Treatment-Related Changes

Abstract

Neoadjuvant, primary, or preoperative chemotherapy refers to the treatment of patients with systemic agents before definitive surgical removal of a tumour. Neoadjuvant chemotherapy was introduced in the early 1970s as the treatment of choice for inoperable, locally advanced breast cancer. This approach resulted in significant responses and downstaging of many tumours, permitting mastectomy in some patients. Gradually, the idea of neoadjuvant chemotherapy was extended to include patients with large but operable early-stage breast cancer, allowing the same possibility of tumour downstaging and breast-conserving surgery. Additionally, several randomised clinical trials and meta-analyses showed similar disease-free and overall survivals for patients who received chemotherapy in either an adjuvant or neoadjuvant setting. Today, based on these findings, neoadjuvant chemotherapy is considered an appropriate treatment option for most patients diagnosed with breast cancer where adjuvant chemotherapy was indicated. For patients with inflammatory breast cancer, neoadjuvant therapy is regarded as the standard of care. It is the preferred option for locally advanced breast cancer, and this approach allows both clinicians and patients to have an in vivo assessment of therapeutic efficacy, which can then be used as a surrogate marker to predict long-term survival. Additionally, neoadjuvant trials have been increasingly recognised as a promising platform for efficient testing of investigational compounds and experimental targeted therapies. Most of the current neoadjuvant therapy regimens include a combination of cytotoxic agents. In recent years, with the development of targeted therapy options, many different treatment protocols, which include hormonal and target-specific agents, have been used in the neoadjuvant setting. Assessment of the quantity and biology of the residual tumour can provide further prognostic information for patients receiving neoadjuvant therapy. The possibility of collecting tumour samples before, during, and after the neoadjuvant treatment offers a unique translational research opportunity to delineate the biologic actions of the often personalised, targeted compounds in vivo. Identifying response markers provides a valuable platform from which to advance personalised cancer therapy.