Nylah Fatima Wasti MD, Presenter: Nothing to Disclose

Nina L. Fabiszewski MD, Abstract Co-Author: Nothing to Disclose

Claire Carman MD, Abstract Co-Author: Nothing to Disclose

MammoSite is an innovative application providing intracavitary brachytherapy as part of breast-conserving treatment of breast cancer. Consisting of high dose radiation administered via a balloon placed in the lumpectomy bed, MammoSite delivers accelerated partial breast irradiation, decreasing therapy time to 5 days, compared with 5-7 weeks for patients receiving whole breast irradiation. The radiographic effects of MammoSite have not been discussed in the medical literature to date. The purpose of our study is to describe the mammographic findings of patients who have received MammoSite therapy.

A total of 79 patients received MammoSite therapy at our institution between February 2005 and July 2006. The authors reviewed mammograms of the 37 patients who had at least two sets of mammograms following MammoSite radiation, and compared these with 37 patients who received whole breast radiation following lumpectomy.

Of the 37 patients who received MammoSite radiation, 7 (19%) developed seromas and 10 (27%) developed features of fat necrosis (increased density, architectural distortion, calcification). Mammographic changes in the lumpectomy bed prompted further evaluation in 6 patients (16%); biopsy in 4, and short interval follow-up mammogram in 2. Of these cases, 1 patient was found to have recurrent disease. By comparison, only 1 patient who received whole breast irradiation developed a seroma (3%) and 3 (8%) developed fat necrosis; no biopsies or short interval follow-ups were recommended.

The high dose intracavitary radiation provided by MammoSite resulted in more pronounced changes on subsequent mammography at the site of lumpectomy and balloon placement. Over a period of 6-24 months, patients were 7 times more likely to develop seromas and 3.3 times more likely to develop fat necrosis in the lumpectomy bed, compared with patients who received whole breast radiation. Mammographic findings prompted further evaluation significantly more often in patients who received MammoSite (P<.001).

Patients who receive Mammosite radiation are more likely to develop seromas and fat necrosis; these changes may make it more difficult to exclude recurrence on subsequent mammograms.

Wasti, N, Fabiszewski, N, Carman, C, Evaluation of Mammographic Features Post Mammo Site Therapy.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5011166.html