Breast Cancer Locator Guided vs. Wire Localized Partial Mastectomy for Breast Cancer

Inclusion Criteria:

• Female gender

• Age > 18 years

• Histologic diagnosis of invasive breast cancer or DCIS

• The surgeon determines that pre-operative tumor localization is required because thetumor cannot be definitively detected by palpation

• The tumor is unifocal or multifocal with satellite lesions < or = 2 cm from primarytumor

• The tumor enhances on prone breast MRI imaging

• The tumor is ≥ 1 cm in diameter on prone breast MRI

• Subject and surgeon agree to perform BCS

• Subject voluntarily provides informed consent

Exclusion Criteria:

• Absolute contraindication to MRI, including presence of implanted electrical device (e.g., pacemaker or neurostimulator), aneurysm clip, or metallic foreign body in ornear eyes

• Severe claustrophobia that precludes prone or supine MRI

• Contraindication to use of gadolinium-based intravenous contrast, including life-threatening allergy

• Compromised renal function including chronic, severe kidney disease (GFR < 30ml/min/1.73m2), or acute kidney injury

• Pregnancy - In women of childbearing potential, a urine pregnancy test will beperformed

• Subjects who have received or plan to receive neoadjuvant chemotherapy

• Sternal notch to nipple distance of > 32 cm as measured in a sitting or standingposition

• Measurement of widest circumference around breasts and arms > 135 cm for sites using 60cm bore scanners, and measurement of widest circumference around breasts and arms >145 cm for sites using 70 cm bore scanners

• Subjects with known allergy to materials present in the device

• Use of localization with devices other than a localization wire, includingintraoperative ultrasound guidance, radiofrequency emitting implants, magneticseeds, radioactive seeds, and tissue inspection devices (MarginProbe)

• Subject would require > 2 localization wires, if randomized to standard of care

• Subjects with multicentric tumors (additional tumors > 2 cm from primary)

• Subject would require chest wall muscle nerve block as part of the operation