Postmastectomy radiation therapy for patients with pT1-2N1 breast cancer over 2 decades in Korea - Korean Radiation Oncology Group 14-21 - Research findings overview

Sep 29, 2026

Patterns of postmastectomy radiation therapy (PMRT) for pT1–2N1 breast cancer in Korea were evaluated across two decades, using retrospective data from 700 patients treated at 16 institutions in three time periods (1990, 2000, 2010). PMRT was delivered to 10.0% overall, with utilization rising from 7.4% to 11.1% across the decades. Hospital-level variation was substantial (0%–87.5%). Axillary irradiation and inclusion of regional nodal sites declined over time. Locoregional recurrence was lower with PMRT, while long-term survival outcomes were similar.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages9

Reading Time23 min

AccessFree to download

Introduction

Purpose

Materials and Methods

Results

Utilization and temporal trends

Survival and recurrence outcomes

Conclusion

Original Article pISSN 2234-1900 · eISSN 2234-3156 Radiat Oncol J 2025;43(4):172-180 [https://doi.org/10.3857/roj.2025.00052](https://doi.org/10.3857/roj.2025.00052) Postmastectomy radiation therapy for patients with pT1-2N1 breast cancer over 2 decades in Korea: Korean Radiation Oncology Group 14-21 Mi Sun Kim1, Seung Do Ahn2, Yong Bae Kim3, Won Park4, Shin-Hyung Park5, Ik Jae Lee6, Byung-Ock Choi7, Juri Kim8, Sung Ja Ahn9, Won Sup Yoon10, Jin-hee Kim11, Jong Hoon Lee12, Donghyun Kim13, Hye Li Park14, Yeon-Joo Kim15, Sun Young Lee16, Kyung Ran Park17, Division for Breast Cancer, Korean Radiation Oncology Group 1Department of Radiation Oncology, Yonsei University Wonju College of Medicine, Wonju, Republic of Korea 2Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea 3Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, Republic of Korea 4Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea 5Department of Radiation Oncology, Kyungpook National University School of Medicine, Daegu, Republic of Korea 6Department of Radiation Oncology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea 7Department of Radiation Oncology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea 8Department of Radiation Oncology, Cheil General Hospital, Seoul, Republic of Korea 9Department of Radiation Oncology, Chonnam National University Hwasun Hospital, Hwasun, Republic of Korea 10Department of Radiation Oncology, Korea University College of Medicine, Seoul, Republic of Korea 11Department of Radiation Oncology, Keimyung University Dongsan Medical Center, Daegu, Republic of Korea 12Department of Radiation Oncology, St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, Suwon, Republic of Korea 13Department of Radiation Oncology, Pusan National University School of Medicine, Busan, Republic of Korea 14Department of Radiation Oncology, Jeonju Jesus Hospital, Jeonju, Republic of Korea 15Department of Radiation Oncology, Research Institute and Hospital, National Cancer Center, Goyang, Republic of Korea 16Department of Radiation Oncology, Jeonbuk National University Hospital, Jeonju, Republic of Korea 17Department of Radiation Oncology, Kosin University College of Medicine, Busan, Republic of Korea Received: January 27, 2025 Revised: June 9, 2025 Accepted: July 3, 2025 Correspondence: Kyung Ran Park Department of Radiation Oncology, Kosin University College of Medicine, 262 Gamcheon-ro, Seo-gu, Busan 49267, Republic of Korea Tel: +82-51-990-6399 [E-mail: krparkia@gmail.com](E-mail: krparkia@gmail.com)[ ](E-mail: krparkia@gmail.com)ORCID: [https://orcid.org/0000-0002-9163-0707](https://orcid.org/0000-0002-9163-0707) Seung Do Ahn Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpagu, Seoul 05505, Republic of Korea Tel: +82-2-3010-4436 [E-mail: sdahn@amc.seoul.kr](E-mail: sdahn@amc.seoul.kr)[ ](E-mail: sdahn@amc.seoul.kr)ORCID: [https://orcid.org/0000-0003-4153-4191](https://orcid.org/0000-0003-4153-4191) Purpose: This study investigates patterns of postmastectomy radiation therapy (PMRT) use in patients with pT1–2N1 breast cancer treated with mastectomy in Korea over 2 decades. Materials and Methods: Data from 700 patients treated at 16 institutions across three decades (1990, 2000, and 2010) were retrospectively reviewed. Results: Overall, 10.0% of patients received PMRT, with utilization rates of 7.4%, 8.8%, and 11.1% in 1990, 2000, and 2010, respectively. The use of PMRT varied substantially among the hospitals (0%–87.5%). The two-dimensional radiotherapy was used in 1990, but the adoption of tangential beam three-dimens

FAQs

What was the purpose of this study?

To investigate the patterns of postmastectomy radiation therapy (PMRT) use in Korean patients with pT1–2N1 breast cancer treated with mastectomy over two decades.

How many patients and institutions were included?

The retrospective review included 700 patients treated at 16 institutions across three decades: 1990, 2000, and 2010.

What were the main findings about PMRT utilization and recurrence?

Overall, 10.0% of patients received PMRT, with rates of 7.4%, 8.8%, and 11.1% in 1990, 2000, and 2010. Locoregional recurrence was lower in the PMRT group (1.4%) than in the no-PMRT group (8.1%), while 10-year OS and RFS were not significantly different.

Sep 29, 2026

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