Additional axillary metastases and stage migration in breast cancer patients with micrometastases or submicrometastases in sentinel lymph nodes.

BACKGROUND

In patients with breast cancer, micrometastases and submicrometastases are increasingly found in sentinel nodes when step sectioning and/or immunohistochemical staining are applied. The aims of the current study were to investigate the incidence of micro- and submicrometastases in the sentinel node, to estimate the risk of additional metastases in the remaining axillary lymph nodes, and to consider implications for staging and treatment.

METHODS

A total of 2150 breast cancer patients who had undergone axillary sentinel node biopsy between 1999 and 2004 were retrospectively evaluated.

RESULTS

In all, 649 patients (30%) had a tumor-positive axillary sentinel node. Of these 649 patients, 148 had (23%) micrometastases and 105 (16%) submicrometastases. Of the 148 patients with micrometastases, 106 underwent axillary lymph node dissection (ALND) and additional metastases were found in 20 patients (19%). Sixteen (15%) had macrometastases and were upstaged. The other 4 patients had additional micrometastases. Seven of the 106 patients (7%) received additional systemic treatment based on the findings in the axillary lymph nodes. Fifty-four of the 105 patients with submicrometastases underwent ALND. Two (4%) of them had additional macrometastases and were upstaged and 2 had additional micrometastases. None received additional treatment based on the ALND findings.

CONCLUSIONS

Of the involved sentinel nodes, 23% contained micrometastases and 16% submicrometastases. Additional macrometastases were found in 15% and 4%, respectively, and treatment was altered in 7%. Based on these findings, offering additional treatment of the axilla is suggested in patients with micrometastases, but refraining from ALND in patients with submicrometastases in their sentinel node.