Introduction: Sentinel node biopsy (SNB) is gaining acceptance as a standard management of early head and neck cancer. Occult nodal metastasis occur in 20–30% of clinically and radiologically N0 necks. Prior studies have used historical data to assess if the positive sentinel and non-sentinel lymph nodes (non SLN) can be predicted from tumour and patient characteristics. The European Sentinel Node Trial (SENT) has shown that the number of positive nodes was the most significant predictor of outcome. Here we present prospectively gathered data derived from SENT data and additional cases that we hope will bring us closer to producing a nomogram to predict the status of sentinel and non-sentinel lymph nodes.
Methods: Prospective data collected from 600 sentinel node biopsies between 2006 and 2013. Of these 25.8% (155) had positive SNB and completion neck dissection pathology data was gained for 77% (120). In this group, tumour and metastasis characteristics were entered into multivariate analysis.
Results: Of 120 patients, 23.3% (28) had further non SLN metastasis and of these 25% (7) were in the same basin as the positive SN. Biological factors related to the tumour (differentiation, lymphovascular (LV) spread, sarcolemmal (SL) spread) and biological factors related to the metastasis (size of deposit, extracapsular spread (ECS)) were significant for more than one positive node. Tumour location, depth of invasion > 4 mm, differentiation and front type were not.
Conclusion: Presence of positive non-SLN is a rare event but significantly impacts on outcome. This data set suggests that some tumour related biological factors (differentiation, LV spread, SL spread) and metastasis related biological characteristics (size of deposit, ECS) are predictive for more than one positive node. While we cannot yet produce a nomogram, with further data gathered, we can combine results to produce a predictive tool that will be of benefit to both patients and clinicians.