INTRODUCTION: The role of sentinel lymph node micrometastases on histopathological analysis is controversial in axillary staging and management in clinically node negative @entity0 . Long-term studies addressing the clinical relevance of occult @entity0 in sentinel lymph nodes based on molecular analysis are lacking. One Step Nucleic Acid Amplification (OSNA), a highly sensitive assay of @entity4166 mRNA, is used intra-operatively for the detection of lymph node macro- and micrometastases in @entity0 . AIM: The aim of this study is to review the rate of micrometastases and further histopathological NSLN @entity3 , in our unit following the introduction of OSNA in Guildford. METHODS: Data was collected prospectively from the period of introduction 01/12/2008 to 31/05/2013. All @entity1 eligible for sentinel lymph node biopsy were offered OSNA and operations were performed by the consultant breast surgeons. Presence or absence of micro- @entity3 depends on the agreed cut-off point on the amplification curve. On detection of micrometastases (+) and positive but inhibited (i+) @entity3 , a level 1 axillary clearance (ANC) was performed and for a macrometastasis (++), a level 3 ANC was carried out. RESULTS: 66% of the @entity1 had negative @entity4298 (n  =  672) and 34% (n  =  336) had positive sentinel lymph nodes who had further axillary surgery. Of these, 45% (n  =  152/336) had macrometastases, 40% (n  =  136/336) had micrometastases and 15% (48/336) had positive but inhibited results. There was no difference in the @entity1 demographics and @entity5 characteristics in the various positive @entity4298 groups. In @entity1 with micrometastases, 15% (20/136) had further positive NLSNs and a further 6% (8/136) had >4 overall positive nodes ( @entity4298  +  NSLN) thus requiring adjuvant supraclavicular/chest wall radiotherapy (p  <  0.05). 25% of node positive @entity1 had further NLSN @entity3 (85/336) and in these @entity1 , the ratio of positive @entity4298 /harvested @entity4298 (+ @entity4298 / @entity4298 ) is constant at 1:1. This shows the likelihood of further positive NSLNs if all the harvested lymph nodes are positive. This linear trend is present in both micro-and macrometastases, thus correlating with the size and number of NSLN @entity3 . CONCLUSION: Our study reflects the @entity5 burden of NSLNs based on the molecular analysis of the @entity4298 . OSNA has the potential to accurately identify axillary micrometastases. Micro- @entity3 are important as some of the @entity1 with micrometastases had overall four positive nodes [ @entity4298  +  NSLN] (criteria for radiotherapy in the absence of other adverse clinicopathological features). Also, our study highlights certain factors that predict the NSLN @entity3 , pending validation by further prospective long-term data. This will allow accurate calculation of the @entity5 burden, particularly in @entity1 with micro- @entity3 .

One Step Nucleic Acid Amplification (OSNA) positive micrometastases and additional histopathological NSLN XXXX : Results from a single institution over 53 months.

@entity1 :: ('9606', 'Species') :: ['patients', 'patient'] @entity4166 :: ('3880', 'Gene') :: ['cytokeratin 19'] @entity0 :: ('MESH:D001943', 'Disease') :: ['breast cancer'] @entity5 :: ('MESH:D009369', 'Disease') :: ['axillary tumour', 'tumour'] @entity4298 :: ('6588', 'Gene') :: ['SLN'] @entity3 :: ('MESH:D009362', 'Disease') :: ['metastases']
@entity3 :: (MESH:D009362,Disease) :: ['metastases']
