Preoperative and Intraoperative Lymphatic Mapping for Radioguided Sentinel Lymph Node Biopsy in Breast Cancer

The axillary lymph node status remains a major prognostic factor in early-stage breast cancer, providing information that is important for tailoring postsurgical treatment. Sentinel lymph node biopsy (SLNB) has radically altered the management of the axilla for patients with early breast cancer, resulting in fewer complications and better quality of life than de novo axillary lymph node dissection. Although SLNB is widely performed in patients with breast cancer, several technical issues such as the choice of the optimal radiopharmaceutical, the site and mode of radiocolloid injection, and the type of preoperative imaging remain a matter of discussion. With optimal preoperative lymphatic mapping high identification rates are achieved, especially when the radiocolloid is combined with blue dye. The performance of SLNB can be further improved with the intraoperative use of portable imaging devices and hybrid approaches, especially in cases of complex drainage. The SLNB procedure is indicated in patients with early-stage breast cancer (cT1-2 tumors) without cytological or histological evidence of axillary lymph node metastases. Controversies remain concerning the application of SLNB in patients with large or multifocal tumors, ductal carcinoma in situ, and recurrent disease. In addition, no consensus exists about the importance of identification and treatment of metastasis in lymph nodes of the internal mammary chain. With the increasing use of neoadjuvant chemotherapy for breast-sparing surgery in patients with locally advanced breast cancer, a new dilemma has arisen concerning appropriate timing of the SLNB procedure in the neoadjuvant setting. The abovementioned issues are discussed in detail in this chapter. In addition, the chapter considers the clinical impact of the SLNB procedure in breast cancer, including the ongoing paradigm shift in axillary management.