Prospective, Multicenter Confirmatory Clinical Evaluation of Novilase® Interstitial Laser Therapy for the Focal Destruction of Malignant Breast Tumors ≤15 mm (BR-003)

Inclusion Criteria: * Females, aged 18 years and older * Able to give written informed consent herself * Definitive pathologic diagnosis by needle core biopsy * Unifocal malignant tumor (T1a-c, N0-1, M0) that does not exceed 15 mm in longest dimension and measures at least 5 mm away from the skin and chest wall, or can be moved at least 5 mm away from the skin and chest wall by injection of saline or local anesthetic * No more than 10 mm of calcifications confined to the tumor on imaging * Tumor is well visualized through ultrasound or x-ray mammography imaging and amenable to image-guidance therapy (i.e., a tumor which is well visualized through imaging can be identified from surrounding breast tissue and does not have margins obscured by other structures or artifacts on the images) * Tumor is well visualized on MRI * Subject with mammographic appearance of overall dense parenchymal tissue may be included, as long as a clearly evident marker is present at tumor site * Tumor with less than 25% intraductal component, as determined by core biopsy * No clinically significant co-morbidities (e.g., chronic illnesses existing simultaneously with and usually independent of breast cancer) that affect life expectancy * Subject weight limited to ≤300 lbs. or ≤136 kg * Subject agrees to comply with standard of care radiation or adjuvant therapy as prescribed by physician Exclusion Criteria: * Subject younger than 18 years of age * Pregnant or breast-feeding * Tumor poorly visualized by ultrasound or x-ray mammography imaging * Contraindications to administration of gadolinium-based contrast agent, including: prior allergic reaction to a gadolinium-based contrast agent, moderate to end-stage kidney disease, and/or acute or chronic severe renal insufficiency (Glomerular filtration rate (GFR) \<30ml/min/1.73 sq. meters) * Contraindications to MRI according to site guidelines (e.g., cardiac pacemaker, metallic implants) * History of severe asthma * Tumor measuring greater than 15 mm in longest dimension * Microcalcifications that extend beyond target tumor such that overall longest dimension of target tumor and calcifications is longer than 15 mm. * Advanced stage breast cancer * Tumors that are lobular neoplasm, metastatic carcinoma to breast, sarcoma, Phyllodes tumor, or Paget's disease * Tumor with only DCIS with microinvasion * Extensive intraductal component in lesion (i.e., \>25%) as determined by core biopsy * Subject who is known to be BRCA positive * Tumor that is ER/PR/HER2 negative (TNBC) * Inability to lie in prone or supine position for one hour * Subject who is currently participating in another investigational treatment, device or drug study through follow up that would interfere with this trial * Subject without a definitive HER2 test according to ASCO/CAP guidelines