The prevalence of and risk factors for four or more metastatic axillary lymph nodes in breast cancer patients undergoing sentinel node biopsy

Background Our aim was to investigate the prevalence of and risk factors for having four or more positive axillary lymph nodes among breast cancer patients undergoing sentinel node (SN) biopsy. Patients and Methods Between February 2005 and July 2007, 1,062 breast cancer patients with the clinical tumour size not larger than 3 cm underwent SN biopsy and axillary clearance (AC), when SN was positive. These patients were identified in a prospectively collected database. Results Four or more positive axillary nodes were detected in 68 patients representing 6% of the entire study population and 16% of the 436 node positive cases. Features regarded as predictive for a very low risk included (1) T1a or T1b tumours, (2) grade I tumours, (3) tumours with a favourable subtype, that is mucinous, tubular or medullary breast cancer, (4) no nodal macrometastases and (5) SN ratio lower than 0.5. Conclusions Only few patients with T1a–b tumours or grade 1 tumours, as well as those with minimal involvement of the sentinel nodes have four or more positive axillary lymph nodes. However, these risk factors can be definitely assessed only after surgery, decreasing their value in the clinical decision making. J. Surg. Oncol. 2008;98:21–26. © 2008 Wiley-Liss, Inc.