Adjuvant radiation therapy in small ductal carcinoma in situ

Background: The objective of this study was to evaluate ipsilateral breast tumor recurrence (IBTR) rates in patients with small (≤1 cm) ductal carcinoma in situ (DCIS) who were followed up for more than 15 years. Methods: We identified 209 patients with primary small (≤1 cm) DCIS without invasion who received curative excision with and without adjuvant radiation therapy (RT) from 1996 to 2009. IBTR rates and prognostic factors in all patients were estimated by univariate and multivariate analyses. Results: With a median follow-up of 104 months, eight (53.3%) had DCIS recurrence and seven (46.7%) had recurrence of invasive ductal carcinoma. IBTR rate of all patients was 7.5% at 10 years and 12.1% at 15 years. In univariate analysis, age and subtypes were significant factors for IBTR. In multivariate analysis, resection margin, adjuvant RT, and endocrine therapy were significant factors for IBTR. Conclusions: IBTR rate of small (≤1 cm) DCIS following excision with or without adjuvant RT was 12.1% at 15 years. Adjuvant RT and endocrine therapy were associated with lower IBTR rate in small DCIS.