Clinicopathologic factors predicting involvement of nonsentinel axillary lymphnodes in breast cancer patients: is axillary dissection always indicated?

The aim of this study was to determine factors that predict non-sentinel axillary lymph nodes (NSLNs) metastases in breast cancer patients with positive sentinel node biopsy (SLNB). We reviewed the records of a consecutive series of 176 breast cancer patients who underwent SLNB at our institution. From the database we analysed those cases with one or more positive sentinel lymph nodes (SLNs) in order to determine factors predicting NSLN metastases. From a series of 176 consecutive patients, we evaluated 41 cases (23.3%) with positive SLNB. Subsequent completion axillary lymph node dissection (CALND) revealed NSLN metastases in 15 cases (36.6%). The significant variables predictive of NSLN involvement were the presence of macrometastases with extranodal extension (p = 0.048), the presence of more than one positive SLN (p = 0.08) and a ratio between positive SLN and SLNs globally dissected higher than 0.5 (p = 0.05). CALND is the gold standard for patients with positive SLNB, but results, in almost 40-70% of cases, in no additional positive nodes and its therapeutic benefit remains controversial. Clinicopathologic factors predictive of NSLN metastases may be useful in identifying a subset of patients with lower risk of further axillary involvement. In patients with early breast carcinoma and a positive SLNB, the size of SLN metastases, the presence of extranodal extension, more than one positive SLN and a nodal ratio higher than 0.5 are the factors that significantly increase the frequency of additional axillary positive lymph nodes.