Multicenter Trial for Eliminating Breast Cancer Surgery or Radiotherapy in Exceptional Responders to Neoadjuvant Systemic Therapy

Inclusion criteria

• ✓. Pathologically confirmed unicentric invasive breast cancer defined as radiologic clinical stage T1 or T2 (≤ 5 cm), N0 or N1 (≤ 4 abnormal axillary nodes on initial ultrasound), clinical stage M0.
• ✓. HER2 positive (IHC 3+ and or FISH amplified) or triple receptor negative (TN, ER/PR\< 10% HER2 negative (IHC 1+ or 2+ FISH non-amplified) receiving any standard routine clinical NST regimen.
• ✓. Patient desires breast conserving therapy.
• ✓. Age 40 years or older. This age cutoff is justified because breast cancers in women under the age of 40 are known to have a significantly higher risk of IBTR presumably due to underlying biologic differences \[124, 125\].
• ✓. Female sex.
• ✓. If the patient has a history of a prior non-breast cancer, all treatment for this cancer must have been completed prior to study registration and the patient must have no evidence of disease for this prior non-breast cancer.
• ✓. Patient must have an initial nodal ultrasound that does not demonstrate more than four suspicious lymph nodes, any suspicious lymph nodes should be biopsied to determine if nodal metastatic disease present.
• ✓. Patient understands that the breast lesion size on final breast imaging must be less than or equal to 2 cm prior to the biopsy procedure being performed on study and if the biopsy shows residual carcinoma the patient will be taken off study.