Sentinel lymphadenectomy without systematic axillary dissection in breast cancer patients: predictors of non-sentinel lymph node metastasis.

Aims: To identify factors predicting metastatic involvement of non sentinel axillary lymph nodes in breast cancer patients who underwent sentinel lymph node (SLN) biopsy followed by complete axillary dissection only in case of metastatic sentinel lymph node.
Methods: A prospective database including 165 breast cancer patients who underwent SLN biopsy without further complete axillary dissection in case of non-metastatic SLN was reviewed. Primary tumor size, pathologic grade, lymphatic invasion in the primary tumor, estrogen receptor status, tumor size in the SLN and number of metastatic SLNs were tested as possible predictors of metastatic involvement of non-SLN.
Results: The sentinel lymph node detection rate was 97% (160/165 patients). The mean number of SLNs per patient was 1.8 (range: 1-5). Fifty patients (31.3%) had a metastatic axillary SLN: 10 of the 42 patients with T1a or T1b breast tumors and 40 of the 118 patients with T1c< or = 15mm tumors. Fifteen of the 50 patients with metastatic SLN had metastatic non-SLN. Primary tumor size, tumor size in the SLN, pathologic grade, estrogen receptor status and age were not significantly associated with metastatic involvement of non-SLN. Number of metastatic SLNs fell short of reaching statistical significance (P: NS). Lymphatic invasion in the primary tumor was the only factor significantly associated with the presence of tumor in the non SLN (P<0.01).
Conclusion: In our series, only lymphatic invasion in the primary tumor was correlated with metastases detection in the non-SLN. We could not identify a subset of patients without metastatic non-SLN in patients with metastatic SLN.