Three Fraction Radiation to Induce Immuno-Oncologic Response

Patients eligible for neoadjuvant chemotherapy for locally advanced stage III (non-inflammatory) breast cancer or stage IIb (triple negative or Her2+) breast cancers will be approached to participate in this single arm trial. Patients with staging investigations ruling out distant disease will be approached to participate and will undergo pre-treatment image guided core biopsy and blood samples for molecular correlative studies, followed by hypofractionated radiation (delivered prone) to entire tumor with dose constraints to skin, critical organs and contralateral breast, plus a 0.5 cm PTV. As much of the tumor that can receive planned dose of 8 Gy per fraction x 3 fractions every second day, with fall off dose to 4 Gy per fraction x 3 fractions for PTV margin. Two weeks following completion of radiation, patients will undergo a second image guided core needle biopsy of tumor and blood sample. They will then begin standard neoadjuvant chemotherapy (anthracycline and taxane based), followed by a third tissue biopsy under image guidance of any residual tumor and blood sample and then standard surgery (breast conserving or lumpectomy). This will be followed by standard whole breast radiation (50 Gy in 25 fractions). Herceptin therapy and hormonal therapy will be administered as per clinical standard when indicated. Primary outcome will be measured as pathological complete response to treatment, and secondary outcomes will include toxicity, immune markers (tumor infiltrating lymphocytes, PD-1 and PD-L1 up-regulation and changes to the circulating lymphocyte counts.