:56:39Z","timestamp":1760302599000},"score":1,"resource":{"primary":{"URL":"https:\/\/acsjournals.onlinelibrary.wiley.com\/doi\/10.1002\/cncr.35729"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,1,30]]},"references-count":15,"journal-issue":{"issue":"3","published-print":{"date-parts":[[2025,2]]}},"alternative-id":["10.1002\/cncr.35729"],"URL":"https:\/\/doi.org\/10.1002\/cncr.35729","archive":["Portico"],"relation":{},"ISSN":["0008-543X","1097-0142"],"issn-type":[{"value":"0008-543X","type":"print"},{"value":"1097-0142","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,1,30]]},"assertion":[{"value":"2024-09-24","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2024-12-26","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-01-30","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"e35729"}}