Clinical applications of sentinel lymph node biopsy in ductal carcinoma in situ of the breast: a dilemma.

Breast cancer is the fifth most common cause of cancer deaths in the world, which often spreads first to the axillary lymph nodes (ALN) from the primary tumor. ALN helps clinician stage breast cancer. In addition, it is one of the key prognostic factors for patients with invasive breast cancer. The sentinel lymph node (SLN) is defined as the first regional lymph node to receive lymphatic fluid from a malignant tumor. As a result, it seems possible to assess the complete nodal status with sentinel lymph node biopsy (SLNB), which is attractive and reliable approach for identifying lymph node metastasis. Ductal carcinoma in situ (DCIS) is the most common type of non-invasive breast cancer. However, the role of SLNB in DCIS is controversial because DCIS does not cause invasion and metastasis theoretically. In this review, clinical applications of SLNB in DCIS will be discussed. The potential benefit of accurately upstaging patients with DCIS and the minimal invasiveness of SLNB justify use of SLNB in selected high-risk DCIS patients. At least DSIS with microinvasion, have DCIS of sufficient extent on mammography or MRI, or indicated invasive or microinvasive focus by final histological examination, are recommended for SLNB. Moreover, large randomized trials to evaluate the usefulness of SLNB in DCIS patients after long-term follow-up on local control and survival are required for further evaluation.