Different criteria for radioactive sentinel lymph nodes has different impact on sentinel node biopsy in breast cancer patients

Background and Objectives: This study set out to determine the impact of different criteria for radioactive sentinel lymph nodes (SLNs) on sentinel lymph node biopsy (SLNB), and the optimal criteria for radioactive SLNs. Methods: Eighty-four breast cancer patients with cT1-2NOMO were studied prospectively. Filtered technetium 99 m sulfur colloid was injected in peritumor parenchyma. Three different definitions of SLNs were adopted in each patient: (1) the lymph node with the highest radioactivity. (2) Any lymph node with an in vivo hot spot-to-background activity ratio of at least 3:1 or an ex vivo SLN-to-non-SLN ratio of at least 10: 1. (3) All radioactive hot nodes. Results: With three different definitions, the success rate of sentinel node biopsy were all 96.4%, the sensitivity was 78.9%, 92.1%, 97.4% respectively; false negative rate 21.1%, 7.9%, 2.6% respectively; predicting accuracy 90.1%, 96.3%, 98.8% respectively (P < 0.05). The first, the first two, the first three, and the first four highest radioactive sentinel nodes identified 81.1%, 89.2%, 94.6%, 100% of the positive-SLN patients, respectively. Conclusions: The different criteria for radioactive SLNs had different impact on the accuracy, sensitivity, and false negative rate, but not on the success rate, during sentinel node biopsy using radioactive sulfur colloid in breast cancer patients. The first four highest radioactive sentinel nodes could accurately predict the status of axillary metastases.