Periareolar or Peritumoral Injection of Isosulfan Blue and the Effect on the Number of Sentinel Lymph Nodes Examined

Abstract

The conduct of sentinel node biopsy (SLNBx) for breast cancer (BC) has evolved substantially since its original description. No national standards for the performance of SLNBx exist, therefore, we sought to determine the effect of isosulfan blue (ISB) injection technique on nodal harvesting and staging accuracy during SLNBx. Our main outcome measures included the number of SLNs examined and the number of positive axillae in patients undergoing SLNBx after injection of filtered sulfur colloid intradermally and either small volume ISB injected in the periareolar dermis (PA,∼0.75 cc) or large volume peritumoral (PT, 5 cc). Between January 1, 2009, and September 30, 2013, 1357 patients at an academic/community practice setting underwent SLNBx of which 966 (71.2%) were node negative. These patients ranged in age from 27 to 97 years (mean 60.1 years). The majority of patients (76%) underwent PT injection of ISB. There was no significant difference in the mean age of these two groups (61.2 PT vs 59.7 PA years). All were female. The majority of patients (72.7%) had T1 primaries. Nearly 73 per cent of patients were Luminal A/B, 10.8 per cent HER, and 16.4 per cent were triple negative. There was no significant difference in the distribution of T stage (P = 0.56) or breast cancer subtypes between the techniques (P = 0.59). The mean number of nodes examined was 3.1 (range, 1-18). PT patients had a mean of 3.5 (range, 1-18) nodes, whereas PA patients had a mean of 2.4 nodes (range, 1-10) (P < 0.001). The technical aspects of injecting ISB affect the number of nodes harvested during SLNBx but not staging accuracy.