Results: Median follow-up was 36 months (range, 2-84); 62 years was the median age (range, 41-93). The following are salient patient and tumor characteristics: tumor size\2.0 cm in 89% of cases, margins of. 2mm in 93% of patients, and 99% node negative. One local recurrence (LR) developed at 18 months for a 3 and 5-year actuarial rate of 1%. Cosmetic results were rated as good/excellent in 90% of evaluable patients at 3 years (n= 10). Grade I and II rates of erythema, hyperpigmentation, breast edema, breast pain, telangiectasia, fibrosis and fat necrosis with a minimum follow-up of 3 years were 0%, 7%, 0%, 0%, 7%, 21% and 7%, respectively. Only 2 patients (3%) developed grade III toxicity (breast pain) which resolved with time.

Conclusions: 3D-CRT to deliver APBI resulted in minimal chronic (36 months) toxicity to date with good/excellent cosmetic results. Additional follow-up will be needed to assess the long-term efficacy of this form of APBI.