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ORIGINAL RESEARCH article
Front. Oncol.
Sec. Breast Cancer
Volume 15 - 2025 | doi: 10.3389/fonc.2025.1484190
De-escalation of Regional Nodal Irradiation Fields in pT1-2N1 Breast Cancer Patients after Breast Conserving Surgery: Retrospective Real-world Clinical Experience
Provisionally accepted- Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Republic of Korea
Purpose: Regional nodal irradiation (RNI) in pN1 patients with one to three positive axillary lymph nodes breast cancer remains controversial. This study aims to evaluate the impact of RNI in patients with pT1-2N1 breast cancer who underwent radiotherapy after breast-conserving surgery (BCS), focusing on risk stratification and defining the extent of RNI as axillary lymph node level I and II. Methods: Female patients with pT1-2N1 breast cancer after BCS with axillary lymph node dissection or sentinel lymph node biopsy treated with radiotherapy between 2009 and 2021 were identified. Radiotherapy included either whole breast irradiation (WBI) alone or WBI with RNI to axillary level I and II. Patients were categorized into three risk groups based on pathological T stage, number of positive lymph nodes, and immunohistochemical classifications. Results: 464 patients were analyzed with a median follow-up of 68.5 months. 212 (45.7%) patients received WBI alone, and 252 (54.3%) received WBI with RNI. Overall, RNI did not significantly improve disease-free survival (DFS) (p=0.317), locoregional recurrence-free survival (LRRFS) (p=0.321), distant metastasis-free survival (DMFS) (p=0.452), or overall survival (OS) (p=0.721). However, RNI demonstrated significant benefit in LRRFS (p=0.014) for high-risk group. Case-control matched analysis showed robust benefits in DFS (p=0.020), LRRFS (p=0.030), and marginal improvement in DMFS (p=0.066) for high-rigk group. Toxicities were comparable between the WBI alone and WBI with RNI. Conclusions: RNI omission may be considered for low-risk patients with pT1 and one positive lymph node. High-risk patients with pT2, two to three lymph nodes, or triple-negative breast cancer might benefit from RNI. De-escalation of RNI extent might be considered for non-inferior survival outcomes with comparable toxicities.
Keywords: breast cancer, regional nodal irradiation, Whole breast irradiation, Breastconserving surgery, Disease-Free Survival, overall survival, local-regional recurrence-free survival
Received: 21 Aug 2024; Accepted: 17 Feb 2025.
Copyright: © 2025 Hong, Song, Choi, Kim and Choi. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Byung-Ock Choi, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Republic of Korea
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