Sentinel lymph node biopsy (SLNB) has been adopted as an applicable alternative to the standard axillary lymph node dissection (ALND) level I and II. It makes possible a less extensive axillary surgery in patients with early breast cancer with negative lymph node, who would not benefit from further dissection, in order to prevent unnecessary morbidity. On the other hand, SLNB is not appropriate in every clinical circumstance. In some clinical situations like tumor size T1 and T2, SLNB is, meanwhile, regarded as a standard procedure. In other settings like increased age and body mass index, pregnancy, ductal carcinoma in situ (DCIS), neoadjuvant chemotherapy, advanced disease (T3 and T4), prior surgery and multifocal/multicentric disease, there is a controversial debate about the importance of SLNB. This article reviews the absolute and relative contraindications of this procedure in respect to the latter three clinical situations.

For the advanced breast cancers T3 and T4, there seems to be an increasing evidence of an acceptable accuracy, although it should be further evaluated in randomized clinical trials (RCT). The indication of SLNB in previously operated patients depends on the type of prior surgery. A diagnostic biopsy does not represent a contraindication, whereas the sentinel node biopsy should not be used after an extensive breast surgery neither in the context of oncologic nor non-oncologic purposes. In the context of multicentric disease, there is growing evidence that SLNB is suitable, but actually it should be restricted to RCT. However, the multifocal disease is only a relative contraindication, that is it could be applied in well-selected patients.