External beam accelerated partial breast irradiation yields favorable outcomes in patients with prior breast augmentation.

[PURPOSE] To report outcomes in breast cancer patients with prior breast augmentation treated with external beam accelerated partial breast irradiation (EB-APBI) utilizing intensity-modulated radiotherapy or 3-dimensional conformal radiotherapy, both with IGRT.

[MATERIALS AND METHODS] Sixteen stage 0/1 breast cancer patients with previous elective bilateral augmentation were treated post-lumpectomy on institutional EB-APBI trials (01185132 and 01185145 on clinicaltrials.gov). Patients received 38.5 Gy in 10 fractions over five consecutive days. Breast/chest wall pain and cosmesis were rated by patient; cosmesis was additionally evaluated by physician per RTOG criteria.

[RESULTS] The median follow-up from accelerated partial breast irradiation (APBI) completion was 23.9 months (range, 1.2-58.6). Little to no change in cosmesis or pain from baseline was reported. Cosmetic outcomes at last follow-up were judged by patients as excellent/good in 81.2% (13/16), and by physicians as excellent/good in 93.8% (15/16). Ten patients (62.5%) reported no breast/chest wall pain, five (31.2%) reported mild pain, and one (6.2%) reported moderate pain. All patients remain disease free at last follow-up. The median ipsilateral breast, planning target volume (PTV), and implant volumes were 614, 57, and 333 cm(3). The median ratios of PTV/ipsilateral breast volume (implant excluded) and PTV/total volume (implant included) were 9 and 6%.

[CONCLUSION] These 16 breast cancer cases with prior bilateral augmentation treated with EB-APBI demonstrate favorable clinical outcomes. Further exploration of EB-APBI as a treatment option for this patient population is warranted.