Mammographic Appearance Following Accelerated Partial Breast Irradiation by Using MammoSite Brachytherapy

Purpose: To describe a single institution's experience with mammographic appearance in low-risk patients with early stage breast cancer who have received accelerated partial breast irradiation (APBI) by using MammoSite balloon brachytherapy. Materials and Methods: This study was approved by an institutional review board and was conducted under strict adherence to the Privacy Rule of HIPAA. This was a retrospective review of patients who underwent MammoSite brachytherapy from October 2003 to March 2007. Informed consent for participation in the research project was waived by the institutional review board. Posttherapy mammograms were categorized as showing mild, moderate, or severe distortion and were correlated with patient complaints and complications. Results: Twenty-two women were included in the study, and 93 mammograms were obtained during a median follow-up period of 46 months (range, 22-58 months). Median age was 61 years (range, 47-81 years). One patient developed severe distortion after APBI, while two patients developed only mild distortion throughout follow-up. Eleven (79%) of 14 patients developed moderate distortion, with a median peak in distortion occurring at 21 months. Four (18%) patients developed fat necrosis, two (9%) developed seromas, and two (9%) developed both fat necrosis and seromas. None of the patients required biopsy, and none had an ipsilateral breast recurrence. One patient died of metastatic disease with no evidence of local recurrence. Conclusion: Patients treated with MammoSite APBI developed peak distortion 21 months following therapy, which may be sooner than distortion following conventional whole breast radiation. (C) RSNA, 2010