Surgery Following Primary Systemic Therapy: How to Increase Breast Conservation Rate

Primary systemic therapy (PST) in breast cancer treatment can be used to downstage tumor size and increase the rate of breast conservation with consequent less morbidity and better aesthetic outcome. Current data on locoregional recurrence (LRR) are encouraging, showing that breast conservation (BCS) after PST is a safe option with no difference in overall survival (OS) and disease-free survival (DFS) when compared to mastectomy. When BCS is considered challenging or impossible at first instance, PST could be a good solution to enable BCS and spare the patient from mastectomy. Patient selection should be based on biological and anatomical factors, considering both tumor-to-breast ratio and the breast tumors for whom tumor downstaging is expected after PST (i.e., hormone receptor negative, high-grade, Her2-positive or triple negative breast cancer). However, for some subgroups of patients, primary surgery remains preferable (i.e. extensive microcalcifications, lobular carcinoma). A reliable local re-staging after PST, accurately reflecting the extent of residual disease, is crucial for an optimal surgery: physical examination, ultrasound, mammography, and magnetic resonance imaging (MRI) should guide the surgeon. The surgical excision should include residual tumor or part of the initial tumor bed around the clip that should be placed before PST. Surgical complications after PST are the same of ordinary breast surgery, despite a more challenging procedure due to the lack of clearly palpable margins that can reduce surgical precision and the difficulty of obtaining negative margins. In order to increase the breast conservation rate, the surgeons should work on: patient selection, accurate pre-and post-PST staging, surgeon-related factors, tumor-related factors, and patient-related factors. A better understanding of the PST potential benefits and of the equivalence of BCS and mastectomy after PST could improve aesthetic outcome and quality of life in more and more breast cancer patients.