Evaluate The Accuracy Of Breast MRI Biopsy In Diagnosing A Complete Tumor Response For Some Women Following Neoadjuvant Chemotherapy For Breast Cancer

Inclusion Criteria:

- Women age 18 years or older

- Confirmed histologic diagnosis of operable HER2 overexpressing (ER<10%, PR<10%, and
HER2 2+ or FISH amplified) OR triple negative (ER<10%, PR<10%, and HER2 0/1+ or
2+/FISH not amplified) OR ER positive invasive ductal or invasive lobular breast
cancer including MSKCC pathology confirmation

- Operable breast cancer treated with NAC undergoing either breast conservation or total
Mastectomy who have had a post-NAC clinical bilateral breast MRI demonstrating a
complete imaging response, which is defined as no residual tumor enhancement.

- No indication of distant metastases (M0)

- Tumor site amenable to MRI guided biopsy as determined by the radiologist

- Definitive surgery being performed at MSKCC within within 0-60 days of completing NAC

- ECOG performance status score of 0 to ≤ 2

- Women of childbearing potential (WOCBP) must not be pregnant.

- Women must not be breastfeeding

- Willing and able to provide informed consent and adhere to the study visit schedule
and plan as specified in this protocol

Exclusion Criteria:

- Medical history and concurrent disease:

- Prior history of treated breast cancer

- Any underlying medical or psychiatric conditions, which in the opinion of the
investigator, will make performing the study intervention hazardous or obscure
the interpretation of the results

- Prohibited Treatments and/or Therapies:

- Prior history of breast cancer surgery and/or radiotherapy.