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.)