Title: Neoadjuvant Therapy in the Treatment of Breast Cancer
Abstract: Neoadjuvant systemic therapy in the treatment of breast cancer was initially employed for patients with inoperable disease.Over the past several decades this treatment approach has proved beneficial in many other patients including those with early-stage, operable breast cancer.Several randomized prospective studies have shown comparable survival rates when compared with adjuvant systemic therapy.Additionally, neoadjuvant chemotherapy can decrease the tumor burden facilitating breast conservation in selected patients without significant increases in local recurrence.Response to therapy has proven to be a strong predictor of outcome, with patients achieving pathologic complete response (pCR) demonstrating improved survival compared with those achieving less than a pCR.Furthermore, molecular subtype analysis has shown improved response following neoadjuvant chemotherapy in certain tumor types providing patients with the most aggressive subtypes a chance at cure with targeted therapies.In particular, targeting the HER2-positive subtype with trastuzumab and other HER2-directed therapies has markedly improved the outcome in these patients.Conversely, the early recognition of poor responders is important in limiting the toxicity of ineffective therapy and altering management.Neoadjuvant endocrine therapy in postmenopausal women with hormone receptor-positive tumors consistently decreases tumor size improving rates of breast conservation.Aromatase inhibitors have demonstrated superiority to tamoxifen with improved response and favorable toxicity profiles.Imaging modalities have shown promise in predicting patients with pCR, however they have not yet eliminated the need for surgical intervention.Less invasive surgical strategies such as breast conserving surgery and sentinel lymph node dissection have been shown to be safe following neoadjuvant chemotherapy in selected patients.A multidisciplinary approach with primary systemic therapy when indicated, improves the likelihood for breast conservation, provides a window into tumor biology and predicts patient outcomes.