Factors affecting the number of sentinel lymph nodes removed in patients having surgery for breast cancer

PURPOSE: The goal of sentinel lymph node biopsy is to establish the presence or absence of cancer cells in regional axillary nodes. The number of sentinel nodes harvested from each patient varies. The aim of this study was to determine what factors influence the number of sentinel nodes excised at sentinel node biopsy. METHODS: Data from 426 patients with breast cancer who underwent sentinel lymph node biopsy at the Edinburgh Breast Unit by 10 different experienced breast surgeons were included in this analysis. Univariate and multivariable statistical analysis was performed. RESULTS: In the multivariate analysis the number of sentinel nodes biopsied varied significantly between operating surgeon (p < 0.0001) and was also statistically associated with the use of neoadjuvant chemotherapy (p < 0.0001) and with the number of involved lymph nodes (p < 0.0001). More nodes were removed in patients who received neoadjuvant chemotherapy and had metastases in sentinel lymph nodes. CONCLUSIONS: This study shows that the surgeon plays a pivotal and significant role in determining the numbers of sentinel nodes removed by sentinel lymph node biopsy. Surgeons should monitor their own data on the average numbers of sentinel nodes they remove. Some surgeons may not be removing sufficient numbers of sentinel nodes to maintain a low false negative rate for this procedure. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s10549-020-05843-8) contains supplementary material, which is available to authorized users.