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. The proportional reduction in ipsilateral breast events was greater in older than in younger women (2P < .0004 for difference between proportional reductions; 10-year absolute risks: 18.5% vs 29.1% at ages <50 years, 10.8% vs 27.8% at ages ≥ 50 years) but did not differ significantly according to any other available factor. Even for women with negative margins and small low-grade tumors, the absolute reduction in the 10-year risk of ipsilateral breast events was 18.0% (SE 5.5, 12.1% vs 30.1%, 2P = .002). After 10 years of follow-up, there was, however, no significant effect on breast cancer mortality, mortality from causes other than breast cancer, or all-cause mortality.

Original publication

DOI

10.1093/jncimonographs/lgq039

Type

Journal article

Journal

J Natl Cancer Inst Monogr

Publication Date

2010

Volume

2010

Pages

162 - 177

Keywords

Adult, Aged, Antineoplastic Agents, Hormonal, Breast Neoplasms, Carcinoma, Ductal, Breast, Carcinoma, Intraductal, Noninfiltrating, Chemotherapy, Adjuvant, Combined Modality Therapy, Female, Humans, Mastectomy, Segmental, Meta-Analysis as Topic, Middle Aged, Multicenter Studies as Topic, Neoplasm Recurrence, Local, Neoplasms, Second Primary, Radiotherapy, Adjuvant, Randomized Controlled Trials as Topic, Tamoxifen