This study will evaluate the immune-priming effects of stereotactic body radiation therapy (SBRT) regimen coupled with two injections of pembrolizumab in high-risk primary breast carcinoma prior to neoadjuvant chemotherapy. Preliminary results from the investigators' local TRIO Trial suggest that SBRT prior to neoadjuvant chemotherapy (NAC) may result in improved response rates due to the combined effect of radiation therapy (RT) and chemotherapy. The investigators aim to augment this effect with the addition of pembrolizumab, a monoclonal antibody that binds to and blocks programmed cell death protein 1 (PD-1).
Invasive ductal carcinoma of any subtype (including invasive mammary carcinoma with lobular features), excluding sarcomatous, signet or metaplastic subtypes.
Invasive mammary carcinoma of stages IIB - III (excluding inflammatory breast cancer). Stage IIA is eligible for triple negative and HER2+ breast cancers.
Lesion palpable by treating physician.
Plan to be treated with neoadjuvant chemotherapy.
Any serious medical comorbidities or other contraindications to radiotherapy, chemotherapy, or surgery (e.g., uncontrolled diabetes, serious heart condition, etc).
Prior treatment for current breast cancer.
Previous radiation therapy to the same breast.
Inflammatory breast carcinoma.