Sentinel lymph node involvement in ductal carcinoma in-situ of the breast: two different causes.

Introduction Worldwide, breast cancer is the most frequently diagnosed cancer in women and the leading cause of cancer death, accounting for 23% of total cancer cases and 14% of cancer deaths. Lymph node involvement is the most important prognostic factor and varies with several tumor and patient characteristics (ie, age at diagnosis, tumor size, tumor type, tumor grade, lymphovascular invasion, multifocality, and estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 [HER-2] status). Factors o be considered in clinical decision making include not only