Surgical Excision Without Radiation for Ductal Carcinoma in Situ of the Breast: 12-Year Results From the ECOG-ACRIN E5194 Study

Abstract

Purpose: To determine the 12-year risk of developing an ipsilateral breast event (IBE) for women with ductal carcinoma in situ (DCIS) of the breast treated with surgical excision (lumpectomy) without radiation.

Patients and methods: A prospective clinical trial was performed for women with DCIS who were selected for low-risk clinical and pathologic characteristics. Patients were enrolled onto one of two study cohorts (not randomly assigned): cohort 1: low- or intermediate-grade DCIS, tumor size 2.5 cm or smaller (n = 561); or cohort 2: high-grade DCIS, tumor size 1 cm or smaller (n = 104). Protocol specifications included excision of the DCIS tumor with a minimum negative margin width of at least 3 mm. Tamoxifen (not randomly assigned) was given to 30% of the patients. An IBE was defined as local recurrence of DCIS or invasive carcinoma in the treated breast. Median follow-up time was 12.3 years.

Results: There were 99 IBEs, of which 51 (52%) were invasive. The IBE and invasive IBE rates increased over time in both cohorts. The 12-year rates of developing an IBE were 14.4% for cohort 1 and 24.6% for cohort 2 (P = .003). The 12-year rates of developing an invasive IBE were 7.5% and 13.4%, respectively (P = .08). On multivariable analysis, study cohort and tumor size were both significantly associated with developing an IBE (P = .009 and P = .03, respectively).

Conclusion: For patients with DCIS selected for favorable clinical and pathologic characteristics and treated with excision without radiation, the risks of developing an IBE and an invasive IBE increased through 12 years of follow-up, without plateau. These data help inform the treatment decision-making process for patients and their physicians.

Trial registration: ClinicalTrials.gov NCT00002934.

Conflict of interest statement

Authors' disclosures of potential conflicts of interest are found in the article online at www.jco.org. Author contributions are found at the end of this article.

© 2015 by American Society of Clinical Oncology.

Figures

Fig 1.

Ipsilateral breast events (IBEs) for cohort 1 and cohort 2. Cohort 1 was defined as low- or intermediate-grade ductal carcinoma in situ (DCIS), tumor size 2.5 cm or smaller. Cohort 2 was defined as high-grade DCIS, tumor size 1.0 cm or smaller. Cohort assignment was based on clinical evaluation and pathology assessment from the treating institution at the time of enrollment. The numbers at risk are given beneath the x-axis. (A) Any IBE. (B) Subset of invasive IBE. (C) Subset of DCIS-only IBE.

Fig 2.

Ipsilateral breast events (IBEs) according to tumor size. The numbers at risk are given beneath the x-axis.

Fig A1.

Ipsilateral breast events (IBEs) according to grade as scored using current College of American Pathology guidelines. Analyses exclude cases not evaluated. The numbers at risk are given beneath the x-axis. (A) Any IBE. (B) Subset of invasive IBE.