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

Inclusion Criteria:

   - The patient must have signed and dated an Institutional Review Board (IRB)-approved
   consent form that conforms to federal and institutional guidelines

   - The patient must have an Eastern Cooperative Oncology Group (ECOG) performance status
   of 0 or 1

   - Patients must have had ER analysis performed on the primary breast tumor collected
   prior to neoadjuvant therapy according to current American Society of Clinical
   Oncology (ASCO)/College of American Pathologists (CAP) guideline recommendations for
   hormone receptor testing; if negative for ER, assessment of progesterone receptor
   (PgR) must also be performed according to current ASCO/CAP Guideline Recommendations
   for hormone receptor testing. Patients who have a primary tumor that is hormone
   receptor-positive or hormone receptor-negative are eligible.

   - Patients must have had HER2 testing performed on the primary breast tumor collected
   prior to neoadjuvant chemotherapy according to the current ASCO/CAP guideline
   recommendations for human epidermal growth factor receptor 2 testing in breast cancer;
   patients who have a primary tumor that is HER2-positive, HER2-equivocal, or
   HER2-negative are eligible

   - Patients must have had a biopsy marker placed within the tumor bed with imaging
   confirmation (preferably mammogram but ultrasound or magnetic resonance imaging [MRI]
   is acceptable) of marker placement prior to neoadjuvant chemotherapy

   - Patients with operable focal or multifocal (T1-T3, stage II or III invasive ductal
   carcinoma [all receptor phenotypes]), and who have completed neoadjuvant chemotherapy
   with a clinical complete response (by clinical examination)

   - Patients with synchronous bilateral breast cancer are eligible if at least one of the
   synchronous breast cancers has a cCR, and the side with a cCR meets criteria.
   (Patients with previous contralateral invasive breast cancer treated with anti-cancer
   therapy are eligible.)

   - Patients must have achieved a complete or near complete radiologic tumor response on
   breast imaging with mammogram, ultrasound, and MRI during or after completion of
   appropriate neoadjuvant chemotherapy defined as:

      - Mammogram with malignant appearing calcification or mass ≤ 1 cm; or

      - Ultrasound with a hypoechoic area ≤ 2 cm; or

      - Breast MRI not demonstrating a residual mass with rapid rise and washout type III
      kinetics.

   - At the time of consent, the patient's intent must be to undergo breast conserving
   therapy.

   - Patient must be able to undergo stereotactic-vacuum-assisted breast biopsy with clip
   placement after completion of neoadjuvant chemotherapy. (The patient must be enrolled
   on the study before performing the post-neoadjuvant stereotactic-vacuum-assisted
   breast biopsy.)

   - Patient must have completed neoadjuvant chemotherapy.

   - Patients with HER2-positive tumors must have received neoadjuvant anti-HER2 therapy
   (either with all or with a portion of the neoadjuvant chemotherapy regimen), unless
   medically contraindicated.

   - Patients treated with PD-1 or PD-L1 inhibitors, CDK 4/6 inhibitors, or other
   immune-based therapy are eligible.

Exclusion Criteria:

   - T4 tumors including inflammatory breast cancer

   - Patients with distant metastatic disease

   - Lumpectomy performed prior to study entry

   - Patients with any history of prior radiation therapy in the affected breast

   - Patients with a prior history of ipsilateral invasive breast cancer; (patients with
   previous ipsilateral/contralateral DCIS or previous contralateral invasive breast
   cancer treated with anti-cancer therapy are eligible)

   - Patients with invasive lobular carcinoma

   - Patients who have multicentric disease

   - Patients treated with neoadjuvant hormonal therapy only are not eligible

   - Patients who are medically unfit to undergo surgical resection

   - Patients without breast biopsy marker documented by imaging at tumor bed site prior to
   initiation of neoadjuvant therapy

   - Patients with one or more of the following imaging criteria from any of the 3 imaging
   modalities after completion of NCT demonstrating incomplete radiologic response are
   not eligible:

      - Mammogram with malignant appearing calcifications or mass > 1 cm; or

      - Ultrasound with a hypoechoic area > 2 cm; or

      - Breast MRI demonstrating a residual mass with rapid rise and washout type III
      kinetics.

   - Psychiatric or addictive disorders or other conditions that, in the opinion of the
   investigator, would preclude the patient from meeting the study requirements or
   interfere with interpretation of study results

   - Pregnancy or lactation at the time of study registration; (Note: Pregnancy testing
   according to institutional standards for women of childbearing potential must be
   performed within 2 weeks prior to study registration.)