The study deals with the treatment efficacy, cosmetic results and toxicities of patients enrolled in the American Society of Breast Surgeons MammoSite Breast Brachytherapy Registry Trial. The trial includes a total of 1,440 patients with early stage breast cancer, who were undergoing breast-conserving therapy and were treated with MammoSite between May 2002 and July 2004. Of the total, 87% of the patients had invasive breast cancer and 13% had been diagnosed with ductal carcinoma in situ (DCIS).
The authors presented a subset analysis of the first 400 cases enrolled in the study with a median follow-up of 37.5 months. The three-year actuarial rate of local or regional recurrence was less than 2% in this group. The percentage of breasts with good or excellent cosmetic results was 93% at 36 months. The authors also reported a three-year actuarial local control rate of 100% in the first 48 patients enrolled with DCIS. An analysis of the overall registry population with a median follow-up of 30.1 months, showed a two-year actuarial rate of local or regional recurrence of one percent; good or excellent cosmetic results of 94% at 24 months and a 10.6% rate of symptomatic seromas.