Positive sentinel lymph node biopsy predicts the number of metastatic axillary nodes of breast cancer.

It remains to be clarified whether a positive sentinel lymph node biopsy (SLNB) can predict the number of metastatic axillary nodes. This study examined a consecutive series of women with unilateral invasive breast cancer who underwent axillary lymph node dissection after an intra-operative positive SLNB. The numbers of positive and negative sentinel lymph nodes (SLNs) were analyzed for a likelihood of pN1a, pN2a, and pN3a diseases as per the UICC TNM classification. Of the 368 study patients, 165 (45%) had one positive SLN and one or more negative SLNs. This result represented the most common combination of positive and negative SLNs. It was also the most predictive indicator (93%) of pN1a disease and the least predictive indicator (7% or 0%) of pN2a or pN3a disease, respectively. The numbers of positive and negative SLNs can predict the number of metastatic axillary nodes in breast cancer patients.