Lymph Node Ratio is More Predictive than Traditional Lymph Node Stratification for Invasive Breast Cancer

Over the past three decades, the breast cancer (BC) incidence has been steadily increasing and becoming the most common malignancy in large cities, like Shanghai (Fan et al., 2009) in China. Accurate evaluation for each patient is fundamental for BC personalized care. TNM staging system is the essential classification for BC treatment decision and prognosis prediction over the past 60 years, which consists of the tumor size (T), lymph nodes metastasis (N) and distant metastasis (M) on the basis of anatomy (Singletary and Connolly, 2006; Goldhirsch et al., 2009; Veronesi et al., 2009). Among of them, lymph nodes status is the most important prognostic factor in early BC, making it one of the most important indicators for chemotherapy stretagies and radiotherapy seclection. Currently, the BC patients could be divided into four grades (N0-N3) by absolute positive numbers of lymph nodes metastasis (traditional lymph nodes classification, pN classification) according to the International Union Against Cancer (UICC)/American Joint Committee on