AIMS: It has been suggested that patients with T1-2 breast tumours and sentinel node (SLN) micrometastases, defined as foci of tumour cells smaller than 2 mm, may be spared completion axillary lymph node dissection because of the low incidence of further metastatic disease. To gain insight into the extent of non-sentinel lymph node (n-SLN) involvement, SLNs and complementary axillary clearance specimens in patients with SLN micrometastases were examined. METHODS: A set of 32 patients with SLN micrometastases was selected on the basis of pathology reports and review of SLNs. Five hundred and thirteen n-SLNs from the axillary clearance specimens were serially sectioned and analysed by means of immunohistochemistry for metastatic disease. Lymph node metastases were grouped as macrometastases (> 2 mm), and micrometastases (< 2 mm), and further subdivided as isolated tumour cells (ITCs) or clusters. RESULTS: In 11 of 32 patients, one or more n-SLN was involved. Grade 3 tumours and tumours > 2 cm (T2-3 v T1) were significantly associated with n-SLN micrometastases as clusters (grade: odds ratio (OR), 8.3; 95% confidence interval (CI), 1.4 to 50.0; size: T2-3 tumours v T1: OR, 15; 95% CI, 2.18 to 103.0). However, no subgroup of tumours with regard to size and grade was identified that did not have n-SLN metastases. CONCLUSIONS: In patients with breast cancer and SLN micrometastases, n-SLN involvement is relatively common. The incidence of metastatic clusters in n-SLN is greatly increased in patients with T2-3 tumours and grade 3 tumours. Therefore, axillary lymph node dissection is especially warranted in these patients. However, because n-SLN metastases also occur in T1 and low grade tumours, even these should be subjected to routine axillary dissection to achieve local control.

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Keywords *Sentinel Lymph Node Biopsy, Axilla, Breast Neoplasms/chemistry/*pathology, Carcinoma, Ductal, Breast/chemistry/*secondary, Carcinoma, Lobular/chemistry/*secondary, Female, Humans, Keratin/analysis, Lymph Node Excision, Lymphatic Metastasis, Neoplasm Staging, Tumor Markers, Biological/analysis
Persistent URL hdl.handle.net/1765/8373
Citation
den Bakker, M.A., van Weeszenberg, A., de Kanter, A.Y., Beverdam, F.H., Pritchard, C., van der Kwast, Th.H., & Menke-Pluymers, M.B.E.. (2002). Non-sentinel lymph node involvement in patients with breast cancer and sentinel node micrometastasis; too early to abandon axillary clearance. Journal of Clinical Pathology: an international peer-reviewed journal for health professionals and researchers in clinical pathology. Retrieved from http://hdl.handle.net/1765/8373