Non-sentinel lymph node metastases in breast cancer patients with metastatic sentinel nodes

BACKGROUND: Sentinel lymph node biopsy (SLNB) has been shown to be relatively accurate in axillary nodal staging in breast cancer. In more than half of the patients with metastatic sentinel lymph node (SLN), the SLN was the only lymph node involved in the axilla. Methods: A retrospective analysis was performed for those female Chinese breast cancer patients who underwent SLNB. All patients had axillary dissection after SLNB. Those patients with metastatic SLN were selected for analysis. Various tumour factors and SLN factors were analysed to study the association with residual lymph node metastasis. Results: A total of 139 SLNB was performed. The success rate of SLN localization, false negative rate and accuracy were 92%, 9% and 95%, respectively. Fifty-five patients had metastases in the SLN. In 38 patients (69%), SLN was the only lymph node involved in the axilla. Tumours <3 cm, a single metastatic SLN, presence of micro metastases and the absence of extracapsular spread in the SLN were associated with the absence of metastasis in the non-sentinel lymph nodes. Conclusion: Sentinel lymph node biopsy is accurate in the nodal staging of Chinese breast cancer patients. Several factors such as tumour <3 cm, a single metastatic SLN, micro metastases and the absence of extracapsular spread in the sentinel node(s) are useful predictors for the absence of residual disease in the axilla. With further studies and verification, these factors may prove to be important in determining which patients with metastatic SLN will require further axillary treatment. Until such information is available, axillary dissection should be performed when positive sentinel nodes are found.