#5149 Purpose: Phase IV prospective post market study to evaluate the safety and device performance of electronic brachytherapy treatment using the Xoft Axxent System as adjuvant therapy for early stage breast cancer.
 Methods and Materials: 44 patients were enrolled between April 2007 and March 2008, and 13 patients have completed 6 months of follow up to date. Patients were eligible if they were older than 50 years, had completely resected DCIS (<2.0cm) or invasive ductal carcinoma (<2.0cm), and microscopic surgical margins of at least 1mm. The balloon applicator was placed in a closed cavity and a balloon surface to skin distance of at least 7mm was required for treatment. The radiation treatment (RT) consisted of delivering 3.4 Gy/fraction twice a day for 10 total fractions. The primary endpoint was the successful delivery of the prescribed RT. Secondary endpoint was adverse device related events.
 Results: Thirteen of the forty-four patients that were enrolled and treated on this study have been followed a minimum of 6 months. The three month follow-up included cosmesis evaluation using the Harvard Cosmesis Scale, and adverse events. The three month cosmesis evaluated by physicians' showed 100% of the patients rated with excellent to good cosmesis. Related adverse events reported through three months included a total of fifteen CTC v3 Grade One AEs. Events included erythema, itching, induration, skin firmness, rash/ desquamation, fatigue. Of these events 90% were resolved. The six month cosmesis physician evaluations showed 82% of the patients had excellent to good cosmesis. Twelve of the 13 patients rated the appearance of their breast, in addition to the physician assessment, and 12 out of 12 rated their appearance good to excellent, one patient did not select any rating. Adverse events reported at six months were a total of three new CTC v3 Grade One. These AEs included occurrences of induration, skin firmness, and hyperpigmentation. A patient satisfaction survey at 6 months follow-up was completed by the patients. Certain survey questions required an answer using a scale of 0-6 for the ratings, where six was the best score. The patients' mean overall rating of satisfaction with the study participation was 5.55 out of 6 (min 3, max 6), satisfied with the radiation treatment was rated 5.54 out of 6 (min 3, max 6). All 13 patients, 100%, stated they would recommend this treatment to a friend.
 Conclusion: This report provides an early look at the experience of using electronic brachytherapy as a means for intracavitary partial breast radiotherapy. The first cohort has reached a minimum of 6 months of follow up and the results appear promising. Additional patient follow up will be presented at the meeting. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5149.