The Impact of Neoadjuvant Treatment on Surgical Options and Outcomes.

Neoadjuvant systemic therapy (NST) has become a well-established treatment method for patients with breast cancer, not only for those with large tumors, but also for patients with early high-risk cancers. In earlier times, the clinical advantage of NST was seen in improvement of tumor shrinkage for better operability, conversion of mastectomy candidates to breast conservation, and optimization of cosmetic results. Over the decades, therapy regimens were optimized, resulting in significantly higher response rates. Rates for breast conservation and for conversion from mastectomy to breast conservation, especially for patients with advanced breast cancers, rose significantly for patients undergoing NST. A multidisciplinary approach with close and accurate diagnostic assessment of the breast, axillary tumor, or both during NST and individual-response-guided surgery is mandatory. To reduce unnecessary surgery and prevent mastectomies, more conclusive prediction models and minimally invasive methods for selection of patients with pathologic complete remission after NST are needed. Furthermore, prospective studies demonstrate that sentinel node biopsy for patients with initial clinically node-positive axillary nodes converting to clinically node-negative axillary nodes is oncologically safe and offers less morbidity, avoiding complete axillary node dissection. Initial concerns regarding surgical complications and morbidity due to potential immune frailty of patients with NST were not observed.