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Abstract

PURPOSE:

The optimal indications for omitting adjuvant radiation therapy (RT) after breast-conserving surgery are still controversial in ductalcarcinoma in situ (DCIS) of the breast. The purpose of this study was to validate the role of postoperative RT in DCIS patients aged ≤50 years and with tumor margin widths of <1 cm, both of which have been proven to be high-risk features for recurrence in cohorts not receiving RT.

METHODS:

Using two multicenter retrospective studies on DCIS, a pooled analysis was performed among patients aged ≤50 years and with margin widths <1 cm. All patients underwent breast-conserving surgery. Two hundred thirty-two patients received postoperative RT, while 54 did not. The median follow-up period was 77 months (range, 2-190 months) and 70 months (range, 5-166 months) in the patients who received RT and those who did not, respectively.

RESULTS:

The patients who received RT had larger tumors (p<0.001), higher nuclear grade (p<0.001), closer margin width (p<0.001), and negative estrogen receptor expression (p=0.010) compared with those who did not receive RT. During the follow-up period, there were 17 ipsilateral breast tumor recurrences (IBTRs) as follows: invasive carcinoma in 10 patients and DCIS in seven. In the univariate analysis, the treatment with RT and human epidermal growth factor receptor 2 (HER2) status were significant risk factors for IBTR. The 7-year IBTR rates with and without postoperative RT were 3.6% and 13.1%, respectively (p=0.008). HER2-positive tumors had a higher IBTR rate than the HER2-negative tumors (7-year rate, 13.6% vs. 3.9%; p=0.003).

CONCLUSION:

Postoperative RT following breast-conserving surgery significantly reduced the 7-year IBTR rate in the DCIS patients aged ≤50 years and with margin widths <1 cm. HER2 positivity was associated with increased IBTR in these patients.

Author information

Kim K1, Kim JH2, Kim YB3, Suh CO3, Shin KH4, Kim JH4, Kim TH5, Jung SY6, Choi DH7, Park W7, Ahn SD8, Kim SS8, Yea JW9, Kang MK10, Kim DW11, Kim YJ1.

1 Department of Radiation Oncology, Ewha Womans University College of Medicine, Seoul, Korea.
2 Department of Radiation Oncology, Keimyung University Dongsan Medical Center, Keimyung University School of Medicine, Daegu, Korea.
3 Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, Korea.
4 Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea.
5 Proton Therapy Center, National Cancer Center, Goyang, Korea.
6 Center for Breast Cancer, National Cancer Center, Goyang, Korea.
7 Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
8 Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
9 Department of Radiation Oncology, Yeungnam University College of Medicine, Daegu, Korea.
10 Department of Radiation Oncology, Kyungpook National University School of Medicine, Daegu, Korea.
11 Department of Radiation Oncology, Pusan National University School of Medicine, Busan, Korea.