Novel double injection technique for sentinel lymph node biopsy in oral cancer

Purpose Development of new lymphatic tracers and advancement of hybrid tracers, such as Indocyanine Green (ICG)-Nanocoll, represent an exciting step in the future of sentinel lymph node biopsy (SLNB). These tracers aim to improve our ability to detect sentinel lymph nodes by enhancing their localisation. The aim of this study was to assess the performance of a novel dual tracer, double injection technique of ICG-“cold”-Nanocoll and radiolabeled Nanocoll, in SLNB for early stage oral cancer. Methods Double injection technique was performed firstly using 99mTc-Nancoll prior to sentinel node imaging followed by ICG-“cold”-Nanocoll injection in theatre. Analysis involved examination of number, labelling and location of nodes harvested, sentinel node status, survival analysis, false negative rate and complications associated with use of our technique. Results ICG “cold” Nanocoll results showed concordance of fluorescence and radioactivity detection in 74 nodes in 24 patients. Most importantly, all nodes found positive for metastasis (6 nodes) were discovered to be both “hot” and fluorescent; 74 nodes removed were both “hot” and fluorescent, 8 fluorescent only and 6 “hot” only. Conclusion Our results indicate that two sets of tracer injection given at two different time points will flow to the same sentinel nodes. This double labelling increased our confidence that the retrieved node with double labelling does represent a sentinel node.