The role of axillary lymph node dissection in breast cancer patients with sentinel lymph node micrometastases.

AIM: To identify by means of clinical and histopathological features a subset of breast cancer patients with sentinel lymph-node (sN) micrometastases and metastatic disease confined only to the sN in order to spare them an unnecessary axillary lymph node dissection (ALND).
MATERIALS AND METHODS: From January 1998 to December 2004, 116 patients with sN micrometastases underwent standard ALND for early-stage (T1-2 N0 M0) invasive breast cancer; clinical and histopathologic parameters were prospectively collected and evaluated by means of univariate and logistic regression analysis in order to identify which patients with sN micrometastases were free of metastasis in axillary non-sN.
RESULTS: Sixteen of 116 patients with sN micrometastases had tumour involvement of non-sN, with six and 10 patients having non-sN micrometastases and macrometastases, respectively. None of 19 patients with primary tumour measuring </= 10 mm had tumour-positive non-sN; moreover, none of 15 patients with G1 tumours had non-sN metastases. The mean tumour size in patients with non-sN involvement was 21.3 mm (range, 12-40 mm). Univariate test of association between clinical and histopathologic features and non-sN status showed that the primary tumour size (P=0.005) and the presence of lymphovascular invasion (P=0.000) were the only significant predictors of non-sN involvement. By logistic regression, primary tumour size (P=0.011), lymphovascular invasion (P=0.001), and size of sN micrometastases were the only variables remaining into the model, although the latter parameter was not statistically significant.
CONCLUSIONS: In patients with sN micrometastases, primary tumour size and lymphovascular invasion significantly predict non-sN status; notably, no patient with T1a-T1b and/or G1 tumours had non-sN metastases so that they could be spared an unnecessary ALND.