Assessing the Accuracy of Tumor Biopsies After Chemotherapy to Determine if Patients Can Avoid Breast Surgery

This phase II trial studies how well biopsy of breast after chemotherapy works in predicting pathologic response in patients with stage II-IIIA breast cancer undergoing breast conserving surgery. Tumor tissue collected from biopsy before surgery may help to check if chemotherapy destroyed the breast cancer cells and may be compared to the tumor removed during surgery to check if they are the same.

PRIMARY OBJECTIVES: I. To assess the accuracy of post-neoadjuvant systemic therapy (NST) image-directed tumor bed biopsy for pathologic complete response (pCR), defined as resolution of both invasive disease and ductal carcinoma in situ (DCIS), in cases of clinical and radiologic complete response with trimodality imaging. SECONDARY OBJECTIVES: I. To collect axillary pathology results, surgical staging methods (sentinel lymph node biopsy and/or axillary lymph node dissection), and management (surgery and/or radiation) in order to determine axillary nodal response to neoadjuvant chemotherapy and its relationship to breast pCR. II. To correlate imaging results with pathologic nodal status following neoadjuvant chemotherapy for future planning of axillary management in the next study. III. To retrospectively assess the negative predictive value (NPV) of a trimodality imaging algorithm in combination with the tumor bed biopsy for predicting pCR. IV. To collect all trimodality imaging data to determine which combination of the trimodality imaging best identifies the group achieving pCR. V. To correlate the number of needle cores and tumor bed clip retrieval with the NPV of the tumor site biopsy. VI. To determine the clinical, imaging, pathologic, and molecular tumor factors associated with the highest NPVs of post-NST tumor bed biopsies. VII. To improve identification and selection of patients with breast and possible axillary pCR for future trial planning, routine biomarkers (estrogen receptor \[ER\], progesterone receptor \[PR\], HER2 neu, and Ki67) will be collected to allow comparison to image/clinical complete response (CR), and tumor bed biopsies. OUTLINE: After completion of neoadjuvant therapy, patients undergo stereotactic biopsy of breast tumor any time prior to breast conserving surgery. Patients then undergo breast conserving surgery as per standard of care. Patients may also undergo postoperative radiation therapy per standard of care or adjuvant therapy at the investigator's discretion.