Is there a requirement for axillary lymph node dissection following identification of micro-metastasis or isolated tumour cells at sentinel node biopsy for breast cancer?

ABSTRACT

INTRODUCTION: Recent decades have seen a significant shift towards conservative management of the axilla. Increasingly, immunohistochemical analysis of sentinel nodes leads to the detection of small tumour deposits, the significance of which remains uncertain. The aims of this study are to examine patients whose sentinel lymph nodes are positive for macro-metastasis, micro-metastasis or isolated tumour cells (ITCs) and to determine the rate of further nodal disease after axillary lymph node dissection (ALND). METHODS: A retrospective analysis of all patients undergoing a sentinel lymph node biopsy (SLNB) between January 2007 and December 2010 in a tertiary referral breast unit was performed. Patients who underwent an axillary lymph node dissection for macro-metastasis, micro-metastasis or ITCs were identified. Demographics, histological data and the rate of further axillary disease were examined. RESULTS: In total, 664 breast cancer patients attended the symptomatic breast unit during the study period, 360 of whom underwent a SLNB. Seventy patients had a SLNB positive for macro-metastasis. All of these patients underwent ALND. A positive SLNB with either micro-metastasis or ITCs was identified in 58 patients. Only 41 of the 58 patients went on to have an ALND, due primarily to variations in surgeons' preferences. Nineteen patients with micro-metastasis underwent an ALND. Four patients had further axillary disease (21%). Twenty-two patients had ITCs identified, of whom only one had further disease (4.5%). No statistically significant difference was found between the two groups in terms of tumour size, grade, lymphovascular invasion or oestrogen receptor status. CONCLUSION: ALND should be considered in patients with micro-metastasis at SLNB. It should rarely be employed in the setting of SLNB positive for ITCs.