The risk of non-sentinel metastases in primary breast cancer.

Background: Sentinel node biopsy (SNB) has been established as standard of surgical care in primary breast cancer. If the sentinel node (SN) is negative, axillary dissection (ALND) is not necessary, but if the SN is positive ALND is warranted. This analysis evaluated associated risk factors for non-sentinel metastases in the case of a positive SN.