A single institutional experience of factors affecting successful identification of sentinel lymph node in breast cancer patients

BackgroundSentinel lymph node biopsy (SLNB) has become the standard of care in axillary staging of clinically node-negative breast cancer patients. We hypothesized that certain clinical parameters are associated with failure to identify a SLN.MethodsWe performed an institutional review board–approved, retrospective analysis of 402 consecutive breast cancer patients who underwent SLNB from 2000 to 2007.ResultsOf 402 patients, 399 had lymphoscintigraphy (LSG) performed at the time of radiocolloid injection. No significant differences in successful identification of a SLN were found with respect to patient age, histology, or pathologic status of the SLN. Thirteen of 27 patients with no nodes imaged on LSG failed to have a SLN identified at surgery, whereas only 8 of 372 patients with positive imaging on LSG failed to have a SLN identified at surgery (P < .0001). Patients with a body mass index (BMI) ≥40 had a significantly higher rate of failure to detect a SLN by LSG (5/29 patients) compared with patients with a normal BMI (4/145 patients; P < .01). There was a trend for association with increasing BMI and failure to identify a SLN at surgery. The rate of failure to identify a SLN demonstrated a significant improvement in LSG after 200 patients and in surgical success after 100 patients (P < .001).ConclusionSuccessful identification of a SLN was influenced by BMI, institutional experience, and successful imaging by LSG. After gaining appropriate experience, the probability of successfully identifying a SLN at the time of surgery in a patient with BMI <40 who imaged on LSG was 99.7%.