From the Division of Oncology and Siteman Cancer Center, Washington University in St. Louis, St. Louis, Missouri
Author's disclosure of potential conflicts of interest is found at the end of this article.
Address reprint requests to Matthew J. C. Ellis, MB, PhD, FRCP, the Division of Oncology and Siteman Cancer Center, Washington University in St. Louis, 660 South Euclid Avenue, Campus Box 8056, St. Louis, MO 63110; E-mail: mellis{at}wustl.edu
Overview: Neoadjuvant systemic therapy for breast cancer is used increasingly for patients with clinical stages II and III breast cancer to improve surgical outcomes. However, because clinical studies have not shown an improvement in relapse-free survival with the neoadjuvant approach, patient benefit can only be stated in terms of an improvement in the chance of breast conservation or the recovery of a surgical option for patients with extension of disease into adjacent structures (i.e., skin and muscle). One of the more compelling theoretical arguments for primary systemic therapy is its value as an in vivo test for drug sensitivity. For neoadjuvant chemotherapy, data on the favorable effects of a pathologic complete response on relapse-free survival drive this concept. More recently, postmenopausal patients with clinical stages II and III estrogen receptor-positive disease who are downstaged to stage I with neoadjuvant endocrine therapy also have shown a very favorable prognosis. An increasing number of neoadjuvant studies are coming into focus as an essential way forward, both in terms of the identification of mechanisms of response or resistance and for proof of concept for the activation of definitive adjuvant studies.
