Elizabeth Nichols, Susan B. Kesmodel, Emily Bellavance, Cynthia Drogula, Katherine Tkaczuk, Randi J. Cohen, Wendla Citron, Michelle Morgan, Paul Staats, Steven Feigenberg, William F. Regine

To assess the feasibility of utilizing 3-dimensional conformal accelerated partial-breast irradiation (APBI) in the preoperative setting followed by standard breast-conserving therapy. This was a prospective trial testing the feasibility of preoperative APBI followed by lumpectomy for patients with early-stage invasive ductal breast cancer. Eligible patients had T1-T2 (<3 cm), N0 tumors. Patients received 38.5 Gy in 3.85-Gy fractions delivered twice daily. Surgery was performed >21 days after radiation therapy. Adjuvant therapy was given as per standard of care. Twenty-seven patients completed treatment. With a median follow-up of 3.6 years (range, 0.5-5 years), there have been no local or regional failures. A complete pathologic response according to hematoxylin and eosin stains was seen in 4 patients (15%). There were 4 grade 3 seromas. Patient-reported cosmetic outcome was rated as good to excellent in 79% of patients after treatment. Preoperative 3-dimensional conformal radiation therapy-APBI is feasible and well tolerated in select patients with early-stage breast cancer, with no reported local recurrences and good to excellent cosmetic results. The pathologic response rates associated with this nonablative APBI dose regimen are particularly encouraging and support further exploration of this paradigm.