Small Triple-Negative and HER2-Positive Early Breast Cancer: Upfront Surgery or Neoadjuvant Chemotherapy?

Breast cancer (BC) can be treated by combinations of surgery, radiotherapy, chemotherapy, endocrine therapy and targeted therapies. High-risk patients, including all patients with axillary involved lymph nodes with triple-negative BC (TNBC) and Her2-positive BC, are treated by neoadjuvant chemotherapy (NAC). For high-risk patients, immunotherapy for TNBC, trastuzumab and pertuzumab then trastuzumab deruxtecan for Her2-positive BC have improved survival. In this narrative review, we will discuss therapy for small triple-negative and HER2-positive early BC without involved or suspicious axillary lymph nodes. Upfront surgery is recommended for cT1a-b cN0 usN0 TNBC and Her2-positive BC with adjuvant therapy for pT1b pN0 BC, discussed case by case for pT1a pN0 Her2-positive BC. No adjuvant chemotherapy is considered for pT1a TNBC. However, lymph vascular invasion can also be contributive on pathologic results. For pT1c pN0 TNBC and Her2-positive BC, adjuvant therapy is recommended. For cT2 or cN+ TNBC and Her2-positive BC, NAC is the treatment recommended with adjuvant therapy after surgery according to pathologic results. For cT1c cN0 usN0 TNBC and Her2-positive BC, upfront surgery is the usual treatment proposed but NAC can be strongly considered according to clinic pathologic characteristics, tumor size 10-15 mm or 16-20 mm, grade, young age (≤35-years) and co-morbidities, particularly for elderly patients. Recent tools such as TIL level determined on core needle biopsy may help when considering NAC or upfront surgery and systemic therapy regimens. Other prognostic tools can contribute to the determined therapeutic strategy and systemic therapy regimens with escalation or de-escalation, such as TNBCDX or HER2DX, possibly in combination with TIL level.