ABSTRACT
BACKGROUND: Sentinel lymph node biopsy (SLNB) historically involves a separate appointment in the Radiology Department to undergo injection of the radiocolloid tracer (RT) the day of, or prior to, surgery, which can lead to disruptions in scheduling. Furthermore, the patient must endure an additional procedure. In a pilot study, intraoperative injection of the RT was previously shown to be equally as effective as preoperative injection. This study evaluates the efficacy of this method in a large cohort and examines factors associated with failure of the RT to reach the axilla. METHODS: A retrospective review of patients who underwent SLNB between June 2010 and June 2017 was performed. All patients were injected immediately following intubation with sulfur colloid and blue dye, unless contraindicated. Operative records were reviewed to determine whether sentinel nodes were identified and if gamma counts were detected. Patient and tumor characteristics were examined to identify factors related to failed RT uptake in the axilla. RESULTS: In 7 years, 453 SLNBs were performed, with sentinel nodes being detected in 447 (98.7%) of these SLNBs. In the six cases where no nodes were detected, all had a prior ipsilateral axillary procedure. Sentinel nodes were undetectable with the gamma probe in 16 (3.5%) cases; a prior axillary procedure was the only statistically significant independent variable associated with this failure. CONCLUSION: Intraoperative injection of the RT is highly effective in the detection of sentinel nodes in clinically node-negative breast cancer patients. Eliminating the need for a preoperative injection of RT can avoid scheduling conflicts and decrease patient morbidity.