Individual patient data were available for all four of the randomized trials that began before 1995, and that compared adjuvant radiotherapy vs no radiotherapy following breast-conserving surgery for ductal carcinoma in situ (DCIS). A total of 3729 women were eligible for analysis. Radiotherapy reduced the absolute 10-year risk of any ipsilateral breast event (ie, either recurrent DCIS or invasive cancer) by 15.2% (SE 1.6%, 12.9% vs 28.1% 2 P <.00001), and it was effective regardless of the age at diagnosis, extent of breast-conserving surgery, use of tamoxifen, method of DCIS detection, margin status, focality, grade, comedonecrosis, architecture, or tumor size. Jon Godwin is a member of the EBCTCG, which is the group author for this article.
- breast cancer
- clinical trials