PET Dynamics to Response-Adapted Neoadjuvant Therapy in TNBC

Eligible participants will undergo baseline procedures including research bloodwork, MRI and PET scan. Participants will then be treated with one cycle of paclitaxel, carboplatin and pembrolizumab (TCarbo/pembro). At the end of Cycle one patients will undergo repeat procedures (bloodwork and PET scan), and then continue with treatment for an additional three cycles. ctDNA will be collected on day 1 of each cycle. At the end of treatment patients will undergo repeat MRI. Patients achieving a clinical complete response (CR) on MRI will proceed with surgery. Patients with clinical residual disease (RD) on MRI will be recommended a biopsy, and be recommended "rescue" neoadjuvant doxorubicin and cyclophosphamide with pembrolizumab (AC/pembro) for four additional cycles, and then proceed with surgery. Note: patients/treating physician may opt to proceed with surgery. Archival tissue will be collected from the surgical product. Patients achieving a pathologic CR (pCR) may proceed with adjuvant pembrolizumab per standard of care, and treating physician's discretion. Patients with pathological RD may proceed with "rescue" adjuvant AC/pembrolizumab for four additional cycles (if not given neoadjuvantly), per treating physician discretion. The participants may also receive Aadjuvant capecitabine or olaparib as indicated and per treating physician's discretion.