Ductal carcinoma in situ of the breast treated with accelerated partial breast irradiation using balloon-based brachytherapy.

Abstract

We reviewed our institution's experience treating patients with ductal carcinoma in situ (DCIS) of the breast with balloon-based accelerated partial breast irradiation (APBI) to determine the efficacy of this treatment approach in this group of patients. A total of 126 cases of DCIS seen and treated with APBI using balloon-based brachytherapy constitute the study population. The median age at diagnosis was 59 years (range, 37-82) with 21% younger than age 50. Nuclear grade distribution was 52.5, 41.4, and 6.1% high, intermediate and low, respectively. Of these patients, 86% had estrogen receptor positive DCIS. The median tumor size was 6 mm (range, 1-26). Margins of excision were negative in 98.4% of patients. All patients were treated with 34 Gy in 10 fractions using either the MammoSite™ or Contura™ breast brachytherapy catheter. A total of 87 patients (73.1%) were placed on adjuvant tamoxifen or arimedex. With a median follow-up of 24 months (range, 0.7-73.9), three (2.4%) ipsilateral breast tumor recurrences (IBTRs) developed for a 2-year actuarial rate of 0.81%. Recurrences developed 4.8, 24.7, and 24.9 months after treatment. On univariate analysis, no variable was associated with IBTR. A subset analysis of the first 50 consecutive patients treated was also performed. With a median follow-up of 40 months (range, 15.6-73.9), one IBTR developed for a 3-year actuarial rate of 2.15%. Early results in patients with DCIS treated with APBI using balloon-based brachytherapy produced results similar to those with invasive cancer treated with APBI or DCIS treated with whole breast irradiation.