Omitting surgery for early breast cancer showing clinical complete response to primary systemic therapy

Breast cancer is highly sensitive to systemic therapy. High probability of pathological complete response suggests a clinical question that omitting surgery is an effective alternative to surgery in breast cancer showing clinical complete response to primary systemic therapy. However, the validity of omitting surgery for early breast cancer after primary systemic therapy has not been sufficiently established; thus, even if pathological complete response is expected in patients showing clinical complete response, excision of the primary tumor site remains the standard treatment of breast cancer. Inappropriate omitting surgery increases the incidence of local recurrence, which can be the risk of a subsequent distant metastasis and reduced overall survival. To achieve acceptable local control rate, omitting surgery should be investigated in patients with early breast cancer where a high percentage of pathological complete response, a high concordance rate between clinical complete response and pathological complete response and an acceptable local control rate are expected. This review presents concept and ongoing clinical trials for omitting surgery for patients with breast cancer showing clinical complete response to primary systemic therapy.