Survival benefit of postoperative radiotherapy for ductal carcinoma in situ after breast-conserving surgery: a Korean population-based cohort study
It has been accepted that radiation therapy (RT) for ductal carcinoma in situ (DCIS) has no survival benefit despite increasing local control. However, a recent large database study reported a small but significant benefit. Using a Korean population-based large database, we examined the survival benefit of RT for DCIS after breast-conserving surgery (BCS) and analyzed which subgroup might derive benefit from it.
Data from 6038 female DCIS patients who underwent BCS with or without RT between 1993 and 2012 were included in this study. We used propensity score analysis to control for differences in baseline characteristics.
Before adjusting, patients who received RT were more likely to have a large-sized tumor, poor histologic grade, poor nuclear grade, and less hormone receptor positivity. Ten-year overall survival (OS) rates were 95.0% in the non-RT group and 97.1% in the RT group (p < 0.001). After adjusting, previously noted differences of characteristics were substantially reduced, and then ten-year OS rates were 94.3% in the non-RT group and 97.6% in the RT group (p = 0.001). When examining the benefit of RT according to proposed prognostic scores, patients with a score of 0 showed no difference in OS by adding RT after BCS, whereas those with high scores demonstrated a significant benefit.
We demonstrated the significant OS benefit of postoperative RT after BCS based on a large database, and for the first time beyond the western population. The omission of RT for selected patients to prevent overtreatment needs to be more elaborately studied.
KeywordsPostoperative radiotherapy Ductal carcinoma in situ Breast-conserving surgery
This article was supported by the Korean Breast Cancer Society (WA35-20170205-01).
The research for this manuscript was not financially supported and none of the authors had any relevant financial relationships.
Compliance with ethical standards
Conflict of interest
The authors declare that no actual or potential conflict of interest exists. The Institutional Review Boards approved this study (Seoul Metropolitan Government Seoul National University Boramae Medical Center, 07-2017-6).
All procedures performed in studies involving human participants were in accordance with the Ethical Standards of the Institutional and/or National Research Committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
For this type of study formal consent is not required.
Research involving human participants and/or animals
This article does not contain any studies with animals performed by any of the authors.
- 3.Kim K, Jung S-Y, Shin KH et al (2017) 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). Breast Cancer Res Treat 162:77–83. https://doi.org/10.1007/s10549-017-4111-1 CrossRefPubMedGoogle Scholar
- 6.EORTC Breast Cancer Cooperative Group, EORTC Radiotherapy Group, Bijker N et al (2006) Breast-conserving treatment with or without radiotherapy in ductal carcinoma-in situ: ten-year results of European Organisation for Research and Treatment of Cancer randomized phase III trial 10853—a study by the EORTC Breast Cancer Cooperative Group and EORTC Radiotherapy Group. J Clin Oncol 24:3381–3387. https://doi.org/10.1200/JCO.2006.06.1366 CrossRefGoogle Scholar
- 10.Sagara Y, Freedman RA, Vaz-Luis I et al (2016) Patient prognostic score and associations with survival improvement offered by radiotherapy after breast-conserving surgery for ductal carcinoma in situ: a population-based longitudinal cohort study. J Clin Oncol 34:1190–1196. https://doi.org/10.1200/JCO.2015.65.1869 CrossRefPubMedPubMedCentralGoogle Scholar
- 17.Early Breast Cancer Trialists’ Collaborative Group (EBCTCG), Darby S, McGale P et al (2011) Effect of radiotherapy after breast-conserving surgery on 10-year recurrence and 15-year breast cancer death: meta-analysis of individual patient data for 10,801 women in 17 randomised trials. Lancet 378:1707–1716. https://doi.org/10.1016/S0140-6736(11)61629-2 CrossRefGoogle Scholar
- 20.van Maaren MC, de Munck L, de Bock GH et al (2016) 10 Year survival after breast-conserving surgery plus radiotherapy compared with mastectomy in early breast cancer in the Netherlands: a population-based study. Lancet Oncol 17:1158–1170. https://doi.org/10.1016/S1470-2045(16)30067-5 CrossRefPubMedGoogle Scholar
- 22.Hofvind S, Holen Å, Aas T et al (2015) Women treated with breast conserving surgery do better than those with mastectomy independent of detection mode, prognostic and predictive tumor characteristics. Eur J Surg Oncol 41:1417–1422. https://doi.org/10.1016/j.ejso.2015.07.002 CrossRefPubMedGoogle Scholar
- 26.Sayan M, Wilson K, Nelson C et al (2017) A novel schedule of accelerated partial breast radiation using intensity-modulated radiation therapy in elderly patients: survival and toxicity analysis of a prospective clinical trial. Radiat Oncol J 35:32–38. https://doi.org/10.3857/roj.2016.01963 CrossRefPubMedPubMedCentralGoogle Scholar