title: Recurrence outcomes after omission of postoperative radiotherapy following breast-conserving surgery for ductal carcinoma in situ of the breast: a multicenter, retrospective study in Korea (KROG 16-02).
abstract: To evaluate the loco-regional recurrence (LRR) rate after breast-conserving surgery without postoperative radiotherapy (RT) for ductal carcinoma in situ (DCIS) of the breast.
  
  
  
  Between 2000 and 2010, 311 DCIS patients from 9 institutions were analyzed retrospectively. The median age was 47 (range, 20-82). The median tumor size was 7 mm (range, 0.01-76). Margin width was <1 cm in 85 patients (27.3%), and nuclear grade was high in 37 patients (11.9%). Two hundred and three patients (65.3%) received tamoxifen.
  
  
  
  With a median follow-up of 74 months (range, 5-189), there were 11 local recurrences (invasive carcinoma in 6 and DCIS in 5) and 1 regional recurrence. The 7-year LRR rate was 3.8%. On univariate analysis, age and margin width were significant risk factors influencing LRR (p = 0.017 and 0.014, respectively). When age and margin width were combined among 211 patients whose margin width were available, the 7-year LRR rates were as follows (p < 0.001): (1) 0% in patients with age >50 years and any margin width status (n = 64), (2) 1.2% in age ≤50 years and margin width ≥1 cm (n = 93), (3) 13.1% in age ≤50 years and margin width <1 cm (n = 54).
  
  
  
  The LRR rate was very low in selected DCIS patients treated with breast-conserving surgery without postoperative RT. However, adjuvant RT should be considered for those with age ≤50 years and margin width <1 cm.
authors.affiliation: Department of Radiation Oncology, Ewha Womans University School of Medicine, Seoul, Republic of Korea.
authors.forename: Kyubo
authors.initials: K
authors.lastname: Kim
authors.affiliation: Center for Breast Cancer, National Cancer Center, Goyang, Gyeonggi, Republic of Korea.
authors.forename: So-Youn
authors.initials: SY
authors.lastname: Jung
authors.affiliation: Department of Radiation Oncology, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul, 110-744, Republic of Korea. radiat@snu.ac.kr.
authors.forename: Kyung Hwan
authors.initials: KH
authors.lastname: Shin
authors.affiliation: Department of Radiation Oncology, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul, 110-744, Republic of Korea.
authors.forename: Jin Ho
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Surgery, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Wonshik
authors.initials: W
authors.lastname: Han
authors.affiliation: Department of Surgery, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Han-Byoel
authors.initials: HB
authors.lastname: Lee
authors.affiliation: Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Seung Jae
authors.initials: SJ
authors.lastname: Huh
authors.affiliation: Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Doo Ho
authors.initials: DH
authors.lastname: Choi
authors.affiliation: Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Won
authors.initials: W
authors.lastname: Park
authors.affiliation: Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: Seung Do
authors.initials: SD
authors.lastname: Ahn
authors.affiliation: Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: Su Ssan
authors.initials: SS
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Dongsan Medical Center, Keimyung University School of Medicine, Daegu, Republic of Korea.
authors.forename: Jin Hee
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Chang-Ok
authors.initials: CO
authors.lastname: Suh
authors.affiliation: Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Yong Bae
authors.initials: YB
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul, 110-744, Republic of Korea.|Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam, Gyeonggi, Republic of Korea.
authors.forename: In Ah
authors.initials: IA
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul, 110-744, Republic of Korea.|Department of Radiation Oncology, SMG-SNU Boramae Medical Center, Seoul, Republic of Korea.
authors.forename: Suzy
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Ewha Womans University School of Medicine, Seoul, Republic of Korea.
authors.forename: Yi-Jun
authors.initials: YJ
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy*; D002285:Carcinoma, Intraductal, Noninfiltrating; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D015412:Mastectomy, Segmental / Q000379:methods; D008875:Middle Aged; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local; D011379:Prognosis; D018714:Radiotherapy, Adjuvant; D056910:Republic of Korea; D012189:Retrospective Studies; D016896:Treatment Outcome; D047368:Tumor Burden; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor
keywords: Age; Ductal carcinoma in situ; Radiation therapy; Resection margin